# embedding_metadata

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executor. But first, we’ll declare a few aliases to shorten the names.usingrclcpp::memory_strategies::allocator_memory_strategy::AllocatorMemoryStrategy;usingAlloc=std::pmr::polymorphic_allocator<void>;usingMessageAllocTraits=rclcpp::allocator::AllocRebind<std_msgs::msg::UInt32,Alloc>;usingMessageAlloc=MessageAllocTraits::allocator_type;usingMessageDeleter=rclcpp::allocator::Deleter<MessageAlloc,std_msgs::msg::UInt32>;usingMessageUniquePtr=std::unique_ptr<std_msgs::msg::UInt32,MessageDeleter>;Now we can create our resources with the custom


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we can create our resources with the custom allocator:CustomMemoryResourcemem_resource{};autoalloc=std::make_shared<Alloc>(&mem_resource);rclcpp::PublisherOptionsWithAllocator<Alloc>publisher_options;publisher_options.allocator=alloc;autopublisher=node->create_publisher<std_msgs::msg::UInt32>("allocator_tutorial",10,publisher_options);rclcpp::SubscriptionOptionsWithAllocator<Alloc>subscription_options;subscription_options.allocator=alloc;automsg_mem_strat=std::make_shared<rclcpp::message_memory_strategy::MessageMemoryStrategy<std_msgs::msg::UInt32,Alloc>>(alloc);autosubscriber=node->create_subscription<std_msgs::msg::UInt32>("allocator_tutorial",10,callback,subscription_options,msg_mem_strat);std::shared_ptr<rclcpp::memory_strategy::MemoryStrategy>memory_strategy=std::make_shared<AllocatorMemoryStrategy<Alloc>>(alloc);rclcpp::ExecutorOptionsoptions;options.memory_strategy=memory_strategy;rclcpp::executors::SingleThreadedExecutorexecutor(options);You must also instantiate a custom deleter and allocator for


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must also instantiate a custom deleter and allocator for use when allocating messages:MessageDeletermessage_deleter;MessageAllocmessage_alloc=*alloc;rclcpp::allocator::set_allocator_for_deleter(&message_deleter,&message_alloc);Once you’ve add the node to the executor, it is time to spin. We’ll use the custom allocator to allocate each message:uint32_ti=0;while(rclcpp::ok()){autoptr=MessageAllocTraits::allocate(message_alloc,1);MessageAllocTraits::construct(message_alloc,ptr);MessageUniquePtrmsg(ptr,message_deleter);msg->data=i;++i;publisher->publish(std::move(msg));rclcpp::sleep_for(10ms);executor.spin_some();}Passing an allocator to the intra-process pipelineEven though we instantiated a publisher and subscriber in the same process, we aren’t using the intra-process pipeline yet.The IntraProcessManager is a class that is usually hidden from the user, but in order to pass a custom allocator to it we need to expose it by getting it from the rclcpp Context. The IntraProcessManager makes use of several


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rclcpp Context. The IntraProcessManager makes use of several standard library structures, so without a custom allocator it will call the defaultnew.autocontext=rclcpp::contexts::get_global_default_context();autooptions=rclcpp::NodeOptions().context(context).use_intra_process_comms(true);autonode=rclcpp::Node::make_shared("allocator_example",options);Make sure to instantiate publishers and subscribers AFTER constructing the node in this way.Testing and verifying the codeHow do you know that your custom allocator is actually getting called?The obvious thing to do would be to count the calls made to your custom allocator’sallocateanddeallocatefunctions and compare that to the calls tonewanddelete.Adding counting to the custom allocator is easy:void*do_allocate(std::size_tsize,std::size_talignment)override{// ...num_allocs++;// ...}voiddo_deallocate(void*p,std::size_tbytes,std::size_talignment)override{// ...num_deallocs++;// ...}You can also override the


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...num_deallocs++;// ...}You can also override the globalnewanddeleteoperators:void*operatornew(std::size_tsize){if(is_running){global_runtime_allocs++;}returnstd::malloc(size);}voidoperatordelete(void*ptr,size_t)noexcept{if(ptr!=nullptr){if(is_running){global_runtime_deallocs++;}std::free(ptr);}}voidoperatordelete(void*ptr)noexcept{if(ptr!=nullptr){if(is_running){global_runtime_deallocs++;}std::free(ptr);}}where the variables we are incrementing are just global static integers, andis_runningis a global static boolean that gets toggled right before the call tospin.Theexample executableprints the value of the variables. To run the example executable, use:ros2 run demo_nodes_cpp allocator_tutorialor, to run the example with the intra-process pipeline on:ros2 run demo_nodes_cpp allocator_tutorial intraYou should get numbers like:Global new was called 15590 times during spinGlobal delete was called 15590 times during spinAllocator new was called 27284 times during spinAllocator delete was called 27281 times


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27284 times during spinAllocator delete was called 27281 times during spinWe’ve caught about 2/3 of the allocations/deallocations that happen on the execution path, but where do the remaining 1/3 come from?As a matter of fact, these allocations/deallocations originate in the underlying DDS implementation used in this example.Proving this is out of the scope of this tutorial, but you can check out the test for the allocation path that gets run as part of the ROS 2 continuous integration testing, which backtraces through the code and figures out whether certain function calls originate in the rmw implementation or in a DDS implementation:https://github.com/ros2/realtime_support/blob/jazzy/tlsf_cpp/test/test_tlsf.cpp#L41Note that this test is not using the custom allocator we just created, but the TLSF allocator (see below).The TLSF allocatorROS 2 offers support for the TLSF (Two Level Segregate Fit) allocator, which was designed to meet real-time


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Segregate Fit) allocator, which was designed to meet real-time requirements:https://github.com/ros2/realtime_support/tree/jazzy/tlsf_cppFor more information about TLSF, seehttp://www.gii.upv.es/tlsf/Note that the TLSF allocator is licensed under a dual-GPL/LGPL license.A full working example using the TLSF allocator is here:https://github.com/ros2/realtime_support/blob/jazzy/tlsf_cpp/example/allocator_example.cpp


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Code Examples:

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classCustomMemoryResource:publicstd::pmr::memory_resource{private:void

do_allocate(std::size_tbytes,std::size_talignment)override;voiddo_deallocate(void

p,std::size_tbytes,std::size_talignment)override;booldo_is_equal(conststd::pmr::memory_resource&other)constnoexceptoverride;};

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usingrclcpp::memory_strategies::allocator_memory_strategy::AllocatorMemoryStrategy;usingAlloc=std::pmr::polymorphic_allocator<void>;usingMessageAllocTraits=rclcpp::allocator::AllocRebind<std_msgs::msg::UInt32,Alloc>;usingMessageAlloc=MessageAllocTraits::allocator_type;usingMessageDeleter=rclcpp::allocator::Deleter<MessageAlloc,std_msgs::msg::UInt32>;usingMessageUniquePtr=std::unique_ptr<std_msgs::msg::UInt32,MessageDeleter>;

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CustomMemoryResourcemem_resource{};autoalloc=std::make_shared<Alloc>(&mem_resource);rclcpp::PublisherOptionsWithAllocator<Alloc>publisher_options;publisher_options.allocator=alloc;autopublisher=node


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>create_publisher<std_msgs::msg::UInt32>("allocator_tutorial",10,publisher_options);rclcpp::SubscriptionOptionsWithAllocator<Alloc>subscription_options;subscription_options.allocator=alloc;automsg_mem_strat=std::make_shared<rclcpp::message_memory_strategy::MessageMemoryStrategy<std_msgs::msg::UInt32,Alloc>>(alloc);autosubscriber=node

>create_subscription<std_msgs::msg::UInt32>("allocator_tutorial",10,callback,subscription_options,msg_mem_strat);std::shared_ptr<rclcpp::memory_strategy::MemoryStrategy>memory_strategy=std::make_shared<AllocatorMemoryStrategy<Alloc>>(alloc);rclcpp::ExecutorOptionsoptions;options.memory_strategy=memory_strategy;rclcpp::executors::SingleThreadedExecutorexecutor(options);

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MessageDeletermessage_deleter;MessageAllocmessage_alloc=

alloc;rclcpp::allocator::set_allocator_for_deleter(&message_deleter,&message_alloc);

Language: unknown


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uint32_ti=0;while(rclcpp::ok()){autoptr=MessageAllocTraits::allocate(message_alloc,1);MessageAllocTraits::construct(message_alloc,ptr);MessageUniquePtrmsg(ptr,message_deleter);msg

>data=i;++i;publisher

>publish(std::move(msg));rclcpp::sleep_for(10ms);executor.spin_some();}

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autocontext=rclcpp::contexts::get_global_default_context();autooptions=rclcpp::NodeOptions().context(context).use_intra_process_comms(true);autonode=rclcpp::Node::make_shared("allocator_example",options);

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void

do_allocate(std::size_tsize,std::size_talignment)override{// ...num_allocs++;// ...}voiddo_deallocate(void

p,std::size_tbytes,std::size_talignment)override{// ...num_deallocs++;// ...}

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void

operatornew(std::size_tsize){if(is_running){global_runtime_allocs++;}returnstd::malloc(size);}voidoperatordelete(void

ptr,size_t)noexcept{if(ptr!=nullptr){if(is_running){global_runtime_deallocs++;}std::free(ptr);}}voidoperatordelete(void


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ptr)noexcept{if(ptr!=nullptr){if(is_running){global_runtime_deallocs++;}std::free(ptr);}}

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ros2 run demo_nodes_cpp allocator_tutorial

Language: unknown ros2 run demo_nodes_cpp allocator_tutorial intra

Language: unknown Global new was called 15590 times during spinGlobal delete was called 15590 times during spinAllocator new was called 27284 times during spinAllocator delete was called 27281 times during spin


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Title: Deployment Guidelines

URL: https://docs.ros.org/en/jazzy/Tutorials/Advanced/Security/Deployment

Guidelines.html

Section: Installation

--------------------------------------------------------------------------------


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Deployment GuidelinesGoal:Understand the best practices when deploying security artifacts into production systems.Tutorial level:AdvancedTime:20 minutesContentsBackgroundPrerequisitesGeneral GuidelinesBuilding a deployment scenarioGenerating the Docker ImageUnderstanding the compose fileRunning the exampleExamining the containersBackgroundTypical deployment scenarios often involve shipping containerized applications, or packages, into remote systems. Special attention should be payed when deploying security enabled applications, requiring users to reason about the sensitivity of packaged files.Complying with theDDS Security standard, thesros2package provides a collection of utilities for managing security under ROS 2 environments in a highly modular and flexible fashion.Basic core guidelines on how to organize the different certificates, keys and directories remains a critical factor to avoid compromising the security of the system. This includes protection-awareness and criteria for selecting the minimum


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protection-awareness and criteria for selecting the minimum set of necessary files to be deployed upon remote production systems for minimizing security exposure.PrerequisitesA docker installation with the compose plugin. Please refer to the installation steps detailed inDocker installationandCompose Plugin.(Recommended) A basic understanding onROS 2 Security design.(Recommended) Previous security tutorials completion. In particular:Setting up securityUnderstanding the security keystoreSetting access controlsGeneral GuidelinesROS 2 leverages DDS Security extensions to ensure security on message exchanges within the same enclave. The different signed files and certificates within an enclave are generated from the private keys and certificates of aCertificate Authority (CA)trusted entity. In fact, two different CA’s can be selected for identity and permissions, per enclave. Those CA artifacts are stored insideprivate/andpublic/sub-directories of aKeystorewith the following folder structure:keystore ├──


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of aKeystorewith the following folder structure:keystore ├── enclaves │   └── ... │       └── ... ├── private │   └── ... └── public └── ...A good practice for the creation and usage of a certain Certificate Authority on a typical deployment for a production system, is to:Create it within the organization system intended for internal use only.Generate/modify desired enclaves bearing in mind that:Not all the generated enclaves should be deployed to all target devices.A reasonable way to proceed would be having one enclave per application, allowing for a separation of concerns.Shippublic/alongside with correspondingenclaves/into the different remote production devices during setup.Keep and protectprivate/keys and/or certification requests in the organization.It is important to note that ifprivate/files are lost, it won’t be possible to change access permissions, add or modify security profiles anymore.In addition, further practices may be taken into consideration:Granting read-only permissions to


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be taken into consideration:Granting read-only permissions to theenclaves/directory contents.If a PKCS#11 compliant URI is given for generating enclave’s private keys, aHardware Security Module (HSM)could be used to store them.The following table depicts a summary of the previous statements relating the Keystore directory with the Recommended location:Directory / LocationOrganizationTarget DeviceMaterial Sensitivitypublic✓✓Lowprivate✓✕Highenclaves✓✓MediumBuilding a deployment scenarioTo illustrate a simple deployment scenario, a new docker image will be built on top of the one provided byros:<DISTRO>. Starting from the image, three containers will be created with the aim of:Initializing the keystore in a local host’s shared volume.Simulating two deployed remote devices that interact with each other in a secure way.In this example, the local host serves as the organization’s system. Let us start by creating a workspace folder:mkdir~/security_gd_tutorialcd~/security_gd_tutorialGenerating the Docker ImageIn


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the Docker ImageIn order to build a new docker image, a Dockerfile is required. The one proposed for this tutorial can be retrieved with the following command:# Download the Dockerfilewgethttps://raw.githubusercontent.com/ros2/ros2_documentation/jazzy/source/Tutorials/Advanced/Security/resources/deployment_gd/DockerfileNow, build the docker image with the command:# Build the base imagedockerbuild-tros2_security/deployment_tutorial--build-argROS_DISTRO=jazzy.Understanding the compose fileA compose configration file takes an image to create containers as services. In this tutorial, three services are defined within the configuration:keystore-creator: That, similarly to previous tutorials, it internally initializes a new keystore tree directory. This will createenclaves/public/andprivate/, which are explained in more detail inROS 2 Security enclaves. Thekeystoredirectory is configured to be a shared volume across containers.listenerandtalker: Act as the remote device actors in this tutorial.


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Act as the remote device actors in this tutorial. RequiredSecurityenvironment variables are sourced as well as the necessary keystore files from the shared volume.The compose configuration yaml file can be downloaded with:# Download the compose filewgethttps://raw.githubusercontent.com/ros2/ros2_documentation/jazzy/source/Tutorials/Advanced/Security/resources/deployment_gd/compose.deployment.yamlRunning the exampleIn the same working directory~/security_gd_tutorial, run:# Start the exampledockercompose-fcompose.deployment.yamlupThis should result in the following output:tutorial-listener-1:Foundsecuritydirectory:/keystore/enclaves/talker_listener/listenertutorial-talker-1:Foundsecuritydirectory:/keystore/enclaves/talker_listener/talkertutorial-listener-1:Publishing:'HelloWorld:<number>'tutorial-talker-1:Iheard:[HelloWorld:<number>]Examining the containersWhile having the containers running that simulate the two remote devices for this tutorial, attach to each of them by opening two different terminals and


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attach to each of them by opening two different terminals and enter:# Terminal 1dockerexec-ittutorial-listener-1bashcdkeystore tree# Terminal 2dockerexec-ittutorial-talker-1bashcdkeystore treeA similar output to the one depicted below should be obtained:# Terminal 1keystore├──enclaves│├──governance.p7s│├──governance.xml│└──talker_listener│└──listener│├──cert.pem│├──governance.p7s│├──identity_ca.cert.pem│├──key.pem│├──permissions_ca.cert.pem│├──permissions.p7s│└──permissions.xml└──public├──ca.cert.pem├──identity_ca.cert.pem└──permissions_ca.cert.pem# Terminal 2keystore├──enclaves│├──governance.p7s│├──governance.xml│└──talker_listener│└──talker│├──cert.pem│├──governance.p7s│├──identity_ca.cert.pem│├──key.pem│├──permissions_ca.cert.pem│├──permissions.p7s│└──permissions.xml└──public├──ca.cert.pem├──identity_ca.cert.pem└──permissions_ca.cert.pemNote that:private/folder is not moved but left in the local host (organization).Each one of the deployed devices contain its own minimum enclave required for its


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devices contain its own minimum enclave required for its application.NoteFor the sake of simplicity, the same CA is used within this enclave for both identity and permissions.


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Code Examples:

Language: unknown keystore ├── enclaves │   └── ... │       └── ... ├── private │   └── ... └── public └── ...

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mkdir~/security_gd_tutorialcd~/security_gd_tutorial

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# Download the Dockerfilewgethttps://raw.githubusercontent.com/ros2/ros2_documentation/jazzy/source/Tutorials/Advanced/Security/resources/deployment_gd/Dockerfile

Language: unknown # Build the base imagedockerbuild-tros2_security/deployment_tutorial--build-argROS_DISTRO=jazzy.

Language: unknown # Download the compose filewgethttps://raw.githubusercontent.com/ros2/ros2_documentation/jazzy/source/Tutorials/Advanced/Security/resources/deployment_gd/compose.deployment.yaml

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# Start the exampledockercompose

fcompose.deployment.yamlup

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# Terminal 1dockerexec

ittutorial

listener

1bashcdkeystore

tree# Terminal 2dockerexec

ittutorial

talker

1bashcdkeystore

tree


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ittutorial

talker

1bashcdkeystore

tree

Language: unknown # Terminal 1keystore├──enclaves│├──governance.p7s│├──governance.xml│└──talker_listener│└──listener│├──cert.pem│├──governance.p7s│├──identity_ca.cert.pem│├──key.pem│├──permissions_ca.cert.pem│├──permissions.p7s│└──permissions.xml└──public├──ca.cert.pem├──identity_ca.cert.pem└──permissions_ca.cert.pem# Terminal 2keystore├──enclaves│├──governance.p7s│├──governance.xml│└──talker_listener│└──talker│├──cert.pem│├──governance.p7s│├──identity_ca.cert.pem│├──key.pem│├──permissions_ca.cert.pem│├──permissions.p7s│└──permissions.xml└──public├──ca.cert.pem├──identity_ca.cert.pem└──permissions_ca.cert.pem


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Title: Eloquent Elusor (eloquent)

URL: https://docs.ros.org/en/jazzy/Releases/Release

Eloquent

Elusor.html

Section: Installation

--------------------------------------------------------------------------------


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Eloquent Elusor (eloquent)Table of ContentsSupported PlatformsInstallationNew features in this ROS 2 releaseChanges since the Dashing releasegeometry_msgsrclcpprmwros2clirvizTF2 BufferrclKnown IssuesTimeline before the releaseEloquent Elusoris the fifth release of ROS 2.Supported PlatformsEloquent Elusor is primarily supported on the following platforms:Tier 1 platforms:Ubuntu 18.04 (Bionic):amd64andarm64Mac macOS 10.14 (Mojave)Windows 10 (Visual Studio 2019)Tier 2 platforms:Ubuntu 18.04 (Bionic):arm32Tier 3 platforms:Debian Stretch (9):amd64,arm64andarm32OpenEmbedded Thud (2.6) / webOS OSE:arm32andx86For more information about RMW implementations, compiler / interpreter versions, and system dependency versions seeREP 2000.InstallationInstall Eloquent ElusorNew features in this ROS 2 releaseA few features and improvements we would like to highlight:Support for markup-based launch files (XML/YAML)Improved launch-based testingPassing key-value parameters on CLISupport stream logging macrosPer-node logging-


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parameters on CLISupport stream logging macrosPer-node logging- All stdout/stderr output from nodes are logged in ~/.rosros2doctorImproved performance of sourcing setup filesrviz:interactive markers,torque ring,tf message filtersrqt:parameter plugin,tf tree plugin,robot steering plugin(also backported to Dashing)turtlesim(also backported to Dashing)RMW implementations:API to loan message for zero copy, used byrmw_iceoryxFast RTPS 1.9.3New Tier-2 implementation:rmw_cyclonedds(also backported to Dashing)Environment variableROS_LOCALHOST_ONLYto limit communication to localhostMacOS Mojave SupportTracing instrumentationfor rcl and rclcppDuring the development theEloquent meta ticketon GitHub contains an up-to-date state of the ongoing high level tasks as well as references specific tickets with more details.Changes since the Dashing releasegeometry_msgsThegeometry_msgs/msg/Quaternion.msginterface now default initializes to a valid quaternion, with the following values:\[\begin{split}x = 0 \\ y = 0 \\ z = 0 \\


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the following values:\[\begin{split}x = 0 \\ y = 0 \\ z = 0 \\ w = 1\end{split}\]Here is the pull request for more detail:https://github.com/ros2/common_interfaces/pull/74Static transform broadcasters and listeners now use QoS durabilitytransient_localon the/tf_statictopic. Similar to the latched setting in ROS 1, static transforms only need to be published once. New listeners will receive transforms from all static broadcasters that are alive and have published before. All publishers must be updated to use this durability setting or their messages won’t be received by transform listeners. See this pull request for more detail:https://github.com/ros2/geometry2/pull/160rclcppAPI Break withget_actual_qos()Introduced in Dashing, theget_actual_qos()method on thePublisherBaseandSubscriptionBasepreviously returned an rmw type,rmw_qos_profile_t, but that made it awkward to reuse with the creation of other entities. Therefore it was updated to return arclcpp::QoSinstead.Existing code will need to use


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to return arclcpp::QoSinstead.Existing code will need to use therclcpp::QoS::get_rmw_qos_profile()method if the rmw profile is still required. For example:voidmy_func(constrmw_qos_profile_t&rmw_qos);/* Previously: */// my_func(some_pub->get_actual_qos());/* Now: */my_func(some_pub->get_actual_qos()->get_rmw_qos_profile());The rationale for breaking this directly rather than doing a tick-tock is that it is a new function and is expected to be used infrequently by users. Also, since only the return type is changing, adding a new function with a different would be to only way to do a deprecation cycle andget_actual_qos()is the most appropriate name, so we would be forced to pick a less obvious name for the method.API Break with Publisher and Subscription ClassesIn an effort to streamline the construction of Publishers and Subscriptions, the API of the constructors were changed.It would be impossible to support a deprecation cycle, because the old signature takes an rcl type and the new one takes


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the old signature takes an rcl type and the new one takes theNodeBaseInterfacetype so that it can get additional information it now needs, and there’s no way to get the additional information needed from just the rcl type. The new signature could possibly be backported if that would help contributors, but since the publishers and subscriptions are almost always created using the factory functions or some other higher level API, we do not expect this to be a problem for most users.Please see the original pr for more detail and comment there if this causes issues:https://github.com/ros2/rclcpp/pull/867Compiler warning about unused result ofadd_on_set_parameters_callbackSince Eloquent Patch Release 2 (2020-12-04)Users should retain the  handle returned byrclcpp::Node::add_on_set_parameters_callback, otherwise their callback may be unregistered. A warning has been added to help identify bugs where the returned handle is not used.https://github.com/ros2/rclcpp/pull/1243rmwAPI Break Due to Addition of Publisher


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Break Due to Addition of Publisher and Subscription OptionsThermw_create_publisher()method had a new argument added of typeconstrmw_publisher_options_t*. This new structure holds options (beyond the typesupport, topic name, and QoS) for new publishers.Thermw_create_subscription()method had one argument removed,boolignore_local_publications, and replaced by the new options of typeconstrmw_subscription_options_t*. Theignore_local_publicationsoption was moved into the newrmw_subscription_options_ttype.In both cases the new argument, which are pointers, may never be null, and so the rmw implementations should check to make sure the options are not null. Additionally, the options should be copied into the corresponding rmw structure.See this pull request, and the associated pull requests for more details:https://github.com/ros2/rmw/pull/187ros2cliros2msg and ros2srv deprecatedThe CLI toolsros2msgandros2srvare deprecated. They have been replaced by the toolros2interface, which also supports action and IDL


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by the toolros2interface, which also supports action and IDL interfaces. You can runros2interface--helpfor usage.ros2nodeService clients have been added to ros2node info. As part of that change the Python functionros2node.api.get_service_infohas been renamed toros2node.api.get_service_server_info.rvizRenamed ‘2D Nav Goal’ toolThe tool was renamed to ‘2D Goal Pose’ and the default topic was changed from/move_base_simple/goalto/goal_pose.Here is the related pull request:https://github.com/ros2/rviz/pull/455TF2 BufferTF2 buffers now have to be given a timer interface.If a timer interface is not given, an exception will be thrown.For example:tf=std::make_shared<tf2_ros::Buffer>(get_clock());// The next two lines are new in Eloquentautotimer_interface=std::make_shared<tf2_ros::CreateTimerROS>(this->get_node_base_interface(),this->get_node_timers_interface());tf->setCreateTimerInterface(timer_interface);// Pass the Buffer to the TransformListener as


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Pass the Buffer to the TransformListener as beforetransform_listener=std::make_shared<tf2_ros::TransformListener>(*tf);rclROS command line argument changesTo cope with an increasingly complex interface, with a now extended set of configuration options, ROS CLI syntax has been changed. As an example, a command line using Dashing syntax like:ros2 run some_package some_node foo:=bar __params:=/path/to/params.yaml __log_level:=WARN --user-flagis written using Eloquent (and onwards) syntax as:ros2 run some_package some_node --ros-args --remap foo:=bar --params-file /path/to/params.yaml --log-level WARN -- --user-flagThis explicit syntax affords new features, like single parameter assignment--paramname:=value. For further reference and rationale, check theROS command line arguments design document.WarningFormer syntax has been deprecated and is due for removal in the next release.Known Issues[ros2/rosidl#402]find_package(PCL)interferes with ROS interface generation. Workaround:


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with ROS interface generation. Workaround: invokefind_package(PCL)afterrosidl_generate_interfaces().[ros2/rclcpp#893]rclcpp::Contextis not destroyed because of a reference cycle withrclcpp::GraphListener. This causes a memory leak. A fix has not been backported because of the risk of breaking ABI.Timeline before the releaseA few milestones leading up to the release:Mon. Sep 30th (alpha)First releases of core packages available. Testing can happen from now on (some features might not have landed yet).Fri. Oct 18thAPI and feature freeze for core packages Only bug fix releases should be made after this point. New packages can be released independently.Thu. Oct 24th (beta)Updated releases of core packages available. Additional testing of the latest features.Wed. Nov 13th (release candidate)Updated releases of core packages available.Tue. Nov 19thFreeze rosdistro. No PRs for Eloquent on therosdistrorepo will be merged (reopens after the release announcement).


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Code Examples:

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voidmy_func(constrmw_qos_profile_t&rmw_qos);/

Previously:

/// my_func(some_pub

>get_actual_qos());/

Now:

/my_func(some_pub

>get_actual_qos()

>get_rmw_qos_profile());

Language: unknown tf=std::make_shared<tf2_ros::Buffer>(get_clock());// The next two lines are new in Eloquentautotimer_interface=std::make_shared<tf2_ros::CreateTimerROS>(this->get_node_base_interface(),this->get_node_timers_interface());tf->setCreateTimerInterface(timer_interface);// Pass the Buffer to the TransformListener as beforetransform_listener=std::make_shared<tf2_ros::TransformListener>(*tf);

Language: unknown ros2 run some_package some_node foo:=bar __params:=/path/to/params.yaml __log_level:=WARN --user-flag

Language: unknown ros2 run some_package some_node --ros-args --remap foo:=bar --params-file /path/to/params.yaml --log-level WARN -- --user-flag


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Title: Contributing

URL: https://docs.ros.org/en/jazzy/The-ROS2-Project/Contributing.html

Section: Installation

--------------------------------------------------------------------------------

ContributingTable of ContentsTenetsDiscussions and supportContributing codeA few things to remember before you start contributing to the ROS 2 project.TenetsRespect what came beforeROS has been around for more than a decade and is used by developers and across the world.

Keep a humble attitude and an open mindset while contributing.Engage Open Robotics as early as possibleOpen Robotics acts as a gate-keeper and advocate for the ROS community.

Rely on their expertise and technical judgement from the design phase.Start discussions with Open Robotics and the community early.

Long time ROS contributors may have a clearer vision of the bigger picture.


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If you implement a feature and send a pull request without discussing with the community first, you are taking the risk of it being rejected, or you may be asked to largely rethink your design.Opening issues or using Discourse to socialize an idea before starting the implementation is generally preferable.Adopt community best-practices whenever possible instead of ad-hoc processesThink about your end-user’s experience when developing and contributing.

Avoid using non-standard tools or libraries that may not be accessible to everyone.Think about the community as a wholeThink about the bigger picture.

There are developers building different robots with different constraints.

ROS needs to accommodate requirements of the whole community.There are a number of ways you can contribute to the ROS 2 project.Discussions and supportSome of the easiest ways to contribute to ROS 2 involve engaging in community discussions and support.


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You can find more information on how to pitch in on theContactpage.Contributing codeSetting up your development environmentTo get started, you’ll want to install from source; followthe source installation instructionsfor your platform.Development GuidesROS 2 developer guideCode style and language versionsQuality guide: ensuring code qualityROS Build FarmsWindows Tips and TricksContributing to ROS 2 DocumentationWhat to work onWe have identified a number of tasks that could be worked on by community members: they can be listed bysearching across the ROS 2 repositories for issues labeled as “help wanted”.

If you see something on that list that you would like to work on, please comment on the item to let others know that you are looking into it.We also have a label for issues that we think should be more accessible for first-time contributors,labeled “good first issue”.

If you are interested in contributing to the ROS 2 project, we encourage you to take a look at those issues first.


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If you’d like to cast a wider net, we welcome contributions on any open issue (or others that you might propose), particularly tasks that have a milestone signifying they’re targeted for the next ROS 2 release (the milestone will be the next release’s e.g. ‘crystal’).If you have some code to contribute that fixes a bug or improves documentation, please submit it as a pull request to the relevant repository.

For larger changes, it is a good idea to discuss the proposalon the ROS 2 forumbefore you start to work on it so that you can identify if someone else is already working on something similar.


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If your proposal involves changes to the APIs, it is especially recommended that you discuss the approach before starting work.Submitting your code changesCode contributions should be made via pull requests tothe appropriate ros2 repositories.We ask all contributors to follow the practices explained inthe developer guide.Please be sure torun testsfor your code changes because most packages have tests that check that the code complies with our style guidelines.Becoming a core maintainerThe ROS 2 maintainers ensure that the project is generally making progress.

The responsibilities of the maintainers include:Reviewing incoming code contributions for style, quality, and overall fit into the goals of the repository/ROS 2.Ensuring that CI continues to stay green.Merging pull requests that meet the quality and CI standards above.Addressing issues opened up by users.Each repository in theros2andamentorganizations has a separate set of maintainers.


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Becoming a maintainer of one or more of those repositories is an invitation-only process, and generally involves the following steps:Within the last year, have a substantial number of code contributions to the repository.Within the last year, do a substantial number of reviews on incoming pull requests to the repository.Approximately every 3 months, the ROS 2 team will review the contributions in all of the repositories and send out invitations to new maintainers.

Once the invitation is accepted, the new maintainer will be asked to go through a short training process on the mechanisms and policies of the ROS 2 repositories.

After that training process is completed, the new maintainer will be given write access to the appropriate repositories.


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Title: Marker: Display types

URL: https://docs.ros.org/en/jazzy/Tutorials/Intermediate/RViz/Marker

Display

types/Marker

Display

types.html

Section: Installation

--------------------------------------------------------------------------------


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Marker: Display typesGoal:This tutorial explains the basic Marker types and how to use them.Tutorial level:IntermediateTime:15 MinutesContentsBackgroundThe Marker Message1 Example Usage (C++)2 Message Parameters3 Object types4 Rendering Complexity NotesBackgroundThe Markers display allows programmatic addition of various primitive shapes to the 3D view by sending avisualization_msgs/msg/Markerorvisualization_msgs/msg/MarkerArraymessage.The Marker Message1 Example Usage (C++)First we will create a simple publisher node that publishesMarkermessages from thevisualization_messagespackage to thevisualization_markertopic:automarker_pub=node->create_publisher<visualization_msgs::msg::Marker>("visualization_marker",1);After that it is as simple as filling out avisualization_msgs/msg/Markermessage and publishing


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out avisualization_msgs/msg/Markermessage and publishing it:visualization_msgs::msg::Markermarker;marker.header.frame_id="/my_frame";marker.header.stamp=rclcpp::Clock().now();marker.ns="basic_shapes";marker.id=0;marker.type=visualization_msgs::msg::Marker::SPHERE;marker.action=visualization_msgs::msg::Marker::ADD;marker.pose.position.x=0;marker.pose.position.y=0;marker.pose.position.z=0;marker.pose.orientation.x=0.0;marker.pose.orientation.y=0.0;marker.pose.orientation.z=0.0;marker.pose.orientation.w=1.0;marker.scale.x=1.0;marker.scale.y=1.0;marker.scale.z=1.0;marker.color.r=0.0f;marker.color.g=1.0f;marker.color.b=0.0f;marker.color.a=1.0;// Don't forget to set the alpha!// only if using a MESH_RESOURCE marker type:marker.mesh_resource="package://pr2_description/meshes/base_v0/base.dae";marker.lifetime=rclcpp::Duration::from_nanoseconds(0);marker_pub->publish(marker);There is also avisualization_msgs/msg/MarkerArraymessage, which lets you publish many markers at once.2 Message ParametersThe Marker message


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many markers at once.2 Message ParametersThe Marker message type is defined inROS2CommonInterfaces<https://github.com/ros2/common_interfaces/tree/jazzy/visualization_msgs/msg>_package. The messages in this package include comments that are helpful in understanding each of the fields in the message.ns:Namespace for these markers. This plus the id form a unique identifier.id:Unique id assigned to this marker. It is your responsibility to keep these unique within your namespace.type:Type of marker (Arrow, Sphere, …). The available types are specified in the message definition.action:0 = add/modify, 1 = (deprecated), 2 = delete, 3 = deleteallpose:Pose marker, specified as x/y/z position and x/y/z/w quaternion orientation.scale:Scale of the marker. Applied before the position/orientation. A scale of [1, 1, 1] means the object will be 1m by 1m by 1m.color:Color of the object, specified as r/g/b/a, with values in the range of [0, 1]. The,aor alpha value, denotes the opacity of the marker with 1 indicating opaque


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denotes the opacity of the marker with 1 indicating opaque and 0 indicating completely transparent. The default value is 0, or completely transparent.You must set the a value of your marker to a non-zero value or it will be transparent by default!points:Only used for markers of typePoints,Linestrips, andLine/Cube/Sphere-lists. It’s also used for the Arrow type, if you want to specify the arrow start and end points. This entry represents a list ofgeometry_msgs/Pointtypes for the center or each marker object you would like rendered.colors:This field is only used for markers that use the points member. This field specifies per-vertex color r/g/b/ color  (no alpha yet) for each entry inpoints.lifetime:Aduration message valueused to automatically delete the marker after this period of time. The countdown resets if another marker of the samenamespace/idis received.frame_locked:Without theframe_lockedparameter the marker will be placed based on the current transform and will stay there even if the given transform


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transform and will stay there even if the given transform changes later. Setting this parameter tells RViz to retransform the marker to the new current location of the specified frame on every update cycle.text:The text string used for theTEXT_VIEW_FACINGmarker typemesh_resource:The resource location for theMESH_RESOURCEmarker type. Can be any mesh type supported by RViz (.stlor Ogre.meshin 1.0, with the addition of COLLADA in 1.1). The format is the URI-form used byresource_retriever, including the package:// syntax.3 Object types3.1 Arrow (ARROW=0)The arrow type provides two different ways of specifying where the arrow should begin/end:Position/Orientation:Pivot point is around the tip of its tail. Identity orientation points it along the +X axis.scale.xis the arrow length,scale.yis the arrow width andscale.zis the arrow height.Start/EndPoints:You can also specify a start/end point for the arrow, using the points member. If you put points into the points member, it will assume you want to do things this


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the points member, it will assume you want to do things this way.The point at index 0 is assumed to be the start point, and the point at index 1 is assumed to be the end.scale.xis the shaft diameter, andscale.yis the head diameter. Ifscale.zis not zero, it specifies the head length.3.2 Cube (CUBE=1)Pivot point is at the center of the cube.3.3 Sphere (SPHERE=2)Pivot point is at the center of the sphere.scale.xis diameter in x direction,scale.yin y direction,scale.zin z direction. By setting these to different values you get an ellipsoid instead of a sphere.3.4 Cylinder (CYLINDER=3)Pivot point is at the center of the cylinder.scale.xis diameter in x direction,scale.yin y direction, by setting these to different values you get an ellipse instead of a circle. Usescale.zto specify the height.3.5 Line Strip (LINE_STRIP=4)Line strips use the points member of thevisualization_msgs/msg/Markermessage. It will draw a line between every two consecutive points, so 0-1, 1-2, 2-3, 3-4, 4-5…Line strips also have some


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points, so 0-1, 1-2, 2-3, 3-4, 4-5…Line strips also have some special handling for scale: onlyscale.xis used and it controls the width of the line segments.Note thatposeis still used (the points in the line will be transformed by them), and the lines will be correct relative to theframeidspecified in the header.3.6 Line List (LINE_LIST=5)Line lists use the points member of thevisualization_msgs/msg/Markermessage. It will draw a line between each pair of points, so 0-1, 2-3, 4-5, …Line lists also have some special handling for scale: onlyscale.xis used and it controls the width of the line segments.Note thatposeis still used (the points in the line will be transformed by them), and the lines will be correct relative to theframeidspecified in the header.3.7 Cube List (CUBE_LIST=6)A cube list is a list of cubes with all the same properties except their positions. Using this object type instead of avisualization_msgs/msg/MarkerArrayallows RViz to batch-up rendering, which causes them to render much faster. The


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rendering, which causes them to render much faster. The caveat is that they all must have the same scale.Thepointsmember of thevisualization_msgs/msg/Markermessage is used for the position of each cube.3.8 Sphere List (SPHERE_LIST=7)A sphere list is a list of spheres with all the same properties except their positions. Using this object type instead of avisualization_msgs/msg/MarkerArrayallows RViz to batch-up rendering, which causes them to render much faster. The caveat is that they all must have the same scale.Thepointsmember of thevisualization_msgs/msg/Markermessage is used for the position of each sphere.Note thatposeis still used (thepointsin the line will be transformed by them), and the lines will be correct relative to theframeidspecified in the header.3.9 Points (POINTS=8)Uses thepointsmember of thevisualization_msgs/msg/Markermessage.Pointshave some special handling for scale:scale.xis point width,scale.yis point heightNote thatposeis still used (thepointsin the line will be transformed by


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still used (thepointsin the line will be transformed by them), and the lines will be correct relative to theframeidspecified in the header.3.10 View-Oriented Text (TEXT_VIEW_FACING=9)This marker displays text in a 3D spot in the world. The text always appears oriented correctly for the RViZ user to see the included text. Uses thetextfield in the marker.Onlyscale.zis used.scale.zspecifies the height of an uppercase “A”.3.11 Mesh Resource (MESH_RESOURCE=10)Uses themesh_resourcefield in the marker. Can be any mesh type supported by RViz (binary.stlor Ogre.meshin 1.0, with the addition of COLLADA (.dae) in 1.1). The format is the URI-form used byresource_retriever, including thepackage://syntax.An example of a mesh an its use is:marker.type=visualization_msgs::Marker::MESH_RESOURCE;marker.mesh_resource="package://pr2_description/meshes/base_v0/base.dae";Scale on a mesh is relative. A scale of (1.0, 1.0, 1.0) means the mesh will display as the exact size specified in the mesh file. A scale of (1.0, 1.0, 2.0)


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size specified in the mesh file. A scale of (1.0, 1.0, 2.0) means the mesh will show up twice as tall, but the same width/depth.If themesh_use_embedded_materialsflag is set to true and the mesh is of a type which supports embedded materials (such as COLLADA), the material defined in that file will be used instead of the color defined in the marker.Since version [1.8], even whenmesh_use_embedded_materialsis true, if the markercoloris set to anything other thanr=0,g=0,b=0,a=0the markercolorandalphawill be used to tint the mesh with the embedded material.3.12 Triangle List (TRIANGLE_LIST=11)Uses the points and optionally colors members. Every set of 3 points is treated as a triangle, so indices 0-1-2, 3-4-5, etc.Note thatposeandscaleare still used (the points in the line will be transformed by them), and the lines will be correct relative to theframeidspecified in the header.4 Rendering Complexity NotesA single marker is always less expensive to render than many markers. For example, a single cube list can


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render than many markers. For example, a single cube list can handle thousands of cubes, where we will not be able to render thousands of individual cube markers.


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Code Examples:

Language: unknown

automarker_pub=node

>create_publisher<visualization_msgs::msg::Marker>("visualization_marker",1);

Language: unknown visualization_msgs::msg::Markermarker;marker.header.frame_id="/my_frame";marker.header.stamp=rclcpp::Clock().now();marker.ns="basic_shapes";marker.id=0;marker.type=visualization_msgs::msg::Marker::SPHERE;marker.action=visualization_msgs::msg::Marker::ADD;marker.pose.position.x=0;marker.pose.position.y=0;marker.pose.position.z=0;marker.pose.orientation.x=0.0;marker.pose.orientation.y=0.0;marker.pose.orientation.z=0.0;marker.pose.orientation.w=1.0;marker.scale.x=1.0;marker.scale.y=1.0;marker.scale.z=1.0;marker.color.r=0.0f;marker.color.g=1.0f;marker.color.b=0.0f;marker.color.a=1.0;// Don't forget to set the alpha!// only if using a MESH_RESOURCE marker type:marker.mesh_resource="package://pr2_description/meshes/base_v0/base.dae";marker.lifetime=rclcpp::Duration::from_nanoseconds(0);marker_pub->publish(marker);

Language: unknown


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Language: unknown

marker.type=visualization_msgs::Marker::MESH_RESOURCE;marker.mesh_resource="package://pr2_description/meshes/base_v0/base.dae";


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Title: First Time Release

URL: https://docs.ros.org/en/jazzy/How

To

Guides/Releasing/First

Time

Release.html

Section: Installation

--------------------------------------------------------------------------------


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First Time ReleaseThis guide explains how to release ROS 2 packages that you have not released before. Due to numerous options available when releasing ROS packages, this guide intends to cover the most common scenario and does not cover every corner-case.Table of ContentsBe part of a release teamCreate a new release repositoryInstall dependenciesSet Up a Personal Access TokenEnsure repositories are up-to-dateGenerate ChangelogBump the package versionBloom ReleaseNext StepsBe part of a release teamYou must be part of arelease team. If you are not part of a release team yet, follow either:Join a release teamStart a new release teamCreate a new release repositoryYou need arelease repositoryto release a package. FollowCreate a new release repository.Install dependenciesInstall tools that you will use in the upcoming steps according to your platform:deb (eg. Ubuntu)RPM (eg. RHEL)Othersudoaptinstallpython3-bloompython3-catkin-pkgsudodnfinstallpython3-bloompython3-catkin_pkgpip3install-Ubloomcatkin_pkgMake


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sure you have rosdep initialized:sudorosdepinit rosdepupdateNote that therosdepinitcommand may fail if it has already been initialized in the past; this can safely be ignored.Set Up a Personal Access TokenWarningIf the file~/.config/bloomexists on your computer, it is likely that you have done this before so you should skip this section.During the release process, multiple HTTPS Git operations will be performed that require password authentication. To avoid being repeatedly asked for a password, aPersonal Access Token (PAT)will be set up. If you have multi-factor authentication setup on your GitHub account, youmustsetup a Personal Access Token.Create a Personal Access Token by:Log in to GitHub and go toPersonal access tokens.Click theGenerate new tokenbutton.In the dropdown, selectGenerate new token (classic)SetNoteto something likeBloomtoken.SetExpirationtoNo expiration.Tick thepublic_repoandworkflowcheckboxes.Click theGenerate tokenbutton.After you have created the token, you will end up back at


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you have created the token, you will end up back at thePersonal access tokenspage.Copy the alphanumeric tokenthat is highlighted in green.Save your GitHub username and PAT to a new file called~/.config/bloom, with the format below:{ "github_user": "<your-github-username>", "oauth_token": "<token-you-created-for-bloom>" }Ensure repositories are up-to-dateMake sure that:Your repository is hosted on a remote such as GitHub.You have a clone of the repository on your computer and are on the right branch.Both the remote repository and your clone are up-to-date.Generate ChangelogGenerate aCHANGELOG.rstfile per package in your repo using the following command:catkin_generate_changelog--allOpen allCHANGELOG.rstfiles in an editor. You will see thatcatkin_generate_changeloghas auto-generated a forthcoming section with notes from commit messages:^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^Changelog for package your_package^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^Forthcoming-----------*you can modify this commit message*and thisClean


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can modify this commit message*and thisClean up the list of commit messages to concisely convey the notable changes that have been made to the packages since the last release, andcommit all the CHANGELOG.rst files.Do not modify theForthcomingheader.Bump the package versionEvery release of the package must have a unique version number higher than the previous release. Run:catkin_prepare_releasewhich performs the following:increases the package version inpackage.xmlreplaces the headingForthcomingwithversion(date)(eg.0.0.1(2022-01-08)) inCHANGELOG.rstcommits those changescreates a tag (eg.0.0.1)pushes the changes and the tag to your remote repositoryNoteBy default the patch version of the package is incremented, such as from0.0.0to0.0.1. To increment the minor or major version instead, runcatkin_prepare_release--bumpminororcatkin_prepare_release--bumpmajor. For more details, seecatkin_prepare_release--help.Bloom ReleaseRun the following command, replacingmy_repowith the name of your


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the following command, replacingmy_repowith the name of your repository:bloom-release--new-track--rosdistrojazzy--trackjazzymy_repoTip--new-tracktells bloom to create a newtrackand configure it.--rosdistrojazzyindicates that this release is for thejazzydistro--trackjazzyindicates that you want the track name to bejazzyYou will be prompted to enter information to configure a new track. In a common scenario such as:Your packages are in a repository calledmy_repoYou are releasing a branch calledmainThe repository is hosted on GitHub athttps://github.com/my_organization/my_repo.gitYour release repository is athttps://github.com/ros2-gbp/my_repo-release.gitYou should respond to the prompts as following:ConfigurationValueRelease Repository urlhttps://github.com/ros2-gbp/my_repo-release.gitRepository Namemy_repoUpstream Repository URIhttps://github.com/my_organization/my_repo.gitUpstream VCS TypeVersionRelease TagUpstream Devel BranchmainROS DistroPatches DirectoryRelease Repository Push URLNoteAn empty cell in the


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DirectoryRelease Repository Push URLNoteAn empty cell in the table indicates that the default value should be used. Simply respond to the prompt by pressing Enter.Bloom will automatically create a pull request for you againstrosdistro.Next StepsOnce your pull request has been submitted, usually within one or two days, one of the maintainers of rosdistro will review and merge your Pull Request. If your package build is successful, in 24-48 hours your packages will become available in theros-testingrepository, where you cantest your pre-release binaries.Approximately every two to four weeks, the distribution’s release manager manually synchronizes the contents of ros-testing into the main ROS repository. This is when your packages actually become available to the rest of the ROS community. To get updates on when the next synchronization (sync) is coming, subscribe to thePackaging and Release Management Category on ROS Discourse.


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Code Examples:

Language: unknown

sudoaptinstallpython3

bloompython3

catkin

pkg

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sudodnfinstallpython3

bloompython3

catkin_pkg

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pip3install

Ubloomcatkin_pkg

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sudorosdepinit

rosdepupdate

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{

"github_user": "<your

github

username>",

"oauth_token": "<token

you

created

for

bloom>"

}

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catkin_generate_changelog-

all

Language: unknown ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^Changelog for package your_package^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^Forthcoming-----------*you can modify this commit message*and this

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catkin_prepare_release

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bloom

release-

new

track-

rosdistrojazzy-

trackjazzymy_repo


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Title: Setting up security

URL: https://docs.ros.org/en/jazzy/Tutorials/Advanced/Security/Introducing

ros2

security.html

Section: Installation

--------------------------------------------------------------------------------


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Setting up securityGoal:Set up security withsros2.Tutorial level:AdvancedTime:15 minutesContentsBackgroundInstallationInstalling from sourceSelecting an alternate middlewareRun the demo1. Create a folder for the security files2. Generate a keystore3. Generate keys and certificates4. Configure environment variables5. Run thetalker/listenerdemoTake the Quiz!Learn More!BackgroundThesros2package provides the tools and instructions to use ROS 2 on top of DDS-Security. The security features have been tested across platforms (Linux, macOS, and Windows) as well as across different languages (C++ and Python). The SROS2 has been designed to work with any secure middleware, although not all middleware is open source and support varies depending on the ROS distribution in use.InstallationTypically security is available following installation using theROS 2 Installation Guideand theconfiguration guide. However, if you intend to install from source or switch middleware implementations, consider the following


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or switch middleware implementations, consider the following caveats:Installing from sourceBefore installing from source, you will need to have a recent version openssl (1.0.2g or later) installed:LinuxMacOSWindowssudoaptupdate sudoaptinstalllibssl-devbrewinstallopensslYou will need to have OpenSSL on your library path to run DDS-Security demos. Run the following command, and consider adding to your~/.bash_profile:exportDYLD_LIBRARY_PATH=`brew--prefixopenssl`/lib:$DYLD_LIBRARY_PATHexportOPENSSL_ROOT_DIR=`brew--prefixopenssl`If you don’t have OpenSSL installed, please followthese instructionsFast DDS requires an additional CMake flag to build the security plugins, so the colcon invocation needs to be modified to pass:colconbuild--symlink-install--cmake-args-DSECURITY=ONSelecting an alternate middlewareIf you choose not to use the default middleware implementation, be sure tochange your DDS implementationbefore proceeding.ROS 2 allows you to change the DDS implementation at runtime. Seehow to work with


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change the DDS implementation at runtime. Seehow to work with mulitple RMW implementationsto explore different middleware implementations.Note that secure communication between vendors is not supported.Run the demo1. Create a folder for the security filesBegin by creating folder to store all the files necessary for this demo:LinuxMacOSWindowsmkdir~/sros2_demomkdir~/sros2_demomdC:\dev\ros2\sros2_demo2. Generate a keystoreUse thesros2utilities to create the keystore. Files in the keystore will be used to enable security for all the participants in the ROS 2 graph.LinuxMacOSWindowscd~/sros2_demo ros2securitycreate_keystoredemo_keystorecd~/sros2_demo ros2securitycreate_keystoredemo_keystorecdsros2_demo ros2 security create_keystore demo_keystore3. Generate keys and certificatesOnce the keystore is created, create keys and certificates for each node with security enabled. For our demo, that includes the talker and listener nodes. This command uses thecreate_enclavefeature which is covered in more detail in


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thecreate_enclavefeature which is covered in more detail in the next tutorial.LinuxMacOSWindowsros2securitycreate_enclavedemo_keystore/talker_listener/talker ros2securitycreate_enclavedemo_keystore/talker_listener/listenerros2securitycreate_enclavedemo_keystore/talker_listener/talker ros2securitycreate_enclavedemo_keystore/talker_listener/listenerros2 security create_enclave demo_keystore /talker_listener/talker ros2 security create_enclave demo_keystore /talker_listener/listenerIfunabletowrite'randomstate'appears then set the environment variableRANDFILE.setRANDFILE=C:\dev\ros2\sros2_demo\.rndThen re-run the commands above.4. Configure environment variablesThree environment variables allow the middleware to locate encryption materials and enable (and possibly enforce) security. These and other security-related environment variables are described in theROS 2 DDS-Security Integration design


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are described in theROS 2 DDS-Security Integration design document.LinuxMacOSWindowsexportROS_SECURITY_KEYSTORE=~/sros2_demo/demo_keystoreexportROS_SECURITY_ENABLE=trueexportROS_SECURITY_STRATEGY=EnforceexportROS_SECURITY_KEYSTORE=~/sros2_demo/demo_keystoreexportROS_SECURITY_ENABLE=trueexportROS_SECURITY_STRATEGY=EnforcesetROS_SECURITY_KEYSTORE=%cd%/demo_keystoresetROS_SECURITY_ENABLE=truesetROS_SECURITY_STRATEGY=EnforceThese variables need to be defined in each terminal used for the demo. For convenience you can add them to your boot environment.5. Run thetalker/listenerdemoBegin the demo by launching the talker node.ros2rundemo_nodes_cpptalker--ros-args--enclave/talker_listener/talkerIn another terminal, do the same to launch thelistenernode. The environment variables in this terminal must be properly set as described in step 4 above.ros2rundemo_nodes_pylistener--ros-args--enclave/talker_listener/listenerThese nodes will be communicating using authentication and encryption! If you look at the packet


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using authentication and encryption! If you look at the packet contents (for example, usingtcpdumporWiresharkas covered in another tutorial), you can see that the messages are encrypted.Note: You can switch between the C++ (demo_nodes_cpp) and Python (demo_nodes_py) packages arbitrarily.These nodes are able to communicate because we have created the appropriate keys and certificates for them.Leave both nodes running as you answer the questions below.Take the Quiz!Question 1Answer 1Open another terminal session, butdo notset the environment variables so that security is not enabled. Start the listener. What do you expect to happen?The listener launches but does not receive any messages. All traffic is encrypted, and without security enabled the listener does not receive anything.Question 2Answer 2Stop the listener, set the environment variableROS_SECURITY_ENABLEtotrueand start the listener again. What results do you expect this time?The listener still launches but does not receive messages. Although security


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still launches but does not receive messages. Although security has now been enabled, it is not been configured properly since ROS is unable to locate the key files. The listener launches, but in non-secure mode since security is not enforced, which means that although the properly configured talker is sending encrypted messages, this listener is unable to decrypt them.Question 3Answer 3Stop the listener and setROS_SECURITY_STRATEGYtoEnforce. What happens now?The listener fails to launch. Security has been enabled and is being enforced. Since it still is not properly configured, an error is thrown rather than launching in non-secure mode.Learn More!Are you ready to go further with ROS Security? Take a look at theSecure Turtlebot2 Demo. You’ll find a functioning and complex implementation of ROS 2 security, ready to try out your own custom scenarios. Be sure to create pull requests and issues here so we can continue improving security support in ROS!


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Code Examples:

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sudoaptupdate

sudoaptinstalllibssl

dev

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brewinstallopenssl

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exportDYLD_LIBRARY_PATH=`brew-

prefixopenssl`/lib:$DYLD_LIBRARY_PATHexportOPENSSL_ROOT_DIR=`brew-

prefixopenssl`

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colconbuild-

symlink

install-

cmake

args

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mkdir~/sros2_demo

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mkdir~/sros2_demo

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ros2securitycreate_keystoredemo_keystore

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cd~/sros2_demo

ros2securitycreate_keystoredemo_keystore

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cdsros2_demo

ros2 security create_keystore demo_keystore

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ros2securitycreate_enclavedemo_keystore/talker_listener/talker

ros2securitycreate_enclavedemo_keystore/talker_listener/listener

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ros2securitycreate_enclavedemo_keystore/talker_listener/talker

ros2securitycreate_enclavedemo_keystore/talker_listener/listener


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Language: unknown ros2 security create_enclave demo_keystore /talker_listener/talker ros2 security create_enclave demo_keystore /talker_listener/listener

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setRANDFILE=C:\dev\ros2\sros2_demo\.rnd

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exportROS_SECURITY_KEYSTORE=~/sros2_demo/demo_keystoreexportROS_SECURITY_ENABLE=trueexportROS_SECURITY_STRATEGY=Enforce

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exportROS_SECURITY_KEYSTORE=~/sros2_demo/demo_keystoreexportROS_SECURITY_ENABLE=trueexportROS_SECURITY_STRATEGY=Enforce

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setROS_SECURITY_KEYSTORE=%cd%/demo_keystoresetROS_SECURITY_ENABLE=truesetROS_SECURITY_STRATEGY=Enforce

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ros2rundemo_nodes_cpptalker-

ros

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Title: Migrating Scripts

URL: https://docs.ros.org/en/jazzy/How

To

Guides/Migrating

from

ROS1/Migrating

Scripts.html

Section: Installation

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Migrating ScriptsROS CLIIn ROS 1 there were individual commands for performing various actions, likerosrun,rosparam, etc.In ROS 2, there is a single top-level commands calledros2, and all of the actions are sub-commands of that, likeros2run,ros2param, etc.ROS CLI argumentsIn ROS 1, arguments to nodes were provided directly on the command-line.ROS 2 arguments should be scoped with--ros-argsand a trailing--(the trailing double dash may be elided if no arguments follow it).Remapping names is similar to ROS 1, taking on the formfrom:=to, except that it must be preceded by a--remap(or-r) flag. For example:ros2runsome_packagesome_ros_executable--ros-args-rfoo:=barWe use a similar syntax for parameters, using the--param(or-p) flag:ros2runsome_packagesome_ros_executable--ros-args-pmy_param:=valueNote, this is different than using a leading underscore in ROS 1.To change a node name use__node(the ROS 1 equivalent is__name):ros2runsome_packagesome_ros_executable--ros-args-r__node:=new_node_nameNote the use of


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the use of the-rflag. The same remap flag is needed for changing the namespace__ns:ros2runsome_packagesome_ros_executable--ros-args-r__ns:=/new/namespaceThere is no equivalent in ROS 2 for the following ROS 1 keys:__log(but--log-config-filecan be used to provide a logger configuration file)__ip__hostname__masterFor more information, see thedesign document.Quick referenceFeatureROS 1ROS 2remappingfoo:=bar-r foo:=barparameters_foo:=bar-p foo:=barnode name__name:=foo-r __node:=foonamespace__ns:=foo-r __ns:=foo


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Code Examples:

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ros2runsome_packagesome_ros_executable-

ros

args

rfoo:=bar

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ros2runsome_packagesome_ros_executable-

ros

args

pmy_param:=value

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ros2runsome_packagesome_ros_executable-

ros

args

r__node:=new_node_name

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ros2runsome_packagesome_ros_executable-

ros

args

r__ns:=/new/namespace


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Title: Overview and usage of RQt URL: https://docs.ros.org/en/jazzy/Concepts/Intermediate/About-RQt.html Section: Installation --------------------------------------------------------------------------------


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Overview and usage of RQtTable of ContentsOverviewSystem setupInstalling From debsRQt Components StructureAdvantage of RQt frameworkFurther ReadingOverviewRQt is a graphical user interface framework that implements various tools and interfaces in the form of plugins. One can run all the existing GUI tools as dockable windows within RQt. The tools can still run in a traditional standalone method, but RQt makes it easier to manage all the various windows in a single screen layout.You can run any RQt tools/plugins easily by:rqtThis GUI allows you to choose any available plugins on your system. You can also run plugins in standalone windows. For example, RQt Python Console:ros2runrqt_py_consolerqt_py_consoleUsers can create their own plugins for RQt with eitherPythonorC++. To see what RQt plugins are available for your system, run:ros2pkglistAnd then look for packages that start withrqt_.System setupInstalling From debssudoaptinstallros-jazzy-rqt*RQt Components StructureRQt consists of two metapackages:rqt-


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Components StructureRQt consists of two metapackages:rqt- core infrastucture modules.rqt_common_plugins- Commonly useful debugging tools.Advantage of RQt frameworkCompared to building your own GUIs from scratch:Standardized common procedures for GUI (start-shutdown hook, restore previous states).Multiple widgets can be docked in a single window.Easily turn your existing Qt widgets into RQt plugins.Expect support atRobotics Stack Exchange(ROS community website for the questions).From system architecture’s perspective:Support multi-platform (basically whereverQTand ROS run) and multi-language (Python,C++).Manageable lifecycle: RQt plugins using a common API makes maintainance & reuse easier.Further ReadingROS 2 Discourseannouncement of porting to ROS 2)RQt for ROS 1 documentationBrief overview of RQt (froma Willow Garage intern blog post)


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Code Examples:

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rqt

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ros2runrqt_py_consolerqt_py_console

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ros2pkglist

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sudoaptinstallros

jazzy

rqt*


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Title: Enabling topic statistics (C++) URL: https://docs.ros.org/en/jazzy/Tutorials/Advanced/Topic-Statistics-Tutorial/Topic-Statistics-Tutorial.html Section: Installation --------------------------------------------------------------------------------


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Enabling topic statistics (C++)Goal:Enable ROS 2 Topic Statistics and view the output statistics data.Tutorial level:AdvancedTime:10 minutesTable of ContentsBackgroundPrerequisitesTasks1 Write the subscriber node with statistics enabled1.1 Examine the code1.2 CMakeLists.txt2 Build and run3 Observe published statistic dataSummaryRelated contentBackgroundThis is a short tutorial on how to enable topic statistics in ROS 2 and view the published statistics output using command line tools (ros2topic).ROS 2 provides the integrated measurement of statistics for messages received by any subscription, called Topic Statistics. With Topic Statistics enabled for your subscription, you can characterize the performance of your system or use the data to help diagnose any present issues.For more details please see theTopic Statistics Concepts Page.PrerequisitesAn installation from either binaries or source.In previous tutorials, you learned how tocreate a workspace,create a package, and create aC++publisher and


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a workspace,create a package, and create aC++publisher and subscriber.This tutorial assumes that you still have yourcpp_pubsubpackage from theC++tutorial.Tasks1 Write the subscriber node with statistics enabledNavigate into theros2_ws/src/cpp_pubsub/srcfolder, created in theprevious tutorial, and download the example talker code by entering the following command:LinuxmacOSWindowswget -O member_function_with_topic_statistics.cpp https://raw.githubusercontent.com/ros2/examples/jazzy/rclcpp/topics/minimal_subscriber/member_function_with_topic_statistics.cppwget -O member_function_with_topic_statistics.cpp https://raw.githubusercontent.com/ros2/examples/jazzy/rclcpp/topics/minimal_subscriber/member_function_with_topic_statistics.cppRight click this link and select Save Aspublisher_member_function.cpp:https://raw.githubusercontent.com/ros2/examples/jazzy/rclcpp/topics/minimal_subscriber/member_function_with_topic_statistics.cppNow there will be a new file namedmember_function_with_topic_statistics.cpp. Open the


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file namedmember_function_with_topic_statistics.cpp. Open the file using your preferred text editor.#include<chrono>#include<memory>#include"rclcpp/rclcpp.hpp"#include"rclcpp/subscription_options.hpp"#include"std_msgs/msg/string.hpp"classMinimalSubscriberWithTopicStatistics:publicrclcpp::Node{public:MinimalSubscriberWithTopicStatistics():Node("minimal_subscriber_with_topic_statistics"){// manually enable topic statistics via optionsautooptions=rclcpp::SubscriptionOptions();options.topic_stats_options.state=rclcpp::TopicStatisticsState::Enable;// configure the collection window and publish period (default 1s)options.topic_stats_options.publish_period=std::chrono::seconds(10);// configure the topic name (default '/statistics')// options.topic_stats_options.publish_topic =


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'/statistics')// options.topic_stats_options.publish_topic = "/topic_statistics"autocallback=[this](std_msgs::msg::String::SharedPtrmsg){this->topic_callback(msg);};subscription_=this->create_subscription<std_msgs::msg::String>("topic",10,callback,options);}private:voidtopic_callback(conststd_msgs::msg::String::ConstSharedPtrmsg)const{RCLCPP_INFO(this->get_logger(),"I heard: '%s'",msg->data.c_str());}rclcpp::Subscription<std_msgs::msg::String>::SharedPtrsubscription_;};intmain(intargc,char*argv[]){rclcpp::init(argc,argv);rclcpp::spin(std::make_shared<MinimalSubscriberWithTopicStatistics>());rclcpp::shutdown();return0;}1.1 Examine the codeAs in theC++tutorial, we have a subscriber node which receives string messages from thetopictopic from thetopic_callbackfunction. However, we’ve now added options to configure the subscription to enable topic statistics with therclcpp::SubscriptionOptions()options struct.// manually enable topic statistics via


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struct.// manually enable topic statistics via optionsautooptions=rclcpp::SubscriptionOptions();options.topic_stats_options.state=rclcpp::TopicStatisticsState::Enable;Optionally, fields such as the statistics collection/publish period and the topic used to publish statistics can be configured as well.// configure the collection window and publish period (default 1s)options.topic_stats_options.publish_period=std::chrono::seconds(10);// configure the topic name (default '/statistics')// options.topic_stats_options.publish_topic = "/my_topic"The configurable fields are described in the following table:Subscription Config FieldPurposetopic_stats_options.stateEnable or disable topic statistics (defaultrclcpp::TopicStatisticsState::Disable)topic_stats_options.publish_periodThe period in which to collect statistics data and publish a statistics message (default1s)topic_stats_options.publish_topicThe topic to use when publishing statistics data (default/statistics)1.2 CMakeLists.txtNow open


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statistics data (default/statistics)1.2 CMakeLists.txtNow open theCMakeLists.txtfile.Add the executable and name itlistener_with_topic_statisticsso you can run your node usingros2run:add_executable(listener_with_topic_statistics src/member_function_with_topic_statistics.cpp)ament_target_dependencies(listener_with_topic_statistics rclcpp std_msgs)install(TARGETStalkerlistenerlistener_with_topic_statisticsDESTINATION lib/${PROJECT_NAME})Make sure to save the file, and then your pub/sub system, with topic statistics enabled, should be ready for use.2 Build and runTo build, see theBuild and runsection in the pub/sub tutorial.Run the subscriber with statistics enabled node:ros2 run cpp_pubsub listener_with_topic_statisticsNow run the talker node:ros2 run cpp_pubsub talkerThe terminal should start publishing info messages every 0.5 seconds, like so:[INFO] [minimal_publisher]: Publishing: "Hello World: 0"[INFO] [minimal_publisher]: Publishing: "Hello World: 1"[INFO] [minimal_publisher]: Publishing: "Hello World:


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World: 1"[INFO] [minimal_publisher]: Publishing: "Hello World: 2"[INFO] [minimal_publisher]: Publishing: "Hello World: 3"[INFO] [minimal_publisher]: Publishing: "Hello World: 4"The listener will start printing messages to the console, starting at whatever message count the publisher is on at that time, like so:[INFO] [minimal_subscriber_with_topic_statistics]: I heard: "Hello World: 10"[INFO] [minimal_subscriber_with_topic_statistics]: I heard: "Hello World: 11"[INFO] [minimal_subscriber_with_topic_statistics]: I heard: "Hello World: 12"[INFO] [minimal_subscriber_with_topic_statistics]: I heard: "Hello World: 13"[INFO] [minimal_subscriber_with_topic_statistics]: I heard: "Hello World: 14"Now that the subscriber node is receiving messages, it will periodically publish statistics messages. We will observe these messages in the next section.3 Observe published statistic dataWhile the nodes are running, open a new terminal window. Execute the following command:ros2 topic listThis will list all currently active


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command:ros2 topic listThis will list all currently active topics. You should see the following:/parameter_events/rosout/statistics/topicIf you optionally changed thetopic_stats_options.publish_topicfield earlier in the tutorial, then you will see that name instead of/statistics.The subscriber node you created is publishing statistics, for the topictopic, to the output topic/statistics.We can visualize this usingRQtNow we can view the statistics data published to this topic with the following command:ros2 topic echo /statisticsThe terminal should start publishing statistics messages every 10 seconds, because thetopic_stats_options.publish_periodsubscription configuration was optionally changed earlier in the tutorial.---measurement_source_name: minimal_subscriber_with_topic_statisticsmetrics_source: message_ageunit: mswindow_start:sec: 1594856666nanosec: 931527366window_stop:sec: 1594856676nanosec: 930797670statistics:- data_type: 1data: .nan- data_type: 3data: .nan- data_type: 2data: .nan- data_type: 5data:


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3data: .nan- data_type: 2data: .nan- data_type: 5data: 0.0- data_type: 4data: .nan---measurement_source_name: minimal_subscriber_with_topic_statisticsmetrics_source: message_periodunit: mswindow_start:sec: 1594856666nanosec: 931527366window_stop:sec: 1594856676nanosec: 930797670statistics:- data_type: 1data: 499.2746365105009- data_type: 3data: 500.0- data_type: 2data: 499.0- data_type: 5data: 619.0- data_type: 4data: 0.4463309283488427---From themessage definitionthedata_typesare as followsdata_type valuestatistics1average2minimum3maximum4standard deviation5sample countHere we see the two currently possible calculated statistics for thestd_msgs::msg::Stringmessage published to/topicby theminimal_publisher. Because thestd_msgs::msg::Stringdoes not have a message header, themessage_agecalculation cannot be performed, so NaNs are returned. However, themessage_periodcan be calculated and we see the statistics populated in the message above.SummaryYou created a subscriber node with topic statistics enabled,


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created a subscriber node with topic statistics enabled, which published statistics data from theC++’s publisher node. You were able to compile and run this node. While running, you were able to observe the statistics data.Related contentTo observe how themessage_ageperiod is calculated please see theROS 2 Topic Statistics demo.


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Code Examples:

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wget

O member_function_with_topic_statistics.cpp https://raw.githubusercontent.com/ros2/examples/jazzy/rclcpp/topics/minimal_subscriber/member_function_with_topic_statistics.cpp

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wget

O member_function_with_topic_statistics.cpp https://raw.githubusercontent.com/ros2/examples/jazzy/rclcpp/topics/minimal_subscriber/member_function_with_topic_statistics.cpp


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Language: unknown #include<chrono>#include<memory>#include"rclcpp/rclcpp.hpp"#include"rclcpp/subscription_options.hpp"#include"std_msgs/msg/string.hpp"classMinimalSubscriberWithTopicStatistics:publicrclcpp::Node{public:MinimalSubscriberWithTopicStatistics():Node("minimal_subscriber_with_topic_statistics"){// manually enable topic statistics via optionsautooptions=rclcpp::SubscriptionOptions();options.topic_stats_options.state=rclcpp::TopicStatisticsState::Enable;// configure the collection window and publish period (default 1s)options.topic_stats_options.publish_period=std::chrono::seconds(10);// configure the topic name (default '/statistics')// options.topic_stats_options.publish_topic = "/topic_statistics"autocallback=[this](std_msgs::msg::String::SharedPtrmsg){this->topic_callback(msg);};subscription_=this->create_subscription<std_msgs::msg::String>("topic",10,callback,options);}private:voidtopic_callback(conststd_msgs::msg::String::ConstSharedPtrmsg)const{RCLCPP_INFO(this->get_logger(),"I heard:


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heard: '%s'",msg->data.c_str());}rclcpp::Subscription<std_msgs::msg::String>::SharedPtrsubscription_;};intmain(intargc,char*argv[]){rclcpp::init(argc,argv);rclcpp::spin(std::make_shared<MinimalSubscriberWithTopicStatistics>());rclcpp::shutdown();return0;}


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Language: unknown // manually enable topic statistics via optionsautooptions=rclcpp::SubscriptionOptions();options.topic_stats_options.state=rclcpp::TopicStatisticsState::Enable;

Language: unknown // configure the collection window and publish period (default 1s)options.topic_stats_options.publish_period=std::chrono::seconds(10);// configure the topic name (default '/statistics')// options.topic_stats_options.publish_topic = "/my_topic"

Language: unknown add_executable(listener_with_topic_statistics src/member_function_with_topic_statistics.cpp)ament_target_dependencies(listener_with_topic_statistics rclcpp std_msgs)install(TARGETStalkerlistenerlistener_with_topic_statisticsDESTINATION lib/${PROJECT_NAME})

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ros2 run cpp_pubsub listener_with_topic_statistics

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ros2 run cpp_pubsub talker


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ros2 run cpp_pubsub talker

Language: unknown [INFO] [minimal_publisher]: Publishing: "Hello World: 0"[INFO] [minimal_publisher]: Publishing: "Hello World: 1"[INFO] [minimal_publisher]: Publishing: "Hello World: 2"[INFO] [minimal_publisher]: Publishing: "Hello World: 3"[INFO] [minimal_publisher]: Publishing: "Hello World: 4"

Language: unknown [INFO] [minimal_subscriber_with_topic_statistics]: I heard: "Hello World: 10"[INFO] [minimal_subscriber_with_topic_statistics]: I heard: "Hello World: 11"[INFO] [minimal_subscriber_with_topic_statistics]: I heard: "Hello World: 12"[INFO] [minimal_subscriber_with_topic_statistics]: I heard: "Hello World: 13"[INFO] [minimal_subscriber_with_topic_statistics]: I heard: "Hello World: 14"

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ros2 topic list

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/parameter_events/rosout/statistics/topic

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ros2 topic echo /statistics


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ros2 topic echo /statistics

Language: unknown ---measurement_source_name: minimal_subscriber_with_topic_statisticsmetrics_source: message_ageunit: mswindow_start:sec: 1594856666nanosec: 931527366window_stop:sec: 1594856676nanosec: 930797670statistics:- data_type: 1data: .nan- data_type: 3data: .nan- data_type: 2data: .nan- data_type: 5data: 0.0- data_type: 4data: .nan---measurement_source_name: minimal_subscriber_with_topic_statisticsmetrics_source: message_periodunit: mswindow_start:sec: 1594856666nanosec: 931527366window_stop:sec: 1594856676nanosec: 930797670statistics:- data_type: 1data: 499.2746365105009- data_type: 3data: 500.0- data_type: 2data: 499.0- data_type: 5data: 619.0- data_type: 4data: 0.4463309283488427---


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Title: Citations

URL: https://docs.ros.org/en/jazzy/Citations.html

Section: Installation

--------------------------------------------------------------------------------


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CitationsIf you use ROS 2 in your work please cite the 2022 Science Robotics paperRobot Operating System 2: Design, architecture, and uses in the wild.S. Macenski, T. Foote, B. Gerkey, C. Lalancette, W. Woodall, “Robot Operating System 2: Design, architecture, and uses in the wild,” Science Robotics vol. 7, May 2022.@article{doi:10.1126/scirobotics.abm6074,author={Steven Macenski and Tully Foote and Brian Gerkey and Chris Lalancette and William Woodall},title={Robot Operating System 2: Design, architecture, and uses in the wild},journal={Science Robotics},volume={7},number={66},pages={eabm6074},year={2022},doi={10.1126/scirobotics.abm6074},URL={https://www.science.org/doi/abs/10.1126/scirobotics.abm6074}}If you use ROS 2 Composition in your work, please cite the 2023 IEEE RA-L paperImpact of ROS 2 Node Composition in Robotic Systems.S. Macenski, A. Soragna, M. Carroll, Z. Ge, “Impact of ROS 2 Node Composition in Robotic Systems”, IEEE Robotics and Autonomous Letters (RA-L),


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Robotic Systems”, IEEE Robotics and Autonomous Letters (RA-L), 2023.@article{doi:10.48550/arXiv.2305.09933,author={Steven Macenski and Alberto Soragna and Michael Carroll and Zhenpeng Ge},title={Impact of ROS 2 Node Composition in Robotic Systems},journal={IEEE Robotics and Autonomous Letters (RA-L)},year={2023},doi={10.48550/arXiv.2305.09933},URL={https://arxiv.org/abs/2305.09933}}


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Code Examples:

Language: unknown @article{doi:10.1126/scirobotics.abm6074,author={Steven Macenski and Tully Foote and Brian Gerkey and Chris Lalancette and William Woodall},title={Robot Operating System 2: Design, architecture, and uses in the wild},journal={Science Robotics},volume={7},number={66},pages={eabm6074},year={2022},doi={10.1126/scirobotics.abm6074},URL={https://www.science.org/doi/abs/10.1126/scirobotics.abm6074}}

Language: unknown @article{doi:10.48550/arXiv.2305.09933,author={Steven Macenski and Alberto Soragna and Michael Carroll and Zhenpeng Ge},title={Impact of ROS 2 Node Composition in Robotic Systems},journal={IEEE Robotics and Autonomous Letters (RA-L)},year={2023},doi={10.48550/arXiv.2305.09933},URL={https://arxiv.org/abs/2305.09933}}


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Title: Using parameters in a class (C++) URL: https://docs.ros.org/en/jazzy/Tutorials/Beginner-Client-Libraries/Using-Parameters-In-A-Class-CPP.html Section: Installation --------------------------------------------------------------------------------


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Using parameters in a class (C++)Goal:Create and run a class with ROS parameters using C++.Tutorial level:BeginnerTime:20 minutesContentsBackgroundPrerequisitesTasks1 Create a package2 Write the C++ node3 Build and runSummaryNext stepsBackgroundWhen making your ownnodesyou will sometimes need to add parameters that can be set from the launch file.This tutorial will show you how to create those parameters in a C++ class, and how to set them in a launch file.PrerequisitesIn previous tutorials, you learned how tocreate a workspaceandcreate a package. You have also learned aboutparametersand their function in a ROS 2 system.Tasks1 Create a packageOpen a new terminal andsource your ROS 2 installationso thatros2commands will work.Followthese instructionsto create a new workspace namedros2_ws.Recall that packages should be created in thesrcdirectory, not the root of the workspace. Navigate intoros2_ws/srcand create a new package:ros2 pkg create --build-type ament_cmake --license Apache-2.0 cpp_parameters


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--build-type ament_cmake --license Apache-2.0 cpp_parameters --dependencies rclcppYour terminal will return a message verifying the creation of your packagecpp_parametersand all its necessary files and folders.The--dependenciesargument will automatically add the necessary dependency lines topackage.xmlandCMakeLists.txt.1.1 Updatepackage.xmlBecause you used the--dependenciesoption during package creation, you don’t have to manually add dependencies topackage.xmlorCMakeLists.txt.As always, though, make sure to add the description, maintainer email and name, and license information topackage.xml.<description>C++parametertutorial</description><maintaineremail="you@email.com">YourName</maintainer><license>Apache-2.0</license>2 Write the C++ nodeInside theros2_ws/src/cpp_parameters/srcdirectory, create a new file calledcpp_parameters_node.cppand paste the following code


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file calledcpp_parameters_node.cppand paste the following code within:#include<chrono>#include<functional>#include<string>#include<rclcpp/rclcpp.hpp>usingnamespacestd::chrono_literals;classMinimalParam:publicrclcpp::Node{public:MinimalParam():Node("minimal_param_node"){this->declare_parameter("my_parameter","world");autotimer_callback=[this](){std::stringmy_param=this->get_parameter("my_parameter").as_string();RCLCPP_INFO(this->get_logger(),"Hello %s!",my_param.c_str());std::vector<rclcpp::Parameter>all_new_parameters{rclcpp::Parameter("my_parameter","world")};this->set_parameters(all_new_parameters);};timer_=this->create_wall_timer(1000ms,timer_callback);}private:rclcpp::TimerBase::SharedPtrtimer_;};intmain(intargc,char**argv){rclcpp::init(argc,argv);rclcpp::spin(std::make_shared<MinimalParam>());rclcpp::shutdown();return0;}2.1 Examine the codeThe#includestatements at the top are the package dependencies.The next piece of code creates the class and the constructor. The first line of this constructor


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class and the constructor. The first line of this constructor creates a parameter with the namemy_parameterand a default value ofworld. The parameter type is inferred from the default value, so in this case it would be set to a string type. Next, alambda functioncalledtimer_callbackis declared. It performs a by-reference capture of the current objectthis, takes no input arguments and returns void. The first line of ourtimer_callbackfunction gets the parametermy_parameterfrom the node, and stores it inmy_param. Then theRCLCPP_INFOfunction ensures the event is logged. Theset_parametersfunction sets the parametermy_parameterback to the default string valueworld. In the case that the user changed the parameter externally, this ensures it is always reset back to the original. In the end,timer_is initialized with a period of 1000ms, which causes thetimer_callbackfunction to be executed once a


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which causes thetimer_callbackfunction to be executed once a second.classMinimalParam:publicrclcpp::Node{public:MinimalParam():Node("minimal_param_node"){this->declare_parameter("my_parameter","world");autotimer_callback=[this](){std::stringmy_param=this->get_parameter("my_parameter").as_string();RCLCPP_INFO(this->get_logger(),"Hello %s!",my_param.c_str());std::vector<rclcpp::Parameter>all_new_parameters{rclcpp::Parameter("my_parameter","world")};this->set_parameters(all_new_parameters);};timer_=this->create_wall_timer(1000ms,timer_callback);}Last is the declaration oftimer_.private:rclcpp::TimerBase::SharedPtrtimer_;Following ourMinimalParamis ourmain. Here ROS 2 is initialized, an instance of theMinimalParamclass is constructed, andrclcpp::spinstarts processing data from the node.intmain(intargc,char**argv){rclcpp::init(argc,argv);rclcpp::spin(std::make_shared<MinimalParam>());rclcpp::shutdown();return0;}2.1.1 (Optional) Add ParameterDescriptorOptionally, you can set a descriptor for the parameter.


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you can set a descriptor for the parameter. Descriptors allow you to specify a text description of the parameter and its constraints, like making it read-only, specifying a range, etc. For that to work, the code in the constructor has to be changed to:// ...classMinimalParam:publicrclcpp::Node{public:MinimalParam():Node("minimal_param_node"){autoparam_desc=rcl_interfaces::msg::ParameterDescriptor{};param_desc.description="This parameter is mine!";this->declare_parameter("my_parameter","world",param_desc);autotimer_callback=[this](){std::stringmy_param=this->get_parameter("my_parameter").as_string();RCLCPP_INFO(this->get_logger(),"Hello %s!",my_param.c_str());std::vector<rclcpp::Parameter>all_new_parameters{rclcpp::Parameter("my_parameter","world")};this->set_parameters(all_new_parameters);};timer_=this->create_wall_timer(1000ms,timer_callback);}The rest of the code remains the same. Once you run the node, you can then runros2paramdescribe/minimal_param_nodemy_parameterto see the type and description.2.2 Add


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see the type and description.2.2 Add executableNow open theCMakeLists.txtfile. Below the dependencyfind_package(rclcppREQUIRED)add the following lines of code.add_executable(minimal_param_nodesrc/cpp_parameters_node.cpp)ament_target_dependencies(minimal_param_noderclcpp)install(TARGETSminimal_param_nodeDESTINATIONlib/${PROJECT_NAME})3 Build and runIt’s good practice to runrosdepin the root of your workspace (ros2_ws) to check for missing dependencies before building:LinuxmacOSWindowsrosdep install -i --from-path src --rosdistro jazzy -yrosdep only runs on Linux, so you can skip ahead to next step.rosdep only runs on Linux, so you can skip ahead to next step.Navigate back to the root of your workspace,ros2_ws, and build your new package:LinuxmacOSWindowscolcon build --packages-select cpp_parameterscolcon build --packages-select cpp_parameterscolcon build --merge-install --packages-select cpp_parametersOpen a new terminal, navigate toros2_ws, and source the setup files:LinuxmacOSWindowssource


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toros2_ws, and source the setup files:LinuxmacOSWindowssource install/setup.bash. install/setup.bashcall install/setup.batNow run the node:ros2 run cpp_parameters minimal_param_nodeThe terminal should return the following message every second:[INFO] [minimal_param_node]: Hello world!Now you can see the default value of your parameter, but you want to be able to set it yourself. There are two ways to accomplish this.3.1 Change via the consoleThis part will use the knowledge you have gained from thetutorial about parametersand apply it to the node you have just created.Make sure the node is running:ros2 run cpp_parameters minimal_param_nodeOpen another terminal, source the setup files from insideros2_wsagain, and enter the following line:ros2 param listThere you will see the custom parametermy_parameter. To change it, simply run the following line in the console:ros2 param set /minimal_param_node my_parameter earthYou know it went well if you got the outputSetparametersuccessful. If you look at the other


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got the outputSetparametersuccessful. If you look at the other terminal, you should see the output change to[INFO][minimal_param_node]:Helloearth!3.2 Change via a launch fileYou can also set the parameter in a launch file, but first you will need to add the launch directory. Inside theros2_ws/src/cpp_parameters/directory, create a new directory calledlaunch. In there, create a new file calledcpp_parameters_launch.pyfromlaunchimportLaunchDescriptionfromlaunch_ros.actionsimportNodedefgenerate_launch_description():returnLaunchDescription([Node(package="cpp_parameters",executable="minimal_param_node",name="custom_minimal_param_node",output="screen",emulate_tty=True,parameters=[{"my_parameter":"earth"}])])Here you can see that we setmy_parametertoearthwhen we launch our nodeminimal_param_node. By adding the two lines below, we ensure our output is printed in our console.output="screen",emulate_tty=True,Now open theCMakeLists.txtfile. Below the lines you added earlier, add the following lines of


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Below the lines you added earlier, add the following lines of code.install(DIRECTORY launchDESTINATION share/${PROJECT_NAME})Open a console and navigate to the root of your workspace,ros2_ws, and build your new package:LinuxmacOSWindowscolcon build --packages-select cpp_parameterscolcon build --packages-select cpp_parameterscolcon build --merge-install --packages-select cpp_parametersThen source the setup files in a new terminal:LinuxmacOSWindowssource install/setup.bash. install/setup.bashcall install/setup.batNow run the node using the launch file we have just created:ros2 launch cpp_parameters cpp_parameters_launch.pyThe terminal should return the following message the first time:[INFO] [custom_minimal_param_node]: Hello earth!Further outputs should show[INFO][minimal_param_node]:Helloworld!every second.SummaryYou created a node with a custom parameter that can be set either from a launch file or the command line. You added the dependencies, executables, and a launch file to the package configuration


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executables, and a launch file to the package configuration files so that you could build and run them, and see the parameter in action.Next stepsNow that you have some packages and ROS 2 systems of your own, thenext tutorialwill show you how to examine issues in your environment and systems in case you have problems.


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Code Examples:

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ros2 pkg create -

build

type ament_cmake -

license Apache

2.0 cpp_parameters -

dependencies rclcpp

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<description>C++parametertutorial</description><maintaineremail="you@email.com">YourName</maintainer><license>Apache

2.0</license>

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#include<chrono>#include<functional>#include<string>#include<rclcpp/rclcpp.hpp>usingnamespacestd::chrono_literals;classMinimalParam:publicrclcpp::Node{public:MinimalParam():Node("minimal_param_node"){this

>declare_parameter("my_parameter","world");autotimer_callback=[this](){std::stringmy_param=this

>get_parameter("my_parameter").as_string();RCLCPP_INFO(this

>get_logger(),"Hello %s!",my_param.c_str());std::vector<rclcpp::Parameter>all_new_parameters{rclcpp::Parameter("my_parameter","world")};this

>set_parameters(all_new_parameters);};timer_=this

>create_wall_timer(1000ms,timer_callback);}private:rclcpp::TimerBase::SharedPtrtimer_;};intmain(intargc,char*


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argv){rclcpp::init(argc,argv);rclcpp::spin(std::make_shared<MinimalParam>());rclcpp::shutdown();return0;}

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classMinimalParam:publicrclcpp::Node{public:MinimalParam():Node("minimal_param_node"){this

>declare_parameter("my_parameter","world");autotimer_callback=[this](){std::stringmy_param=this

>get_parameter("my_parameter").as_string();RCLCPP_INFO(this

>get_logger(),"Hello %s!",my_param.c_str());std::vector<rclcpp::Parameter>all_new_parameters{rclcpp::Parameter("my_parameter","world")};this

>set_parameters(all_new_parameters);};timer_=this

>create_wall_timer(1000ms,timer_callback);}

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private:rclcpp::TimerBase::SharedPtrtimer_;

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intmain(intargc,char*

argv){rclcpp::init(argc,argv);rclcpp::spin(std::make_shared<MinimalParam>());rclcpp::shutdown();return0;}


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Language: unknown // ...classMinimalParam:publicrclcpp::Node{public:MinimalParam():Node("minimal_param_node"){autoparam_desc=rcl_interfaces::msg::ParameterDescriptor{};param_desc.description="This parameter is mine!";this->declare_parameter("my_parameter","world",param_desc);autotimer_callback=[this](){std::stringmy_param=this->get_parameter("my_parameter").as_string();RCLCPP_INFO(this->get_logger(),"Hello %s!",my_param.c_str());std::vector<rclcpp::Parameter>all_new_parameters{rclcpp::Parameter("my_parameter","world")};this->set_parameters(all_new_parameters);};timer_=this->create_wall_timer(1000ms,timer_callback);}

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add_executable(minimal_param_nodesrc/cpp_parameters_node.cpp)ament_target_dependencies(minimal_param_noderclcpp)install(TARGETSminimal_param_nodeDESTINATIONlib/${PROJECT_NAME})

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rosdep install

i -

from

path src -

rosdistro jazzy

y

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colcon build -

packages

select cpp_parameters

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colcon build -

packages


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colcon build -

packages

select cpp_parameters

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colcon build -

merge

install -

packages

select cpp_parameters

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source install/setup.bash

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. install/setup.bash

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call install/setup.bat

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ros2 run cpp_parameters minimal_param_node

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[INFO] [minimal_param_node]: Hello world!

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ros2 run cpp_parameters minimal_param_node

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ros2 param list

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fromlaunchimportLaunchDescriptionfromlaunch_ros.actionsimportNodedefgenerate_launch_description():returnLaunchDescription([Node(package="cpp_parameters",executable="minimal_param_node",name="custom_minimal_param_node",output="screen",emulate_tty=True,parameters=[{"my_parameter":"earth"}])])

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output="screen",emulate_tty=True,

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output="screen",emulate_tty=True,

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install(DIRECTORY launchDESTINATION share/${PROJECT_NAME})

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colcon build -

packages

select cpp_parameters

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colcon build -

packages

select cpp_parameters

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colcon build -

merge

install -

packages

select cpp_parameters

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source install/setup.bash

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. install/setup.bash

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call install/setup.bat

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ros2 launch cpp_parameters cpp_parameters_launch.py

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[INFO] [custom_minimal_param_node]: Hello earth!


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Title: Quaternion fundamentals

URL: https://docs.ros.org/en/jazzy/Tutorials/Intermediate/Tf2/Quaternion

Fundamentals.html

Section: Installation

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Quaternion fundamentalsGoal:Learn the basics of quaternion usage in ROS 2.Tutorial level:IntermediateTime:10 minutesContentsBackgroundPrerequisitesComponents of a quaternionQuaternion types in ROS 2Quaternion operations1 Think in RPY then convert to quaternion2 Applying a quaternion rotation3 Inverting a quaternion4 Relative rotationsSummaryBackgroundA quaternion is a 4-tuple representation of orientation, which is more concise than a rotation matrix. Quaternions are very efficient for analyzing situations where rotations in three dimensions are involved. Quaternions are used widely in robotics, quantum mechanics, computer vision, and 3D animation.You can learn more about the underlying mathematical concept onWikipedia. You can also take a look at an explorable video seriesVisualizing quaternionsmade by3blue1brown.In this tutorial, you will learn how quaternions and conversion methods work in ROS 2.PrerequisitesHowever, this is not a hard requirement and you can stick to any other geometric transfromation


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and you can stick to any other geometric transfromation library that suit you best. You can take a look at libraries liketransforms3d,scipy.spatial.transform,pytransform3d,numpy-quaternionorblender.mathutils.Components of a quaternionROS 2 uses quaternions to track and apply rotations. A quaternion has 4 components(x,y,z,w). In ROS 2,wis last, but in some libraries like Eigen,wcan be placed at the first position. The commonly-used unit quaternion that yields no rotation about the x/y/z axes is(0,0,0,1), and can be created in a following way:#include<tf2/LinearMath/Quaternion.h>...tf2::Quaternionq;// Create a quaternion from roll/pitch/yaw in radians (0, 0, 0)q.setRPY(0,0,0);// Print the quaternion components (0, 0, 0, 1)RCLCPP_INFO(this->get_logger(),"%f %f %f %f",q.x(),q.y(),q.z(),q.w());The magnitude of a quaternion should always be one. If numerical errors cause a quaternion magnitude other than one, ROS 2 will print warnings. To avoid these warnings, normalize the quaternion:q.normalize();Quaternion


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warnings, normalize the quaternion:q.normalize();Quaternion types in ROS 2ROS 2 uses two quaternion datatypes:tf2::Quaternionand its equivalentgeometry_msgs::msg::Quaternion. To convert between them in C++, use the methods oftf2_geometry_msgs.C++#include<tf2_geometry_msgs/tf2_geometry_msgs.hpp>...tf2::Quaterniontf2_quat,tf2_quat_from_msg;tf2_quat.setRPY(roll,pitch,yaw);// Convert tf2::Quaternion to geometry_msgs::msg::Quaterniongeometry_msgs::msg::Quaternionmsg_quat=tf2::toMsg(tf2_quat);// Convert geometry_msgs::msg::Quaternion to tf2::Quaterniontf2::convert(msg_quat,tf2_quat_from_msg);// ortf2::fromMsg(msg_quat,tf2_quat_from_msg);Pythonfromgeometry_msgs.msgimportQuaternion...# Create a list of floats, which is compatible with tf2# Quaternion methodsquat_tf=[0.0,1.0,0.0,0.0]# Convert a list to geometry_msgs.msg.Quaternionmsg_quat=Quaternion(x=quat_tf[0],y=quat_tf[1],z=quat_tf[2],w=quat_tf[3])Quaternion operations1 Think in RPY then convert to quaternionIt’s easy for us to think of rotations about axes,


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quaternionIt’s easy for us to think of rotations about axes, but hard to think in terms of quaternions. A suggestion is to calculate target rotations in terms of roll (about an X-axis), pitch (about the Y-axis), and yaw (about the Z-axis), and then convert to a quaternion.# quaternion_from_euler method is available in turtle_tf2_py/turtle_tf2_py/turtle_tf2_broadcaster.pyq=quaternion_from_euler(1.5707,0,-1.5707)print(f'The quaternion representation is x:{q[0]}y:{q[1]}z:{q[2]}w:{q[3]}.')2 Applying a quaternion rotationTo apply the rotation of one quaternion to a pose, simply multiply the previous quaternion of the pose by the quaternion representing the desired rotation. The order of this multiplication matters.C++#include<tf2_geometry_msgs/tf2_geometry_msgs.hpp>...tf2::Quaternionq_orig,q_rot,q_new;q_orig.setRPY(0.0,0.0,0.0);// Rotate the previous pose by 180* about Xq_rot.setRPY(3.14159,0.0,0.0);q_new=q_rot*q_orig;q_new.normalize();Pythonq_orig=quaternion_from_euler(0,0,0)# Rotate the previous pose by 180*


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Rotate the previous pose by 180* about Xq_rot=quaternion_from_euler(3.14159,0,0)q_new=quaternion_multiply(q_rot,q_orig)3 Inverting a quaternionAn easy way to invert a quaternion is to negate the w-component:q[3]=-q[3]4 Relative rotationsSay you have two quaternions from the same frame,q_1andq_2. You want to find the relative rotation,q_r, that convertsq_1toq_2in a following manner:q_2=q_r*q_1You can solve forq_rsimilarly to solving a matrix equation. Invertq_1and right-multiply both sides. Again, the order of multiplication is important:q_r=q_2*q_1_inverseHere’s an example to get the relative rotation from the previous robot pose to the current robot pose in python:defquaternion_multiply(q0,q1):"""Multiplies two quaternions.Input:param q0: A 4 element array containing the first quaternion (q01, q11, q21, q31):param q1: A 4 element array containing the second quaternion (q02, q12, q22, q32)Output:return: A 4 element array containing the final quaternion (q03,q13,q23,q33)"""# Extract the values from


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final quaternion (q03,q13,q23,q33)"""# Extract the values from q0w0=q0[0]x0=q0[1]y0=q0[2]z0=q0[3]# Extract the values from q1w1=q1[0]x1=q1[1]y1=q1[2]z1=q1[3]# Computer the product of the two quaternions, term by termq0q1_w=w0*w1-x0*x1-y0*y1-z0*z1q0q1_x=w0*x1+x0*w1+y0*z1-z0*y1q0q1_y=w0*y1-x0*z1+y0*w1+z0*x1q0q1_z=w0*z1+x0*y1-y0*x1+z0*w1# Create a 4 element array containing the final quaternionfinal_quaternion=np.array([q0q1_w,q0q1_x,q0q1_y,q0q1_z])# Return a 4 element array containing the final quaternion (q02,q12,q22,q32)returnfinal_quaternionq1_inv[0]=prev_pose.pose.orientation.xq1_inv[1]=prev_pose.pose.orientation.yq1_inv[2]=prev_pose.pose.orientation.zq1_inv[3]=-prev_pose.pose.orientation.w# Negate for inverseq2[0]=current_pose.pose.orientation.xq2[1]=current_pose.pose.orientation.yq2[2]=current_pose.pose.orientation.zq2[3]=current_pose.pose.orientation.wqr=quaternion_multiply(q2,q1_inv)SummaryIn this tutorial, you learned about the fundamental concepts of a quaternion and its related mathematical


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concepts of a quaternion and its related mathematical operations, like inversion and rotation. You also learned about its usage examples in ROS 2 and conversion methods between two separate Quaternion classes.


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Code Examples:

Language: unknown #include<tf2/LinearMath/Quaternion.h>...tf2::Quaternionq;// Create a quaternion from roll/pitch/yaw in radians (0, 0, 0)q.setRPY(0,0,0);// Print the quaternion components (0, 0, 0, 1)RCLCPP_INFO(this->get_logger(),"%f %f %f %f",q.x(),q.y(),q.z(),q.w());

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q.normalize();

Language: unknown #include<tf2_geometry_msgs/tf2_geometry_msgs.hpp>...tf2::Quaterniontf2_quat,tf2_quat_from_msg;tf2_quat.setRPY(roll,pitch,yaw);// Convert tf2::Quaternion to geometry_msgs::msg::Quaterniongeometry_msgs::msg::Quaternionmsg_quat=tf2::toMsg(tf2_quat);// Convert geometry_msgs::msg::Quaternion to tf2::Quaterniontf2::convert(msg_quat,tf2_quat_from_msg);// ortf2::fromMsg(msg_quat,tf2_quat_from_msg);

Language: unknown fromgeometry_msgs.msgimportQuaternion...# Create a list of floats, which is compatible with tf2# Quaternion methodsquat_tf=[0.0,1.0,0.0,0.0]# Convert a list to geometry_msgs.msg.Quaternionmsg_quat=Quaternion(x=quat_tf[0],y=quat_tf[1],z=quat_tf[2],w=quat_tf[3])


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Language: unknown # quaternion_from_euler method is available in turtle_tf2_py/turtle_tf2_py/turtle_tf2_broadcaster.pyq=quaternion_from_euler(1.5707,0,-1.5707)print(f'The quaternion representation is x:{q[0]}y:{q[1]}z:{q[2]}w:{q[3]}.')

Language: unknown #include<tf2_geometry_msgs/tf2_geometry_msgs.hpp>...tf2::Quaternionq_orig,q_rot,q_new;q_orig.setRPY(0.0,0.0,0.0);// Rotate the previous pose by 180* about Xq_rot.setRPY(3.14159,0.0,0.0);q_new=q_rot*q_orig;q_new.normalize();

Language: unknown q_orig=quaternion_from_euler(0,0,0)# Rotate the previous pose by 180* about Xq_rot=quaternion_from_euler(3.14159,0,0)q_new=quaternion_multiply(q_rot,q_orig)

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q[3]=

q[3]

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q_2=q_r

q_1

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q_r=q_2

q_1_inverse


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Language: unknown defquaternion_multiply(q0,q1):"""Multiplies two quaternions.Input:param q0: A 4 element array containing the first quaternion (q01, q11, q21, q31):param q1: A 4 element array containing the second quaternion (q02, q12, q22, q32)Output:return: A 4 element array containing the final quaternion (q03,q13,q23,q33)"""# Extract the values from q0w0=q0[0]x0=q0[1]y0=q0[2]z0=q0[3]# Extract the values from q1w1=q1[0]x1=q1[1]y1=q1[2]z1=q1[3]# Computer the product of the two quaternions, term by termq0q1_w=w0*w1-x0*x1-y0*y1-z0*z1q0q1_x=w0*x1+x0*w1+y0*z1-z0*y1q0q1_y=w0*y1-x0*z1+y0*w1+z0*x1q0q1_z=w0*z1+x0*y1-y0*x1+z0*w1# Create a 4 element array containing the final quaternionfinal_quaternion=np.array([q0q1_w,q0q1_x,q0q1_y,q0q1_z])# Return a 4 element array containing the final quaternion (q02,q12,q22,q32)returnfinal_quaternionq1_inv[0]=prev_pose.pose.orientation.xq1_inv[1]=prev_pose.pose.orientation.yq1_inv[2]=prev_pose.pose.orientation.zq1_inv[3]=-prev_pose.pose.orientation.w# Negate for


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Negate for inverseq2[0]=current_pose.pose.orientation.xq2[1]=current_pose.pose.orientation.yq2[2]=current_pose.pose.orientation.zq2[3]=current_pose.pose.orientation.wqr=quaternion_multiply(q2,q1_inv)


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Title: Marketing

URL: https://docs.ros.org/en/jazzy/The

ROS2

Project/Marketing.html

Section: Installation

--------------------------------------------------------------------------------

MarketingGeneral Use ROS ArtworkThe ROS 2 media kit, which includes branding language, high resolution ROS logo graphics, and release images, can be found in theROS art repository.Please refer to this repository for ROS art work and our branding guidelines.Stickers, Posters, and Canvas PrintsOpen Robotics hosts an online storefront onZazzle.comwith artwork available in various formats.PostersPrinted on paper with selectable sizes.Canvas PrintsPrinted on wrapped canvas with selectable sizes.Sticker SheetsPrinted on a sheet, 20 per sheet for the small, 6 per sheet in the large size.Brochure: Why ROS 2?Use this brochure to promote the goals and features of ROS 2 and encourage adoption.License:CC BY-ND 4.0Available formats:A4(forweb/email)A4(forprint)USLetter(forweb/email)USLetter(forprint)


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Title: RHEL (binary)

URL: https://docs.ros.org/en/jazzy/Installation/Alternatives/RHEL

Install

Binary.html

Section: Installation

--------------------------------------------------------------------------------


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RHEL (binary)Table of ContentsSystem requirementsSystem setupSet localeEnable required repositoriesInstall prerequisitesInstall development tools (optional)Install ROS 2Install dependencies using rosdepInstall additional RMW implementations (optional)Setup environmentTry some examplesNext stepsTroubleshootUninstallThis page explains how to install ROS 2 on RHEL from a pre-built binary package.NoteThe pre-built binary does not include all ROS 2 packages. All packages in theROS base variantare included, and only a subset of packages in theROS desktop variantare included. The exact list of packages are described by the repositories listed inthis ros2.repos file.There are alsoRPM packagesavailable.System requirementsWe currently support RHEL 9 64-bit.System setupSet localeMake sure you have a locale which supportsUTF-8. If you are in a minimal environment (such as a docker container), the locale may be something minimal likeC. We test with the following settings. However, it should be fine if you’re using a


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settings. However, it should be fine if you’re using a different UTF-8 supported locale.locale# check for UTF-8sudodnfinstalllangpacks-englibc-langpack-enexportLANG=en_US.UTF-8


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locale# verify settingsEnable required repositoriesThe rosdep database contains packages from the EPEL and PowerTools repositories, which are not enabled by default. They can be enabled by running:sudodnfinstall'dnf-command(config-manager)'epel-release-y sudodnfconfig-manager--set-enabledcrbNoteThis step may be slightly different depending on the distribution you are using. Check the EPEL documentation:https://docs.fedoraproject.org/en-US/epel/#_quickstartInstall prerequisitesThere are a few packages that must be installed in order to get and unpack the binary release.sudodnfinstalltarbzip2wget-yInstall development tools (optional)If you are going to build ROS packages or otherwise do development, you can also install the development tools:sudodnfinstall-y\cmake\gcc-c++\git\make\patch\python3-colcon-common-extensions\python3-mypy\python3-pip\python3-pydocstyle\python3-pytest\python3-pytest-repeat\python3-pytest-rerunfailures\python3-rosdep\python3-setuptools\python3-vcstool\wget# install some pip packages


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install some pip packages needed for testing and# not available as RPMspython3-mpipinstall-U--user\flake8-blind-except==0.1.1\flake8-class-newline\flake8-deprecatedInstall ROS 2Go to thereleases pageDownload the latest package for RHEL; let’s assume that it ends up at~/Downloads/ros2-package-linux-x86_64.tar.bz2.Note: there may be more than one binary download option which might cause the file name to differ.Unpack it:mkdir-p~/ros2_jazzycd~/ros2_jazzy tarxf~/Downloads/ros2-package-linux-x86_64.tar.bz2Install dependencies using rosdepROS 2 packages are built on frequently updated RHEL systems. It is always recommended that you ensure your system is up to date before installing new packages.sudodnfupdatesudorosdepinit rosdepupdate rosdepinstall--from-paths~/ros2_jazzy/ros2-linux/share--ignore-src-y--skip-keys"cyclonedds fastcdr fastrtps iceoryx_binding_c rti-connext-dds-6.0.1 urdfdom_headers"Install additional RMW implementations (optional)The default middleware that ROS 2 uses isFastDDS, but the middleware


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middleware that ROS 2 uses isFastDDS, but the middleware (RMW) can be replaced at runtime. See theguideon how to work with multiple RMWs.Setup environmentSet up your environment by sourcing the following file.# Replace ".bash" with your shell if you're not using bash# Possible values are: setup.bash, setup.sh, setup.zsh.~/ros2_jazzy/ros2-linux/setup.bashTry some examplesIn one terminal, source the setup file and then run a C++talker:.~/ros2_jazzy/ros2-linux/setup.bash ros2rundemo_nodes_cpptalkerIn another terminal source the setup file and then run a Pythonlistener:.~/ros2_jazzy/ros2-linux/setup.bash ros2rundemo_nodes_pylistenerYou should see thetalkersaying that it’sPublishingmessages and thelistenersayingIheardthose messages. This verifies both the C++ and Python APIs are working properly. Hooray!Next stepsContinue with thetutorials and demosto configure your environment, create your own workspace and packages, and learn ROS 2 core concepts.TroubleshootTroubleshooting techniques can be


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2 core concepts.TroubleshootTroubleshooting techniques can be foundhere.UninstallIf you installed your workspace with colcon as instructed above, “uninstalling” could be just a matter of opening a new terminal and not sourcing the workspace’ssetupfile. This way, your environment will behave as though there is no Jazzy install on your system.If you’re also trying to free up space, you can delete the entire workspace directory with:rm-rf~/ros2_jazzy


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Title: Writing Basic Tests with Python URL: https://docs.ros.org/en/jazzy/Tutorials/Intermediate/Testing/Python.html Section: Installation --------------------------------------------------------------------------------


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Writing Basic Tests with PythonStarting point: we’ll assume you have abasic ament_python packageset up already and you want to add some tests to it.If you are using ament_cmake_python, refer to the theament_cmake_python docsfor how to make tests dicoverable. The test contents and invocation withcolconremain the same.Package Setupsetup.pyYoursetup.pymust have a test dependency onpytestwithin the call tosetup(...):tests_require=['pytest'],Test Files and FoldersYour test code needs to go in a folder namedtestsin the root of your package.Any file that contains tests that you want to run must have the patterntest_FOO.pywhereFOOcan be replaced with anything.Example package layout:awesome_ros_package/awesome_ros_package/__init__.pyfozzie.pypackage.xmlsetup.cfgsetup.pytests/test_init.pytest_copyright.pytest_fozzie.pyTest ContentsYou can now write tests to your heart’s content. There areplenty of resources on pytest, but in short, you can write functions with thetest_prefix and include whatever assert


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write functions with thetest_prefix and include whatever assert statements you’d like.deftest_math():assert2+2==5# This should fail for most mathematical systemsRunning TestsSee thetutorial on how to run tests from the command linefor more information on running the tests and inspecting the test results.Special CommandsBeyond thestandard colcon testing commandsyou can also specify arguments to thepytestframework from the command line with the--pytest-argsflag. For example, you can specify the name of the function to run withcolcon test --packages-select <name-of-pkg> --pytest-args -k name_of_the_test_functionTo see the pytest output while running the tests, use these flags:colcon test --event-handlers console_cohesion+


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Title: RTI Connext DDS

URL: https://docs.ros.org/en/jazzy/Installation/DDS

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RTI Connext DDSA libraries-only version of RTI Connext DDS 6.0.1 may be installed per theinstallation instructionsfor Debian/Ubuntu Linux (amd64) platforms only, under anon-commercial license.A full-suite installation of RTI Connext DDS is available for many additional platforms, for universities, evaluation, or purchase. This installation includes diagnostic tools, layered services, and security.  See below for installation details.RTI University ProgramUniversity researchers and classroom users may be eligible for a free academic license through theRTI University Program. This includes a one-year (renewable) license to the unabridged version of Connext DDS Secure, which includes diagnostic tools and layered services. The university license application can be foundhere.RTI Connext DDS EvaluationTo install RTI Connext DDSversion 6.0.1Evalution:Visit theRTI Free Trial (6.0.1) site.Download the version(s) to match your environment.Contactlicense@rti.comfor an evaluation license.Install RTI Connext 6.0.1 by


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an evaluation license.Install RTI Connext 6.0.1 by running the installation program.  When finished, it will run the RTI Launcher.Use the RTI Launcher to install the license file (rti_license.dat) if needed.  The launcher may also be used to launch the diagnostic tools and services.


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Title: Tutorials

URL: https://docs.ros.org/en/jazzy/Tutorials.html

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Title: Recording a bag from a node (C++) URL: https://docs.ros.org/en/jazzy/Tutorials/Advanced/Recording-A-Bag-From-Your-Own-Node-CPP.html Section: Installation --------------------------------------------------------------------------------


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Recording a bag from a node (C++)Goal:Record data from your own C++ node to a bag.Tutorial level:AdvancedTime:20 minutesContentsBackgroundPrerequisitesTasks1 Create a package2 Write the C++ node3 Build and run4 Record synthetic data from a node5 Record synthetic data from an executableSummaryBackgroundrosbag2doesn’t just provide theros2bagcommand line tool. It also provides a C++ API for reading from and writing to a bag from your own source code. This allows you to subscribe to a topic and save the received data to a bag at the same time as performing any other processing of your choice on that data.PrerequisitesYou should have therosbag2packages installed as part of your regular ROS 2 setup.If you’ve installed from deb packages on Linux, it may be installed by default. If it is not, you can install it using this command.sudo apt install ros-jazzy-rosbag2This tutorial discusses using ROS 2 bags, including from the terminal. You should have already completed thebasic ROS 2 bag tutorial.Tasks1 Create a


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already completed thebasic ROS 2 bag tutorial.Tasks1 Create a packageOpen a new terminal andsource your ROS 2 installationso thatros2commands will work.Navigate into theros2_wsdirectory created in aprevious tutorial. Navigate into theros2_ws/srcdirectory and create a new package:ros2 pkg create --build-type ament_cmake --license Apache-2.0 bag_recorder_nodes --dependencies example_interfaces rclcpp rosbag2_cpp std_msgsYour terminal will return a message verifying the creation of your packagebag_recorder_nodesand all its necessary files and folders. The--dependenciesargument will automatically add the necessary dependency lines topackage.xmlandCMakeLists.txt. In this case, the package will use therosbag2_cpppackage as well as therclcpppackage. A dependency on theexample_interfacespackage is also required for later parts of this tutorial.1.1 Updatepackage.xmlBecause you used the--dependenciesoption during package creation, you don’t have to manually add dependencies topackage.xmlorCMakeLists.txt. As always,


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add dependencies topackage.xmlorCMakeLists.txt. As always, though, make sure to add the description, maintainer email and name, and license information topackage.xml.<description>C++bagwritingtutorial</description><maintaineremail="you@email.com">YourName</maintainer><license>Apache-2.0</license>2 Write the C++ nodeInside theros2_ws/src/bag_recorder_nodes/srcdirectory, create a new file calledsimple_bag_recorder.cppand paste the following code into


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calledsimple_bag_recorder.cppand paste the following code into it.#include<rclcpp/rclcpp.hpp>#include<std_msgs/msg/string.hpp>#include<rosbag2_cpp/writer.hpp>classSimpleBagRecorder:publicrclcpp::Node{public:SimpleBagRecorder():Node("simple_bag_recorder"){writer_=std::make_unique<rosbag2_cpp::Writer>();writer_->open("my_bag");autosubscription_callback_lambda=[this](std::shared_ptr<rclcpp::SerializedMessage>msg){rclcpp::Timetime_stamp=this->now();writer_->write(msg,"chatter","std_msgs/msg/String",time_stamp);};subscription_=create_subscription<std_msgs::msg::String>("chatter",10,subscription_callback_lambda);}private:rclcpp::Subscription<std_msgs::msg::String>::SharedPtrsubscription_;std::unique_ptr<rosbag2_cpp::Writer>writer_;};intmain(intargc,char*argv[]){rclcpp::init(argc,argv);rclcpp::spin(std::make_shared<SimpleBagRecorder>());rclcpp::shutdown();return0;}2.1 Examine the codeThe#includestatements at the top are the package dependencies. Note the inclusion of headers from therosbag2_cpppackage for the


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the inclusion of headers from therosbag2_cpppackage for the functions and structures necessary to work with bag files.In the class constructor we begin by creating the writer object we will use to write to the bag.writer_=std::make_unique<rosbag2_cpp::Writer>();Now that we have a writer object, we can open the bag using it. We specify just the URI of the bag to create, leaving other options at their defaults. The default storage options are used, which means that anmcap-format bag will be created. The default conversion options are used, too, which will perform no conversion, instead storing messages in the serialisation format they are received in.writer_->open("my_bag");With the writer now set up to record data we pass to it, we create a subscription and specify a callback for it. We will write data to the bag in the


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specify a callback for it. We will write data to the bag in the callback.autosubscription_callback_lambda=[this](std::shared_ptr<rclcpp::SerializedMessage>msg){rclcpp::Timetime_stamp=this->now();writer_->write(msg,"chatter","std_msgs/msg/String",time_stamp);};subscription_=create_subscription<std_msgs::msg::String>("chatter",10,subscription_callback_lambda);The callback itself is different from a typical callback. Rather than receiving an instance of the data type of the topic, we instead receive arclcpp::SerializedMessage. We do this for two reasons.The message data will need to be serialized byrosbag2before being written to the bag, so rather than unserializing it when receiving the data and then re-serializing it, we ask ROS to just give us the serialized message as-is.The writer API can accept a serialized message.autosubscription_callback_lambda=[this](std::shared_ptr<rclcpp::SerializedMessage>msg){Within the subscription callback, the first thing to do is determine the time stamp to use for the stored


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thing to do is determine the time stamp to use for the stored message. This can be anything appropriate to your data, but two common values are the time at which the data was produced, if known, and the time it is received. The second option, the time of reception, is used here.rclcpp::Timetime_stamp=this->now();We can then write the message into the bag. Because we have not yet registered any topics with the bag, we must specify the full topic information with the message. This is why we pass in the topic name and the topic type.writer_->write(msg,"chatter","std_msgs/msg/String",time_stamp);The class contains two member variables.The subscription object.A managed pointer to the writer object used to write to the bag. Note the type of writer used here is therosbag2_cpp::Writer, the generic writer interface. Other writers may be available with different behaviours.rclcpp::Subscription<std_msgs::msg::String>::SharedPtrsubscription_;std::unique_ptr<rosbag2_cpp::Writer>writer_;The file finishes with


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file finishes with themainfunction used to create an instance of the node and start ROS processing it.intmain(intargc,char*argv[]){rclcpp::init(argc,argv);rclcpp::spin(std::make_shared<SimpleBagRecorder>());rclcpp::shutdown();return0;}2.2 Add executableNow open theCMakeLists.txtfile.Near the top of the file, changeCMAKE_CXX_STANDARDfrom14to17.#DefaulttoC++17if(NOT CMAKE_CXX_STANDARD)set(CMAKE_CXX_STANDARD 17)endif()Below the dependencies block, which containsfind_package(rosbag2_cppREQUIRED), add the following lines of code.add_executable(simple_bag_recorder src/simple_bag_recorder.cpp)ament_target_dependencies(simple_bag_recorder rclcpp rosbag2_cpp std_msgs)install(TARGETSsimple_bag_recorderDESTINATION lib/${PROJECT_NAME})3 Build and runNavigate back to the root of your workspace,ros2_ws, and build your new package.LinuxmacOSWindowscolcon build --packages-select bag_recorder_nodescolcon build --packages-select bag_recorder_nodescolcon build --merge-install --packages-select bag_recorder_nodesOpen a new


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--merge-install --packages-select bag_recorder_nodesOpen a new terminal, navigate toros2_ws, and source the setup files.LinuxmacOSWindowssource install/setup.bashsource install/setup.bashcall install/setup.batNow run the node:ros2 run bag_recorder_nodes simple_bag_recorderOpen a second terminal and run thetalkerexample node.ros2 run demo_nodes_cpp talkerThis will start publishing data on thechattertopic. As the bag-writing node receives this data, it will write it to themy_bagbag.Terminate both nodes. Then, in one terminal start thelistenerexample node.ros2 run demo_nodes_cpp listenerIn the other terminal, useros2bagto play the bag recorded by your node.ros2 bag play my_bagYou will see the messages from the bag being received by thelistenernode.If you wish to run the bag-writing node again, you will first need to delete themy_bagdirectory.4 Record synthetic data from a nodeAny data can be recorded into a bag, not just data received over a topic. A common use case for writing to a bag from your own node is


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A common use case for writing to a bag from your own node is to generate and store synthetic data. In this section you will learn how to write a node that generates some data and stores it in a bag. We will demonstrate two approaches for doing this. The first uses a node with a timer; this is the approach that you would use if your data generation is external to the node, such as reading data directly from hardware (e.g. a camera). The second approach does not use a node; this is the approach you can use when you do not need to use any functionality from the ROS infrastructure.4.1 Write a C++ nodeInside theros2_ws/src/bag_recorder_nodes/srcdirectory, create a new file calleddata_generator_node.cppand paste the following code into


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calleddata_generator_node.cppand paste the following code into it.#include<chrono>#include<example_interfaces/msg/int32.hpp>#include<rclcpp/rclcpp.hpp>#include<rosbag2_cpp/writer.hpp>usingnamespacestd::chrono_literals;classDataGenerator:publicrclcpp::Node{public:DataGenerator():Node("data_generator"){data_.data=0;writer_=std::make_unique<rosbag2_cpp::Writer>();writer_->open("timed_synthetic_bag");writer_->create_topic({0u,"synthetic","example_interfaces/msg/Int32",rmw_get_serialization_format(),{},"",});autotimer_callback_lambda=[this](){returnthis->timer_callback();};timer_=create_wall_timer(1s,timer_callback_lambda);}private:voidtimer_callback(){writer_->write(data_,"synthetic",now());++data_.data;}rclcpp::TimerBase::SharedPtrtimer_;std::unique_ptr<rosbag2_cpp::Writer>writer_;example_interfaces::msg::Int32data_;};intmain(intargc,char*argv[]){rclcpp::init(argc,argv);rclcpp::spin(std::make_shared<DataGenerator>());rclcpp::shutdown();return0;}4.2 Examine the codeMuch of this code is the same as the first


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Examine the codeMuch of this code is the same as the first example. The important differences are described here.First, the name of the bag is changed.writer_->open("timed_synthetic_bag");In this example we are registering the topic with the bag in advance. This is optional in most cases, but it must be done when passing in a serialized message without topic information.writer_->create_topic({0u,"synthetic","example_interfaces/msg/Int32",rmw_get_serialization_format(),{},"",});Rather than a subscription to a topic, this node has a timer. The timer fires with a one-second period, and calls the given member function when it does.autotimer_callback_lambda=[this](){returnthis->timer_callback();};timer_=create_wall_timer(1s,timer_callback_lambda);Within the timer callback, we generate (or otherwise obtain, e.g. read from a serial port connected to some hardware) the data we wish to store in the bag. The important difference between this and the previous sample is that the data is not yet serialized. Instead we


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sample is that the data is not yet serialized. Instead we are passing a ROS message data type to the writer object, in this case an instance ofexample_interfaces/msg/Int32. The writer will serialize the data for us before writing it into the bag.writer_->write(data_,"synthetic",now());4.3 Add executableOpen theCMakeLists.txtfile and add the following lines after the previously-added lines (specifically, after theinstall(TARGETS...)macro call).add_executable(data_generator_node src/data_generator_node.cpp)ament_target_dependencies(data_generator_node rclcpp rosbag2_cpp example_interfaces)install(TARGETSdata_generator_nodeDESTINATION lib/${PROJECT_NAME})4.4 Build and runNavigate back to the root of your workspace,ros2_ws, and build your package.LinuxmacOSWindowscolcon build --packages-select bag_recorder_nodescolcon build --packages-select bag_recorder_nodescolcon build --merge-install --packages-select bag_recorder_nodesOpen a new terminal, navigate toros2_ws, and source the setup


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a new terminal, navigate toros2_ws, and source the setup files.LinuxmacOSWindowssource install/setup.bashsource install/setup.bashcall install/setup.bat(If thetimed_synthetic_bagdirectory already exists, you must first delete it before running the node.)Now run the node:ros2 run bag_recorder_nodes data_generator_nodeWait for 30 seconds or so, then terminate the node withctrl-c. Next, play back the created bag.ros2 bag play timed_synthetic_bagOpen a second terminal and echo the/synthetictopic.ros2 topic echo /syntheticYou will see the data that was generated and stored in the bag printed to the console at a rate of one message per second.5 Record synthetic data from an executableNow that you can create a bag that stores data from a source other than a topic, you will learn how to generate and record synthetic data from a non-node executable. The advantage of this approach is simpler code and rapid creation of a large quantity of data.5.1 Write a C++ executableInside


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of a large quantity of data.5.1 Write a C++ executableInside theros2_ws/src/bag_recorder_nodes/srcdirectory, create a new file calleddata_generator_executable.cppand paste the following code into it.#include<chrono>#include<rclcpp/rclcpp.hpp>// For rclcpp::Clock, rclcpp::Duration and rclcpp::Time#include<example_interfaces/msg/int32.hpp>#include<rosbag2_cpp/writer.hpp>#include<rosbag2_cpp/writers/sequential_writer.hpp>#include<rosbag2_storage/serialized_bag_message.hpp>usingnamespacestd::chrono_literals;intmain(int,char**){example_interfaces::msg::Int32data;data.data=0;std::unique_ptr<rosbag2_cpp::Writer>writer_=std::make_unique<rosbag2_cpp::Writer>();writer_->open("big_synthetic_bag");writer_->create_topic({0u,"synthetic","example_interfaces/msg/Int32",rmw_get_serialization_format(),{},"",});rclcpp::Clockclock;rclcpp::Timetime_stamp=clock.now();for(int32_tii=0;ii<100;++ii){writer_->write(data,"synthetic",time_stamp);++data.data;time_stamp+=rclcpp::Duration(1s);}return0;}5.2 Examine the codeA comparison of


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Examine the codeA comparison of this sample and the previous sample will reveal that they are not that different. The only significant difference is the use of a for loop to drive the data generation rather than a timer.Notice that we are also now generating time stamps for the data rather than relying on the current system time for each sample. The time stamp can be any value you need it to be. The data will be played back at the rate given by these time stamps, so this is a useful way to control the default playback speed of the samples. Notice also that while the gap between each sample is a full second in time, this executable does not need to wait a second between each sample. This allows us to generate a lot of data covering a wide span of time in much less time than playback will take.rclcpp::Clockclock;rclcpp::Timetime_stamp=clock.now();for(int32_tii=0;ii<100;++ii){writer_->write(data,"synthetic",time_stamp);++data.data;time_stamp+=rclcpp::Duration(1s);}5.3 Add executableOpen theCMakeLists.txtfile


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Add executableOpen theCMakeLists.txtfile and add the following lines after the previously-added lines.add_executable(data_generator_executable src/data_generator_executable.cpp)ament_target_dependencies(data_generator_executable rclcpp rosbag2_cpp example_interfaces)install(TARGETSdata_generator_executableDESTINATION lib/${PROJECT_NAME})5.4 Build and runNavigate back to the root of your workspace,ros2_ws, and build your package.LinuxmacOSWindowscolcon build --packages-select bag_recorder_nodescolcon build --packages-select bag_recorder_nodescolcon build --merge-install --packages-select bag_recorder_nodesOpen a terminal, navigate toros2_ws, and source the setup files.LinuxmacOSWindowssource install/setup.bashsource install/setup.bashcall install/setup.bat(If thebig_synthetic_bagdirectory already exists, you must first delete it before running the executable.)Now run the executable:ros2 run bag_recorder_nodes data_generator_executableNote that the executable runs and finishes very quickly.Now play back the


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the executable runs and finishes very quickly.Now play back the created bag.ros2 bag play big_synthetic_bagOpen a second terminal and echo the/synthetictopic.ros2 topic echo /syntheticYou will see the data that was generated and stored in the bag printed to the console at a rate of one message per second. Even though the bag was generated rapidly it is still played back at the rate the time stamps indicate.SummaryYou created a node that records data it receives on a topic into a bag. You tested recording a bag using the node, and verified the data was recorded by playing back the bag. You then went on to create a node and an executable to generate synthetic data and store it in a bag.


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Code Examples:

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sudo apt install ros

jazzy

rosbag2

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<description>C++bagwritingtutorial</description><maintaineremail="you@email.com">YourName</maintainer><license>Apache

2.0</license>

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#include<rclcpp/rclcpp.hpp>#include<std_msgs/msg/string.hpp>#include<rosbag2_cpp/writer.hpp>classSimpleBagRecorder:publicrclcpp::Node{public:SimpleBagRecorder():Node("simple_bag_recorder"){writer_=std::make_unique<rosbag2_cpp::Writer>();writer_

>open("my_bag");autosubscription_callback_lambda=[this](std::shared_ptr<rclcpp::SerializedMessage>msg){rclcpp::Timetime_stamp=this

>now();writer_


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>now();writer_

>write(msg,"chatter","std_msgs/msg/String",time_stamp);};subscription_=create_subscription<std_msgs::msg::String>("chatter",10,subscription_callback_lambda);}private:rclcpp::Subscription<std_msgs::msg::String>::SharedPtrsubscription_;std::unique_ptr<rosbag2_cpp::Writer>writer_;};intmain(intargc,char

argv[]){rclcpp::init(argc,argv);rclcpp::spin(std::make_shared<SimpleBagRecorder>());rclcpp::shutdown();return0;}

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writer_=std::make_unique<rosbag2_cpp::Writer>();

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writer_

>open("my_bag");

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autosubscription_callback_lambda=[this](std::shared_ptr<rclcpp::SerializedMessage>msg){rclcpp::Timetime_stamp=this

>now();writer_

>write(msg,"chatter","std_msgs/msg/String",time_stamp);};subscription_=create_subscription<std_msgs::msg::String>("chatter",10,subscription_callback_lambda);

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autosubscription_callback_lambda=[this](std::shared_ptr<rclcpp::SerializedMessage>msg){

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rclcpp::Timetime_stamp=this

>now();


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rclcpp::Timetime_stamp=this

>now();

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writer_

>write(msg,"chatter","std_msgs/msg/String",time_stamp);

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rclcpp::Subscription<std_msgs::msg::String>::SharedPtrsubscription_;std::unique_ptr<rosbag2_cpp::Writer>writer_;

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intmain(intargc,char

argv[]){rclcpp::init(argc,argv);rclcpp::spin(std::make_shared<SimpleBagRecorder>());rclcpp::shutdown();return0;}

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#DefaulttoC++17if(NOT CMAKE_CXX_STANDARD)set(CMAKE_CXX_STANDARD 17)endif()

Language: unknown add_executable(simple_bag_recorder src/simple_bag_recorder.cpp)ament_target_dependencies(simple_bag_recorder rclcpp rosbag2_cpp std_msgs)install(TARGETSsimple_bag_recorderDESTINATION lib/${PROJECT_NAME})

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colcon build -

packages

select bag_recorder_nodes

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colcon build -

packages

select bag_recorder_nodes

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colcon build -

merge

install -

packages

select bag_recorder_nodes

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packages

select bag_recorder_nodes

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source install/setup.bash

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source install/setup.bash

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call install/setup.bat

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ros2 run bag_recorder_nodes simple_bag_recorder

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ros2 run demo_nodes_cpp talker

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ros2 run demo_nodes_cpp listener

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ros2 bag play my_bag

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#include<chrono>#include<example_interfaces/msg/int32.hpp>#include<rclcpp/rclcpp.hpp>#include<rosbag2_cpp/writer.hpp>usingnamespacestd::chrono_literals;classDataGenerator:publicrclcpp::Node{public:DataGenerator():Node("data_generator"){data_.data=0;writer_=std::make_unique<rosbag2_cpp::Writer>();writer_

>open("timed_synthetic_bag");writer_

>create_topic({0u,"synthetic","example_interfaces/msg/Int32",rmw_get_serialization_format(),{},"",});autotimer_callback_lambda=[this](){returnthis

>timer_callback();};timer_=create_wall_timer(1s,timer_callback_lambda);}private:voidtimer_callback(){writer_


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>write(data_,"synthetic",now());++data_.data;}rclcpp::TimerBase::SharedPtrtimer_;std::unique_ptr<rosbag2_cpp::Writer>writer_;example_interfaces::msg::Int32data_;};intmain(intargc,char

argv[]){rclcpp::init(argc,argv);rclcpp::spin(std::make_shared<DataGenerator>());rclcpp::shutdown();return0;}

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writer_

>open("timed_synthetic_bag");

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writer_

>create_topic({0u,"synthetic","example_interfaces/msg/Int32",rmw_get_serialization_format(),{},"",});

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autotimer_callback_lambda=[this](){returnthis

>timer_callback();};timer_=create_wall_timer(1s,timer_callback_lambda);

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writer_

>write(data_,"synthetic",now());

Language: unknown add_executable(data_generator_node src/data_generator_node.cpp)ament_target_dependencies(data_generator_node rclcpp rosbag2_cpp example_interfaces)install(TARGETSdata_generator_nodeDESTINATION lib/${PROJECT_NAME})

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colcon build -

packages

select bag_recorder_nodes

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packages

select bag_recorder_nodes

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colcon build -

packages

select bag_recorder_nodes

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colcon build -

merge

install -

packages

select bag_recorder_nodes

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source install/setup.bash

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source install/setup.bash

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call install/setup.bat

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ros2 run bag_recorder_nodes data_generator_node

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ros2 bag play timed_synthetic_bag

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ros2 topic echo /synthetic


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ros2 topic echo /synthetic

Language: unknown #include<chrono>#include<rclcpp/rclcpp.hpp>// For rclcpp::Clock, rclcpp::Duration and rclcpp::Time#include<example_interfaces/msg/int32.hpp>#include<rosbag2_cpp/writer.hpp>#include<rosbag2_cpp/writers/sequential_writer.hpp>#include<rosbag2_storage/serialized_bag_message.hpp>usingnamespacestd::chrono_literals;intmain(int,char**){example_interfaces::msg::Int32data;data.data=0;std::unique_ptr<rosbag2_cpp::Writer>writer_=std::make_unique<rosbag2_cpp::Writer>();writer_->open("big_synthetic_bag");writer_->create_topic({0u,"synthetic","example_interfaces/msg/Int32",rmw_get_serialization_format(),{},"",});rclcpp::Clockclock;rclcpp::Timetime_stamp=clock.now();for(int32_tii=0;ii<100;++ii){writer_->write(data,"synthetic",time_stamp);++data.data;time_stamp+=rclcpp::Duration(1s);}return0;}

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rclcpp::Clockclock;rclcpp::Timetime_stamp=clock.now();for(int32_tii=0;ii<100;++ii){writer_


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>write(data,"synthetic",time_stamp);++data.data;time_stamp+=rclcpp::Duration(1s);}

Language: unknown add_executable(data_generator_executable src/data_generator_executable.cpp)ament_target_dependencies(data_generator_executable rclcpp rosbag2_cpp example_interfaces)install(TARGETSdata_generator_executableDESTINATION lib/${PROJECT_NAME})

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colcon build -

packages

select bag_recorder_nodes

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colcon build -

packages

select bag_recorder_nodes

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colcon build -

merge

install -

packages

select bag_recorder_nodes

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source install/setup.bash

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source install/setup.bash

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call install/setup.bat

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ros2 run bag_recorder_nodes data_generator_executable

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ros2 bag play big_synthetic_bag

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ros2 topic echo /synthetic


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Title: Creating a launch file URL: https://docs.ros.org/en/jazzy/Tutorials/Intermediate/Launch/Creating-Launch-Files.html Section: Installation --------------------------------------------------------------------------------


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Creating a launch fileGoal:Create a launch file to run a complex ROS 2 system.Tutorial level:IntermediateTime:10 minutesContentsPrerequisitesBackgroundTasks1 Setup2 Write the launch file3 ros2 launch4 Introspect the system with rqt_graphSummaryPrerequisitesThis tutorial uses therqt_graph and turtlesimpackages.You will also need to use a text editor of your preference.As always, don’t forget to source ROS 2 inevery new terminal you open.BackgroundThe launch system in ROS 2 is responsible for helping the user describe the configuration of their system and then execute it as described. The configuration of the system includes what programs to run, where to run them, what arguments to pass them, and ROS-specific conventions which make it easy to reuse components throughout the system by giving them each a different configuration. It is also responsible for monitoring the state of the processes launched, and reporting and/or reacting to changes in the state of those processes.Launch files written in Python,


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in the state of those processes.Launch files written in Python, XML, or YAML can start and stop different nodes as well as trigger and act on various events. SeeUsing Python, XML, and YAML for ROS 2 Launch Filesfor a description of the different formats. The package providing this framework islaunch_ros, which uses the non-ROS-specificlaunchframework underneath.Thedesign documentdetails the goal of the design of ROS 2’s launch system (not all functionality is currently available).Tasks1 SetupCreate a new directory to store your launch files:mkdir launch2 Write the launch fileLet’s put together a ROS 2 launch file using theturtlesimpackage and its executables. As mentioned above, this can either be in Python, XML, or YAML.PythonXMLYAMLCopy and paste the complete code into


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XML, or YAML.PythonXMLYAMLCopy and paste the complete code into thelaunch/turtlesim_mimic_launch.pyfile:fromlaunchimportLaunchDescriptionfromlaunch_ros.actionsimportNodedefgenerate_launch_description():returnLaunchDescription([Node(package='turtlesim',namespace='turtlesim1',executable='turtlesim_node',name='sim'),Node(package='turtlesim',namespace='turtlesim2',executable='turtlesim_node',name='sim'),Node(package='turtlesim',executable='mimic',name='mimic',remappings=[('/input/pose','/turtlesim1/turtle1/pose'),('/output/cmd_vel','/turtlesim2/turtle1/cmd_vel'),])])Copy and paste the complete code into thelaunch/turtlesim_mimic_launch.xmlfile:<launch><nodepkg="turtlesim"exec="turtlesim_node"name="sim"namespace="turtlesim1"/><nodepkg="turtlesim"exec="turtlesim_node"name="sim"namespace="turtlesim2"/><nodepkg="turtlesim"exec="mimic"name="mimic"><remapfrom="/input/pose"to="/turtlesim1/turtle1/pose"/><remapfrom="/output/cmd_vel"to="/turtlesim2/turtle1/cmd_vel"/></node></launch>Copy and paste the complete code into


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and paste the complete code into thelaunch/turtlesim_mimic_launch.yamlfile:launch:-node:pkg:"turtlesim"exec:"turtlesim_node"name:"sim"namespace:"turtlesim1"-node:pkg:"turtlesim"exec:"turtlesim_node"name:"sim"namespace:"turtlesim2"-node:pkg:"turtlesim"exec:"mimic"name:"mimic"remap:-from:"/input/pose"to:"/turtlesim1/turtle1/pose"-from:"/output/cmd_vel"to:"/turtlesim2/turtle1/cmd_vel"2.1 Examine the launch fileAll of the launch files above are launching a system of three nodes, all from theturtlesimpackage. The goal of the system is to launch two turtlesim windows, and have one turtle mimic the movements of the other.When launching the two turtlesim nodes, the only difference between them is their namespace values. Unique namespaces allow the system to start two nodes without node name or topic name conflicts. Both turtles in this system receive commands over the same topic and publish their pose over the same topic. With unique namespaces, messages meant for different turtles can be distinguished.The final


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meant for different turtles can be distinguished.The final node is also from theturtlesimpackage, but a different executable:mimic. This node has added configuration details in the form of remappings.mimic’s/input/posetopic is remapped to/turtlesim1/turtle1/poseand it’s/output/cmd_veltopic to/turtlesim2/turtle1/cmd_vel. This meansmimicwill subscribe to/turtlesim1/sim’s pose topic and republish it for/turtlesim2/sim’s velocity command topic to subscribe to. In other words,turtlesim2will mimicturtlesim1’s movements.PythonXMLYAMLThese import statements pull in some Pythonlaunchmodules.fromlaunchimportLaunchDescriptionfromlaunch_ros.actionsimportNodeNext, the launch description itself begins:defgenerate_launch_description():returnLaunchDescription([])The first two actions in the launch description launch the two turtlesim windows:Node(package='turtlesim',namespace='turtlesim1',executable='turtlesim_node',name='sim'),Node(package='turtlesim',namespace='turtlesim2',executable='turtlesim_node',name='sim'),The final


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final action launches the mimic node with the remaps:Node(package='turtlesim',executable='mimic',name='mimic',remappings=[('/input/pose','/turtlesim1/turtle1/pose'),('/output/cmd_vel','/turtlesim2/turtle1/cmd_vel'),])The first two actions launch the two turtlesim windows:<nodepkg="turtlesim"exec="turtlesim_node"name="sim"namespace="turtlesim1"/><nodepkg="turtlesim"exec="turtlesim_node"name="sim"namespace="turtlesim2"/>The final action launches the mimic node with the remaps:<nodepkg="turtlesim"exec="mimic"name="mimic"><remapfrom="/input/pose"to="/turtlesim1/turtle1/pose"/><remapfrom="/output/cmd_vel"to="/turtlesim2/turtle1/cmd_vel"/></node>The first two actions launch the two turtlesim windows:-node:pkg:"turtlesim"exec:"turtlesim_node"name:"sim"namespace:"turtlesim1"-node:pkg:"turtlesim"exec:"turtlesim_node"name:"sim"namespace:"turtlesim2"The final action launches the mimic node with the


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final action launches the mimic node with the remaps:-node:pkg:"turtlesim"exec:"mimic"name:"mimic"remap:-from:"/input/pose"to:"/turtlesim1/turtle1/pose"-from:"/output/cmd_vel"to:"/turtlesim2/turtle1/cmd_vel"3 ros2 launchTo run the launch file created above, enter into the directory you created earlier and run the following command:PythonXMLYAMLcd launchros2 launch turtlesim_mimic_launch.pycd launchros2 launch turtlesim_mimic_launch.xmlcd launchros2 launch turtlesim_mimic_launch.yamlNoteIt is possible to launch a launch file directly (as we do above), or provided by a package. When it is provided by a package, the syntax is:ros2 launch <package_name> <launch_file_name>You learned about creating packages inCreating a package.NoteFor packages with launch files, it is a good idea to add anexec_dependdependency on theros2launchpackage in your package’spackage.xml:<exec_depend>ros2launch</exec_depend>This helps make sure that theros2launchcommand is available after building your package. It also ensures that


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is available after building your package. It also ensures that alllaunch file formatsare recognized.Two turtlesim windows will open, and you will see the following[INFO]messages telling you which nodes your launch file has started:[INFO] [launch]: Default logging verbosity is set to INFO[INFO] [turtlesim_node-1]: process started with pid [11714][INFO] [turtlesim_node-2]: process started with pid [11715][INFO] [mimic-3]: process started with pid [11716]To see the system in action, open a new terminal and run theros2topicpubcommand on the/turtlesim1/turtle1/cmd_veltopic to get the first turtle moving:ros2 topic pub -r 1 /turtlesim1/turtle1/cmd_vel geometry_msgs/msg/Twist "{linear: {x: 2.0, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: -1.8}}"You will see both turtles following the same path.4 Introspect the system with rqt_graphWhile the system is still running, open a new terminal and runrqt_graphto get a better idea of the relationship between the nodes in your launch file.Run the command:rqt_graphA hidden


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the nodes in your launch file.Run the command:rqt_graphA hidden node (theros2topicpubcommand you ran) is publishing data to the/turtlesim1/turtle1/cmd_veltopic on the left, which the/turtlesim1/simnode is subscribed to. The rest of the graph shows what was described earlier:mimicis subscribed to/turtlesim1/sim’s pose topic, and publishes to/turtlesim2/sim’s velocity command topic.SummaryLaunch files simplify running complex systems with many nodes and specific configuration details. You can create launch files using Python, XML, or YAML, and run them using theros2launchcommand.


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Code Examples:

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mkdir launch

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fromlaunchimportLaunchDescriptionfromlaunch_ros.actionsimportNodedefgenerate_launch_description():returnLaunchDescription([Node(package='turtlesim',namespace='turtlesim1',executable='turtlesim_node',name='sim'),Node(package='turtlesim',namespace='turtlesim2',executable='turtlesim_node',name='sim'),Node(package='turtlesim',executable='mimic',name='mimic',remappings=[('/input/pose','/turtlesim1/turtle1/pose'),('/output/cmd_vel','/turtlesim2/turtle1/cmd_vel'),])])

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<launch><nodepkg="turtlesim"exec="turtlesim_node"name="sim"namespace="turtlesim1"/><nodepkg="turtlesim"exec="turtlesim_node"name="sim"namespace="turtlesim2"/><nodepkg="turtlesim"exec="mimic"name="mimic"><remapfrom="/input/pose"to="/turtlesim1/turtle1/pose"/><remapfrom="/output/cmd_vel"to="/turtlesim2/turtle1/cmd_vel"/></node></launch>

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launch:

node:pkg:"turtlesim"exec:"turtlesim_node"name:"sim"namespace:"turtlesim1"


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node:pkg:"turtlesim"exec:"turtlesim_node"name:"sim"namespace:"turtlesim2"

node:pkg:"turtlesim"exec:"mimic"name:"mimic"remap:

from:"/input/pose"to:"/turtlesim1/turtle1/pose"

from:"/output/cmd_vel"to:"/turtlesim2/turtle1/cmd_vel"

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fromlaunchimportLaunchDescriptionfromlaunch_ros.actionsimportNode

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defgenerate_launch_description():returnLaunchDescription([])

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Node(package='turtlesim',namespace='turtlesim1',executable='turtlesim_node',name='sim'),Node(package='turtlesim',namespace='turtlesim2',executable='turtlesim_node',name='sim'),

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Node(package='turtlesim',executable='mimic',name='mimic',remappings=[('/input/pose','/turtlesim1/turtle1/pose'),('/output/cmd_vel','/turtlesim2/turtle1/cmd_vel'),])

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<nodepkg="turtlesim"exec="turtlesim_node"name="sim"namespace="turtlesim1"/><nodepkg="turtlesim"exec="turtlesim_node"name="sim"namespace="turtlesim2"/>

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<nodepkg="turtlesim"exec="mimic"name="mimic"><remapfrom="/input/pose"to="/turtlesim1/turtle1/pose"/><remapfrom="/output/cmd_vel"to="/turtlesim2/turtle1/cmd_vel"/></node>

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node:pkg:"turtlesim"exec:"turtlesim_node"name:"sim"namespace:"turtlesim1"

node:pkg:"turtlesim"exec:"turtlesim_node"name:"sim"namespace:"turtlesim2"

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node:pkg:"turtlesim"exec:"mimic"name:"mimic"remap:

from:"/input/pose"to:"/turtlesim1/turtle1/pose"

from:"/output/cmd_vel"to:"/turtlesim2/turtle1/cmd_vel"

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cd launchros2 launch turtlesim_mimic_launch.py

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cd launchros2 launch turtlesim_mimic_launch.xml

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cd launchros2 launch turtlesim_mimic_launch.yaml

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ros2 launch <package_name> <launch_file_name>

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<exec_depend>ros2launch</exec_depend>


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<exec_depend>ros2launch</exec_depend>

Language: unknown [INFO] [launch]: Default logging verbosity is set to INFO[INFO] [turtlesim_node-1]: process started with pid [11714][INFO] [turtlesim_node-2]: process started with pid [11715][INFO] [mimic-3]: process started with pid [11716]

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rqt_graph


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Title: Roadmap

URL: https://docs.ros.org/en/jazzy/The-ROS2-Project/Roadmap.html

Section: Installation

--------------------------------------------------------------------------------

RoadmapTable of ContentsKilted RoadmapPlanned releasesContributing to ROS 2This page describes planned work for ROS 2.

The set of planned features and development efforts should provide insight into the overall direction of ROS 2.

If you would like to see other features on the roadmap, please get in touch with us atinfo@openrobotics.org.Kilted RoadmapKilted Kaiju is the ROS 2 release expected in May 2025.

See therelease pagefor a detailed timeline.The items in the roadmap below are the major features being worked on by the ROS 2 community.


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The “Size” is an estimated size of the task, whereSmallmeans person-days to complete,Mediummeans person-weeks to complete, andLargemeans person-months to complete.If you are working on a feature for ROS 2 and would like to have it listed, please open a pull request toROS 2 Documentation.


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If you’d like to take on one of these tasks, pleaseget in touch with us.TaskSizeOwnerExpected CompletionMakermw_zenoh_cppa Tier-1 RMWLargeIntrinsicMay 2025Planned releasesPlease see theDistributions pagefor the timeline of and information about future distributions.Contributing to ROS 2Looking for something to work on, or just want to help out? Here are a few resources to get you going.TheContributingguide describes how to make a contribution to ROS 2.Check out the list ofFeature Ideasfor inspiration.For more information on the design of ROS 2 please seedesign.ros2.org.The core code for ROS 2 is in theros2 GitHub organization.The Discourse forum/mailing list for discussing ROS 2 design isng-ros.Questions should be asked onRobotics Stack Exchange, make sure to include at least theros2tag and the rosdistro version you are running, e.g.jazzy.


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Title: Running ROS 2 nodes in Docker [community-contributed] URL: https://docs.ros.org/en/jazzy/How-To-Guides/Run-2-nodes-in-single-or-separate-docker-containers.html Section: Installation --------------------------------------------------------------------------------


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Running ROS 2 nodes in Docker [community-contributed]Run two nodes in a single docker containerPull the ROS docker image with tag “jazzy-desktop”.dockerpullosrf/ros:jazzy-desktopRun the image in a container in interactive mode.$dockerrun-itosrf/ros:jazzy-desktop root@<container-id>:/#Your best friend is theros2command line help now.root@<container-id>:/#ros2--helpE.g. list all installed packages.root@<container-id>:/#ros2pkglist(youwillseealistofpackages)E.g. list all executables:root@<container-id>:/#ros2pkgexecutables(youwillseealistof<package><executable>)Run a minimal example of 2 C++ nodes (1 topic subscriberlistener, 1 topic publishertalker) from the packagedemo_nodes_cppin this container:ros2rundemo_nodes_cpplistener&ros2rundemo_nodes_cpptalkerRun two nodes in two separate docker containersOpen a terminal. Run the image in a container in interactive mode and launch a topic publisher (executabletalkerfrom the packagedemo_nodes_cpp)


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publisher (executabletalkerfrom the packagedemo_nodes_cpp) withros2run:dockerrun-it--rmosrf/ros:jazzy-desktopros2rundemo_nodes_cpptalkerOpen a second terminal. Run the image in a container in interactive mode and launch a topic subscriber (executablelistenerfrom the packagedemo_nodes_cpp)  withros2run:dockerrun-it--rmosrf/ros:jazzy-desktopros2rundemo_nodes_cpplistenerAs an alternative to the command line invocation, you can create adocker-compose.ymlfile (here version 2) with the following (minimal) content:version:'2'services:talker:image:osrf/ros:jazzy-desktopcommand:ros2 run demo_nodes_cpp talkerlistener:image:osrf/ros:jazzy-desktopcommand:ros2 run demo_nodes_cpp listenerdepends_on:-talkerTo run the containers calldockercomposeupin the same directory. You can close the containers withCtrl+C.


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Code Examples:

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dockerpullosrf/ros:jazzy

desktop

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$dockerrun

itosrf/ros:jazzy

desktop

root@<container

id>:/#

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root@<container

id>:/#ros2-

help

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root@<container

id>:/#ros2pkglist(youwillseealistofpackages)

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root@<container

id>:/#ros2pkgexecutables(youwillseealistof<package><executable>)

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ros2rundemo_nodes_cpplistener&ros2rundemo_nodes_cpptalker

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dockerrun

it-

rmosrf/ros:jazzy

desktopros2rundemo_nodes_cpptalker

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dockerrun

it-

rmosrf/ros:jazzy

desktopros2rundemo_nodes_cpplistener

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version:'2'services:talker:image:osrf/ros:jazzy

desktopcommand:ros2 run demo_nodes_cpp talkerlistener:image:osrf/ros:jazzy

desktopcommand:ros2 run demo_nodes_cpp listenerdepends_on:

talker


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Title: Configuring environment

URL: https://docs.ros.org/en/jazzy/Tutorials/Beginner

CLI

Tools/Configuring

ROS2

Environment.html

Section: Installation

--------------------------------------------------------------------------------


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Configuring environmentGoal:This tutorial will show you how to prepare your ROS 2 environment.Tutorial level:BeginnerTime:5 minutesContentsBackgroundPrerequisitesTasks1 Source the setup files2 Add sourcing to your shell startup script3 Check environment variablesSummaryNext stepsBackgroundROS 2 relies on the notion of combining workspaces using the shell environment. “Workspace” is a ROS term for the location on your system where you’re developing with ROS 2. The core ROS 2 workspace is called the underlay. Subsequent local workspaces are called overlays. When developing with ROS 2, you will typically have several workspaces active concurrently.Combining workspaces makes developing against different versions of ROS 2, or against different sets of packages, easier. It also allows the installation of several ROS 2 distributions (or “distros”, e.g. Dashing and Eloquent) on the same computer and switching between them.This is accomplished by sourcing setup files every time you open a new shell, or by adding


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setup files every time you open a new shell, or by adding the source command to your shell startup script once. Without sourcing the setup files, you won’t be able to access ROS 2 commands, or find or use ROS 2 packages. In other words, you won’t be able to use ROS 2.PrerequisitesBefore starting these tutorials, install ROS 2 by following the instructions on the ROS 2Installationpage.The commands used in this tutorial assume you followed the binary packages installation guide for your operating system (deb packages for Linux). You can still follow along if you built from source, but the path to your setup files will likely be different. You also won’t be able to use thesudoaptinstallros-<distro>-<package>command (used frequently in the beginner level tutorials) if you install from source.If you are using Linux or macOS, but are not already familiar with the shell,this tutorialwill help.Tasks1 Source the setup filesYou will need to run this command on every new shell you open to have access to the ROS 2


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command on every new shell you open to have access to the ROS 2 commands, like so:LinuxmacOSWindows# Replace ".bash" with your shell if you're not using bash# Possible values are: setup.bash, setup.sh, setup.zshsource/opt/ros/jazzy/setup.bash. ~/ros2_install/ros2-osx/setup.bashcall C:\dev\ros2\local_setup.batNoteThe exact command depends on where you installed ROS 2. If you’re having problems, ensure the file path leads to your installation.2 Add sourcing to your shell startup scriptIf you don’t want to have to source the setup file every time you open a new shell (skipping task 1), then you can add the command to your shell startup script:LinuxmacOSWindowsecho "source /opt/ros/jazzy/setup.bash" >> ~/.bashrcTo undo this, locate your system’s shell startup script and remove the appended source command.echo "source ~/ros2_install/ros2-osx/setup.bash" >> ~/.bash_profileTo undo this, locate your system’s shell startup script and remove the appended source command.Only for PowerShell users, create a folder in


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source command.Only for PowerShell users, create a folder in ‘My Documents’ called ‘WindowsPowerShell’. Within ‘WindowsPowerShell’, create file ‘Microsoft.PowerShell_profile.ps1’. Inside the file, paste:C:\dev\ros2_jazzy\local_setup.ps1PowerShell will request permission to run this script everytime a new shell is opened. To avoid that issue you can run:Unblock-File C:\dev\ros2_jazzy\local_setup.ps1To undo this, remove the new ‘Microsoft.PowerShell_profile.ps1’ file.3 Check environment variablesSourcing ROS 2 setup files will set several environment variables necessary for operating ROS 2. If you ever have problems finding or using your ROS 2 packages, make sure that your environment is properly set up using the following command:LinuxmacOSWindowsprintenv | grep -i ROSprintenv | grep -i ROSset | findstr -i ROSCheck that variables likeROS_DISTROandROS_VERSIONare set.ROS_VERSION=2ROS_PYTHON_VERSION=3ROS_DISTRO=jazzyIf the environment variables are not set correctly, return to the ROS 2 package installation


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are not set correctly, return to the ROS 2 package installation section of the installation guide you followed. If you need more specific help (because environment setup files can come from different places), you canget answersfrom the community.3.1 TheROS_DOMAIN_IDvariableSee thedomain IDarticle for details on ROS domain IDs.Once you have determined a unique integer for your group of ROS 2 nodes, you can set the environment variable with the following command:LinuxmacOSWindowsexport ROS_DOMAIN_ID=<your_domain_id>To maintain this setting between shell sessions, you can add the command to your shell startup script:echo "export ROS_DOMAIN_ID=<your_domain_id>" >> ~/.bashrcexport ROS_DOMAIN_ID=<your_domain_id>To maintain this setting between shell sessions, you can add the command to your shell startup script:echo "export ROS_DOMAIN_ID=<your_domain_id>" >> ~/.bash_profileset ROS_DOMAIN_ID=<your_domain_id>If you want to make this permanent between shell sessions, also run:setx ROS_DOMAIN_ID <your_domain_id>3.2


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shell sessions, also run:setx ROS_DOMAIN_ID <your_domain_id>3.2 TheROS_AUTOMATIC_DISCOVERY_RANGEvariableBy default, ROS 2 communication is not limited to localhost.ROS_AUTOMATIC_DISCOVERY_RANGEenvironment variable allows you to limit ROS 2 discovery range. UsingROS_AUTOMATIC_DISCOVERY_RANGEis helpful in certain settings, such as classrooms, where multiple robots may publish to the same topic causing strange behaviors. SeeImproved Dynamic Discoveryfor more details.SummaryThe ROS 2 development environment needs to be correctly configured before use. This can be done in two ways: either sourcing the setup files in every new shell you open, or adding the source command to your startup script.If you ever face any problems locating or using packages with ROS 2, the first thing you should do is check your environment variables and ensure they are set to the version and distro you intended.Next stepsNow that you have a working ROS 2 installation and you know how to source its setup files, you can start learning


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you know how to source its setup files, you can start learning the ins and outs of ROS 2 with theturtlesim tool.


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Code Examples:

Language: unknown # Replace ".bash" with your shell if you're not using bash# Possible values are: setup.bash, setup.sh, setup.zshsource/opt/ros/jazzy/setup.bash

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. ~/ros2_install/ros2

osx/setup.bash

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call C:\dev\ros2\local_setup.bat

Language: unknown echo "source /opt/ros/jazzy/setup.bash" >> ~/.bashrc

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echo "source ~/ros2_install/ros2

osx/setup.bash" >> ~/.bash_profile

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C:\dev\ros2_jazzy\local_setup.ps1

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Unblock

File C:\dev\ros2_jazzy\local_setup.ps1

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printenv | grep

i ROS

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printenv | grep

i ROS

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set | findstr

i ROS

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ROS_VERSION=2ROS_PYTHON_VERSION=3ROS_DISTRO=jazzy

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export ROS_DOMAIN_ID=<your_domain_id>

Language: unknown echo "export ROS_DOMAIN_ID=<your_domain_id>" >> ~/.bashrc

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export ROS_DOMAIN_ID=<your_domain_id>


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Language: unknown

export ROS_DOMAIN_ID=<your_domain_id>

Language: unknown echo "export ROS_DOMAIN_ID=<your_domain_id>" >> ~/.bash_profile

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set ROS_DOMAIN_ID=<your_domain_id>

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setx ROS_DOMAIN_ID <your_domain_id>


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Title: Topics vs Services vs Actions URL: https://docs.ros.org/en/jazzy/How-To-Guides/Topics-Services-Actions.html Section: Installation --------------------------------------------------------------------------------


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Topics vs Services vs ActionsContentsTopicsServicesActionsWhen designing a system there are three primary styles of interfaces. The specifications for the content is in theInterfaces Overview. This is written to provide the reader with guidelines about when to use each type of interface.TopicsShould be used for continuous data streams (sensor data, robot state, …).Are for continuous data flow. Data might be published and subscribed at any time independent of any senders/receivers. Many to many connection. Callbacks receive data once it is available. The publisher decides when data is sent.ServicesShould be used for remote procedure calls that terminate quickly, e.g. for querying the state of a node or doing a quick calculation such as IK. They should never be used for longer running processes, in particular processes that might be required to preempt if exceptional situations occur and they should never change or depend on state to avoid unwanted side effects for other nodes.Simple blocking call. Mostly


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side effects for other nodes.Simple blocking call. Mostly used for comparably fast tasks as requesting specific data. Semantically for processing requests.ActionsShould be used for any discrete behavior that moves a robot or that runs for a longer time but provides feedback during execution.The most important property of actions is that they can be preempted and preemption should always be implemented cleanly by action servers.Actions can keep state for the lifetime of a goal, i.e. if executing two action goals in parallel on the same server, for each client a separate state instance can be kept since the goal is uniquely identified by its id.Slow perception routines which take several seconds to terminate or initiating a lower-level control mode are good use cases for actions.More complex non-blocking background processing. Used for longer tasks like execution of robot actions. Semantically for real-world actions.


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Title: ROS 2 developer guide

URL: https://docs.ros.org/en/jazzy/The-ROS2-Project/Contributing/Developer-Guide.html

Section: Installation

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ROS 2 developer guideTable of ContentsGeneral PrinciplesQuality PracticesVersioningChange control processDocumentationTestingGeneral PracticesIssuesBranchesPull requestsLibrary versioningDevelopment processChanges to RMW APITracking tasksPackage Naming ConventionsUnits of Measure and Coordinate System ConventionsProgramming conventionsFilesystem layoutUpstream PackagesDeveloper WorkflowArchitectural Development PracticesSoftware Development LifecycleBuild Farm IntroductionNote on Coverage runsHow to read the coverage rate from the buildfarm reportHow to calculate the coverage rate from the buildfarm reportHow to measure coverage locally using lcov (Ubuntu)This page defines the practices and policies we employ when developing ROS 2.General PrinciplesSome principles are common to all ROS 2 development:Shared ownership:

Everybody working on ROS 2 should feel ownership over all parts of the system.


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The original author of a chunk of code does not have any special permission or obligation to control or maintain that chunk of code.

Everyone is free to propose changes anywhere, to handle any type of ticket, and to review any pull request.Be willing to work on anything:

As a corollary to shared ownership, everybody should be willing to take on any available task and contribute to any aspect of the system.Ask for help:

If you run into trouble on something, ask your fellow developers for help, via tickets, comments, or email, as appropriate.Quality PracticesPackages can ascribe to different levels of quality based on the development practices they adhere to, as per the guidelines inREP 2004: Package Quality Categories.

The categories are differentiated by their policies on versioning, testing, documentation, and more.The following sections are the specific development rules we follow to ensure core packages are of the highest quality (‘Level 1’).


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We recommend all ROS developers strive to adhere to the following policies to ensure quality across the ROS ecosystem.For more specific code recommendations please seethe Quality Guide.VersioningWe will use theSemantic Versioning guidelines(semver) for versioning.We will also adhere to some ROS-specific rules built on top ofsemver'sfull meaning:Major version increments (i.e. breaking changes) should not be made within a released ROS distribution.Patch (interface-preserving) and minor (non-breaking) version increments do not break compatibility, so these sorts of changesareallowed within a release.Major ROS releases are the best time to release breaking changes.


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If a core package needs multiple breaking changes, they should be merged into their integration branch (e.g. rolling) to allow catching problems in CI quickly, but released together to reduce the number of major releases for ROS users.Though major increments require a new distribution, a new distribution does not necessarily require a major bump (if development and release can happen without breaking API).For compiled code, the ABI is considered part of the public interface.

Any change that requires recompiling dependent code is considered major (breaking).ABI breaking changescanbe made in a minor version bumpbeforea distribution release (getting added to the rolling release).We enforce API stability for core packages in Dashing and Eloquent even though their major version components are0, despiteSemVer’s specificationregarding initial development.Subsequently, packages should strive to reach a mature state and increase to version1.0.0so to matchsemver'sspecifications.CaveatsThese rules arebest-effort.


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Whether an unplanned break increments the major or minor version will be assessed on a case-by-case basis.For example, consider a situation involving released X-turtle, corresponding to major version1.0.0, and released Y-turtle, corresponding to major version2.0.0.If an API-breaking fix is identified to be absolutely necessary in X-turtle, bumping to2.0.0is obviously not an option because2.0.0already exists.The solutions for handling X-turtle’s version in such a case, both non-ideal, are:Bumping X-turtle’s minor version: non-ideal because it violates SemVer’s principle that breaking changes must bump the major version.Bumping X-turtle’s major version past Y-turtle (to3.0.0): non-ideal because the older distro’s version would become higher than the already-available version of a newer distro, which would invalidate/break version-specific conditional code.The developer will have to decide which solution to use, or more importantly, which principle they are willing to break.


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We cannot suggest one or the other, but in either case we do require that explicit measures be taken to communicate the disruption and its explanation to users manually (beyond just the version increment).If there were no Y-turtle, even though the fix would technically just be a patch, X-turtle would have to bump to2.0.0.

This case adheres to SemVer, but breaks from our own rule that major increments should not be introduced in a released distribution.This is why we consider the versioning rulesbest-effort.

As unlikely as the examples above are, it is important to accurately define our versioning system.Public API declarationAccording tosemver, every package must clearly declare a public API.

We will use the “Public API Declaration” section of the quality declaration of a package to declare what symbols are part of the public API.For most C and C++ packages the declaration is any header that it installs.

However, it is acceptable to define a set of symbols which are considered private.


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Avoiding private symbols in headers can help with ABI stability, but is not required.For other languages like Python, a public API must be explicitly defined, so that it is clear what symbols can be relied on with respect to the versioning guidelines.

The public API can also be extended to build artifacts like configuration variables, CMake config files, etc. as well as executables and command-line options and output.

Any elements of the public API should be clearly stated in the package’s documentation.

If something you are using is not explicitly listed as part of the public API in the package’s documentation, then you cannot depend on it not changing between minor or patch versions.Deprecation strategyWhere possible, we will also use the tick-tock deprecation and migration strategy for major version increments.

New deprecations will come in a new distribution release, accompanied by compiler warnings expressing that the functionality is being deprecated.


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In the next release, the functionality will be completely removed (no warnings).Example of functionfoodeprecated and replaced by functionbar:VersionAPIX-turtlevoid foo();Y-turtle[[deprecated(“use bar()”)]] void foo(); <br> void bar();Z-turtlevoid bar();We must not add deprecations after a distribution is released.

Deprecations do not necessarily require a major version bump, though.

A deprecation can be introduced in a minor version bump if the bump happens before the distro is released (similar to ABI breaking changes).For example, if X-turtle begins development as2.0.0, a deprecation can be added in2.1.0before X-turtle is released.We will attempt to maintain compatibility across distros as much as possible.


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However, like the caveats associated with SemVer, tick-tock or even deprecation in general may be impossible to completely adhere to in certain cases.Change control processAll changes must go through a pull request.We will enforce theDeveloper Certificate of Origin (DCO)on pull requests in ROSCore repositories.It requires all commit messages to contain theSigned-off-byline with an email address that matches the commit author.You can pass-s/--signoffto thegitcommitinvocation or write the expected message manually (e.g.Signed-off-by:YourNameDeveloper<your.name@example.com>).DCO isnotrequired for pull requests that only address whitespace removal, typo correction, and othertrivial changes.Always run CI jobs for alltier 1 platformsfor every pull request and include links to jobs in the pull request.

(If you don’t have access to the Jenkins jobs someone will trigger the jobs for you.)A minimum of 1 approval from a fellow developer who did not author the pull request is required to consider it approved.


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Approval is required before merging.Packages may choose to increase this number.Any required changes to documentation (API documentation, feature documentation, release notes, etc.) must be proposed before merging related changes.Guidelines for backporting PRsWhen changing an older version of ROS:Make sure the features or fixes are accepted and merged in the rolling branch before opening a PR to backport the changes to older versions.When backporting to older versions, also consider backporting to any otherstill supported versions, even non-LTS versions.If you are backporting a single PR in its entirety, title the backport PR “[Distro] <name of original PR>”.

If backporting a subset of changes from one or multiple PRs, the title should be “[Distro] <description of changes>”.Link to all PRs whose changes you’re backporting from the description of your backport PR.


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In a Dashing backport of a Foxy change, you do not need to link to the Eloquent backport of the same change.DocumentationAll packages should have these documentation elements present in their README or linked to from their README:Description and purposeDefinition and description of the public APIExamplesHow to build and install (should reference external tools/workflows)How to build and run testsHow to build documentationHow to develop (useful for describing things likepythonsetup.pydevelop)License and copyright statementsEach source file must have a license and copyright statement, checked with an automated linter.Each package must have a LICENSE file, typically the Apache 2.0 license, unless the package has an existing permissive license (e.g. rviz uses three-clause BSD).Each package should describe itself and its purpose assuming, as much as possible, that the reader has stumbled onto it without previous knowledge of ROS or other related projects.Each package should define and describe its public API so


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package should define and describe its public API so that there is a reasonable expectation for users about what is covered by the semantic versioning policy.


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Even in C and C++, where the public API can be enforced by API and ABI checking, it is a good opportunity to describe the layout of the code and the function of each part of the code.It should be easy to take any package and from that package’s documentation understand how to build, run, build and run tests, and build the documentation.

Obviously we should avoid repeating ourselves for common workflows, like building a package in a workspace, but the basic workflows should be either described or referenced.Finally, it should include any documentation for developers.


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This might include workflows for testing the code using something likepythonsetup.pydevelop, or it might mean describing how to make use of extension points provided by your package.Examples:capabilities:https://docs.ros.org/hydro/api/capabilities/html/This one gives an example of docs which describe the public APIcatkin_tools:https://catkin-tools.readthedocs.org/en/latest/development/extending_the_catkin_command.htmlThis is an example of describing an extension point for a packageAPI Documetation for ROS PackagesAPI documentation for all released ROS packages can befound here.

We recommend usingindex.ros.orgto search through available ROS packages to find their documentation.If you are a ROS package developer looking for guidance on documenting your package please seeour “how to” guide on package level documentation.


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The documentation for all released ROS 2 packages is automatically hosted ondocs.ros.org.TestingAll packages should have some level ofsystem, integration, and/or unit tests.Unit testsshould always be in the package which is being tested and should make use of tools likeMockto try and test narrow parts of the codebase in constructed scenarios.

Unit tests should not bring in test dependencies that are not testing tools, e.g. gtest, nosetest, pytest, mock, etc…Integration testscan test interactions between parts of the code or between parts of the code and the system.

They often test software interfaces in ways that we expect the user to use them.


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Like Unit tests, Integration tests should be in the package which is being tested and should not bring in non-tool test dependencies unless absolutely necessary, i.e. all non-tool dependencies should only be allowed under extreme scrutiny so they should be avoided if possible.System testsare designed to test end-to-end situations between packages and should be in their own packages to avoid bloating or coupling packages and to avoid circular dependencies.In general external or cross package test dependencies should be minimized to prevent circular dependencies and tightly coupled test packages.All packages should have some unit tests and possibly integration tests, but the degree to which they should have them is based on the package’s quality category.

The following subsections apply to ‘Level 1’ packages:Code coverageWe will provide line coverage, and achieve line coverage above 95%.

If a lower percentage target is justifiable, it must be prominently documented.


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We may provide branch coverage, or exclude code from coverage (test code, debug code, etc.).

We require that coverage increase or stay the same before merging a change, but it may be acceptable to make a change that decreases code coverage with proper justification (e.g. deleting code that was previously covered can cause the percentage to drop).PerformanceWe strongly recommend performance tests, but recognize they don’t make sense for some packages.

If there are performance tests, we will choose to either check each change or before each release or both.

We will also require justification for merging a change or making a release that lowers performance.Linters and static analysisWe will useROS code styleand enforce it with linters fromament_lint_common.


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All linters/static analysis that are part ofament_lint_commonmust be used.Theament_lint_autodocumentation provides information on runningament_lint_common.General PracticesSome practices are common to all ROS 2 development.These practices don’t affect package quality level as described inREP 2004, but are still highly recommended for the development process.IssuesWhen filing an issue please make sure to:Include enough information for another person to understand the issue.

In ROS 2, the following points are needed for narrowing down the cause of an issue.

Testing with as many alternatives in each category as feasible will be especially helpful.The operating system and version.Reasoning: ROS 2 supports multiple platforms, and some bugs are specific to particular versions of operating systems/compilers.The installation method.Reasoning: Some issues only manifest if ROS 2 has been installed from binary archives or from debs.


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This can help us determine if the issue is with the packaging process.The specific version of ROS 2.Reasoning: Some bugs may be present in a particular ROS 2 release and later fixed.

It is important to know if your installation includes these fixes.The DDS/RMW implementation being used(seethis pagefor how to determine which one).

Reasoning: Communication issues may be specific to the underlying ROS middleware being used.The ROS 2 client library being used.Reasoning: This helps us narrow down the layer in the stack at which the issue might be.Include a list of steps to reproduce the issue.In case of a bug consider to provide ashort, self contained, correct (compilable), example.

Issues are much more likely to be resolved if others can reproduce them easily.Mention troubleshooting steps that have been tried already, including:Upgrading to the latest version of the code, which may include bug fixes that have not been released yet.


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Seethis sectionand follow the instructions to get the “rolling” branches.Trying with a different RMW implementation.

Seethis pagefor how to do that.BranchesNoteThese are just guidelines.

It is up to the package maintainer to choose branch names that match their own workflow.It is good practice to haveseparate branchesin a package’s source repository for each ROS distribution it is targeting.

These branches are typically named after the distribution they target.

For example, ahumblebranch for development targeted specifically at the Humble distribution.Releases are also made from these branches, targeting the appropriate distribution.

Development targeted at a specific ROS distribution can happen on the appropriate branch.

For example: Development commits targetingfoxyare made to thefoxybranch, and package releases forfoxyare made from that same branch.NoteThis requires the package maintainers to perform backports or forwardports as appropriate to keep all branches up to date with features.


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The maintainers must also perform general maintenance (bug fixes, etc.) on all branches from which package releases are still made.For example, if a feature is merged into the Rolling-specific branch (e.g.rollingormain), and that feature is also appropriate

to the Humble distribution (does not break API, etc.), then it is good practice to backport the feature to the Humble-specific branch.The maintainers may make releases for those older distributions if there are new features or bug fixes available.What aboutmainandrolling?maintypically targetsRolling(and so, the next unreleased ROS distribution), though the maintainers may decide to develop and release from arollingbranch instead.Pull requestsA pull request should only focus on one change.

Separate changes should go into separate pull requests.


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Separate changes should go into separate pull requests.

SeeGitHub’s guide to writing the perfect pull request.A patch should be minimal in size and avoid any kind of unnecessary changes.A pull request must contain minimum number of meaningful commits.You can create new commits while the pull request is under review.Before merging a pull request all changes should be squashed into a small number of semantic commits to keep the history clear.But avoid squashing commits while a pull request is under review.

Your reviewers might not notice that you made the change, thereby introducing potential for confusion.

Plus, you’re going to squash before merging anyway; there’s no benefit to doing it early.Any developer is welcome to review and approve a pull request (seeGeneral Principles).When you are working on a change that is not ready for review or to be merged, use a draft pull request.

When that change is ready for review, move the pull request out of the draft state.


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Note that if you want early feedback from specific people on a draft pull request, you can @ mention them in the pull request’s description or in a comment on the pull request.If your pull request depends on other pull requests, link to each depended on pull request by adding-Dependson<link>at the top of your pull request’s description.

Doing so helps reviewers understand the context of the pull request.When you start reviewing a pull request, comment on the pull request so that other developers know that you’re reviewing it.Pull-request review is not read-only, with the reviewer making comments and then waiting for the author to address them.

As a reviewer, feel free to make minor improvements (typos, style issues, etc.) in-place.

As the opener of a pull-request, if you are working in a fork, checking the box toallow edits from upstream contributorswill assist with the aforementioned.


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As a reviewer, also feel free to make more substantial improvements, but consider putting them in a separate branch (either mention the new branch in a comment, or open another pull request from the new branch to the original branch).Any developer (the author, the reviewer, or somebody else) can merge any approved pull request.Library versioningWe will version all libraries within a package together.

This means that libraries inherit their version from the package.

This keeps library and package versions from diverging and shares reasoning with the policy of releasing packages which share a repository together.

If you need libraries to have different versions then consider splitting them into different packages.Development processThe default branch (in most cases the rolling branch) must always build, pass all tests and compile without warnings.


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If at any time there is a regression it is the top priority to restore at least the previous state.Always build with tests enabled.Always run tests locally after changes and before proposing them in a pull request.

Besides using automated tests, also run the modified code path manually to ensure that the patch works as intended.Always run CI jobs for all platforms for every pull request and include links to the jobs in the pull request.For more details on recommended software development workflow, seeSoftware Development Lifecyclesection.Changes to RMW APIWhen updatingRMW API, it is required that RMW implementations for the Tier 1 middleware libraries are updated as well.

For example, a new functionrmw_foo()introduced to the RMW API must be implemented in the following packages (as of ROS Galactic):rmw_connextddsrmw_cycloneddsrmw_fastrtpsUpdates for non-Tier 1 middleware libraries should also be considered if feasible (e.g. depending on the size of the change).


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SeeREP-2000for the list of middleware libraries and their tiers.Tracking tasksTo help organize work on ROS 2, the core ROS 2 development team uses kanban-styleGitHub project boards.Not all issues and pull requests are tracked on the project boards, however.

A board usually represents an upcoming release or specific project.

Tickets can be browsed on a per-repo basis by browsing theROS 2 repositories’individual issue pages.The names and purposes of columns in any given ROS 2 project board vary, but typically follow the same general structure:To do:

Issues that are relevant to the project, ready to be assignedIn progress:

Active pull requests on which work is currently in progressIn review:

Pull requests where work is complete and ready for review, and for those currently under active reviewDone:

Pull requests and related issues are merged/closed (for informational purposes)To request permission to make changes, simply comment on the tickets you’re interested in.


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Depending on the complexity, it might be useful to describe how you plan to address it.

We will update the status (if you don’t have the permission) and you can start working on a pull request.

If you contribute regularly we will likely just grant you permission to manage the labels etc. yourself.Package Naming ConventionsNames play an important role in ROS and following naming conventions simplifies the process of learning and understanding large systems.The ROS packages occupy a flat namespace, so naming should be done carefully and consistently. There is a standard for package naming inREP-144Package names should follow common C variable naming conventions: lower case, start with a letter, use underscore separators, e.g. laser_viewerPackage names should be specific enough to identify what the package does.

For example, a motion planner is not called planner.

If it implements the wavefront propagation algorithm, it might be called wavefront_planner.


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There’s obviously tension between making a name specific and keeping it from becoming overly verbose.Using catchall names such as utils should be avoided as they do not scope what goes into the package or what should be outside the package.To check whether a name is taken, consulthttps://index.ros.org/packages/.

If you’d like your repository included in that list, see therosdistro Contributing Guide.Our goal is to develop a canonical set of tools for making robots do interesting things.

The package name should tell you what the package does, not where it came from.

It should be possible for us, as a community, to make this work.

An Ubuntu distribution offers approximately 33,000 packages without inserting origin or authorship into names.Prefixing a package name is recommended only when the package is not meant to be used more widely (e.g., packages that are specific to the PR2 robot use thepr2_prefix).


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You might prefix the package name when forking an existing package, but again, the prefix would hopefully communicate what changed, not who changed it.Prefixing a package name with ‘ros’ is redundant for a ROS package.

This is not recommended except for very core packages.Units of Measure and Coordinate System ConventionsStandard units and coordinate conventions for use in ROS have been formalized inREP-103.

All messages should follow these guidelines unless there’s a very strong reason which is very clearly documented to avoid confusion.Representation of special conditions within distance measurements like “too close” or “too far” in ROS have been formalized inREP-0117.Programming conventionsDefensive programming: ensure that assumptions are held as early as possible.


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E.g. check every return code and make sure to at least throw an exception until the case is handled more gracefully.All error messages must be directed tostderr.Declare variables in the narrowest scope possible.Keep group of items (dependencies, imports, includes, etc.) ordered alphabetically.C++ specificAvoid using direct streaming (<<) tostdout/stderrto prevent interleaving between multiple threads.Avoid using references forstd::shared_ptrsince that subverts the reference counting.


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If the original instance goes out of scope and the reference is being used it accesses freed memory.Filesystem layoutThe filesystem layout of packages and repositories should follow the same conventions in order to provide a consistent experience for users browsing our source code.Package layoutsrc: contains all C and C++ codeAlso contains C/C++ headers which are not installedinclude: contains all C and C++ headers which are installed<packagename>: for all C and C++ installed headers they should be folder namespaced by the package name<package_name>: contains all Python codetest: contains all automated tests and test dataconfig: contains configuration files, e.g. YAML parameters files and RViz config filesdoc: contains all the documentationlaunch: contains all launch filesmsg: contains all ROS Message definitionssrv: contains all ROS Service definitionsaction: contains all ROS Action definitionspackage.xml: as defined byREP-0140(may be updated for prototyping)CMakeLists.txt: only ROS packages which use


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for prototyping)CMakeLists.txt: only ROS packages which use CMakesetup.py: only ROS packages which use Python code onlyREADME: can be rendered on GitHub as a landing page for the projectThis can be as short or detailed as is convenient, but it should at least link to project documentationConsider putting a CI or code coverage tag in this READMEIt can also be.rstor anything else that GitHub supportsCONTRIBUTING: describes the contribution guidelinesThis might include license implication, e.g. when using the Apache 2 License.LICENSE: a copy of the license or licenses for this packageCHANGELOG.rst:REP-0132compliant changelogRepository layoutEach package should be in a subfolder which has the same name as the package.


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If a repository contains only a single package it can optionally be in the root of the repository.Upstream PackagesPackages in Debian and Ubuntu UpstreamThanks to diligent effort from Jochen Sprickerhof and Leopold Palomo-Avellaneda, some of theROS 2 packages are now availablefrom the main Debian and Ubuntu repositories.Here is a short overview of the process from Jochen at ROSCon 2015.

The original ROS packages have been modified to follow Debian guidelines, which includes splitting packages into multiple pieces, changing names in some cases, installing to /usr according to FHS guidelines, and using soversions on shared libraries.In addition several of the bootstrap dependencies such as command line tools likevcstoolandcolconas well as some libraries likeosrf-pycommonandamentare also packaged upstream.Unlike the OSRF-provided ROS packages fromhttp://packages.ros.org, the packages in the upstream repositories are not attached to a specificROS distribution.


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Rather, they represent a snapshot in time that will be updated periodically within Debian unstable and then latched at various points into downstream Debian and Ubuntu distributions.Don’t mix the streamsWe strongly recommend against mixing ROS packages from upstream Debian/Ubuntu and fromhttp://packages.ros.orgon the same system.

In some cases such a mixed system will work correctly, but there can be negative interactions between the two sets of packages.

We’re working with Jochen and friends to minimize the chance of problems via documentation and package conflict specifications, but we expect some risks to remain, including some fairly subtle issues.As such, we recommend that you choose to either install packages from upstream or fromhttp://packages.ros.org, but not both.


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Not only should you not install packages from both at the same time, but if you intend to use the upstream packages then you should not even have thehttp://packages.ros.orgentries in your apt sources (i.e. in any files in/etc/apt/sources*).


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Having both of them enabled can cause mixing of packages which overlap by name between the two sources, e.g.python3-rospkg.Known DifferencesAs compared to the ROS packages from packages.ros.org, there are some differences in the upstream ROS packages that people should be aware of:The package set is incomplete.Packages may have different names and be partitioned differently.Developer WorkflowWe track open tickets and active PRs related to upcoming releases and larger projects usingGitHub project boards.The usual workflow is:Discuss design (GitHub ticket on the appropriate repository, and a design PR tohttps://github.com/ros2/designif needed)Write implementation on a feature branch on a forkPlease check out thedeveloper guidefor guidelines and best practicesWrite testsEnable and run lintersRun tests locally usingcolcontest(see thecolcon tutorial)Once everything builds locally without warnings and all tests are passing, run CI on your feature branch:Go to ci.ros2.orgLog in (top right corner)Click on


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branch:Go to ci.ros2.orgLog in (top right corner)Click on theci_launcherjobClick “Build with Parameters” (left column)In the first box “CI_BRANCH_TO_TEST” enter your feature branch nameHit thebuildbutton(if you are not a ROS 2 committer, you don’t have access to the CI farm. In that case, ping the reviewer of your PR to run CI for you)If your use case requires running code coverage:Go to ci.ros2.orgLog in (top right corner)Click on theci_linux_coveragejobClick “Build with Parameters” (left column)Be sure of leaving “CI_BUILD_ARGS” and “CI_TEST_ARGS” with the default valuesHit thebuildbuttonAt the end of the document there are instructions on how tointerpret the result of the reportandcalculate the coverage rateIf the CI job built without warnings, errors and test failures, post the links of your jobs on your PR or high-level ticket aggregating all your PRs (see examplehere)Note that the markdown for these badges is in the console output of theci_launcherjobWhen the PR has been approved:the person who


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theci_launcherjobWhen the PR has been approved:the person who submitted the PR merges it using “Squash and Merge” option so that we keep a clean historyIf the commits deserve to keep separated: squash all the nitpick/linters/typo ones together and merge the remaining setNote: each PR should target a specific feature so Squash and Merge should make sense 99% of the timeDelete the branch once mergedArchitectural Development PracticesThis section describes the ideal lifecycle that should be employed when making large architectural changes to ROS 2.Software Development LifecycleThis section describes step-by-step how to plan, design, and implement a new feature:Task CreationCreating the Design DocumentDesign ReviewImplementationCode ReviewTask creationTasks requiring changes to critical parts of ROS 2 should have design reviews during early stages of the release cycle.


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If a design review is happening in the later stages, the changes will be part of a future release.An issue should be created in the appropriateros2 repository, clearly describing the task being worked on.It should have a clear success criteria and highlight the concrete improvements expected from it.If the feature is targeting a ROS release, ensure this is tracked in the ROS release ticket (example).Writing the design documentDesign docs must never include confidential information.


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Whether or not a design document is required for your change depends on how big the task is.You are making a small change or fixing a bug:A design document is not required, but an issue should be opened in the appropriate repository to track the work and avoid duplication of efforts.You are implementing a new feature or would like to contribute to OSRF-owned infrastructure (like Jenkins CI):Design doc is required and should be contributed toros2/designto be made accessible onhttps://design.ros2.org/.You should fork the repository and submit a pull request detailing the design.Mention the related ros2 issue (for example,Designdocfortaskros2/ros2#<issueid>) in the pull request or the commit message.

Detailed instructions are on theROS 2 Contributepage.


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Detailed instructions are on theROS 2 Contributepage.

Design comments will be made directly on the pull request.If the task is planned to be released with a specific version of ROS, this information should be included in the pull request.Design document reviewOnce the design is ready for review, a pull request should be opened and appropriate reviewers should be assigned.

It is recommended to include project owner(s) -

maintainers of all impacted packages (as defined bypackage.xmlmaintainer field, seeREP-140) - as reviewers.If the design doc is complex or reviewers have conflicting schedules, an optional design review meeting can be set up.


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In this case,Before the meetingSend a meeting invite at least one week in advanceMeeting duration of one hour is recommendedMeeting invite should list all decisions to be made during the review (decisions requiring package maintainer approval)Meeting required attendees: design pull request reviewersMeeting optional attendees: all OSRF engineers, if applicableDuring the meetingThe task owner drives the meeting, presents their ideas and manages discussions to ensure an agreement is reached on timeAfter the meetingThe task owner should send back meeting notes to all attendeesIf minor issues have been raised about the design:The task owner should update the design doc pull request based on the feedbackAdditional review is not requiredIf major issues have been raised about the design:It is acceptable to remove sections for which there is no clear agreementThe debatable parts of the design can be resubmitted as a separate task in the futureIf removing the debatable parts is not an option, work directly with


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the debatable parts is not an option, work directly with package owners to reach an agreementOnce consensus is reached:Ensure theros2/designpull request has been merged, if applicableUpdate and close the GitHub issue associated with this design taskImplementationBefore starting, go through thePull requestssection for best practices.For each repo to be modified:Modify the code, go to the next step if finished or at regular intervals to backup your work.Self-reviewyour changes usinggitadd-i.Create a new signed commit usinggitcommit-s.A pull request should contain minimal semantically meaningful commits (for instance, a large number of 1-line commits is not acceptable).


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Create new fixup commits while iterating on feedback, or optionally, amend existing commits usinggitcommit--amendif you don’t want to create a new commit every time.Each commit must have a properly written, meaningful, commit message.

More instructionshere.Moving files must be done in a separate commit, otherwise git may fail to accurately track the file history.Either the pull request description or the commit message must contain a reference to the related ros2 issue, so it gets automatically closed when the pull request is merged.


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See thisdocfor more details.Push the new commits.Code reviewOnce the change is ready for code review:Open a pull request for each modified repository.Remember to followPull requestsbest practices.GitHubcan be used to create pull requests from the command-line.If the task is planned to be released with a specific version of ROS, this information should be included in each pull request.Package owners who reviewed the design document should be mentioned in the pull request.Code review SLO: although reviewing pull requests is best-effort,

it is helpful to have reviewers comment on pull requests within a week and


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code authors to reply back to comments within a week, so there is no loss of context.Iterate on feedback as usual, amend and update the development branch as needed.Once the PR is approved, package maintainers will merge the changes in.Build Farm IntroductionThe build farm is located atci.ros2.org.Every night we run nightly jobs which build and run all the tests in various scenarios on various platforms.


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Additionally, we test all pull requests against these platforms before merging.This is the current set of target platforms and architectures, though it evolves overtime:Ubuntu 24.04 Nobleamd64aarch64Windows 10amd64There are several categories of jobs on the buildfarm:manual jobs (triggered manually by developers):ci_linux: build + test the code on Ubuntuci_linux-aarch64: build + test the code on Ubuntu on an ARM 64-bit machine (aarch64)ci_linux_coverage: build + test + generation of test coverageci_windows: build + test the code on Windowsci_launcher: trigger all the jobs listed abovenightly (run every night):Debug: build + test the code with CMAKE_BUILD_TYPE=Debugnightly_linux_debugnightly_linux-aarch64_debugnightly_win_debRelease: build + test the code with CMAKE_BUILD_TYPE=Releasenightly_linux_releasenightly_linux-aarch64_releasenightly_win_relRepeated: build then run each test up to 20 times or until failed (aka flakiness


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run each test up to 20 times or until failed (aka flakiness hunter)nightly_linux_repeatednightly_linux-aarch64_repeatednightly_win_repCoverage:nightly_linux_coverage: build + test the code + analyses coverage for c/c++ and pythonresults are exported as a cobertura reportpackaging (run every night; result is bundled into an archive):packaging_linuxpackaging_windowsTwo additional build farms support the ROS / ROS 2 ecosystem by providing building of source and


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binary packages, continuous integration, testing, and analysis.For details, frequently asked questions, and troubleshooting seebuild farms.Note on Coverage runsROS 2 packages are organized in a way that the testing code for a given package is not only contained within the package, but could also be present in a different package.

In other words: packages can exercise code belonging to other packages during the testing phase.To achieve the coverage rate reached by all code available in the ROS 2 core packages it is recommended to run builds using a fixed set of proposed repositories.


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That set is defined in the default parameters of coverage jobs in Jenkins.How to read the coverage rate from the buildfarm reportTo see the coverage report for a given package:When theci_linux_coveragebuild finishes, click onCoverageReportScroll down to theCoverageBreakdownbyPackagetableIn the table, look at the first column called “Name”The coverage reports in the buildfarm include all the packages that were used in the ROS workspace.


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The coverage report includes different paths corresponding to the same package:Name entries with the form:src.*.<repository_name>.<package_name>.*These correspond to the unit test runs available in a package against its own source codeName entries with the form:build.<repository_name>.<package_name>.*These correspond to the unit test runs available in a package against its files generated at building or configuring timeName entries with the form:install.<package_name>.*These correspond to the system/integration tests coming from testing runs of other packagesHow to calculate the coverage rate from the buildfarm reportGet the combined unit coverage rate using the automatic script:From the ci_linux_coverage Jenkins build copy the URL of the buildDownload theget_coverage_ros2_pkgscriptExecute the script:./get_coverage_ros2_pkg.py<jenkins_build_url><ros2_package_name>(README)Grab the results from the “Combined unit testing” final line in the output of the scriptAlternative: get the combined unit coverage rate


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of the scriptAlternative: get the combined unit coverage rate from coverage report (require manual calculation):When the ci_linux_coverage build finishes, click onCoberturaCoverageReportScroll down to theCoverageBreakdownbyPackagetableIn the table, under the first column “Name”, look for (where <package_name> is your package under testing):all the directories under the patternsrc.*.<repository_name>.<package_name>.*grab the two absolute values in the column “Lines”.all the directories under the patternbuild/.<repository_name>.*grab the two absolute values in the column “Lines”.With the previous selection: for each cell, the first value is the lines tested and the second is the total lines of code.


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Aggregate all rows for getting the total of the lines tested and the total of lines of code under test.

Divide to get the coverage rate.How to measure coverage locally using lcov (Ubuntu)To measure coverage on your own machine, installlcov.sudoaptinstall-ylcovThe rest of this section assumes you are working from your colcon workspace.

Compile in debug with coverage flags.

Feel free to use colcon flags to target specific packages.colconbuild--cmake-args-DCMAKE_BUILD_TYPE=Debug-DCMAKE_CXX_FLAGS="${CMAKE_CXX_FLAGS}--coverage"-DCMAKE_C_FLAGS="${CMAKE_C_FLAGS}--coverage"lcovrequires an initial baseline, which you can produce with the following command.

Update the output file location for your needs.lcov--no-external--capture--initial--directory.--output-file~/ros2_base.infoRun tests for the packages that matter for your coverage measurements.


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For example, if measuringrclcppalso withtest_rclcppcolcontest--packages-selectrclcpptest_rclcppCapture the lcov results with a similar command this time dropping the--initialflag.lcov--no-external--capture--directory.--output-file~/ros2.infoCombine the trace .info files:lcov--add-tracefile~/ros2_base.info--add-tracefile~/ros2.info--output-file~/ros2_coverage.infoGenerate html for easy visualization and annotation of covered lines.mkdir-pcoverage

genhtml~/ros2_coverage.info--output-directorycoverage

Code Examples:

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colconbuild--cmake-args-DCMAKE_BUILD_TYPE=Debug-DCMAKE_CXX_FLAGS="${CMAKE_CXX_FLAGS}--coverage"-DCMAKE_C_FLAGS="${CMAKE_C_FLAGS}--coverage"

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lcov--no-external--capture--initial--directory.--output-file~/ros2_base.info

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colcontest--packages-selectrclcpptest_rclcpp

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lcov--add-tracefile~/ros2_base.info--add-tracefile~/ros2.info--output-file~/ros2_coverage.info

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genhtml~/ros2_coverage.info--output-directorycoverage


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Title: Installation

URL: https://docs.ros.org/en/jazzy/Installation.html

Section: Installation

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Title: Documenting a ROS 2 package URL: https://docs.ros.org/en/jazzy/How-To-Guides/Documenting-a-ROS-2-Package.html Section: Installation --------------------------------------------------------------------------------


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Documenting a ROS 2 packageTable of ContentsPrerequisitesPackage Documentation OverviewBuilding Package DocsConfigurationrosdoc2.yamlconf.py, rosdoc2_settingsDoxyfileCustomizing Sphinx DocumentationCreating a Sphinx ProjectCustomizingindex.rstAdding Python API-DocsAdding C++ API-DocsIncluding an existing README.mdCI, docs.ros.orgFurther ReadingThis guide introduces the standard way to create documentation for ROS 2 packages. For packages with binary releases this also results in the docs being hosted atdocs.ros.org/en/<distro>/p/<package>/. For information on how to contribute to this documentation on docs.ros.org, seeContributing to ROS 2 Documentation.PrerequisitesInstall ROSInstall rosdoc2Package Documentation OverviewThe type of documentation discussed in this guide is referred to as “package docs” or “API docs”. For ROS packages that have been released on ROS Index, their documentation will be built on the ROS buildfarm, included on docs.ros.org, and visible via theAPIDocsbutton on index.ros.org.The


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and visible via theAPIDocsbutton on index.ros.org.The tool responsible for generating ROS 2 package docs isrosdoc2.rosdoc2is a convenient wrapper around the commonly usedSphinxdocumentation framework. Sphinx allows freeform written documentation as well as API documentation for python code generated from comments in the code. Thebreathe+exhalepackages allow integration with Doxygen, to include autogenerated C++ API documentation as well.rosdoc2creates a default configuration for packages with no documentation or configuration at all, and applies options for a uniform theme and integration with other packages.Building Package DocsTo generate the documentation for a package in HTML format withrosdoc2, run:rosdoc2 build --package-path <package-path>The documentation is written todocs_output/<package-name>/index.htmland can be viewed in a browser.ConfigurationThere are three configuration locations for ROS package docs:rosdoc2.yamlfor general settings,conf.pyfor sphinx settings and theDoxyfilefor doxygen


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settings,conf.pyfor sphinx settings and theDoxyfilefor doxygen settings. For all of those, a default is assumed or generated if not present, so none of them is strictly required. However, it might be necessary to create and modify those once you want to use features such as custom textual documentation pages.rosdoc2.yamlThis is the main entrypoint for rosdoc2. It specifies generic settings, and can be used to control the execution of specific builders (Doxygen and Sphinx) and decides which builders to run.rosdoc2provides a multitude of configuration options, which can be adjusted in a config filerosdoc2.yaml. To generate a defaultrosdoc2.yamlwhich you can then further customize, run:rosdoc2 default_config --package-path <package-path>And add<rosdoc2>rosdoc2.yaml</rosdoc2>to the export section in yourpackage.xml:<package><!-- [...] --><export><!-- [...] --><rosdoc2>rosdoc2.yaml</rosdoc2></export></package>However, for most packages,  the default settings inrosdoc2will suffice, and no custom config is


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default settings inrosdoc2will suffice, and no custom config is necessary. More information aboutrosdoc2.yamlcan be found in therosdoc2 readme.conf.py, rosdoc2_settingsThe final output of the package docs is (almost) always built by Sphinx. Each Sphinx project is configured by aconf.pyfile in thedocdirectory. If no configuration is present, a default Sphinx project is created and used when building the documentation. If however aconf.pySphinx config is found in thedocsubdirectory of the package, this is used instead. A custom Sphinx project is required if you want to include a standalone reStructuredText documentation page. A standalone documentation page can be used to list multiple tutorials and guides; if that’s something you want for your package you’ll need to create a custom Sphinx project.rosdoc2provides additional settings toconf.pyand overrides some. Information about changes done to the Sphinx settings are logged to the console with a[rosdoc2]prefix.DoxyfileDoxygen is a tool for automatically


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a[rosdoc2]prefix.DoxyfileDoxygen is a tool for automatically generating C++ API docs from code comments. While Doxygen can also generate HTML output directly, in the usual workflow for ROS packages, Doxygen produces machine readable output in XML format which is then consumed by Sphinx and integrated with the rest of the documentation. Doxygen-only docs are possible by only enabling the Doxygen builder inrosdoc2.yaml, but this is uncommon.Customizing Sphinx DocumentationCreating a Sphinx ProjectIn order to add standalone documentation pages in addition to the automatically generated API docs, a custom Sphinx project is necessary. This should be created in a subdirectory calleddocin the package directory. A new Sphinx project can be created by runningsphinx-quickstartin thedocdirectory, answeringnoto “Separate source and build directories”. The wizard requires entering the project name, author and version, but this can later be removed and will be provided to Sphinx byrosdoc2from your packagespackage.xml.


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be provided to Sphinx byrosdoc2from your packagespackage.xml. More information about creating a sphinx project can be found on theSphinx quickstart page,Customizingindex.rstThesphinx-quickstartwizard creates anindex.rstfile, which is the custom landing page for your package, similar to a GithubREADMEfile.Adding Python API-DocsBy defaultrosdoc2uses thesphinx-apidoc tooland theautodoc Sphinx extensionto automatically generate documentation for python code. In order for autodoc to find the Python modules in your package, it must be added to the python search path inconf.py:sys.path.insert(0,os.path.abspath('.'))This is becauserosdoc2wraps the customconf.pywith more configuration from a script which will be placed in the package. In this case the.path inos.path.abspathrefers to the package’s directory root, not the package’sdocdirectory due to the interaction between rosdoc2 andconf.py.By default, package API docs are already reachable through the “Module Index” link that is present on the landing page. For


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“Module Index” link that is present on the landing page. For the API docs to also appear in the table of contents, simply add a link to themodulespage to yourindex.rst:..toctree:::maxdepth:2:caption:Contents:


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Python Modules <modules>Adding C++ API-DocsIf you would like to add your automatically generated API docs back to your custom landing page, add the linegenerated/indexto your documentation page where you would like the API docs to appear:..toctree:::maxdepth:2

C++ API Docs <generated/index>This adds the elements “Class Hierarchy”, “File Hierarchy” and “Reference” to the table of contents in the sidebar. To make those appear under one “C++ API Docs” heading for a less cluttered sidebar, a separate file such ascpp_api_docs.rstcan be added, which links to the generated docs:cpp_api_docs.rstC++ API Docs============These are the autogenerated docs for the internal implementation...toctree:::maxdepth:3:caption:Contents:

generated/indexWhich then also needs to be added inindex.rstto appear in the sidebar:index.rst..toctree:::maxdepth:2:caption:Contents:


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cpp_api_docsIncluding an existing README.mdIf your git repository already has an existingREADME.md, it is possible to reuse this as the landing page for the documentation, without duplicating the contents. To correctly include a Markdown file in Sphinx while preserving relative links and images, some additional effort is required.First, create a proxy-filereadme_include.mdnext toindex.rst. This is a markdown file which just includes the original README.md, but preserves the relative image paths, which would otherwise break in the next step:readme_include.md```{include} ../README.md :relative-images: ```Then, include the contents of this file fromindex.rstusingmystto include markdown from rst:index.rst..include::readme_include.md:parser:myst_parser.sphinx_This also requires addingmyst_parserto the extensions inconf.py:conf.pyextensions=["myst_parser"]CI, docs.ros.orgThe ROS build farm usesrosdoc2to build the package documentation hosted atdocs.ros.org/en/<distro>/p/<package>/. To enable this, the


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atdocs.ros.org/en/<distro>/p/<package>/. To enable this, the repository containing the documentation must be configured inrosdistro/jazzy/distribution.yaml. This would usually be the package source repository:<package_name>:doc:type:giturl:https://github.com/<github_username>/<package_name>.gitversion:mainrelease:[...]The buildfarm hosts the documentation for every distribution separately, and periodically rebuilds it from the latest commit on the specified branch. It is not required to tag a new release to update the hosted documentation. To view the status of your package’s documentation build, search fordoc__<package_name>onhttps://build.ros2.org. One job is created for every distribution for which the package is released. On each job page, you can see when a build was last triggered, as well as the status and logs of each build.Further Readingrosdoc2readme:https://github.com/ros-infrastructure/rosdoc2/blob/main/README.mdROS 2 design document on package


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2 design document on package documentation:https://design.ros2.org/articles/per_package_documentation.htmlThe ROS 2 cookbook:https://github.com/mikeferguson/ros2_cookbook/blob/main/pages/rosdoc2.md


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Code Examples:

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package

path <package

path>

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package

path <package

path>

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[...] -

><export><!-

[...] -

><rosdoc2>rosdoc2.yaml</rosdoc2></export></package>

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Python Modules <modules>

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C++ API Docs <generated/index>

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generated/index

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cpp_api_docs

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:relative

images:

```

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extensions=["myst_parser"]

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<package_name>:doc:type:giturl:https://github.com/<github_username>/<package_name>.gitversion:mainrelease:[...]


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Title: Launching nodes

URL: https://docs.ros.org/en/jazzy/Tutorials/Beginner

CLI

Tools/Launching

Multiple

Nodes/Launching

Multiple

Nodes.html

Section: Installation

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Launching nodesGoal:Use a command line tool to launch multiple nodes at once.Tutorial Level:BeginnerTime:5 minutesContentsBackgroundPrerequisitesTasksRunning a Launch File(Optional) Control the Turtlesim NodesSummaryNext stepsBackgroundIn most of the introductory tutorials, you have been opening new terminals for every new node you run. As you create more complex systems with more and more nodes running simultaneously, opening terminals and reentering configuration details becomes tedious.Launch files allow you to start up and configure a number of executables containing ROS 2 nodes simultaneously.Running a single launch file with theros2launchcommand will start up your entire system - all nodes and their configurations - at once.PrerequisitesBefore starting these tutorials, install ROS 2 by following the instructions on the ROS 2Installationpage.The commands used in this tutorial assume you followed the binary packages installation guide for your operating system (deb packages for Linux). You can still


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your operating system (deb packages for Linux). You can still follow along if you built from source, but the path to your setup files will likely be different. You also won’t be able to use thesudoaptinstallros-<distro>-<package>command (used frequently in the beginner level tutorials) if you install from source.If you are using Linux and are not already familiar with the shell,this tutorialwill help.TasksRunning a Launch FileOpen a new terminal and run:ros2 launch turtlesim multisim.launch.pyThis command will run the following launch file:# turtlesim/launch/multisim.launch.pyfromlaunchimportLaunchDescriptionimportlaunch_ros.actionsdefgenerate_launch_description():returnLaunchDescription([launch_ros.actions.Node(namespace="turtlesim1",package='turtlesim',executable='turtlesim_node',output='screen'),launch_ros.actions.Node(namespace="turtlesim2",package='turtlesim',executable='turtlesim_node',output='screen'),])NoteThe launch file above is written in Python, but you can also use XML and YAML to create


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written in Python, but you can also use XML and YAML to create launch files. You can see a comparison of these different ROS 2 launch formats inUsing Python, XML, and YAML for ROS 2 Launch Files.This will run two turtlesim nodes:For now, don’t worry about the contents of this launch file. You can find more information on ROS 2 launch in theROS 2 launch tutorials.(Optional) Control the Turtlesim NodesNow that these nodes are running, you can control them like any other ROS 2 nodes. For example, you can make the turtles drive in opposite directions by opening up two additional terminals and running the following commands:In the second terminal:ros2 topic pub  /turtlesim1/turtle1/cmd_vel geometry_msgs/msg/Twist "{linear: {x: 2.0, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 1.8}}"In the third terminal:ros2 topic pub  /turtlesim2/turtle1/cmd_vel geometry_msgs/msg/Twist "{linear: {x: 2.0, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: -1.8}}"After running these commands, you should see something like the


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running these commands, you should see something like the following:SummaryThe significance of what you’ve done so far is that you’ve run two turtlesim nodes with one command. Once you learn to write your own launch files, you’ll be able to run multiple nodes - and set up their configuration - in a similar way, with theros2launchcommand.For more tutorials on ROS 2 launch files, see themain launch file tutorial page.Next stepsIn the next tutorial,Recording and playing back data, you’ll learn about another helpful tool,ros2bag.


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Code Examples:

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ros2 launch turtlesim multisim.launch.py

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# turtlesim/launch/multisim.launch.pyfromlaunchimportLaunchDescriptionimportlaunch_ros.actionsdefgenerate_launch_description():returnLaunchDescription([launch_ros.actions.Node(namespace="turtlesim1",package='turtlesim',executable='turtlesim_node',output='screen'),launch_ros.actions.Node(namespace="turtlesim2",package='turtlesim',executable='turtlesim_node',output='screen'),])

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Title: DDS implementations

URL: https://docs.ros.org/en/jazzy/Installation/DDS

Implementations.html

Section: Installation

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DDS implementationsBy default, ROS 2 uses DDS as itsmiddleware. It is compatible with multiple DDS or RTPS (the DDS wire protocol) vendors. There is currently support for eProsima’s Fast DDS, RTI’s Connext DDS, Eclipse Cyclone DDS, and GurumNetworks GurumDDS. Seehttps://ros.org/reps/rep-2000.htmlfor supported DDS vendors by distribution.The default DDS vendor is eProsima’s Fast DDS.Working with Eclipse Cyclone DDSexplains how to utilize Cyclone DDS.Working with eProsima Fast DDSexplains how to utilize Fast DDS.Working with GurumNetworks GurumDDSexplains how to utilize GurumDDS.If you would like to use one of the other vendors you will need to install their software separately before building. The ROS 2 build will automatically build support for vendors that have been installed and sourced correctly.Once you’ve installed a new DDS vendor, you can change the vendor used at runtime:Working with Multiple RMW Implementations.Detailed instructions for installing other DDS vendors are provided below.Platforms /


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for installing other DDS vendors are provided below.Platforms / Installation typesUbuntu Linux source installUbuntu Linux binary installOSX source installOSX binary installWindows source installWindows binary installUbuntu Linux source installRTI Connext (version 6.0.1, amd64 only)Deb packages provided in the ROS 2 apt repositoriesYou can install a deb package of RTI Connext available on the ROS 2 apt repositories. You will need to accept a license from RTI.sudoaptupdate&&sudoaptinstall-q-yrti-connext-dds-6.0.1Source the setup file to set theNDDSHOMEenvironment variable.cd/opt/rti.com/rti_connext_dds-6.0.1/resource/scripts&&source./rtisetenv_x64Linux4gcc7.3.0.bash;cd-Note: when usingzshyou need to be in the directory of the script when sourcing it to have it work properlyNow you can build as normal and support for RTI will be built as well.Official binary packages from RTIYou can install the Connext 6.0.1 package for Linux provided by RTI, via options available foruniversity, purchase or evaluationAfter


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options available foruniversity, purchase or evaluationAfter downloading, usechmod+xon the.runexecutable and then execute it. Note that if you’re installing to a system directory usesudoas well.The default location is~/rti_connext_dds-6.0.1After installation, run RTI launcher and point it to your license file (obtained from RTI).Add the following line to your.bashrcfile pointing to your copy of the license.exportRTI_LICENSE_FILE=path/to/rti_license.datSource the setup file to set theNDDSHOMEenvironment variable.cd~/rti_connext_dds-6.0.1/resource/scripts&&source./rtisetenv_x64Linux4gcc7.3.0.bash;cd-Now you can build as normal and support for RTI will be built as well.Ubuntu Linux binary installRTI Connext (version 6.0.1, amd64 only)To use RTI Connext DDS there are full-suite install options available foruniversity, purchase or evaluationor you can install a libraries-only deb package of RTI Connext 6.0.1, available from the OSRF Apt repository under anon-commercial license.To install the libs-only deb


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under anon-commercial license.To install the libs-only deb package:sudoaptupdate&&sudoaptinstall-q-yrti-connext-dds-6.0.1You will need to accept a license agreement from RTI, and will find an ‘rti_license.dat file in the installation.Add the following line to your.bashrcfile pointing to your copy of the license (and source it).exportRTI_LICENSE_FILE=path/to/rti_license.datAll options need you to source the setup file to set theNDDSHOMEenvironment variable:cd/opt/rti.com/rti_connext_dds-6.0.1/resource/scripts&&source./rtisetenv_x64Linux4gcc7.3.0.bash;cd-Note: the above may need modification to match your RTI installation locationIf you want to install the Connext DDS-Security plugins please refer tothis page.OSX source installRTI Connext (6.0.1)If you would like to also build against RTI Connext DDS there are options available foruniversity, purchase or evaluationYou also need a Java runtime installed to run the RTI code generator, which you can gethere.After installing, run RTI launcher and point it to


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can gethere.After installing, run RTI launcher and point it to your license file.Source the setup file to set theNDDSHOMEenvironment variable before building your workspace.source/Applications/rti_connext_dds-6.0.1/resource/scripts/rtisetenv_x64Darwin17clang9.0.bashYou may need to increase shared memory resources followinghttps://community.rti.com/kb/osx510If you want to install the Connext DDS-Security plugins please refer tothis page.OSX binary installEnable Connext supportTo use RTI Connext DDS there are options available foruniversity, purchase or evaluationAfter installing, run RTI launcher and point it to your license file.Source the setup file to set theNDDSHOMEenvironment variable before building your workspace.source/Applications/rti_connext_dds-6.0.1/resource/scripts/rtisetenv_x64Darwin17clang9.0.bashYou may need to increase shared memory resources followinghttps://community.rti.com/kb/osx510.If you want to install the Connext DDS-Security plugins please refer tothis page.Windows source


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DDS-Security plugins please refer tothis page.Windows source installRTI Connext 6.0.1If you would like to also build against RTI Connext DDS there are options available foruniversity, purchase or evaluationAfter installing, use the RTI Launcher to load your license file.Then before building ROS 2, set up the Connext environment:call"C:\Program Files\rti_connext_dds-6.0.1\resource\scripts\rtisetenv_x64Win64VS2017.bat"Note that this path might need to be slightly altered depending on where you selected to install RTI Connext DDS, and which version of Visual Studio was selected. The path above is the current default path as of version 6.0.1, but will change as the version numbers increment in the future.If you want to install the Connext DDS-Security plugins please refer tothis page.Windows binary installRTI ConnextTo use RTI Connext DDS there are options available foruniversity, purchase or evaluationAfter installing, run RTI launcher and point it to your license file.Then before using ROS 2, set up the


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it to your license file.Then before using ROS 2, set up the Connext environment:call"C:\Program Files\rti_connext_dds-6.0.1\resource\scripts\rtisetenv_x64Win64VS2017.bat"If you want to install the Connext DDS-Security plugins please refer tothis page.


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Code Examples:

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sudoaptupdate&&sudoaptinstall

q

yrti

connext

dds

6.0.1

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cd/opt/rti.com/rti_connext_dds

6.0.1/resource/scripts&&source./rtisetenv_x64Linux4gcc7.3.0.bash;cd-

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exportRTI_LICENSE_FILE=path/to/rti_license.dat

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cd~/rti_connext_dds

6.0.1/resource/scripts&&source./rtisetenv_x64Linux4gcc7.3.0.bash;cd-

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sudoaptupdate&&sudoaptinstall

q

yrti

connext

dds

6.0.1

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exportRTI_LICENSE_FILE=path/to/rti_license.dat

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cd/opt/rti.com/rti_connext_dds

6.0.1/resource/scripts&&source./rtisetenv_x64Linux4gcc7.3.0.bash;cd-

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source/Applications/rti_connext_dds

6.0.1/resource/scripts/rtisetenv_x64Darwin17clang9.0.bash

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source/Applications/rti_connext_dds

6.0.1/resource/scripts/rtisetenv_x64Darwin17clang9.0.bash

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call"C:\Program Files\rti_connext_dds

6.0.1\resource\scripts\rtisetenv_x64Win64VS2017.bat"

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call"C:\Program Files\rti_connext_dds

6.0.1\resource\scripts\rtisetenv_x64Win64VS2017.bat"


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Title: Installation (macOS)

URL: https://docs.ros.org/en/jazzy/Tutorials/Advanced/Simulators/Webots/Installation

MacOS.html

Section: Installation

--------------------------------------------------------------------------------


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Installation (macOS)Goal:Install thewebots_ros2package and run simulation examples on macOS.Tutorial level:AdvancedTime:10 minutesContentsBackgroundPrerequisitesTasks1 Create the VM image2 Configure the VM3 Installwebots_ros24 Launch thewebots_ros2_universal_robotexampleBackgroundThewebots_ros2package provides an interface between ROS 2 and Webots. It includes several sub-packages, includingwebots_ros2_driver, which allows you to start Webots and communicate with it. Other sub-packages are mainly examples that show multiple possible implementations using the interface. In this tutorial, you are going to install the package and learn how to run one of these examples.PrerequisitesIt is recommended to understand basic ROS principles covered in the beginnerTutorials. In particular,Creating a workspaceandCreating a packageare useful prerequisites.It is necessary to install Webots natively on the mac in order to use thewebots_ros2package in the virtual machine as explained below. You can follow theinstallation


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machine as explained below. You can follow theinstallation procedureorbuild it from sources.TasksOn macOS, a solution based on UTM virtual machines provides an improved user experience with ROS 2 compared to native macOS installation, as it runs ROS in a Linux environment. However, Webots should be installed natively on macOS and it will be able to communicate with the ROS nodes running in the Virtual Machine (VM). This solution allows for native 3D hardware acceleration for Webots. The VM runs all the ROS part (including RViz) and connects to the host machine through TCP to start Webots. A shared folder allows the script to transfer the world and other resource files from the VM to macOS where Webots is running.The following steps explain how to create the VM image with the installation of thewebots_ros2released package. It is also possible to install it from sources.1 Create the VM imageInstall UTM on your macOS machine. The link can be found on theofficial UTM website.Download the .iso image ofUbuntu


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on theofficial UTM website.Download the .iso image ofUbuntu 22.04for Humble and Rolling orUbuntu 20.04for Foxy. Be sure to download the image corresponding to your CPU architecture.In the UTM software:Create a new image and chooseVirtualizeoption.Select the ISO image you have downloaded in theBootISOImagefield.Leave all hardware settings at default (including hardware acceleration disabled).In theSharedDirectorywindow, select a folder that will be used bywebots_ros2to transfer all the Webots assets to the host. In this example, the selected folder is/Users/username/shared.Leave all the remaining parameters as default.Start the VM. Note that you can select another shared folder each time you start the VM.During the first launch of the VM, install Ubuntu and choose a username for your account. In this example, the username isubuntu.Once Ubuntu is installed, close the VM, remove the iso image from the CD/DVD field and restart the VM.2 Configure the VMIn this section, ROS 2 is installed in the VM and the shared


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VMIn this section, ROS 2 is installed in the VM and the shared folder is configured. The following instructions and commands are all run inside the VM.Open a terminal in the started VM and install the ROS 2 distribution you need by following the instructions inUbuntu (deb packages):Create a folder in the VM to use as a shared folder. In this example, the shared folder in the VM is/home/ubuntu/shared.mkdir /home/ubuntu/sharedTo mount this folder to the host, execute the following command. Don’t forget to modify the path to the shared folder, if it is different in your case.sudo mount -t 9p -o trans=virtio share /home/ubuntu/shared -oversion=9p2000.LTo automatically mount this folder to the host when starting the VM, add the following line to/etc/fstab. Don’t forget to modify the path to the shared folder, if it is different in your case.share     /home/ubuntu/shared     9p      trans=virtio,version=9p2000.L,rw,_netdev,nofail 0       0The environment variableWEBOTS_SHARED_FOLDERmust always be set in order for


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variableWEBOTS_SHARED_FOLDERmust always be set in order for the package to work properly in the VM. This variable specifies the location of the shared folder that is used to exchange data between the host machine and the virtual machine (VM) to thewebots_ros2package. The value to use for this variable should be in the format of<hostsharedfolder>:<VMsharedfolder>, where<hostsharedfolder>is the path to the shared folder on the host machine and<VMsharedfolder>is the path to the same shared folder on the VM.In this example:export WEBOTS_SHARED_FOLDER=/Users/username/shared:/home/ubuntu/sharedYou can add this command line to the~/.bashrcfile to automatically set this environment variable when starting a new terminal.3 Installwebots_ros2You can either installwebots_ros2from the official released package, or install it from the latest up-to-date sources fromGithub.Installwebots_ros2distributed packageInstallwebots_ros2from sourcesRun the following command in the VM terminal.sudo apt-get install


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the following command in the VM terminal.sudo apt-get install ros-jazzy-webots-ros2Install git.sudo apt-get install gitCreate a ROS 2 workspace with itssrcdirectory.mkdir -p ~/ros2_ws/srcSource the ROS 2 environment.source /opt/ros/jazzy/setup.bashRetrieve the sources from Github.cd ~/ros2_wsgit clone --recurse-submodules https://github.com/cyberbotics/webots_ros2.git src/webots_ros2Install the package dependencies.sudo apt install python3-pip python3-rosdep python3-colcon-common-extensionssudo rosdep init && rosdep updaterosdep install --from-paths src --ignore-src --rosdistro jazzyBuild the package usingcolcon.colcon buildSource this workspace.source install/local_setup.bash4 Launch thewebots_ros2_universal_robotexampleAs mentioned in previous sections, the package uses the shared folder to communicate with Webots from the VM to the host. In order for Webots to be started on the host from the VM’s ROS package, a local TCP simulation server must be run.The server can be downloaded


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TCP simulation server must be run.The server can be downloaded here:local_simulation_server.py. Specify the Webots installation folder inWEBOTS_HOMEenvironment variable (e.g./Applications/Webots.app) and run the server using the following commands in a new terminal on the host (not in the VM):export WEBOTS_HOME=/Applications/Webots.apppython3 local_simulation_server.pyIn the VM, open a terminal and execute the following commands to start a package:First source the ROS 2 environment, if not done already.source /opt/ros/jazzy/setup.bashIf installed from sources, source your ROS 2 workspace, if not done already.cd ~/ros2_wssource install/local_setup.bashIf not already set in~/.bashrc, setWEBOTS_SHARED_FOLDER(see previous sections for details). Be sure to change the paths according to the location of your respective directories.export WEBOTS_SHARED_FOLDER=/Users/username/shared:/home/ubuntu/sharedUse the ROS 2 launch command to start demo packages (e.g.webots_ros2_universal_robot).ros2 launch


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demo packages (e.g.webots_ros2_universal_robot).ros2 launch webots_ros2_universal_robot multirobot_launch.pyIf Webots is closed or the ROS 2 process is interrupted, the local server will automatically wait for a new package launch and the shared folder will be cleaned for the next run.


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Code Examples:

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mkdir /home/ubuntu/shared

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sudo mount

t 9p

o trans=virtio share /home/ubuntu/shared

oversion=9p2000.L

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export WEBOTS_SHARED_FOLDER=/Users/username/shared:/home/ubuntu/shared

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sudo apt

get install ros

jazzy

webots

ros2

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sudo apt

get install git

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mkdir

p ~/ros2_ws/src

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source /opt/ros/jazzy/setup.bash

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cd ~/ros2_wsgit clone -

recurse

submodules https://github.com/cyberbotics/webots_ros2.git src/webots_ros2

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colcon build

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source install/local_setup.bash

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source install/local_setup.bash

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export WEBOTS_HOME=/Applications/Webots.apppython3 local_simulation_server.py

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source /opt/ros/jazzy/setup.bash

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cd ~/ros2_wssource install/local_setup.bash

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export WEBOTS_SHARED_FOLDER=/Users/username/shared:/home/ubuntu/shared

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ros2 launch webots_ros2_universal_robot multirobot_launch.py


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Title: Installation

URL: https://docs.ros.org/en/iron/Installation.html

Section: Installation

--------------------------------------------------------------------------------

You're reading the documentation for an older, but still supported, version of ROS 2.

For information on the latest version, please have a look atJazzy.InstallationOptions for installing ROS 2 Iron Irwini:Binary packagesBinaries are only created for the Tier 1 operating systems listed inREP-2000.


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If you are not running any of the following operating systems you may need to build from source or use acontainer solutionto run ROS 2 on your platform.We provide ROS 2 binary packages for the following platforms:Ubuntu Linux - Jammy Jellyfish (22.04)deb packages(recommended)binary archiveRHEL 9RPM packages(recommended)binary archiveWindows 10Windows Binary (VS 2019)Building from sourceWe support building ROS 2 from source on the following platforms:Ubuntu Linux 22.04Windows 10RHEL-9/FedoramacOSWhich install should you choose?Installing from binary packages or from source will both result in a fully-functional and usable ROS 2 install.

Differences between the options depend on what you plan to do with ROS 2.Binary packagesare for general use and provide an already-built install of ROS 2.


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This is great for people who want to dive in and start using ROS 2 as-is, right away.Linux users have two options for installing binary packages:Packages (debs or RPMS, depending on the platform)binary archiveInstalling from packages is the recommended method, as it installs necessary dependencies automatically and also updates alongside regular system updates.

However, you need root access in order to install deb packages.

If you don’t have root access, the binary archive is the next best choice.Windows users who choose to install from binary packages only have the binary archive option

(deb packages are exclusive to Ubuntu/Debian).Building from sourceis meant for developers looking to alter or explicitly omit parts of ROS 2’s base.

It is also recommended for platforms that don’t support binaries.


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Building from source also gives you the option to install the absolute latest version of ROS 2.Contributing to ROS 2 core?If you plan to contribute directly to ROS 2 core packages, you can install thelatest development from sourcewhich shares installation instructions with theRolling distribution.


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Title: Simulators

URL: https://docs.ros.org/en/jazzy/Tutorials/Advanced/Simulators/Simulation

Main.html

Section: Installation

--------------------------------------------------------------------------------

SimulatorsSeveral advanced robot simulators can be used with ROS 2, such as Gazebo, Webots, etc. Unlike turtlesim, they provide fairly realistic results relying on physics-based models for robots, sensors, actuators and objects. Hence, what you observe in simulation is very close to what you will get when transferring your ROS 2 controllers to a real robot.This set of tutorials will teach you how to configure different simulators with ROS 2.WebotsGazebo


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Title: Writing a simple service and client (Python) URL: https://docs.ros.org/en/jazzy/Tutorials/Beginner-Client-Libraries/Writing-A-Simple-Py-Service-And-Client.html Section: Installation --------------------------------------------------------------------------------


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Writing a simple service and client (Python)Goal:Create and run service and client nodes using Python.Tutorial level:BeginnerTime:20 minutesContentsBackgroundPrerequisitesTasks1 Create a package2 Write the service node3 Write the client node4 Build and runSummaryNext stepsRelated contentBackgroundWhennodescommunicate usingservices, the node that sends a request for data is called the client node, and the one that responds to the request is the service node. The structure of the request and response is determined by a.srvfile.The example used here is a simple integer addition system; one node requests the sum of two integers, and the other responds with the result.PrerequisitesIn previous tutorials, you learned how tocreate a workspaceandcreate a package.Tasks1 Create a packageOpen a new terminal andsource your ROS 2 installationso thatros2commands will work.Navigate into theros2_wsdirectory created in aprevious tutorial.Recall that packages should be created in thesrcdirectory, not the root of the


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should be created in thesrcdirectory, not the root of the workspace. Navigate intoros2_ws/srcand create a new package:ros2 pkg create --build-type ament_python --license Apache-2.0 py_srvcli --dependencies rclpy example_interfacesYour terminal will return a message verifying the creation of your packagepy_srvcliand all its necessary files and folders.The--dependenciesargument will automatically add the necessary dependency lines topackage.xml.example_interfacesis the package that includesthe .srv fileyou will need to structure your requests and responses:int64 aint64 b---int64 sumThe first two lines are the parameters of the request, and below the dashes is the response.1.1 Updatepackage.xmlBecause you used the--dependenciesoption during package creation, you don’t have to manually add dependencies topackage.xml.As always, though, make sure to add the description, maintainer email and name, and license information


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description, maintainer email and name, and license information topackage.xml.<description>Pythonclientservertutorial</description><maintaineremail="you@email.com">YourName</maintainer><license>Apache-2.0</license>1.2 Updatesetup.pyAdd the same information to thesetup.pyfile for themaintainer,maintainer_email,descriptionandlicensefields:maintainer='Your Name',maintainer_email='you@email.com',description='Python client server tutorial',license='Apache-2.0',2 Write the service nodeInside theros2_ws/src/py_srvcli/py_srvclidirectory, create a new file calledservice_member_function.pyand paste the following code within:fromexample_interfaces.srvimportAddTwoIntsimportrclpyfromrclpy.nodeimportNodeclassMinimalService(Node):def__init__(self):super().__init__('minimal_service')self.srv=self.create_service(AddTwoInts,'add_two_ints',self.add_two_ints_callback)defadd_two_ints_callback(self,request,response):response.sum=request.a+request.bself.get_logger().info('Incoming


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request\na:%db:%d'%(request.a,request.b))returnresponsedefmain():rclpy.init()minimal_service=MinimalService()rclpy.spin(minimal_service)rclpy.shutdown()if__name__=='__main__':main()2.1 Examine the codeThe firstimportstatement imports theAddTwoIntsservice type from theexample_interfacespackage. The followingimportstatement imports the ROS 2 Python client library, and specifically theNodeclass.fromexample_interfaces.srvimportAddTwoIntsimportrclpyfromrclpy.nodeimportNodeTheMinimalServiceclass constructor initializes the node with the nameminimal_service. Then, it creates a service and defines the type, name, and callback.def__init__(self):super().__init__('minimal_service')self.srv=self.create_service(AddTwoInts,'add_two_ints',self.add_two_ints_callback)The definition of the service callback receives the request data, sums it, and returns the sum as a response.defadd_two_ints_callback(self,request,response):response.sum=request.a+request.bself.get_logger().info('Incoming


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request\na:%db:%d'%(request.a,request.b))returnresponseFinally, the main class initializes the ROS 2 Python client library, instantiates theMinimalServiceclass to create the service node and spins the node to handle callbacks.2.2 Add an entry pointTo allow theros2runcommand to run your node, you must add the entry point tosetup.py(located in theros2_ws/src/py_srvclidirectory).Add the following line between the'console_scripts':brackets:'service = py_srvcli.service_member_function:main',3 Write the client nodeInside theros2_ws/src/py_srvcli/py_srvclidirectory, create a new file calledclient_member_function.pyand paste the following code within:importsysfromexample_interfaces.srvimportAddTwoIntsimportrclpyfromrclpy.nodeimportNodeclassMinimalClientAsync(Node):def__init__(self):super().__init__('minimal_client_async')self.cli=self.create_client(AddTwoInts,'add_two_ints')whilenotself.cli.wait_for_service(timeout_sec=1.0):self.get_logger().info('service not available, waiting


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not available, waiting again...')self.req=AddTwoInts.Request()defsend_request(self,a,b):self.req.a=aself.req.b=breturnself.cli.call_async(self.req)defmain():rclpy.init()minimal_client=MinimalClientAsync()future=minimal_client.send_request(int(sys.argv[1]),int(sys.argv[2]))rclpy.spin_until_future_complete(minimal_client,future)response=future.result()minimal_client.get_logger().info('Result of add_two_ints: for%d+%d=%d'%(int(sys.argv[1]),int(sys.argv[2]),response.sum))minimal_client.destroy_node()rclpy.shutdown()if__name__=='__main__':main()3.1 Examine the codeAs with the service code, we firstimportthe necessary libraries.importsysfromexample_interfaces.srvimportAddTwoIntsimportrclpyfromrclpy.nodeimportNodeTheMinimalClientAsyncclass constructor initializes the node with the nameminimal_client_async. The constructor definition creates a client with the same type and name as the service node. The type and name must match for the client and service to be able to communicate. Thewhileloop in the constructor


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to be able to communicate. Thewhileloop in the constructor checks if a service matching the type and name of the client is available once a second. Finally it creates a newAddTwoIntsrequest object.def__init__(self):super().__init__('minimal_client_async')self.cli=self.create_client(AddTwoInts,'add_two_ints')whilenotself.cli.wait_for_service(timeout_sec=1.0):self.get_logger().info('service not available, waiting again...')self.req=AddTwoInts.Request()Below the constructor is thesend_requestmethod, which will send the request and spin until it receives the response or fails.defsend_request(self,a,b):self.req.a=aself.req.b=breturnself.cli.call_async(self.req)Finally we have themainmethod, which constructs aMinimalClientAsyncobject, sends the request using the passed-in command-line arguments, callsrclpy.spin_until_future_completeto wait for the result, and logs the


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wait for the result, and logs the results.defmain():rclpy.init()minimal_client=MinimalClientAsync()future=minimal_client.send_request(int(sys.argv[1]),int(sys.argv[2]))rclpy.spin_until_future_complete(minimal_client,future)response=future.result()minimal_client.get_logger().info('Result of add_two_ints: for%d+%d=%d'%(int(sys.argv[1]),int(sys.argv[2]),response.sum))minimal_client.destroy_node()rclpy.shutdown()WarningDo not userclpy.spin_until_future_completein a ROS 2 callback. For more details see thesync deadlock article.3.2 Add an entry pointLike the service node, you also have to add an entry point to be able to run the client node.Theentry_pointsfield of yoursetup.pyfile should look like this:entry_points={'console_scripts':['service = py_srvcli.service_member_function:main','client = py_srvcli.client_member_function:main',],},4 Build and runIt’s good practice to runrosdepin the root of your workspace (ros2_ws) to check for missing dependencies before building:LinuxmacOSWindowsrosdep install -i


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dependencies before building:LinuxmacOSWindowsrosdep install -i --from-path src --rosdistro jazzy -yrosdep only runs on Linux, so you can skip ahead to next step.rosdep only runs on Linux, so you can skip ahead to next step.Navigate back to the root of your workspace,ros2_ws, and build your new package:colcon build --packages-select py_srvcliOpen a new terminal, navigate toros2_ws, and source the setup files:LinuxmacOSWindowssource install/setup.bash. install/setup.bashcall install/setup.batNow run the service node:ros2 run py_srvcli serviceThe node will wait for the client’s request.Open another terminal and source the setup files from insideros2_wsagain. Start the client node, followed by any two integers separated by a space:ros2 run py_srvcli client 2 3If you chose2and3, for example, the client would receive a response like this:[INFO] [minimal_client_async]: Result of add_two_ints: for 2 + 3 = 5Return to the terminal where your service node is running. You will see that it published log messages when it


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is running. You will see that it published log messages when it received the request:[INFO] [minimal_service]: Incoming requesta: 2 b: 3EnterCtrl+Cin the server terminal to stop the node from spinning.SummaryYou created two nodes to request and respond to data over a service. You added their dependencies and executables to the package configuration files so that you could build and run them, allowing you to see a service/client system at work.Next stepsIn the last few tutorials you’ve been utilizing interfaces to pass data across topics and services. Next, you’ll learn how tocreate custom interfaces.Related contentThere are several ways you could write a service and client in Python; check out theminimal_clientandminimal_servicepackages in theros2/examplesrepo.In this tutorial, you used thecall_async()API in your client node to call the service. There is another service call API available for Python called synchronous calls. We do not recommend using synchronous calls, but if you’d like to learn more


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using synchronous calls, but if you’d like to learn more about them, read the guide toSynchronous vs. asynchronous clients.


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Code Examples:

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ros2 pkg create -

build

type ament_python -

license Apache

2.0 py_srvcli -

dependencies rclpy example_interfaces

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int64 aint64 b--

int64 sum

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<description>Pythonclientservertutorial</description><maintaineremail="you@email.com">YourName</maintainer><license>Apache

2.0</license>

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fromexample_interfaces.srvimportAddTwoIntsimportrclpyfromrclpy.nodeimportNodeclassMinimalService(Node):def__init__(self):super().__init__('minimal_service')self.srv=self.create_service(AddTwoInts,'add_two_ints',self.add_two_ints_callback)defadd_two_ints_callback(self,request,response):response.sum=request.a+request.bself.get_logger().info('Incoming request\na:%db:%d'%(request.a,request.b))returnresponsedefmain():rclpy.init()minimal_service=MinimalService()rclpy.spin(minimal_service)rclpy.shutdown()if__name__=='__main__':main()

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fromexample_interfaces.srvimportAddTwoIntsimportrclpyfromrclpy.nodeimportNode

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def__init__(self):super().__init__('minimal_service')self.srv=self.create_service(AddTwoInts,'add_two_ints',self.add_two_ints_callback)

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defadd_two_ints_callback(self,request,response):response.sum=request.a+request.bself.get_logger().info('Incoming request\na:%db:%d'%(request.a,request.b))returnresponse

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'service = py_srvcli.service_member_function:main',

Language: unknown importsysfromexample_interfaces.srvimportAddTwoIntsimportrclpyfromrclpy.nodeimportNodeclassMinimalClientAsync(Node):def__init__(self):super().__init__('minimal_client_async')self.cli=self.create_client(AddTwoInts,'add_two_ints')whilenotself.cli.wait_for_service(timeout_sec=1.0):self.get_logger().info('service not available, waiting again...')self.req=AddTwoInts.Request()defsend_request(self,a,b):self.req.a=aself.req.b=breturnself.cli.call_async(self.req)defmain():rclpy.init()minimal_client=MinimalClientAsync()future=minimal_client.send_request(int(sys.argv[1]),int(sys.argv[2]))rclpy.spin_until_future_complete(minimal_client,future)response=future.result()minimal_client.get_logger().info('Result of add_two_ints: for%d+%d=%d'%(int(sys.argv[1]),int(sys.argv[2]),response.sum))minimal_client.destroy_node()rclpy.shutdown()if__name__=='__main__':main()

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importsysfromexample_interfaces.srvimportAddTwoIntsimportrclpyfromrclpy.nodeimportNode

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defsend_request(self,a,b):self.req.a=aself.req.b=breturnself.cli.call_async(self.req)

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defmain():rclpy.init()minimal_client=MinimalClientAsync()future=minimal_client.send_request(int(sys.argv[1]),int(sys.argv[2]))rclpy.spin_until_future_complete(minimal_client,future)response=future.result()minimal_client.get_logger().info('Result of add_two_ints: for%d+%d=%d'%(int(sys.argv[1]),int(sys.argv[2]),response.sum))minimal_client.destroy_node()rclpy.shutdown()


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rosdep install

i -

from

path src -

rosdistro jazzy

y

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colcon build -

packages

select py_srvcli

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source install/setup.bash

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. install/setup.bash

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call install/setup.bat

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ros2 run py_srvcli service

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Title: Recording and playing back data URL: https://docs.ros.org/en/jazzy/Tutorials/Beginner-CLI-Tools/Recording-And-Playing-Back-Data/Recording-And-Playing-Back-Data.html Section: Installation --------------------------------------------------------------------------------


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Recording and playing back dataGoal:Record data published on a topic and a service so you can replay and examine it any time.Tutorial level:BeginnerTime:15 minutesContentsBackgroundPrerequisitesManaging Topic Data1 Setup2 Choose a topic3 Record topics4 Inspect topic data5 Play topic dataManaging Service Data1 Setup2 Check service availability3 Record services4 Inspect service data5 Play service dataSummaryNext stepsRelated contentBackgroundros2bagis a command line tool for recording data published on topics and services in your ROS 2 system. It accumulates the data passed on any number of topics and services, then saves it in a database. You can then replay the data to reproduce the results of your tests and experiments. Recording topics and services is also a great way to share your work and allow others to recreate it.PrerequisitesYou should haveros2baginstalled as a part of your regular ROS 2 setup.If you need to install ROS 2, see theInstallation instructions.This tutorial talks about concepts covered


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instructions.This tutorial talks about concepts covered in previous tutorials, likenodes,topicsandservices. It also uses theturtlesim packageandService Introspection Demo.As always, don’t forget to source ROS 2 inevery new terminal you open.Managing Topic Data1 SetupYou’ll be recording your keyboard input in theturtlesimsystem to save and replay later on, so begin by starting up the/turtlesimand/teleop_turtlenodes.Open a new terminal and run:ros2 run turtlesim turtlesim_nodeOpen another terminal and run:ros2 run turtlesim turtle_teleop_keyLet’s also make a new directory to store our saved recordings, just as good practice:LinuxmacOSWindowsmkdir bag_filescd bag_filesmkdir bag_filescd bag_filesmd bag_filescd bag_files2 Choose a topicros2bagcan record data from messages published to topics. To see the list of your system’s topics, open a new terminal and run the command:ros2 topic listWhich will return:/parameter_events/rosout/turtle1/cmd_vel/turtle1/color_sensor/turtle1/poseIn the topics tutorial, you


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the topics tutorial, you learned that the/turtle_teleopnode publishes commands on the/turtle1/cmd_veltopic to make the turtle move in turtlesim.To see the data that/turtle1/cmd_velis publishing, run the command:ros2 topic echo /turtle1/cmd_velNothing will show up at first because no data is being published by the teleop. Return to the terminal where you ran the teleop and select it so it’s active. Use the arrow keys to move the turtle around, and you will see data being published on the terminal runningros2topicecho.linear:x: 2.0y: 0.0z: 0.0angular:x: 0.0y: 0.0z: 0.0---3 Record topics3.1 Record a single topicTo record the data published to a topic use the command syntax:ros2 bag record <topic_name>Before running this command on your chosen topic, open a new terminal and move into thebag_filesdirectory you created earlier, because the rosbag file will save in the directory where you run it.Run the command:ros2 bag record /turtle1/cmd_velYou will see the following messages in the terminal (the date and time


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see the following messages in the terminal (the date and time will be different):[INFO] [rosbag2_storage]: Opened database 'rosbag2_2019_10_11-05_18_45'.[INFO] [rosbag2_transport]: Listening for topics...[INFO] [rosbag2_transport]: Subscribed to topic '/turtle1/cmd_vel'[INFO] [rosbag2_transport]: All requested topics are subscribed. Stopping discovery...Nowros2bagis recording the data published on the/turtle1/cmd_veltopic. Return to the teleop terminal and move the turtle around again. The movements don’t matter, but try to make a recognizable pattern to see when you replay the data later.PressCtrl+Cto stop recording.The data will be accumulated in a new bag directory with a name in the pattern ofrosbag2_year_month_day-hour_minute_second. This directory will contain ametadata.yamlalong with the bag file in the recorded format.3.2 Record multiple topicsYou can also record multiple topics, as well as change the name of the fileros2bagsaves to.Run the following command:ros2 bag record -o subset


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to.Run the following command:ros2 bag record -o subset /turtle1/cmd_vel /turtle1/poseThe-ooption allows you to choose a unique name for your bag file. The following string, in this casesubset, is the file name.To record more than one topic at a time, simply list each topic separated by a space.You will see the following message, confirming that both topics are being recorded.[INFO] [rosbag2_storage]: Opened database 'subset'.[INFO] [rosbag2_transport]: Listening for topics...[INFO] [rosbag2_transport]: Subscribed to topic '/turtle1/cmd_vel'[INFO] [rosbag2_transport]: Subscribed to topic '/turtle1/pose'[INFO] [rosbag2_transport]: All requested topics are subscribed. Stopping discovery...You can move the turtle around and pressCtrl+Cwhen you’re finished.NoteThere is another option you can add to the command,-a, which records all the topics on your system.4 Inspect topic dataYou can see details about your recording by running:ros2 bag info <bag_file_name>Running this command on thesubsetbag file will return a


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this command on thesubsetbag file will return a list of information on the file:ros2 bag info subsetFiles:             subset.mcapBag size:          228.5 KiBStorage id:        mcapDuration:          48.47sStart:             Oct 11 2019 06:09:09.12 (1570799349.12)End                Oct 11 2019 06:09:57.60 (1570799397.60)Messages:          3013Topic information: Topic: /turtle1/cmd_vel | Type: geometry_msgs/msg/Twist | Count: 9 | Serialization Format: cdrTopic: /turtle1/pose | Type: turtlesim/msg/Pose | Count: 3004 | Serialization Format: cdr5 Play topic dataBefore replaying the bag file, enterCtrl+Cin the terminal where the teleop is running. Then make sure your turtlesim window is visible so you can see the bag file in action.Enter the command:ros2 bag play subsetThe terminal will return the message:[INFO] [rosbag2_storage]: Opened database 'subset'.Your turtle will follow the same path you entered while recording (though not 100% exactly; turtlesim is sensitive to small changes in the system’s


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turtlesim is sensitive to small changes in the system’s timing).Because thesubsetfile recorded the/turtle1/posetopic, theros2bagplaycommand won’t quit for as long as you had turtlesim running, even if you weren’t moving.This is because as long as the/turtlesimnode is active, it publishes data on the/turtle1/posetopic at regular intervals. You may have noticed in theros2baginfoexample result above that the/turtle1/cmd_veltopic’sCountinformation was only 9; that’s how many times we pressed the arrow keys while recording.Notice that/turtle1/posehas aCountvalue of over 3000; while we were recording, data was published on that topic 3000 times.To get an idea of how often position data is published, you can run the command:ros2 topic hz /turtle1/poseManaging Service Data1 SetupYou’ll be recording service data betweenintrospection_clientandintrospection_service, then display and replay that same data later on. To record service data between service client and server,ServiceIntrospectionmust be enabled on the


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client and server,ServiceIntrospectionmust be enabled on the node.Let’s startintrospection_clientandintrospection_servicenodes and enableServiceIntrospection. You can see more details forService Introspection Demo.Open a new terminal and runintrospection_service, enablingServiceIntrospection:ros2 run demo_nodes_cpp introspection_service --ros-args -p service_configure_introspection:=contentsOpen another terminal and runintrospection_client, enablingServiceIntrospection:ros2 run demo_nodes_cpp introspection_client --ros-args -p client_configure_introspection:=contents2 Check service availabilityros2bagcan only record data from available services. To see the list of your system’s services, open a new terminal and run the command:ros2 service listWhich will


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a new terminal and run the command:ros2 service listWhich will return:/add_two_ints/introspection_client/describe_parameters/introspection_client/get_parameter_types/introspection_client/get_parameters/introspection_client/get_type_description/introspection_client/list_parameters/introspection_client/set_parameters/introspection_client/set_parameters_atomically/introspection_service/describe_parameters/introspection_service/get_parameter_types/introspection_service/get_parameters/introspection_service/get_type_description/introspection_service/list_parameters/introspection_service/set_parameters/introspection_service/set_parameters_atomicallyTo check ifServiceIntrospectionis enabled on the client and service, run the command:ros2 service echo --flow-style /add_two_intsYou should see service communication like below:info:event_type: REQUEST_SENTstamp:sec: 1713995389nanosec: 386809259client_gid: [1, 15, 96, 219, 162, 1, 108, 201, 0, 0, 0, 0, 0, 0, 21, 3]sequence_number: 133request: [{a: 2, b: 3}]response:


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0, 21, 3]sequence_number: 133request: [{a: 2, b: 3}]response: []---3 Record servicesTo record service data, the following options are supported. Service data can be recorded with topics at the same time.To record specific services:ros2 bag record --service <service_names>To record all services:ros2 bag record --all-servicesRun the command:ros2 bag record --service /add_two_intsYou will see the following messages in the terminal (the date and time will be different):[INFO] [1713995957.643573503] [rosbag2_recorder]: Press SPACE for pausing/resuming[INFO] [1713995957.662067587] [rosbag2_recorder]: Event publisher thread: Starting[INFO] [1713995957.662067614] [rosbag2_recorder]: Listening for topics...[INFO] [1713995957.666048323] [rosbag2_recorder]: Subscribed to topic '/add_two_ints/_service_event'[INFO] [1713995957.666092458] [rosbag2_recorder]: Recording...Nowros2bagis recording the service data published on the/add_two_intsservice. To stop the recording, enterCtrl+Cin the terminal.The data will be


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stop the recording, enterCtrl+Cin the terminal.The data will be accumulated in a new bag directory with a name in the pattern ofrosbag2_year_month_day-hour_minute_second. This directory will contain ametadata.yamlalong with the bag file in the recorded format.4 Inspect service dataYou can see details about your recording by running:ros2 bag info <bag_file_name>Running this command will return a list of information on the file:Files:             rosbag2_2024_04_24-14_59_17_0.mcapBag size:          15.1 KiBStorage id:        mcapROS Distro:        rollingDuration:          9.211sStart:             Apr 24 2024 14:59:17.676 (1713995957.676)End:               Apr 24 2024 14:59:26.888 (1713995966.888)Messages:          0Topic information:Service:           1Service information: Service: /add_two_ints | Type: example_interfaces/srv/AddTwoInts | Event Count: 78 | Serialization Format: cdr5 Play service dataBefore replaying the bag file, enterCtrl+Cin the terminal whereintrospection_clientis running.


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enterCtrl+Cin the terminal whereintrospection_clientis running. Whenintrospection_clientstops running,introspection_servicealso stops printing the result because there are no incoming requests.Replaying the service data from the bag file will start sending the requests tointrospection_service.Enter the command:ros2 bag play --publish-service-requests <bag_file_name>The terminal will return the message:[INFO] [1713997477.870856190] [rosbag2_player]: Set rate to 1[INFO] [1713997477.877417477] [rosbag2_player]: Adding keyboard callbacks.[INFO] [1713997477.877442404] [rosbag2_player]: Press SPACE for Pause/Resume[INFO] [1713997477.877447855] [rosbag2_player]: Press CURSOR_RIGHT for Play Next Message[INFO] [1713997477.877452655] [rosbag2_player]: Press CURSOR_UP for Increase Rate 10%[INFO] [1713997477.877456954] [rosbag2_player]: Press CURSOR_DOWN for Decrease Rate 10%[INFO] [1713997477.877573647] [rosbag2_player]: Playback until timestamp: -1Yourintrospection_serviceterminal will once again start printing the


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will once again start printing the following service messages:[INFO] [1713997478.090466075] [introspection_service]: Incoming requesta: 2 b: 3This is becauseros2bagplaysends the service request data from the bag file to the/add_two_intsservice.We can also introspect service communication asros2bagplayis playing it back to verify theintrospection_service.Run this command beforeros2bagplayto see theintrospection_service:ros2 service echo --flow-style /add_two_intsYou can see the service request from the bag file and the service response fromintrospection_service.info:event_type: REQUEST_RECEIVEDstamp:sec: 1713998176nanosec: 372700698client_gid: [1, 15, 96, 219, 80, 2, 158, 123, 0, 0, 0, 0, 0, 0, 20, 4]sequence_number: 1request: [{a: 2, b: 3}]response: []---info:event_type: RESPONSE_SENTstamp:sec: 1713998176nanosec: 373016882client_gid: [1, 15, 96, 219, 80, 2, 158, 123, 0, 0, 0, 0, 0, 0, 20, 4]sequence_number: 1request: []response: [{sum: 5}]SummaryYou can record data passed on topics and services in your ROS


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can record data passed on topics and services in your ROS 2 system using theros2bagcommand. Whether you’re sharing your work with others or introspecting your own experiments, it’s a great tool to know about.Next stepsYou’ve completed the “Beginner: CLI Tools” tutorials! The next step is tackling the “Beginner: Client Libraries” tutorials, starting withCreating a workspace.Related contentA more thorough explanation ofros2bagcan be found in the READMEhere. For more information on service recording and playback can be found in the design documenthere. For more information on QoS compatibility andros2bag, seerosbag2: Overriding QoS Policies.


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Code Examples:

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ros2 run turtlesim turtlesim_node

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ros2 run turtlesim turtle_teleop_key

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mkdir bag_filescd bag_files

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mkdir bag_filescd bag_files

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md bag_filescd bag_files

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ros2 topic list

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/parameter_events/rosout/turtle1/cmd_vel/turtle1/color_sensor/turtle1/pose

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ros2 topic echo /turtle1/cmd_vel

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ros2 bag record <topic_name>

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ros2 bag record /turtle1/cmd_vel

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ros2 bag record

o subset /turtle1/cmd_vel /turtle1/pose


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ros2 bag record

o subset /turtle1/cmd_vel /turtle1/pose

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ros2 bag info <bag_file_name>

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ros2 bag info subset

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ros2 bag play subset


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ros2 bag play subset

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ros2 topic hz /turtle1/pose

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ros2 service list

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ros2 service list

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/add_two_ints/introspection_client/describe_parameters/introspection_client/get_parameter_types/introspection_client/get_parameters/introspection_client/get_type_description/introspection_client/list_parameters/introspection_client/set_parameters/introspection_client/set_parameters_atomically/introspection_service/describe_parameters/introspection_service/get_parameter_types/introspection_service/get_parameters/introspection_service/get_type_description/introspection_service/list_parameters/introspection_service/set_parameters/introspection_service/set_parameters_atomically

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ros2 service echo -

flow

style /add_two_ints

Language: unknown info:event_type: REQUEST_SENTstamp:sec: 1713995389nanosec: 386809259client_gid: [1, 15, 96, 219, 162, 1, 108, 201, 0, 0, 0, 0, 0, 0, 21, 3]sequence_number: 133request: [{a: 2, b: 3}]response: []---

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ros2 bag record -

service <service_names>

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ros2 bag record -


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service <service_names>

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ros2 bag record -

all

services

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ros2 bag record -

service /add_two_ints

Language: unknown [INFO] [1713995957.643573503] [rosbag2_recorder]: Press SPACE for pausing/resuming[INFO] [1713995957.662067587] [rosbag2_recorder]: Event publisher thread: Starting[INFO] [1713995957.662067614] [rosbag2_recorder]: Listening for topics...[INFO] [1713995957.666048323] [rosbag2_recorder]: Subscribed to topic '/add_two_ints/_service_event'[INFO] [1713995957.666092458] [rosbag2_recorder]: Recording...

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ros2 bag info <bag_file_name>


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ros2 bag info <bag_file_name>

Language: unknown Files:             rosbag2_2024_04_24-14_59_17_0.mcapBag size:          15.1 KiBStorage id:        mcapROS Distro:        rollingDuration:          9.211sStart:             Apr 24 2024 14:59:17.676 (1713995957.676)End:               Apr 24 2024 14:59:26.888 (1713995966.888)Messages:          0Topic information:Service:           1Service information: Service: /add_two_ints | Type: example_interfaces/srv/AddTwoInts | Event Count: 78 | Serialization Format: cdr

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ros2 bag play -

publish

service

requests <bag_file_name>


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ros2 bag play -

publish

service

requests <bag_file_name>

Language: unknown [INFO] [1713997477.870856190] [rosbag2_player]: Set rate to 1[INFO] [1713997477.877417477] [rosbag2_player]: Adding keyboard callbacks.[INFO] [1713997477.877442404] [rosbag2_player]: Press SPACE for Pause/Resume[INFO] [1713997477.877447855] [rosbag2_player]: Press CURSOR_RIGHT for Play Next Message[INFO] [1713997477.877452655] [rosbag2_player]: Press CURSOR_UP for Increase Rate 10%[INFO] [1713997477.877456954] [rosbag2_player]: Press CURSOR_DOWN for Decrease Rate 10%[INFO] [1713997477.877573647] [rosbag2_player]: Playback until timestamp: -1

Language: unknown [INFO] [1713997478.090466075] [introspection_service]: Incoming requesta: 2 b: 3

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ros2 service echo -

flow

style /add_two_ints


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ros2 service echo -

flow

style /add_two_ints

Language: unknown info:event_type: REQUEST_RECEIVEDstamp:sec: 1713998176nanosec: 372700698client_gid: [1, 15, 96, 219, 80, 2, 158, 123, 0, 0, 0, 0, 0, 0, 20, 4]sequence_number: 1request: [{a: 2, b: 3}]response: []---info:event_type: RESPONSE_SENTstamp:sec: 1713998176nanosec: 373016882client_gid: [1, 15, 96, 219, 80, 2, 158, 123, 0, 0, 0, 0, 0, 0, 20, 4]sequence_number: 1request: []response: [{sum: 5}]


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Title: Testing

URL: https://docs.ros.org/en/jazzy/Tutorials/Intermediate/Testing/Testing

Main.html

Section: Installation

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TestingWhy automatic tests?Here are some of the many good reasons why should we have automated tests:You can make incremental updates to your code more quickly. ROS has hundreds of packages with many interdependencies, so it can be hard to anticipate the problems a small change might cause. If your change passes the unit tests, you can be more confident that you haven’t introduced problems — or at least the problems aren’t your fault.You can refactor your code with greater confidence. Passing the unit tests verifies that you haven’t introduced any bugs while refactoring. This gives you this wonderful freedom from change fear!It leads to better designed code. Unit tests force you to write your code so that it can be more easily tested. This often means keeping your underlying functions and framework separate, which is one of our design goals with ROS code.They prevent recurring bugs (bug regressions). It’s a good practice to write a unit test for every bug you fix. In fact, write the unit test before you


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for every bug you fix. In fact, write the unit test before you fix the bug. This will help you to precisely, or even deterministically, reproduce the bug, and much more precisely understand what the problem is. As a result, you will also create a better patch, which you can then test with your regression test to verify that the bug is fixed. That way the bug won’t accidentally get reintroduced if the code gets modified later on. It also means that it will be easier to convince the reviewer of the patch that the problem is solved, and the contribution is of high quality.Other people can work on your code more easily (an automatic form of documentation). It can be hard to figure out whether or not you’ve broken someone else’s code when you make a change. The unit tests are a tool for other developers to validate their changes. Automatic tests document your coding decisions, and communicate to other developers automatically about their violation. Thus tests become documentation for your code — a documentation


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Thus tests become documentation for your code — a documentation that does not need to be read for the most time, and when it does need to be inspected the test system will precisely indicate what to read (which tests fail). By writing automatic tests you make other contributors faster. This improves the entire ROS project.It is much easier to become a contributor to ROS if we have automated unit tests. It is very difficult for new external developers to contribute to your components. When they make changes to code, they are often doing it in the blind, driven by a lot of guesswork. By providing a harness of automated tests, you help them in the task. They get immediate feedback for their changes. It becomes easier to contribute to a project, and new contributors to join more easily. Also their first contributions are of higher quality, which decreases the workload on maintainers. A win-win!Automatic tests simplify maintainership. Especially for mature packages, which change more slowly, and mostly need to be


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packages, which change more slowly, and mostly need to be updated to new dependencies, an automatic test suite helps to very quickly establish whether the package still works. This makes it much easier to decide whether the package is still supported or not.Automatic tests amplify the value of Continuous Integration. Regression tests, along with normal scenario-based requirements tests, contribute to overall body of automated tests for your component. Your component is better tested against evolution of other APIs that it depends on (CI servers will tell you better and more precisely what problems develop in your code).Perhaps the most important benefit of writing tests is that tests make you a good citizen. Tests influence quality in the long term. It is a well accepted practice in many open-source projects. By writing regressions tests, you are contributing to long term quality of the ROS ecosystem.Is this all coming for free?Of course, there is never free lunch. To get the benefits of testing, some


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there is never free lunch. To get the benefits of testing, some investment is necessary.You need to develop a test, which sometimes may be difficult or costly. Sometimes it might also be nontrivial, as the test should be automatic. Things get particularly hairy if your tests should involve special hardware (they should not: try to use simulation, mock the hardware, or narrow down the test to a smaller software problem) or require external environment, for instance human operators.Regression tests and other automatic tests need to be maintained. When the design of the component changes, a lot of tests become invalidated (for instance they no longer compile, or throw runtime exceptions related to the API design). These tests fail not only because the redesign re-introduced bugs but also because they need to be updated to the new design. Occasionally, with bigger redesigns, old regression tests should be dropped.Large bodies of tests can take a long time to run, which can increase Continuous Integration server


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time to run, which can increase Continuous Integration server costs.Available Tutorials:Running Tests in ROS 2 from the Command LineWriting Basic Tests with C++ with GTestWriting Basic Tests with PythonTesting Your Code with the ROS Build Farm


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Title: Migrating Packages

URL: https://docs.ros.org/en/jazzy/How-To-Guides/Migrating-from-ROS1/Migrating-Packages.html

Section: Installation

--------------------------------------------------------------------------------

Migrating PackagesTable of ContentsPrerequisitesPackage.xml format versionDependency namesMetapackagesLicensingChanging the LicenseThere are two different kinds of package migrations:Migrating the source code of an existing package from ROS 1 to ROS 2 with the intent that a significant part of the source code will stay the same or at least similar.

An example for this ispluginlibwhere the source code is maintained in different branches within the same repository and common patches can be ported between those branches when necessary.Implementing the same or similar functionality of a ROS 1 package for ROS 2 but with the assumption that the source code will be significantly different.


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An example for this isroscppin ROS 1 andrclcppin ROS 2 which are separate repositories and don’t share any code.PrerequisitesBefore being able to migrate a ROS 1 package to ROS 2 all of its dependencies must be available in ROS 2.Package.xml format versionROS 2 only supportspackage.xmlformat versions 2 and higher.

If your package’spackage.xmluses format 1, then update it using thePackage.xml format 1 to 2 migration guide.Dependency namesDependency names that come fromrosdepshould not need to change, as those are shared across ROS 1 and ROS 2.Some packages released into ROS might have different names in ROS 2 so the dependencies might need to be updated accordingly.MetapackagesROS 2 doesn’t have a special package type for metapackages.

Metapackages can still exist as regular packages that only contain runtime dependencies.

When migrating metapackages from ROS 1, simply remove the<metapackage/>tag in your package manifest.


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SeeUsing variantsfor more information on metapackages/variants.LicensingIn ROS 1 our recommended license was the3-Clause BSD License.

In ROS 2 our recommended license is theApache 2.0 License.For any new project we recommend using the Apache 2.0 License, whether ROS 1 or ROS 2.However, when migrating code from ROS 1 to ROS 2 we cannot simply change the license.

The existing license must be preserved for any preexisting contributions.To that end if a package is being migrated we recommend keeping the existing license and continuing to contribute to that package under the existing OSI license, which we expect to be the BSD license for core elements.This will keep things clear and easy to understand.Changing the LicenseIt is possible to change the license, however you will need to contact all the contributors and get permission.

For most packages this is likely to be a significant effort and not worth considering.

If the package has a small set of contributors then this may be feasible.


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Title: Visualizing ROS 2 data with Foxglove Studio

URL: https://docs.ros.org/en/jazzy/How-To-Guides/Visualizing-ROS-2-Data-With-Foxglove-Studio.html

Section: Installation

--------------------------------------------------------------------------------


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Visualizing ROS 2 data with Foxglove StudioFoxglove Studiois an open source visualization and debugging tool for your robotics data.It is available in a variety of ways to make development as convenient as possible – it can be run as a standalone desktop app, accessed via your browser, or even self-hosted on your own domain.View the source code onGitHub.InstallationTo use the web app, simply open Google Chrome and navigate tostudio.foxglove.dev.To use the desktop app for Linux, macOS, or Windows, download it directly from theFoxglove Studio website.Connect to a data sourceOn opening Foxglove Studio, you will see a dialog with a list ofall possible data sources.To connect to your ROS 2 stack, click “Open connection”, select the “Rosbridge (ROS 1 & 2)” tab, and configure your “WebSocket URL”.You could also drag-and-drop any local ROS 2.db3files directly into the application to load them for playback.NoteIn order toload custom message definitions in your ROS 2 files, try converting them to theMCAP file


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in your ROS 2 files, try converting them to theMCAP file format.Check out theFoxglove Studio docsfor more detailed instructions.Building layouts with panelsPanelsare modular visualization interfaces that can be configured and arranged into Studiolayouts.


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You can also save your layouts for future use, for your own personal reference or with your larger robotics team.Find the full list of available panels in the sidebar’s “Add panel” tab.We’ve highlighted some particularly useful ones below:1 3D: Display visualization markers in a 3D scenePublish marker messages to add primitive shapes (arrows, spheres, etc.) and more complex visualizations (occupancy grids, point clouds, etc.) to your 3D panel’s scene.Choose the topics you want to display via the topic picker on the left, and configure each topic’s visualization settings in the “Edit topic settings” menu.Reference thedocsfor a full list ofsupported message typesand some usefuluser interactions.2 Diagnostics: Filter and sort diagnostics messagesDisplay the status of seen nodes (i.e. stale, error, warn, or OK) from topics with adiagnostic_msgs/msg/DiagnosticArraydatatype in a running feed, and display the diagnostics data for a givendiagnostic_name/hardware_id.Reference thedocsfor more details.3 Image: View


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thedocsfor more details.3 Image: View camera feed imagesSelect asensor_msgs/msg/Imageorsensor_msgs/msg/CompressedImagetopic to display.Reference thedocsfor more details.4 Log: View log messagesTo viewrcl_interfaces/msg/Logmessages live, use the desktop app toconnectto your running ROS stack.


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To viewrcl_interfaces/msg/Logmessages from a pre-recorded data file, you can drag-and-drop your file into either thewebor desktop app.Next, add aLogpanel to your layout.

If you’ve connected to your ROS stack correctly, you should now see a list of your log messages, with the ability to filter them by node name or severity level.Reference thedocsfor more details.5 Plot: Plot arbitrary values over timePlot arbitrary values from your topics’ message paths over playback time.Specify the topic values you want to plot along the y-axis.


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For the x-axis, choose between plotting the y-axis value’s timestamp, element index, or another custom topic message path.Reference thedocsfor more details.6 Raw Messages: View incoming topic messagesDisplay incoming topic data in an easy-to-read collapsible JSON tree format.Reference thedocsfor more details.7 Teleop: Teleoperate your robotTeleoperate your physical robot by publishinggeometry_msgs/msg/Twistmessages on a given topic back to your live ROS stack.Reference thedocsfor more details.8 URDF Viewer: View and manipulate your URDF modelTo visualize and control your robot model in Foxglove Studio, open the web or desktop application and add aURDF Viewerpanel to your layout.


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Then, drag and drop your URDF file into that panel to visualize your robot model.Select any topic publishing aJointStatemessage to update the visualization based on the published joint states (defaults to/joint_states).Toggle to “Manual joint control” to set joint positions using the provided controls.Reference thedocsfor more details.Other basic actions1 View your ROS graphUsing the desktop app,connectto your running ROS stack.

Next, add aTopic Graphpanel to your layout.

If you’ve connected to your ROS stack correctly, you should now see a computational graph of your ROS nodes, topics, and services in that panel.

Use the controls on the right side of the panel to select which topics to display or to toggle services.2 View and edit your ROS paramsUsing the desktop app,connectto your running ROS stack.

Next, add aParameterspanel to your layout.

If you’ve connected to your ROS stack correctly, you should now see a live view of your currentrosparams.


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You can edit these parameter values to publishrosparamupdates back to your ROS stack.3 Publish messages back to your live ROS stackUsing the desktop app,connectto your running ROS stack.

Next, add aPublishpanel to your layout.Specify the topic you want to publish on to infer its datatype and populate the text field with a JSON message template.Selecting a datatype in the dropdown of common ROS datatypes will also populate the text field with a JSON message template.Edit the template to customize your message before hitting “Publish”.


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Title: Using variants

URL: https://docs.ros.org/en/jazzy/How

To

Guides/Using

Variants.html

Section: Installation

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Using variantsMetapackages do not provide software directly but depend on a group of other related packages to provide a convienent installation mechanism for the complete group of packages.[1][2]Variants are a list of official metapackages for commonly useful groups of ROS packages.[1]https://wiki.debian.org/metapackage[2]https://help.ubuntu.com/community/MetaPackagesThe different variants in ROS 2 are specified inREP-2001.In addition to the official variants, there may be metapackages for specific institutions or robots as described inREP-108.Adding variantsAdditional variants that are of general use to the ROS community can be proposed by contributing an update toREP-2001 via pull requestdescribing the packages included in the new variant. Institution and robot specific variants can be published directly by their respective maintainers and no update to REP-2001 is required.Creating project-specific variantsIf you are creating ROS packages to use privately in your own projects, you can create variants


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to use privately in your own projects, you can create variants specific to your projects using the official variants as examples. To do so you need only create two files:A minimal variant package is created as a package with theament_cmakebuild type, abuildtool_dependonament_cmakeandexec_dependentries for each package you want to include in the variant.<?xml version="1.0"?><?xml-model href="http://download.ros.org/schema/package_format2.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?><packageformat="2"><name>my_project_variant</name><version>1.0.0</version><description>Apackagetoaggregateallpackagesinmy_project.</description><maintaineremail="maintainer-email">MaintainerName</maintainer><license>Apache-2.0</license><!-- packages in my_project --><exec_depend>my_project_msgs</exec_depend><exec_depend>my_project_services</exec_depend><exec_depend>my_project_examples</exec_depend><export><build_type>ament_cmake</build_type></export></package>A minimal ament_cmake package includes aCMakeLists.txtwhich


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minimal ament_cmake package includes aCMakeLists.txtwhich registers the package.xml as an ament package for use in ROS 2.cmake_minimum_required(VERSION3.5)project(my_project_variantNONE)find_package(ament_cmakeREQUIRED)ament_package()You can then build and install your variant package alongside your other private packages.Creating custom variants with platform-specific toolsSome platforms have tools for creating basic packages that do not require a full ROS build farm environment or equivalent infrastructure. It is possible to use these tools to create platform-dependent variants. This approach does not include support for ROS packaging tools and is platform dependent but requires much less infrastructure to produce if you are creating collections of existing packages rather than a mix of public and private ROS packages. For example, on Debian or Ubuntu systems you can use theequivsutilities. The Debian Administrator’s handbook has aSection on meta-packages.


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Code Examples:

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<?xml version="1.0"?><?xml

model href="http://download.ros.org/schema/package_format2.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?><packageformat="2"><name>my_project_variant</name><version>1.0.0</version><description>Apackagetoaggregateallpackagesinmy_project.</description><maintaineremail="maintainer

email">MaintainerName</maintainer><license>Apache

2.0</license><!-

packages in my_project -

><exec_depend>my_project_msgs</exec_depend><exec_depend>my_project_services</exec_depend><exec_depend>my_project_examples</exec_depend><export><build_type>ament_cmake</build_type></export></package>

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cmake_minimum_required(VERSION3.5)project(my_project_variantNONE)find_package(ament_cmakeREQUIRED)ament_package()


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Title: Services

URL: https://docs.ros.org/en/jazzy/Concepts/Basic/About

Services.html

Section: Installation

--------------------------------------------------------------------------------


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ServicesTable of ContentsService serverService clientIn ROS 2, a service refers to a remote procedure call. In other words, a node can make a remote procedure call to another node which will do a computation and return a result.This structure is reflected in how a service message definition looks:uint32request---uint32responseIn ROS 2, services are expected to return quickly, as the client is generally waiting on the result. Services should never be used for longer running processes, in particular processes that might need to be preempted for exceptional situations. If you have a service that will be doing a long-running computation, consider using anactioninstead.Services are identified by a service name, which looks much like a topic name (but is in a different namespace).A service consists of two parts: the service server and the service client.Service serverA service server is the entity that will accept a remote procedure request, and perform some computation on it. For instance, suppose the ROS 2


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perform some computation on it. For instance, suppose the ROS 2 message contains the following:uint32auint32b---uint32sumThe service server would be the entity that receives this message, addsaandbtogether, and returns thesum.NoteThere should only ever be one service server per service name. It is undefined which service server will receive client requests in the case of multiple service servers on the same service name.Service clientA service client is an entity that will request a remote service server to perform a computation on its behalf. Following from the example above, the service client is the entity that creates the initial message containingaandb, and waits for the service server to compute the sum and return the result.Unlike the service server, there can be arbitrary numbers of service clients using the same service name.


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Code Examples:

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uint32request--

uint32response

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uint32auint32b--

uint32sum


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Title: Installation troubleshooting

URL: https://docs.ros.org/en/jazzy/How

To

Guides/Installation

Troubleshooting.html

Section: Installation

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Installation troubleshootingTroubleshooting techniques for installation are sorted by the platforms they apply to.PlatformsGeneralLinuxmacOSWindowsGeneralGeneral troubleshooting techniques apply to all platforms.Enable multicastIn order to communicate successfully via DDS, the used network interface has to be multicast enabled. We’ve seen in past experiences that this might not necessarily be enabled by default (on Ubuntu or OSX) when using the loopback adapter. See theoriginal issueor aconversation on ros-answers. You can verify that your current setup allows multicast with the ROS 2 tool:In Terminal 1:ros2multicastreceiveIn Terminal 2:ros2multicastsendIf the first command did not return a response similar to:Receivedfromxx.xxx.xxx.xx:43751:'Hello World!'then you will need to update your firewall configuration to allow multicast usingufw.sudoufwallowinprotoudpto224.0.0.0/4 sudoufwallowinprotoudpfrom224.0.0.0/4You can check if the multicast flag is enabled for your network interface using theifconfigtool


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is enabled for your network interface using theifconfigtool and looking forMULITCASTin the flags section:eno1:flags=4163<...,MULTICAST>...Import failing without library present on the systemSometimesrclpyfails to be imported because the expected C extension libraries are not found. If so, compare the libraries present in the directory with the one mentioned in the error message. Assuming a file with a similar name exists (same prefix like_rclpy.and same suffix like.sobut a different Python version / architecture) you are using a different Python interpreter than which was used to build the C extension. Be sure to use the same Python interpreter as the one used to build the binary.For example, such a mismatch can crop up after an update of the OS. Then, rebuilding the workspace may fix the issue.LinuxInternal compiler errorIf you experience an ICE when trying to compile on a memory constrained platform like a Raspberry PI you might want to build single threaded (prefix the build invocation


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want to build single threaded (prefix the build invocation withMAKEFLAGS=-j1).Out of memoryTheros1_bridgein its current form requires 4Gb of free RAM to compile. If you don’t have that amount of RAM available it’s suggested to useCOLCON_IGNOREin that folder and skip its compilation.Multiple host interferenceIf you’re running multiple instances on the same network you may get interference. To avoid this you can set the environment variableROS_DOMAIN_IDto a different integer, the default is zero. This will define the DDS domain id for your system.Exception sourcing setup.bashIf you encounter exceptions when trying to source the environment after building from source, try to upgradecolconrelated packages usingcolconversion-check# check if newer versions availablesudoaptinstallpython3-colcon*--only-upgrade# upgrade installed colcon packages to latest versionAnaconda Python Conflictcondadoes not work in conjunction with ROS 2. Make sure that yourPATHenvironment variable does not have any conda paths in it.


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variable does not have any conda paths in it. You may have to check your.bashrcfor this line and comment it out.Cannot start rviz2rviz2may fail to start on a Wayland display system with errors like:QSocketNotifier:CanonlybeusedwiththreadsstartedwithQThread[INFO][1714730141.758659580][rviz2]:StereoisNOTSUPPORTED[INFO][1714730141.758813709][rviz2]:OpenGlversion:3.1(GLSL1.4)[ERROR][1714730141.797879232][rviz2]:rviz::RenderSystem:errorcreatingrenderwindow:RenderingAPIException:InvalidparentWindowHandle(wrongserverorscreen)inGLXWindow::createat./.obj-aarch64-linux-gnu/ogre_vendor-prefix/src/ogre_vendor/RenderSystems/GLSupport/src/GLX/OgreGLXWindow.cpp(line246)...[ERROR][1714730141.808124283][rviz2]:Unabletocreatetherenderingwindowafter100triesterminatecalledafterthrowinganinstanceof'std::runtime_error'what():Unabletocreatetherenderingwindowafter100triesAborted(coredumped)This is due to an incompatibility between Wayland and RViz2. You may be able to workaround this problem by running RViz2 in X11 compatibility


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workaround this problem by running RViz2 in X11 compatibility mode:QT_QPA_PLATFORM=xcbrviz2macOSSegmentation fault when usingpyenvpyenvseems to default to building Python with.afiles, but that causes issues withrclpy, so it’s recommended to build Python with Frameworks enabled on macOS when usingpyenv:https://github.com/pyenv/pyenv/wiki#how-to-build-cpython-with-framework-support-on-os-xLibrary not loaded; image not foundIf you are seeing library loading issues at runtime (either running tests or running nodes), such as the following:ImportError:dlopen(.../ros2_<distro>/ros2-osx/lib/python3.7/site-packages/rclpy/_rclpy.cpython-37m-darwin.so,2):Librarynotloaded:@rpath/librcl_interfaces__rosidl_typesupport_c.dylibReferencedfrom:.../ros2_<distro>/ros2-osx/lib/python3.7/site-packages/rclpy/_rclpy.cpython-37m-darwin.soReason:imagenotfoundThen you probably have System Integrity Protection enabled. Followthese instructionsto disable System Integrity Protection (SIP).Qt build error:unknowntypename'Q_ENUM'If you


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Protection (SIP).Qt build error:unknowntypename'Q_ENUM'If you see build errors related to Qt, e.g.:Infileincludedfrom/usr/local/opt/qt/lib/QtGui.framework/Headers/qguiapplication.h:46: /usr/local/opt/qt/lib/QtGui.framework/Headers/qinputmethod.h:87:5:error:unknowntypename'Q_ENUM'Q_ENUM(Action)^you may be using qt4 instead of qt5: seehttps://github.com/ros2/ros2/issues/441Missing symbol when opencv (and therefore libjpeg, libtiff, and libpng) are installed with HomebrewIf you have opencv installed you might get this:dyld:Symbolnotfound:__cg_jpeg_resync_to_restartReferencedfrom:/System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIOExpectedin:/usr/local/lib/libJPEG.dylibin/System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO /bin/sh:line1:25274Trace/BPTtrap:5/usr/local/bin/cmakeIf so, to build you’ll have to do this:$brewunlinklibpnglibtifflibjpegBut this will break opencv, so you’ll also need to update it to continue


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will break opencv, so you’ll also need to update it to continue working:$sudoinstall_name_tool-change/usr/local/lib/libjpeg.8.dylib/usr/local/opt/jpeg/lib/libjpeg.8.dylib/usr/local/lib/libopencv_highgui.2.4.dylib $sudoinstall_name_tool-change/usr/local/lib/libpng16.16.dylib/usr/local/opt/libpng/lib/libpng16.16.dylib/usr/local/lib/libopencv_highgui.2.4.dylib $sudoinstall_name_tool-change/usr/local/lib/libtiff.5.dylib/usr/local/opt/libtiff/lib/libtiff.5.dylib/usr/local/lib/libopencv_highgui.2.4.dylib $sudoinstall_name_tool-change/usr/local/lib/libjpeg.8.dylib/usr/local/opt/jpeg/lib/libjpeg.8.dylib/usr/local/Cellar/libtiff/4.0.4/lib/libtiff.5.dylibThe first command is necessary to avoid things built against the system libjpeg (etc.) from getting the version in /usr/local/lib. The others are updating things built by Homebrew so that they can find the version of libjpeg (etc.) without having them in /usr/local/lib.Xcode-select error: toolxcodebuildrequires Xcode, but active developer directory is a command line


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Xcode, but active developer directory is a command line instanceIf you recently installed Xcode, you may encounter this error:Xcode:xcode-select:error:tool'xcodebuild'requiresXcode, butactivedeveloperdirectory'/Library/Developer/CommandLineTools'isacommandlinetoolsinstanceTo resolve this error, you will need to:Double check that you have the command line tool installed:$xcode-select--installAccept the terms and conditions of Xcode by typing in terminal:$sudoxcodebuild-licenseacceptEnsure Xcode app is in the/Applicationsdirectory (NOT/Users/{user}/Applications)Pointxcode-selectto the Xcode app Developer directory using the following command:$sudoxcode-select-s/Applications/Xcode.app/Contents/Developerrosdep install errorhomebrew:Failedtodetectsuccessfulinstallationof[qt5]While following theCreating a workspacetutorial, you might encounter the following error stating thatrosdepfailes to install Qt5.$rosdepinstall-i--from-pathsrc--rosdistrojazzy-y


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to install Qt5.$rosdepinstall-i--from-pathsrc--rosdistrojazzy-y executingcommand[brewinstallqt5]Warning:qt5.15.0isalreadyinstalledandup-to-date Toreinstall5.15.0,run`brewreinstallqt`ERROR:thefollowingrosdepsfailedtoinstallhomebrew:Failedtodetectsuccessfulinstallationof[qt5]This error seems to stem from alinking issueand can be resolved by running the following command.$cd/usr/local/Cellar $sudoln-sqtqt5Running therosdepcommand should now execute normally:$rosdepinstall-i--from-pathsrc--rosdistrojazzy-y#All required rosdeps installed successfullyWindowsImport failing even with library present on the systemSometimesrclpyfails to be imported because of some missing DLLs on your system. If so, make sure to install all the dependencies listed in the “Installing prerequisites” sections of theinstallation instructions).If you are installing from binaries, you may need to update your dependencies: they must be the same version as those used to build the binaries.If you are still having issues, you can use


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build the binaries.If you are still having issues, you can use theDependenciestool to determine which dependencies are missing on your system. Use the tool to load the corresponding.pydfile, and it should report unavailableDLLmodules. Be sure that the current workspace is sourced before you execute the tool, otherwise there will be unresolved ROS DLL files. Use this information to install additional dependencies or adjust your path as necessary.CMake error setting modification timeIf you run into the CMake errorfileINSTALLcannotsetmodificationtimeon...when installing files it is likely that an anti virus software or Windows Defender are interfering with the build. E.g. for Windows Defender you can list the workspace location to be excluded to prevent it from scanning those files.260 character path limitTheinputlineistoolong. Thesyntaxofthecommandisincorrect.Depending on your directory hierarchy, you may see path length limit errors when building ROS 2 from source or your own libraries.To allow deeper path


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ROS 2 from source or your own libraries.To allow deeper path lengths:Runregedit.exe, navigate toComputer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem, and setLongPathsEnabledto 0x00000001 (1).Hit the windows key and typeEditGroupPolicy. Navigate to Local Computer Policy > Computer Configuration > Administrative Templates > System > Filesystem. Right clickEnableWin32longpaths, click Edit. In the dialog, select Enabled and click OK.Close and open your terminal to reset the environment and try building again.CMake packages unable to find asio, tinyxml2, tinyxml, or eigenWe’ve seen that sometimes the chocolatey packages forasio,tinyxml2, etc. do not add important registry entries and CMake will be unable to find them when building ROS 2. We’ve not yet been able to identify the root cause, but uninstalling the chocolatey packages (with-nif the uninstall fails the first time), and then reinstalling them will fix the issue.patch.exe opens a new command window and asks for administratorThis will


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opens a new command window and asks for administratorThis will also cause the build of packages which need to use patch to fail, even you allow it to use administrator rights.chocouninstallpatch;colconbuild--cmake-clean-cache- This is a bug in theGNU Patch For Windows package. If this package is not installed, the build process will instead use the version of Patch distributed with git.Failed to load Fast RTPS shared libraryFast RTPS requiresmsvcr20.dll, which is part of theVisualC++RedistributablePackagesforVisualStudio2013. Although it is usually installed by default in Windows 10, we know that some Windows 10-like versions don’t have it installed by default (e.g.: Windows Server 2019). In case you don’t have it installed, you can download it fromhere.Failed to create processIf running a ROS binary gives the error:|failedtocreateprocess.It is likely the Python interpreter was not found. For each executable, the shebang (first line) of the accompanying script is used, so make sure Python is available


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accompanying script is used, so make sure Python is available under the expected path (default:C:\Python38\).Binary installation specificIf your example does not start because of missing DLLs, please verify that all libraries from external dependencies such as OpenCV are located inside yourPATHvariable.If you forget to call thelocal_setup.batfile from your terminal, the demo programs will most likely crash immediately.Running RViz with WSL2If you are usingWSL2to run ROS 2 on Windows, you may run into an issue running RViz that looks like:$rviz2[INFO] [1695823660.091830699] [rviz2]: Stereo is NOT SUPPORTED[INFO] [1695823660.091943524] [rviz2]: OpenGl version: 4.1 (GLSL 4.1)D3D12: Removing Device.Segmentation faultOne possible solution to this is to force RViz to use software rendering:$exportLIBGL_ALWAYS_SOFTWARE=true$rviz2[INFO] [1695823660.091830699] [rviz2]: Stereo is NOT SUPPORTED


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Code Examples:

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ros2multicastreceive

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ros2multicastsend

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Receivedfromxx.xxx.xxx.xx:43751:'Hello World!'

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sudoufwallowinprotoudpto224.0.0.0/4

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eno1:flags=4163<...,MULTICAST>...

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QSocketNotifier:CanonlybeusedwiththreadsstartedwithQThread[INFO][1714730141.758659580][rviz2]:StereoisNOTSUPPORTED[INFO][1714730141.758813709][rviz2]:OpenGlversion:3.1(GLSL1.4)[ERROR][1714730141.797879232][rviz2]:rviz::RenderSystem:errorcreatingrenderwindow:RenderingAPIException:InvalidparentWindowHandle(wrongserverorscreen)inGLXWindow::createat./.obj

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aarch64

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QT_QPA_PLATFORM=xcbrviz2

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ImportError:dlopen(.../ros2_<distro>/ros2

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darwin.so,2):Librarynotloaded:@rpath/librcl_interfaces__rosidl_typesupport_c.dylibReferencedfrom:.../ros2_<distro>/ros2

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dyld:Symbolnotfound:__cg_jpeg_resync_to_restartReferencedfrom:/System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIOExpectedin:/usr/local/lib/libJPEG.dylibin/System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO

/bin/sh:line1:25274Trace/BPTtrap:5/usr/local/bin/cmake

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$brewunlinklibpnglibtifflibjpeg

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$sudoinstall_name_tool

change/usr/local/lib/libjpeg.8.dylib/usr/local/opt/jpeg/lib/libjpeg.8.dylib/usr/local/lib/libopencv_highgui.2.4.dylib

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Xcode:xcode


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Xcode:xcode

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Title: The build system

URL: https://docs.ros.org/en/jazzy/Concepts/Advanced/About-Build-System.html

Section: Installation

--------------------------------------------------------------------------------

The build systemTable of ContentsBuild toolBuild helpersTheament_packagepackageTheament_cmakerepositoryTheament_lintrepositoryMeta-build toolThe build system is what allows developers to build their ROS 2 code as needed.

ROS 2 relies heavily on the division of code into packages, with each package containing a manifest file (package.xml).

This manifest file contains essential metadata about the package, including its dependencies on other packages.

This manifest is required for the meta-build tool to function.The ROS 2 build system consists of 3 major concepts.Build toolThis is the software that controls the compilation and testing of a single package.


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In ROS 2 this is usually CMake for C++, and setuptools for Python, but other build tools are supported.Build helpersThese are helper functions that hook into the build tool to developer experience.

ROS 2 packages typically rely on theamentseries of packages for this.amentconsists of a few important repositories which are all in theGitHub organization.Theament_packagepackageLocated onGitHubatament/ament_package, this repository contains a singleament Python packagethat provides various utilities forament packages, e.g. templates for environment hooks.Allament packagesmust contain a singlepackage.xmlfile at the root of the package regardless of their underlying build system.

Thepackage.xml“manifest” file contains information that is required in order to process and operate on apackage.

Thispackageinformation includes things like thepackage’s name, which is globally unique, and the package’s dependencies.


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Thepackage.xmlfile also serves as the marker file which indicates the location of thepackageon the file system.Parsing of thepackage.xmlfiles is provided bycatkin_pkg(as in ROS 1), while functionality to locatepackagesby searching the file system for thesepackage.xmlfiles is provided by build tools such ascolcon.package.xmlPackage manifest file which marks the root of apackageand contains meta information about thepackageincluding its name, version, description, maintainer, license, dependencies, and more.


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The contents of the manifest are in machine readable XML format and the contents are described in theREPs127and140, with the possibility of further modifications in futureREPs.So anytime somepackageis referred to as anament package, it means that it is a single unit of software (source code, build files, tests, documentation, and other resources) which is described using apackage.xmlmanifest file.ament packageAnypackagewhich contains apackage.xmland follows the packaging guidelines ofament, regardless of the underlying build system.Since the termament packageis build system agnostic, there can be different kinds ofament packages, e.g.ament CMake package,ament Python package, etc.Here is a list of common package types that you might run into in this software stack:CMake packageAnypackagecontaining a plain CMake project and apackage.xmlmanifest file.ament CMake packageACMake packagethat also follows theamentpackaging guidelines.Python packageAnypackagecontaining asetuptoolsbased Python project and


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asetuptoolsbased Python project and apackage.xmlmanifest file.ament Python packageAPython packagethat also follows theamentpackaging guidelines.Theament_cmakerepositoryLocated onGitHubatament/ament_cmake, this repository contains many “ament CMake” and pure CMake packages which provide the infrastructure in CMake that is required to create “ament CMake” packages.


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In this context “ament CMake” packages means:amentpackages that are built using CMake.

So thepackagesin this repository provide the necessary CMake functions/macros and CMake Modules to facilitate creating more “ament CMake” (orament_cmake) packages.

Packages of this type are identified with the<build_type>ament_cmake</build_type>tag in the<export>tag of thepackage.xmlfile.Thepackagesin this repository are extremely modular, but there is a single “bottleneck”packagecalledament_cmake.

Anyone can depend on theament_cmakepackageto get all of the aggregate functionality of thepackagesin this repository.


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Here a list of thepackagesin the repository along with a short description:ament_cmakeaggregates all otherpackagesin this repository, users need only to depend on thisament_cmake_autoprovides convenience CMake functions which automatically handle a lot of the tedious parts of writing apackage’sCMakeLists.txtfileament_cmake_coreprovides all built-in core concepts forament, e.g. environment hooks, resource indexing, symbolic linking install and othersament_cmake_gmockadds convenience functions for making gmock based unit testsament_cmake_gtestadds convenience functions for making gtest based automated testsament_cmake_noseadds convenience functions for making nosetests based python automated testsament_cmake_pythonprovides CMake functions forpackagesthat contain Python codesee theament_cmake_python user documentationament_cmake_testaggregates different kinds of tests, e.g. gtest and nosetests, under a single target usingCTestTheament_cmake_corepackagecontains a lot of the CMake infrastructure that makes it


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a lot of the CMake infrastructure that makes it possible to cleanly pass information betweenpackagesusing conventional interfaces.


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This makes thepackageshave more decoupled build interfaces with otherpackages, promoting their reuse and encouraging conventions in the build systems of differentpackages.

For instance, it provides a standard way to pass include directories, libraries, definitions, and dependencies betweenpackagesso that consumers of this information can access this information in a conventional way.Theament_cmake_corepackagealso provides features of theamentbuild system like symbolic link installation, which allows you to symbolically link files from either the source space or the build space into the install space rather than copying them.

This allows you to install once and then edit non-generated resources like Python code and configuration files without having to rerun the install step for them to take effect.


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This feature essentially replaces the “devel space” fromcatkinbecause it has most of the advantages with few of the complications or drawbacks.Another feature provided byament_cmake_coreis thepackageresource indexing which is a way forpackagesto indicate that they contain a resource of some type.

The design of this feature makes it much more efficient to answer simple questions like whatpackagesare in this prefix (e.g./usr/local) because it only requires that you list the files in a single possible location under that prefix.

You can read more about this feature in thedesign docsfor the resource index.Likecatkin,ament_cmake_corealso provides environment setup files andpackagespecific environment hooks.

The environment setup files, often named something likesetup.bash, are a place forpackagedevelopers to define changes to the environment that are needed to utilize theirpackage.


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The developers are able to do this using an “environment hook” which is basically an arbitrary bit of shell code that can set or modify environment variables, define shell functions, setup auto-completion rules, etc…

This feature is how, for example, ROS 1 set theROS_DISTROenvironment variable withoutcatkinknowing anything about the ROS distribution.Theament_lintrepositoryLocated onGitHubatament/ament_lint, this repository provides severalpackageswhich provide linting and testing services in a convenient and consistent manner.

Currently there arepackagesto support C++ style linting usinguncrustify, static C++ code checks usingcppcheck, checking for copyright in source code, Python style linting usingpep8, and other things.

The list of helper packages will likely grow in the future.Meta-build toolThis is a piece of software that knows how to topologically order a group of packages, and build or test them in the correct dependency order.


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This software will call into the Build Tool to do the actual work of compiling, testing, and installing the package.In ROS 2, the tool namedcolconis used for this.


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Title: Logging

URL: https://docs.ros.org/en/jazzy/Tutorials/Demos/Logging

and

logger

configuration.html

Section: Installation

--------------------------------------------------------------------------------


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LoggingTable of ContentsUsing log statements in codeBasic loggingLogging only the first timeLogging all but the first timeLogging throttledLogging throttled all but the first timeLogging demoLogging directory configurationLogger level configuration: programmaticallyLogger level configuration: externallyUsing the logger config componentLogger level configuration: command lineConsole output formattingConsole output colorizingDefault stream for console outputLine buffered console outputSetting the log file name prefixSeethe logging pagefor details on available functionality.Using log statements in codeBasic loggingThe following code will output a log message from a ROS 2 node atDEBUGseverity:C++Python// printf styleRCLCPP_DEBUG(node->get_logger(),"My log message %d",4);// C++ stream styleRCLCPP_DEBUG_STREAM(node->get_logger(),"My log message "<<4);node.get_logger().debug('My log message%d'%(4))Note that in both cases, no trailing newline is added, as the logging infrastructure will automatically add


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is added, as the logging infrastructure will automatically add one.Logging only the first timeThe following code will output a log message from a ROS 2 node atINFOseverity, but only the first time it is hit:C++Python// printf styleRCLCPP_INFO_ONCE(node->get_logger(),"My log message %d",4);// C++ stream styleRCLCPP_INFO_STREAM_ONCE(node->get_logger(),"My log message "<<4);num=4node.get_logger().info(f'My log message{num}',once=True)Logging all but the first timeThe following code will output a log message from a ROS 2 node atWARNseverity, but not the very first time it is hit:C++Python// printf styleRCLCPP_WARN_SKIPFIRST(node->get_logger(),"My log message %d",4);// C++ stream styleRCLCPP_WARN_STREAM_SKIPFIRST(node->get_logger(),"My log message "<<4);num=4node.get_logger().warning('My log message{0}'.format(num),skip_first=True)Logging throttledThe following code will output a log message from a ROS 2 node atERRORseverity, but no more than once per second.The interval parameter specifying milliseconds


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once per second.The interval parameter specifying milliseconds between messages should have an integer data type so it can be converted to arcutils_duration_value_t(anint64_t):C++Python// printf styleRCLCPP_ERROR_THROTTLE(node->get_logger(),*node->get_clock(),1000,"My log message %d",4);// C++ stream styleRCLCPP_ERROR_STREAM_THROTTLE(node->get_logger(),*node->get_clock(),1000,"My log message "<<4);// For now, use the nanoseconds() method to use an existing rclcpp::Duration value, see https://github.com/ros2/rclcpp/issues/1929RCLCPP_ERROR_STREAM_THROTTLE(node->get_logger(),*node->get_clock(),msg_interval.nanoseconds()/1000000,"My log message "<<4);num=4node.get_logger().error(f'My log message{num}',throttle_duration_sec=1)Logging throttled all but the first timeThe following code will output a log message from a ROS 2 node atDEBUGseverity, no more than once per second, skipping the very first time it is hit:C++Python// printf styleRCLCPP_DEBUG_SKIPFIRST_THROTTLE(node->get_logger(),*node->get_clock(),1000,"My


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log message %d",4);RCLCPP_DEBUG_SKIPFIRST_THROTTLE(node->get_logger(),*node->get_clock(),1000,"My log message "<<4);num=4node.get_logger().debug(f'My log message{num}',skip_first=True,throttle_duration_sec=1.0)Logging demoIn thisdemo, different types of log calls are shown and the severity level of different loggers is configured locally and externally.Start the demo with:ros2runlogging_demologging_demo_mainOver time you will see output from various log calls with different properties. To start with you will only see output from log calls with severityINFOand above (WARN,ERROR,FATAL). Note that the first message will only be logged once, though the line is reached on each iteration, as that is a property of the log call used for that message.Logging directory configurationThe logging directory can be configured through two environment variables:ROS_LOG_DIRandROS_HOME. The logic is as follows:Use$ROS_LOG_DIRifROS_LOG_DIRis set and not empty.Otherwise, use$ROS_HOME/log, using~/.rosforROS_HOMEif not set or if


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use$ROS_HOME/log, using~/.rosforROS_HOMEif not set or if empty.For example, to set the logging directory to~/my_logs:LinuxmacOSWindowsexportROS_LOG_DIR=~/my_logs ros2runlogging_demologging_demo_mainexportROS_LOG_DIR=~/my_logs ros2runlogging_demologging_demo_mainset"ROS_LOG_DIR=~/my_logs"ros2runlogging_demologging_demo_mainYou will then find the logs under~/my_logs/.Alternatively, you can setROS_HOMEand the logging directory will be relative to it ($ROS_HOME/log).ROS_HOMEis intended to be used by anything that needs a base directory. Note thatROS_LOG_DIRhas to be either unset or empty. For example, withROS_HOMEset to~/my_ros_home:LinuxmacOSWindowsexportROS_HOME=~/my_ros_home ros2runlogging_demologging_demo_mainexportROS_HOME=~/my_ros_home ros2runlogging_demologging_demo_mainset"ROS_HOME=~/my_ros_home"ros2runlogging_demologging_demo_mainYou will then find the logs under~/my_ros_home/log/.Logger level configuration: programmaticallyAfter 10 iterations the level of the logger will be set toDEBUG, which will


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the level of the logger will be set toDEBUG, which will cause additional messages to be logged.Some of these debug messages cause additional functions/expressions to be evaluated, which were previously skipped asDEBUGlog calls were not enabled. Seethe source codeof the demo for further explanation of the calls used, and see the rclcpp logging documentation for a full list of supported logging calls.Logger level configuration: externallyROS 2 nodes have services available to configure the logging level externally at runtime. These services are disabled by default. The following code shows how to enable the logger service while creating the node.C++Python// Create a node with logger service enabledautonode=std::make_shared<rclcpp::Node>("NodeWithLoggerService",rclcpp::NodeOptions().enable_logger_service(true))# Create a node with logger service enablednode=Node('NodeWithLoggerService',enable_logger_service=True)If you run one of the nodes as configured above, you will find 2 services when


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of the nodes as configured above, you will find 2 services when runningros2servicelist:$ros2servicelist ... /NodeWithLoggerService/get_logger_levels /NodeWithLoggerService/set_logger_levels ...get_logger_levelsUse this service to get logger levels for specified logger names.Runros2servicecallto get logger levels forNodeWithLoggerServiceandrcl.$ros2servicecall/NodeWithLoggerService/get_logger_levelsrcl_interfaces/srv/GetLoggerLevels'{names: ["NodeWithLoggerService", "rcl"]}'requester:makingrequest:rcl_interfaces.srv.GetLoggerLevels_Request(names=['NodeWithLoggerService','rcl'])response: rcl_interfaces.srv.GetLoggerLevels_Response(levels=[rcl_interfaces.msg.LoggerLevel(name='NodeWithLoggerService',level=0),rcl_interfaces.msg.LoggerLevel(name='rcl',level=0)])set_logger_levelsUse this service to set logger levels for specified logger names.Runros2servicecallto set logger levels forNodeWithLoggerServiceandrcl.$ros2servicecall/NodeWithLoggerService/set_logger_levelsrcl_interfaces/srv/SetLoggerLevels'{levels:


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[{name: "NodeWithLoggerService", level: 20}, {name: "rcl", level: 10}]}'requester:makingrequest:rcl_interfaces.srv.SetLoggerLevels_Request(levels=[rcl_interfaces.msg.LoggerLevel(name='NodeWithLoggerService',level=20),rcl_interfaces.msg.LoggerLevel(name='rcl',level=10)])response: rcl_interfaces.srv.SetLoggerLevels_Response(results=[rcl_interfaces.msg.SetLoggerLevelsResult(successful=True,reason=''),rcl_interfaces.msg.SetLoggerLevelsResult(successful=True,reason='')])There is also demo code showing how to set or get the logger level via the logger service.rclcpp:demo code$ros2rundemo_nodes_cppuse_logger_servicerclpy:demo code$ros2rundemo_nodes_pyuse_logger_serviceWarningCurrently, there is a limitation thatget_logger_levelsandset_logger_levelsservices are not thread-safe. This means that you need to ensure that only one thread is calling the services at a time. Please see the details inhttps://github.com/ros2/rcutils/issues/397Using the logger config componentThe server that responds to the logger


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logger config componentThe server that responds to the logger configuration requests has been developed as a component so that it may be added to an existing composition-based system. For example, if you are usinga container to run your nodes, to be able to configure your loggers you only need to request that it additionally load thelogging_demo::LoggerConfigcomponent into the container.As an example, if you want to debug thecomposition::Talkerdemo, you can start the talker as normal with:Shell 1:ros2runrclcpp_componentscomponent_containerShell 2:ros2componentload/ComponentManagercompositioncomposition::TalkerAnd then when you want to enable debug logging, load theLoggerConfigcomponent with:Shell 2ros2componentload/ComponentManagerlogging_demologging_demo::LoggerConfigAnd finally, configure all unset loggers to the debug severity by addressing the empty-named logger. Note that loggers that have been specifically configured to use a particular severity will not be affected by this call.Shell


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a particular severity will not be affected by this call.Shell 2:ros2servicecall/config_loggerlogging_demo/srv/ConfigLogger"{logger_name: '', level: DEBUG}"You should see debug output from any previously unset loggers in the process start to appear, including from the ROS 2 core.Logger level configuration: command lineAs of the Bouncy ROS 2 release, the severity level for loggers that have not had their severity set explicitly can be configured from the command line. Restart the demo including the following command line argument:ros2runlogging_demologging_demo_main--ros-args--log-leveldebugThis configures the default severity for any unset logger to the debug severity level. You should see debug output from loggers from the demo itself and from the ROS 2 core.The severity level for individual loggers can be configured from the command-line. Restart the demo including the following command line arguments:ros2runlogging_demologging_demo_main--ros-args--log-levellogger_usage_demo:=debugConsole output


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output formattingIf you would like more or less verbose formatting, you can use theRCUTILS_CONSOLE_OUTPUT_FORMATenvironment variable. For example, to additionally get the timestamp and location of the log calls, stop the demo and restart it with the environment variable set:LinuxmacOSWindowsexportRCUTILS_CONSOLE_OUTPUT_FORMAT="[{severity} {time}] [{name}]: {message} ({function_name}() at {file_name}:{line_number})"ros2runlogging_demologging_demo_mainexportRCUTILS_CONSOLE_OUTPUT_FORMAT="[{severity} {time}] [{name}]: {message} ({function_name}() at {file_name}:{line_number})"ros2runlogging_demologging_demo_mainset"RCUTILS_CONSOLE_OUTPUT_FORMAT=[{severity} {time}] [{name}]: {message} ({function_name}() at {file_name}:{line_number})"ros2runlogging_demologging_demo_mainYou should see the timestamp in seconds and the function name, filename and line number additionally printed with each message.For more information on configuring the console logger formatting, see thelogger console configurationConsole output


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formatting, see thelogger console configurationConsole output colorizingBy default, the output is colorized when it’s targeting a terminal. If you would like to force enabling or disabling it, you can use theRCUTILS_COLORIZED_OUTPUTenvironment variable. For example:LinuxmacOSWindowsexportRCUTILS_COLORIZED_OUTPUT=0# 1 for forcing itros2runlogging_demologging_demo_mainexportRCUTILS_COLORIZED_OUTPUT=0# 1 for forcing itros2runlogging_demologging_demo_mainset"RCUTILS_COLORIZED_OUTPUT=0"::1forforcingit ros2runlogging_demologging_demo_mainYou should see that debug, warn, error and fatal logs aren’t colorized now.NoteIn Linux and MacOS forcing colorized output means that if you redirect the output to a file, the ansi escape color codes will appear on it. In windows the colorization method relies on console APIs. If it is forced you will get a new warning saying that colorization failed. The default behavior already checks if the output is a console or not, so forcing colorization is not recommended.Default stream


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not, so forcing colorization is not recommended.Default stream for console outputIn Foxy and later, the output from all debug levels goes to stderr by default.  It is possible to force all output to go to stdout by setting theRCUTILS_LOGGING_USE_STDOUTenvironment variable to1. For example:LinuxmacOSWindowsexportRCUTILS_LOGGING_USE_STDOUT=1exportRCUTILS_LOGGING_USE_STDOUT=1set"RCUTILS_LOGGING_USE_STDOUT=1"Line buffered console outputBy default, all logging output is unbuffered. You can force it to be buffered by setting theRCUTILS_LOGGING_BUFFERED_STREAMenvironment variable to 1. For example:LinuxmacOSWindowsexportRCUTILS_LOGGING_BUFFERED_STREAM=1exportRCUTILS_LOGGING_BUFFERED_STREAM=1set"RCUTILS_LOGGING_BUFFERED_STREAM=1"Then run:ros2runlogging_demologging_demo_mainSetting the log file name prefixBy default, the log file name is based on the executable file name followed by process ID and system timestamp on file creation. You can change the log file name prefix to one of your choice using


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can change the log file name prefix to one of your choice using the--log-file-namecommand line argument:ros2rundemo_nodes_cpptalker--ros-args--log-file-namefilenameThis configures the log file name prefix tofilename, instead of the executable file name (which istalkerin this case).


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Code Examples:

Language: unknown // printf styleRCLCPP_DEBUG(node->get_logger(),"My log message %d",4);// C++ stream styleRCLCPP_DEBUG_STREAM(node->get_logger(),"My log message "<<4);

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node.get_logger().debug('My log message%d'%(4))

Language: unknown // printf styleRCLCPP_INFO_ONCE(node->get_logger(),"My log message %d",4);// C++ stream styleRCLCPP_INFO_STREAM_ONCE(node->get_logger(),"My log message "<<4);

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num=4node.get_logger().info(f'My log message{num}',once=True)

Language: unknown // printf styleRCLCPP_WARN_SKIPFIRST(node->get_logger(),"My log message %d",4);// C++ stream styleRCLCPP_WARN_STREAM_SKIPFIRST(node->get_logger(),"My log message "<<4);

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num=4node.get_logger().warning('My log message{0}'.format(num),skip_first=True)


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Language: unknown // printf styleRCLCPP_ERROR_THROTTLE(node->get_logger(),*node->get_clock(),1000,"My log message %d",4);// C++ stream styleRCLCPP_ERROR_STREAM_THROTTLE(node->get_logger(),*node->get_clock(),1000,"My log message "<<4);// For now, use the nanoseconds() method to use an existing rclcpp::Duration value, see https://github.com/ros2/rclcpp/issues/1929RCLCPP_ERROR_STREAM_THROTTLE(node->get_logger(),*node->get_clock(),msg_interval.nanoseconds()/1000000,"My log message "<<4);

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num=4node.get_logger().error(f'My log message{num}',throttle_duration_sec=1)

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// printf styleRCLCPP_DEBUG_SKIPFIRST_THROTTLE(node

>get_logger(),

node

>get_clock(),1000,"My log message %d",4);RCLCPP_DEBUG_SKIPFIRST_THROTTLE(node

>get_logger(),

node

>get_clock(),1000,"My log message "<<4);

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num=4node.get_logger().debug(f'My log message{num}',skip_first=True,throttle_duration_sec=1.0)

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ros2runlogging_demologging_demo_main

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ros2runlogging_demologging_demo_main

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exportROS_LOG_DIR=~/my_logs

ros2runlogging_demologging_demo_main

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exportROS_LOG_DIR=~/my_logs

ros2runlogging_demologging_demo_main

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set"ROS_LOG_DIR=~/my_logs"ros2runlogging_demologging_demo_main

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exportROS_HOME=~/my_ros_home

ros2runlogging_demologging_demo_main

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exportROS_HOME=~/my_ros_home

ros2runlogging_demologging_demo_main

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set"ROS_HOME=~/my_ros_home"ros2runlogging_demologging_demo_main

Language: unknown // Create a node with logger service enabledautonode=std::make_shared<rclcpp::Node>("NodeWithLoggerService",rclcpp::NodeOptions().enable_logger_service(true))

Language: unknown # Create a node with logger service enablednode=Node('NodeWithLoggerService',enable_logger_service=True)

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$ros2servicelist

...

/NodeWithLoggerService/get_logger_levels

/NodeWithLoggerService/set_logger_levels

...

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...

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$ros2servicecall/NodeWithLoggerService/get_logger_levelsrcl_interfaces/srv/GetLoggerLevels'{names: ["NodeWithLoggerService", "rcl"]}'requester:makingrequest:rcl_interfaces.srv.GetLoggerLevels_Request(names=['NodeWithLoggerService','rcl'])response:

rcl_interfaces.srv.GetLoggerLevels_Response(levels=[rcl_interfaces.msg.LoggerLevel(name='NodeWithLoggerService',level=0),rcl_interfaces.msg.LoggerLevel(name='rcl',level=0)])


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Language: unknown $ros2servicecall/NodeWithLoggerService/set_logger_levelsrcl_interfaces/srv/SetLoggerLevels'{levels: [{name: "NodeWithLoggerService", level: 20}, {name: "rcl", level: 10}]}'requester:makingrequest:rcl_interfaces.srv.SetLoggerLevels_Request(levels=[rcl_interfaces.msg.LoggerLevel(name='NodeWithLoggerService',level=20),rcl_interfaces.msg.LoggerLevel(name='rcl',level=10)])response: rcl_interfaces.srv.SetLoggerLevels_Response(results=[rcl_interfaces.msg.SetLoggerLevelsResult(successful=True,reason=''),rcl_interfaces.msg.SetLoggerLevelsResult(successful=True,reason='')])

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$ros2rundemo_nodes_cppuse_logger_service

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$ros2rundemo_nodes_pyuse_logger_service

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ros2runrclcpp_componentscomponent_container

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ros2componentload/ComponentManagercompositioncomposition::Talker

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ros2componentload/ComponentManagerlogging_demologging_demo::LoggerConfig

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ros2servicecall/config_loggerlogging_demo/srv/ConfigLogger"{logger_name: '', level: DEBUG}"

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ros2runlogging_demologging_demo_main-

ros

args-

log

leveldebug

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ros2runlogging_demologging_demo_main-

ros

args-

log

levellogger_usage_demo:=debug

Language: unknown exportRCUTILS_CONSOLE_OUTPUT_FORMAT="[{severity} {time}] [{name}]: {message} ({function_name}() at {file_name}:{line_number})"ros2runlogging_demologging_demo_main

Language: unknown exportRCUTILS_CONSOLE_OUTPUT_FORMAT="[{severity} {time}] [{name}]: {message} ({function_name}() at {file_name}:{line_number})"ros2runlogging_demologging_demo_main

Language: unknown set"RCUTILS_CONSOLE_OUTPUT_FORMAT=[{severity} {time}] [{name}]: {message} ({function_name}() at {file_name}:{line_number})"ros2runlogging_demologging_demo_main

Language: unknown exportRCUTILS_COLORIZED_OUTPUT=0# 1 for forcing itros2runlogging_demologging_demo_main


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Language: unknown exportRCUTILS_COLORIZED_OUTPUT=0# 1 for forcing itros2runlogging_demologging_demo_main

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set"RCUTILS_COLORIZED_OUTPUT=0"::1forforcingit

ros2runlogging_demologging_demo_main

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exportRCUTILS_LOGGING_USE_STDOUT=1

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exportRCUTILS_LOGGING_USE_STDOUT=1

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set"RCUTILS_LOGGING_USE_STDOUT=1"

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exportRCUTILS_LOGGING_BUFFERED_STREAM=1

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exportRCUTILS_LOGGING_BUFFERED_STREAM=1

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set"RCUTILS_LOGGING_BUFFERED_STREAM=1"

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ros2runlogging_demologging_demo_main

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ros2rundemo_nodes_cpptalker-

ros

args-

log

file

namefilename


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Title: Configure service introspection

URL: https://docs.ros.org/en/jazzy/Tutorials/Demos/Service

Introspection.html

Section: Installation

--------------------------------------------------------------------------------


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Configure service introspectionGoal:Configure service introspection for a service client and a server.Tutorial level:AdvancedTime:15 minutesTable of ContentsOverviewInstalling the demoIntrospection Configuration StateIntrospection demoRelated contentOverviewROS 2 applications usually consist of services to execute specific procedures in remote nodes. It is possible to introspect service data communication with service introspection.In this demo, we’ll be highlighting how to configure service introspection state for a service client and a server and monitor service communication withros2serviceecho.Installing the demoSee theinstallation instructionsfor details on installing ROS 2.If you’ve installed ROS 2 binary packages, ensure that you haveros-jazzy-demo-nodes-cppinstalled. If you downloaded the archive or built ROS 2 from source, it will already be part of the installation.Introspection Configuration StateThere are 3 configuration states for service introspection.Service Introspection Configuration


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for service introspection.Service Introspection Configuration StateRCL_SERVICE_INTROSPECTION_OFFDisabledRCL_SERVICE_INTROSPECTION_METADATAOnly metadata without any user data contentsRCL_SERVICE_INTROSPECTION_CONTENTSUser data contents with metadataIntrospection demoThis demo shows how to manage service introspection and monitor the service data communication with usingros2serviceecho.IntrospectionServiceNode:https://github.com/ros2/demos/blob/jazzy/demo_nodes_cpp/src/services/introspection_service.cppnamespacedemo_nodes_cpp{classIntrospectionServiceNode:publicrclcpp::Node{public:DEMO_NODES_CPP_PUBLICexplicitIntrospectionServiceNode(constrclcpp::NodeOptions&options):Node("introspection_service",options){autohandle_add_two_ints=[this](conststd::shared_ptr<rmw_request_id_t>request_header,conststd::shared_ptr<example_interfaces::srv::AddTwoInts::Request>request,std::shared_ptr<example_interfaces::srv::AddTwoInts::Response>response)->void{(void)request_header;RCLCPP_INFO(this->get_logger(),"Incoming request\na:


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request\na: %"PRId64" b: %"PRId64,request->a,request->b);response->sum=request->a+request->b;};// Create a service that will use the callback function to handle requests.srv_=create_service<example_interfaces::srv::AddTwoInts>("add_two_ints",handle_add_two_ints);autoon_set_parameter_callback=[](std::vector<rclcpp::Parameter>parameters){rcl_interfaces::msg::SetParametersResultresult;result.successful=true;for(constrclcpp::Parameter&param:parameters){if(param.get_name()!="service_configure_introspection"){continue;}if(param.get_type()!=rclcpp::ParameterType::PARAMETER_STRING){result.successful=false;result.reason="must be a string";break;}if(param.as_string()!="disabled"&&param.as_string()!="metadata"&&param.as_string()!="contents"){result.successful=false;result.reason="must be one of 'disabled', 'metadata', or


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'contents'";break;}}returnresult;};autopost_set_parameter_callback=[this](conststd::vector<rclcpp::Parameter>&parameters){for(constrclcpp::Parameter&param:parameters){if(param.get_name()!="service_configure_introspection"){continue;}rcl_service_introspection_state_tintrospection_state=RCL_SERVICE_INTROSPECTION_OFF;if(param.as_string()=="disabled"){introspection_state=RCL_SERVICE_INTROSPECTION_OFF;}elseif(param.as_string()=="metadata"){introspection_state=RCL_SERVICE_INTROSPECTION_METADATA;}elseif(param.as_string()=="contents"){introspection_state=RCL_SERVICE_INTROSPECTION_CONTENTS;}this->srv_->configure_introspection(this->get_clock(),rclcpp::SystemDefaultsQoS(),introspection_state);break;}};on_set_parameters_callback_handle_=this->add_on_set_parameters_callback(on_set_parameter_callback);post_set_parameters_callback_handle_=this->add_post_set_parameters_callback(post_set_parameter_callback);this->declare_parameter("service_configure_introspection","disabled");}private:rclcpp::Service<example_interfaces::srv


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on","disabled");}private:rclcpp::Service<example_interfaces::srv::AddTwoInts>::SharedPtrsrv_;rclcpp::node_interfaces::OnSetParametersCallbackHandle::SharedPtron_set_parameters_callback_handle_;rclcpp::node_interfaces::PostSetParametersCallbackHandle::SharedPtrpost_set_parameters_callback_handle_;};}//


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namespace demo_nodes_cppService introspection is disable in default, so users need to enable it to callconfigure_introspectionon service server. In this demo,IntrospectionServiceNodeuses a parameter named`service_configure_introspectionto configure the service introspection state.1st we need to startIntrospectionServiceNode.$ros2rundemo_nodes_cppintrospection_serviceTo change service introspection state, we need to set theconfigure_introspectionparameter as following.### User data contents with metadata$ros2paramset/introspection_serviceservice_configure_introspectioncontents### Or only metadata$ros2paramset/introspection_serviceservice_configure_introspectionmetadata### To


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To disable$ros2paramset/introspection_serviceservice_configure_introspectiondisabledIntrospectionClientNode:https://github.com/ros2/demos/blob/jazzy/demo_nodes_cpp/src/services/introspection_client.cppnamespacedemo_nodes_cpp{classIntrospectionClientNode:publicrclcpp::Node{public:DEMO_NODES_CPP_PUBLICexplicitIntrospectionClientNode(constrclcpp::NodeOptions&options):Node("introspection_client",options){client_=create_client<example_interfaces::srv::AddTwoInts>("add_two_ints");autoon_set_parameter_callback=[](std::vector<rclcpp::Parameter>parameters){rcl_interfaces::msg::SetParametersResultresult;result.successful=true;for(constrclcpp::Parameter&param:parameters){if(param.get_name()!="client_configure_introspection"){continue;}if(param.get_type()!=rclcpp::ParameterType::PARAMETER_STRING){result.successful=false;result.reason="must be a string";break;}if(param.as_string()!="disabled"&&param.as_string()!="metadata"&&param.as_string()!="contents"){result.successful=false;result.reason="must be one of 'disabled',


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'contents'";break;}}returnresult;};autopost_set_parameter_callback=[this](conststd::vector<rclcpp::Parameter>&parameters){for(constrclcpp::Parameter&param:parameters){if(param.get_name()!="client_configure_introspection"){continue;}rcl_service_introspection_state_tintrospection_state=RCL_SERVICE_INTROSPECTION_OFF;if(param.as_string()=="disabled"){introspection_state=RCL_SERVICE_INTROSPECTION_OFF;}elseif(param.as_string()=="metadata"){introspection_state=RCL_SERVICE_INTROSPECTION_METADATA;}elseif(param.as_string()=="contents"){introspection_state=RCL_SERVICE_INTROSPECTION_CONTENTS;}this->client_->configure_introspection(this->get_clock(),rclcpp::SystemDefaultsQoS(),introspection_state);break;}};on_set_parameters_callback_handle_=this->add_on_set_parameters_callback(on_set_parameter_callback);post_set_parameters_callback_handle_=this->add_post_set_parameters_callback(post_set_parameter_callback);this->declare_parameter("client_configure_introspection","disabled");timer_=this->create_wall_timer(std::chrono::mil


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ion","disabled");timer_=this->create_wall_timer(std::chrono::milliseconds(500),[this](){if(!client_->service_is_ready()){return;}if(!request_in_progress_){autorequest=std::make_shared<example_interfaces::srv::AddTwoInts::Request>();request->a=2;request->b=3;request_in_progress_=true;client_->async_send_request(request,[this](rclcpp::Client<example_interfaces::srv::AddTwoInts>::SharedFuturecb_f){request_in_progress_=false;RCLCPP_INFO(get_logger(),"Result


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of add_two_ints: %ld",cb_f.get()->sum);});return;}});}private:rclcpp::Client<example_interfaces::srv::AddTwoInts>::SharedPtrclient_;rclcpp::TimerBase::SharedPtrtimer_;rclcpp::node_interfaces::OnSetParametersCallbackHandle::SharedPtron_set_parameters_callback_handle_;rclcpp::node_interfaces::PostSetParametersCallbackHandle::SharedPtrpost_set_parameters_callback_handle_;boolrequest_in_progress_{false};};}// namespace demo_nodes_cppAnd then, we start and configureIntrospectionClientNodein the same way.$ros2rundemo_nodes_cppintrospection_clientChange service introspection state to setconfigure_introspectionparameter as following.### User data contents with metadata$ros2paramset/introspection_clientclient_configure_introspectioncontents### Or only metadata$ros2paramset/introspection_clientclient_configure_introspectionmetadata### To disable$ros2paramset/introspection_clientclient_configure_introspectiondisabledIn this tutorial the following is example output with service introspection


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the following is example output with service introspection stateCONTENTSonIntrospectionServiceNodeandMETADATAonIntrospectionClientNode. To monitor service communication betweenIntrospectionClientNodeandIntrospectionServiceNode, let’s run it:$ros2serviceecho--flow-style/add_two_ints info:event_type:REQUEST_SENTstamp:sec:1709432402nanosec:680094264client_gid:[1,15,0,18,86,208,115,86,0,0,0,0,0,0,21,3]sequence_number:247request:[]response:[]--- info:event_type:REQUEST_RECEIVEDstamp:sec:1709432402nanosec:680459568client_gid:[1,15,0,18,86,208,115,86,0,0,0,0,0,0,20,4]sequence_number:247request:[{a:2,b:3}]response:[]--- info:event_type:RESPONSE_SENTstamp:sec:1709432402nanosec:680765280client_gid:[1,15,0,18,86,208,115,86,0,0,0,0,0,0,20,4]sequence_number:247request:[]response:[{sum:5}]--- info:event_type:RESPONSE_RECEIVEDstamp:sec:1709432402nanosec:681027998client_gid:[1,15,0,18,86,208,115,86,0,0,0,0,0,0,21,3]sequence_number:247request:[]response:[]--- ...You can see


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...You can see theevent_type:REQUEST_SENTandevent_type:RESPONSE_RECEIVED, those introspection service event take place inIntrospectionClientNode. And those events does not include any contents inrequestandresponsefield, this is becauseIntrospectionClientNode’s service introspection state is set toMETADATA. On the other hand,event_type:REQUEST_RECEIVEDandevent_type:RESPONSE_SENTevent fromIntrospectionServiceNodeincludesrequest:[{a:2,b:3}]andresponse:[{sum:5}]as introspection state is set toCONTENTS.Related contentservice introspection client example (rclcpp)andservice introspection service example (rclcpp).service introspection client and service example (rclpy).Service Introspection REP-2012.


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Language: unknown namespacedemo_nodes_cpp{classIntrospectionServiceNode:publicrclcpp::Node{public:DEMO_NODES_CPP_PUBLICexplicitIntrospectionServiceNode(constrclcpp::NodeOptions&options):Node("introspection_service",options){autohandle_add_two_ints=[this](conststd::shared_ptr<rmw_request_id_t>request_header,conststd::shared_ptr<example_interfaces::srv::AddTwoInts::Request>request,std::shared_ptr<example_interfaces::srv::AddTwoInts::Response>response)->void{(void)request_header;RCLCPP_INFO(this->get_logger(),"Incoming request\na: %"PRId64" b: %"PRId64,request->a,request->b);response->sum=request->a+request->b;};// Create a service that will use the callback function to handle


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Create a service that will use the callback function to handle requests.srv_=create_service<example_interfaces::srv::AddTwoInts>("add_two_ints",handle_add_two_ints);autoon_set_parameter_callback=[](std::vector<rclcpp::Parameter>parameters){rcl_interfaces::msg::SetParametersResultresult;result.successful=true;for(constrclcpp::Parameter&param:parameters){if(param.get_name()!="service_configure_introspection"){continue;}if(param.get_type()!=rclcpp::ParameterType::PARAMETER_STRING){result.successful=false;result.reason="must be a string";break;}if(param.as_string()!="disabled"&&param.as_string()!="metadata"&&param.as_string()!="contents"){result.successful=false;result.reason="must be one of 'disabled', 'metadata', or


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Language: unknown

$ros2rundemo_nodes_cppintrospection_service

Language: unknown ### User data contents with metadata$ros2paramset/introspection_serviceservice_configure_introspectioncontents### Or only metadata$ros2paramset/introspection_serviceservice_configure_introspectionmetadata### To disable$ros2paramset/introspection_serviceservice_configure_introspectiondisabled


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Language: unknown namespacedemo_nodes_cpp{classIntrospectionClientNode:publicrclcpp::Node{public:DEMO_NODES_CPP_PUBLICexplicitIntrospectionClientNode(constrclcpp::NodeOptions&options):Node("introspection_client",options){client_=create_client<example_interfaces::srv::AddTwoInts>("add_two_ints");autoon_set_parameter_callback=[](std::vector<rclcpp::Parameter>parameters){rcl_interfaces::msg::SetParametersResultresult;result.successful=true;for(constrclcpp::Parameter&param:parameters){if(param.get_name()!="client_configure_introspection"){continue;}if(param.get_type()!=rclcpp::ParameterType::PARAMETER_STRING){result.successful=false;result.reason="must be a string";break;}if(param.as_string()!="disabled"&&param.as_string()!="metadata"&&param.as_string()!="contents"){result.successful=false;result.reason="must be one of 'disabled', 'metadata', or


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of add_two_ints: %ld",cb_f.get()->sum);});return;}});}private:rclcpp::Client<example_interfaces::srv::AddTwoInts>::SharedPtrclient_;rclcpp::TimerBase::SharedPtrtimer_;rclcpp::node_interfaces::OnSetParametersCallbackHandle::SharedPtron_set_parameters_callback_handle_;rclcpp::node_interfaces::PostSetParametersCallbackHandle::SharedPtrpost_set_parameters_callback_handle_;boolrequest_in_progress_{false};};}// namespace demo_nodes_cpp


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Language: unknown

$ros2rundemo_nodes_cppintrospection_client

Language: unknown ### User data contents with metadata$ros2paramset/introspection_clientclient_configure_introspectioncontents### Or only metadata$ros2paramset/introspection_clientclient_configure_introspectionmetadata### To disable$ros2paramset/introspection_clientclient_configure_introspectiondisabled

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$ros2serviceecho-

flow

style/add_two_ints

info:event_type:REQUEST_SENTstamp:sec:1709432402nanosec:680094264client_gid:[1,15,0,18,86,208,115,86,0,0,0,0,0,0,21,3]sequence_number:247request:[]response:[]--

info:event_type:REQUEST_RECEIVEDstamp:sec:1709432402nanosec:680459568client_gid:[1,15,0,18,86,208,115,86,0,0,0,0,0,0,20,4]sequence_number:247request:[{a:2,b:3}]response:[]--

info:event_type:RESPONSE_SENTstamp:sec:1709432402nanosec:680765280client_gid:[1,15,0,18,86,208,115,86,0,0,0,0,0,0,20,4]sequence_number:247request:[]response:[{sum:5}]--


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info:event_type:RESPONSE_RECEIVEDstamp:sec:1709432402nanosec:681027998client_gid:[1,15,0,18,86,208,115,86,0,0,0,0,0,0,21,3]sequence_number:247request:[]response:[]--

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Title: Beginner: Client libraries

URL: https://docs.ros.org/en/jazzy/Tutorials/Beginner

Client

Libraries.html

Section: Installation

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Beginner: Client librariesUsingcolconto build packagesCreating a workspaceCreating a packageWriting a simple publisher and subscriber (C++)Writing a simple publisher and subscriber (Python)Writing a simple service and client (C++)Writing a simple service and client (Python)Creating custom msg and srv filesImplementing custom interfacesUsing parameters in a class (C++)Using parameters in a class (Python)Usingros2doctorto identify issuesCreating and using plugins (C++)


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Title: IDEs and Debugging [community-contributed] URL: https://docs.ros.org/en/jazzy/How-To-Guides/ROS-2-IDEs.html Section: Installation --------------------------------------------------------------------------------


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IDEs and Debugging [community-contributed]ROS 2 is not made around a specific development environment and the main focus is on building / running from the command line. Nonetheless Integrated Development Environments (IDEs) can be used to develop, run and/or debug ROS 2 nodes.Below are listed some IDEs and instructions on how to use them with ROS 2.ContentsGeneralInstalled Python CodeVisual Studio CodePythonPyCharmIntegrate for code inspectionAttach to ProcessRun/DebugGeneralInstalled Python CodeBy default, when building workspaces with:colconbuildThe Python code will be coped over into thebuild/installdirectories. So when attaching a debugger to aros2runcommand from within an IDE, the code being run (from thebuild/install) is not the same as the files opened in the IDE project.There are 2 options to deal with this:Open the source files frombuild/installdirectory and place breakpoints there.Build the workspace with the–symlink-installflag to colcon, which will symlink the source files to


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to colcon, which will symlink the source files to thebuild/installdirectory instead.Visual Studio CodeVSCodeis a versatile and free development environment.VSCode is relatively easy to use with ROS 2. Simply activate your environment in a command line and start the VSCode application from the same terminal and use as normal. So:Create your ROS workspace as you would normally.In a terminal, source both ROS 2 and your install (if it was built already).Start VSCode from the same command line. The terminal will be blocked until the application is closed again.LinuxmacOSWindowssource/opt/ros/jazzy/setup.bashcd~/dev_wssource./install/setup.bash /usr/bin/code./src/my_node/. ~/ros2_install/ros2-osx/setup.bashcd ~/dev_ws. ./install/setup.bash/Applications/Visual Studio Code.app/Contents/Resources/app/bin/code ./src/my_node/#ForCMD:call C:\dev\ros2\local_setup.batcd C:\dev_wscall .\install\local_setup.bat"C:\Program Files\Microsoft VS Code\Code.exe" .\src\my_node\#ForPowerShell:C:\dev\ros2\local_setup.ps1cd


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.\src\my_node\#ForPowerShell:C:\dev\ros2\local_setup.ps1cd C:\dev_ws.\install\local_setup.ps1& "C:\Program Files\Microsoft VS Code\Code.exe" .\src\my_node\VSCode and any terminal created inside VSCode will correctly inherit from the parent environment and should have ROS and installed package available.NoteAfter adding packages or making major changes you might need to source your install again. The simplest way to do this is to close VSCode and restart it as above.PythonIn your workspace, verify the correct interpreter is used. Through sourcing the basic commandpythonshould be correct, but VSCode likes to resort to an absolute path for Python. In the bottom right corner click on “Selected Python Interpreter” to change it.If your ROS 2 Python version is from a virtual environment, VSCode will try to source it at each run command. But we already started VSCode from a sourced environment, so this extra step is not necessary. You can disable this for the current workspace by finding “Settings” > “Extensions” >


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the current workspace by finding “Settings” > “Extensions” > “Python” > “Activate Environment” and disabling the check.Now simply run a file or create a configuration inlaunch.json. Debugging a node is easiest by creating a configuration like apython...command, instead ofros2run/launch.... An example oflaunch.jsoncould be:{"version":"0.2.0","configurations":[{"name":"Python: File","type":"python","request":"launch","program":"my_node.py"},]}Instead you could also create a configuration for attaching to a running process, under “Attach using Process Id”.SeeSetup ROS 2 with VSCode and Dockerfor full instructions on how to use VSCode, in combination with Docker.PyCharmPyCharmis an IDE specifically for Python.Of course it can only be meaningfully used for nodes made in Python.With PyCharm you can either attach to an existing process (probably started by you viaros2run...orros2launch...) or run the node directly from Python (equivalent topython[file.py].Integrate for code inspectionYou can setup your PyCharm


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for code inspectionYou can setup your PyCharm project such that it is fully aware of ROS 2 code, allowing code completion and suggestion.LinuxOpen a terminal, source ROS and start PyCharm:source/opt/ros/humble/setup.bashcdpath/to/dev_ws /opt/pycharm/bin/pycharm.shAfter selecting the correct interpreter, everything should work.NoteThis is untested.WindowsFirst sourcing ROS and then starting PyCharm from the command line seems to have no effect on Windows. Instead, some settings need to be tweaked.Create your ROS workspace as you would normally.Start PyCharm normally.Open a project. This should be the root directory of the ROS node you’re developing, e.g.C:\dev_ws\src\my_node.Click “Add new interpreter” > “Add local interpreter…”. Select a system interpreter (or virtual environment if you’re using one) and select the executable of your ROS Python version (typicallyC:\Python38\python.exe).If you now open one of your code files, you will see warnings about missing imports. Trying to run the file will confirm


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about missing imports. Trying to run the file will confirm these issues.Under the “Python Interpreters” window, find and select your ROS interpreter. Edit the name to something recognizable. More importantly, now click the “Show Interpreter Paths” button.In the new window, you will see the paths already associated with this interpreter. Click the “+” button and add two more paths (according to your ROS install):C:\dev\ros2_humble\binC:\dev\ros2_humble\Lib\site-packagesPyCharm will re-index and when finished it should correctly interpret your project, recognising the ROS 2 system packages. You can navigate through code, get completion and read doc blurbs as expected.If there are dependencies built alongside with your package, they are probably not yet recognized and result in invalid IDE warnings and runtime errors.Resolve this by:Making sure thePATHoverride in the run/debug configuration includes both the ROS 2 install and your workspace, e.g.:C:\dev\ros2_humble\local_setup.ps1


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and your workspace, e.g.:C:\dev\ros2_humble\local_setup.ps1 C:\dev_ws\install\local_setup.ps1echo$ENV:PathAdding the relevant folders from theinstall/directory to your project sources.Go to “Settings…” and under “Project: “ > “Project Structure” click “Add content root”. Add all the relevantsite-packagesfolders underinstall/Lib/*.Finally, make sure your run/debug configuration has the option “include content roots in PYTHONPATH” enabled.TipUsing the–merge-installoption with your colcon build will limit the number of depending directories, making it easier to configure PyCharm.Attach to ProcessEven without any configuration to PyCharm, you can always just attach to a running Python node. Open your project source and simply run your node as usual:ros2runmy_nodemainThen in PyCharm select “Run” > “Attach to Process…”. It might take a second, but a small window should show listing the currently running Python instances, including your node. There can be multiple Python processes, so there may be some


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There can be multiple Python processes, so there may be some trial-and-error to find the right one.After selecting an instance, the usual debugging tools are available. You can pause it or create breakpoints in the code and step through it.NoteThe code in your project might not be the files being executed, seethis.Run/DebugFollow the steps for integration first.Running your Python file from PyCharm will likely result in import errors. This is because PyCharm extends thePYTHONPATHenvironment variable, but it leavesPATHuntouched. Necessary library files inros/binare not found.Edit the run/debug configuration for your file and under “Environment Variables:” add a new variable. It is currently not supported to extend the existingPATH, so we need to override it. From a sourced ROS terminal, export the content ofPATHwith:echo$Env:PATH. Copy the result.Back in PyCharm, paste it asPATH, apply changes and run or debug your node. It should work like any Python project now, allowing easy additions of breakpoints and


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Python project now, allowing easy additions of breakpoints and other debug methods.NoteOn Windows it seems the capitalization of thePATHvariable under “Environment Variables:” must be “path” (all lowercase) in order to work.


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Code Examples:

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colconbuild

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source/opt/ros/jazzy/setup.bashcd~/dev_wssource./install/setup.bash

/usr/bin/code./src/my_node/

Language: unknown . ~/ros2_install/ros2-osx/setup.bashcd ~/dev_ws. ./install/setup.bash/Applications/Visual Studio Code.app/Contents/Resources/app/bin/code ./src/my_node/

Language: unknown #ForCMD:call C:\dev\ros2\local_setup.batcd C:\dev_wscall .\install\local_setup.bat"C:\Program Files\Microsoft VS Code\Code.exe" .\src\my_node\#ForPowerShell:C:\dev\ros2\local_setup.ps1cd C:\dev_ws.\install\local_setup.ps1& "C:\Program Files\Microsoft VS Code\Code.exe" .\src\my_node\

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{"version":"0.2.0","configurations":[{"name":"Python: File","type":"python","request":"launch","program":"my_node.py"},]}

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source/opt/ros/humble/setup.bashcdpath/to/dev_ws

/opt/pycharm/bin/pycharm.sh

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C:\dev\ros2_humble\local_setup.ps1

C:\dev_ws\install\local_setup.ps1echo$ENV:Path

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ros2runmy_nodemain


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Title: Installation (Ubuntu)

URL: https://docs.ros.org/en/jazzy/Tutorials/Advanced/Simulators/Webots/Installation

Ubuntu.html

Section: Installation

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Installation (Ubuntu)Goal:Install thewebots_ros2package and run simulation examples on Ubuntu.Tutorial level:AdvancedTime:10 minutesContentsBackgroundPrerequisitesMultiple Installations of WebotsTasks1 Installwebots_ros22 Launch thewebots_ros2_universal_robotexampleBackgroundThewebots_ros2package provides an interface between ROS 2 and Webots. It includes several sub-packages, includingwebots_ros2_driver, which allows you to start Webots and communicate with it. This interface is used in most of the following tutorials, so it is required to install it beforehand. Other sub-packages are mainly examples that show multiple possible implementations using the interface. In this tutorial, you are going to install the package and learn how to run one of these examples.PrerequisitesIt is recommended to understand basic ROS principles covered in the beginnerTutorials. In particular,Creating a workspaceandCreating a packageare useful prerequisites.The Webots software should be installed in order to use


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Webots software should be installed in order to use thewebots_ros2interface. You can follow theinstallation procedureorbuild it from sources.Alternatively, you can also letwebots_ros2download and install Webots automatically. This option appears when you launch an example of the package and no Webots installation is found.Multiple Installations of WebotsIf you have installed different versions of Webots on your computer,webots_ros2will look for Webots at the following locations (in this order):If theROS2_WEBOTS_HOMEenvironment variable is set, ROS 2 will use the Webots in this folder, regardless of its version.If theWEBOTS_HOMEenvironment variable is set, ROS 2 will use the Webots in this folder, regardless of its version.If none of these variables is set,webots_ros2will look for Webots in the default installation paths for a compatible version:/usr/local/webotsand/snap/webots/current/usr/share/webots.If Webots couldn’t be found,webots_ros2will show a window offering the automatic installation of the latest


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show a window offering the automatic installation of the latest compatible version of Webots.Tasks1 Installwebots_ros2You can either install the official released package, or install it from the latest up-to-date sources fromGithub.Installwebots_ros2distributed packageInstallwebots_ros2from sourcesRun the following command in a terminal.sudo apt-get install ros-jazzy-webots-ros2Create a ROS 2 workspace with itssrcdirectory.mkdir -p ~/ros2_ws/srcSource the ROS 2 environment.source /opt/ros/jazzy/setup.bashRetrieve the sources from Github.cd ~/ros2_wsgit clone --recurse-submodules https://github.com/cyberbotics/webots_ros2.git src/webots_ros2Install the package dependencies.sudo apt install python3-pip python3-rosdep python3-colcon-common-extensionssudo rosdep init && rosdep updaterosdep install --from-paths src --ignore-src --rosdistro jazzyBuild the package usingcolcon.colcon buildSource this workspace.source install/local_setup.bash2 Launch thewebots_ros2_universal_robotexampleThe following instructions


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following instructions explain how to start a provided example.First source the ROS 2 environment, if not done already.source /opt/ros/jazzy/setup.bashSetting theWEBOTS_HOMEenvironment variable allows you to start a specific Webots installation.export WEBOTS_HOME=/usr/local/webotsIf installed from sources, source your ROS 2 workspace, if not done already.cd ~/ros2_wssource install/local_setup.bashUse the ROS 2 launch command to start demo packages (e.g.webots_ros2_universal_robot).ros2 launch webots_ros2_universal_robot multirobot_launch.py


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Code Examples:

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sudo apt

get install ros

jazzy

webots

ros2

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mkdir

p ~/ros2_ws/src

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source /opt/ros/jazzy/setup.bash

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cd ~/ros2_wsgit clone -

recurse

submodules https://github.com/cyberbotics/webots_ros2.git src/webots_ros2

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colcon build

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source install/local_setup.bash

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source /opt/ros/jazzy/setup.bash

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export WEBOTS_HOME=/usr/local/webots

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cd ~/ros2_wssource install/local_setup.bash

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ros2 launch webots_ros2_universal_robot multirobot_launch.py


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Title: Usingros2doctorto identify issues

URL: https://docs.ros.org/en/jazzy/Tutorials/Beginner

Client

Libraries/Getting

Started

With

Ros2doctor.html

Section: Installation

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Usingros2doctorto identify issuesGoal:Identify issues in your ROS 2 setup using theros2doctortool.Tutorial level:BeginnerTime:10 minutesContentsBackgroundPrerequisitesTasks1 Check your setup2 Check a system3 Get a full reportSummaryRelated contentNext stepsBackgroundWhen your ROS 2 setup is not running as expected, you can check its settings with theros2doctortool.ros2doctorchecks all aspects of ROS 2, including platform, version, network, environment, running systems and more, and warns you about possible errors and reasons for issues.Prerequisitesros2doctoris part of theros2clipackage. As long as you haveros2cliinstalled (which any normal install should have), you will be able to useros2doctor.This tutorial usesturtlesimto illustrate some of the examples.Tasks1 Check your setupLet’s examine your general ROS 2 setup as a whole withros2doctor. First, source ROS 2 in a new terminal, then enter the command:ros2 doctorThis will conduct checks over all your setup modules and return warnings and errors.If


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over all your setup modules and return warnings and errors.If your ROS 2 setup is in perfect shape, you’ll see a message similar to this:All <n> checks passedHowever, it’s not unusual to have a few warnings returned. AUserWarningdoesn’t mean your setup is unusable; it’s more likely just an indication that something is configured in a way that’s not ideal.If you do receive a warning, it will look something like this:<path>: <line>: UserWarning: <message>For example,ros2doctorwill find this warning if you’re using an unstable ROS 2 distribution:UserWarning: Distribution <distro> is not fully supported or tested. To get more consistent features, download a stable version at https://index.ros.org/doc/ros2/Installation/Ifros2doctoronly finds warnings in your system, you will still receive theAll<n>checkspassedmessage.Most checks are categorized as warnings as opposed to errors. It’s mostly up to you, the user, to determine the importance of the feedbackros2doctorreturns. If it does find a rare error in your


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feedbackros2doctorreturns. If it does find a rare error in your setup, indicated byUserWarning:ERROR:, the check is considered failed.You will see a message similar to the following list of issue feedback:1/3 checks failedFailed modules:  networkAn error indicates the system is missing important settings or functions that are crucial to ROS 2. Errors should be addressed to ensure the system functions properly.2 Check a systemYou can also examine a running ROS 2 system to identify possible causes for issues. To seeros2doctorworking on a running system, let’s run turtlesim, which has nodes actively communicating with each other.Start up the system by opening a new terminal, sourcing ROS 2, and entering the command:ros2 run turtlesim turtlesim_nodeOpen another terminal and source ROS 2 to run the teleop controls:ros2 run turtlesim turtle_teleop_keyNow runros2doctoragain in its own terminal. You will see the warnings and errors you had the last time you ranros2doctoron your setup if you had any. Following those


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you ranros2doctoron your setup if you had any. Following those will be a couple new warnings relating to the system itself:UserWarning: Publisher without subscriber detected on /turtle1/color_sensor.UserWarning: Publisher without subscriber detected on /turtle1/pose.It seems that the/turtlesimnode publishes data to two topics that aren’t being subscribed to, andros2doctorthinks this could possibly lead to issues.If you run commands to echo the/color_sensorand/posetopics, those warnings will disappear because the publishers will have subscribers.You can try this by opening two new terminals while turtlesim is still running, sourcing ROS 2 in each, and running each of the following commands in their own terminal:ros2 topic echo /turtle1/color_sensorros2 topic echo /turtle1/poseThen runros2doctorin its terminal again. Thepublisherwithoutsubscriberwarnings will be gone. (Make sure to enterCtrl+Cin the terminals where you ranecho).Now try exiting either the turtlesim window or quitting the teleop and


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exiting either the turtlesim window or quitting the teleop and runningros2doctoragain. You’ll see more warnings indicatingpublisherwithoutsubscriberorsubscriberwithoutpublisherfor different topics, now that one node in the system isn’t available.In a complex system with many nodes,ros2doctorwould be invaluable for identifying possible reasons for communication issues.3 Get a full reportWhileros2doctorwill let you know warnings about your network, system, etc., running it with the--reportargument will give you much more detail to help you analyze issues.You might want to use--reportif you get a warning about your network setup and want to find out exactly what part of your configuration is causing the warning.It’s also very helpful when you need to open a support ticket to get help with ROS 2. You can copy and paste the relevant parts of your report into the ticket so the people helping you can better understand your environment and provide better assistance.To get a full report, enter the following command


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assistance.To get a full report, enter the following command in the terminal:ros2 doctor --reportWhich will return a list of information categorized into five groups:NETWORK CONFIGURATION...PLATFORM INFORMATION...RMW MIDDLEWARE...ROS 2 INFORMATION...TOPIC LIST...You can crosscheck the information here against the warnings you get when runningros2doctor. For example, ifros2doctorreturned the warning (mentioned earlier) that your distribution is “not fully supported or tested”, you might take a look at theROS2INFORMATIONsection of the report:distribution name      : <distro>distribution type      : ros2distribution status    : prereleaserelease platforms      : {'<platform>': ['<version>']}Here you can see thedistributionstatusisprerelease, which explains why it’s not fully supported.Summaryros2doctorwill inform you of problems in your ROS 2 setup and running systems. You can get a deeper look at information behind those warnings by using the--reportargument.Keep in mind,ros2doctoris not a debug tool; it


