text:
Next: Introduction, Up: (dir) [Contents][Index]
This document describes GNU Guix version 0.6, a functional package management tool written for the GNU system.
• Introduction: | What is Guix about? | |
• Installation: | Installing Guix. | |
• Package Management: | Package installation, upgrade, etc. | |
• Programming Interface: | Using Guix in Scheme. | |
• Utilities: | Package management commands. | |
• GNU Distribution: | Software for your friendly GNU system. | |
• Contributing: | Your help needed! | |
• Acknowledgments: | Thanks! | |
• GNU Free Documentation License: | The license of this manual. | |
• Concept Index: | Concepts. | |
• Function Index: | Functions. |
Next: Installation, Previous: Top, Up: Top [Contents][Index]
GNU Guix1 is a functional package management tool for the GNU system. Package management consists of all activities that relate to building packages from sources, honoring their build-time and run-time dependencies, installing packages in user environments, upgrading installed packages to new versions or rolling back to a previous set, removing unused software packages, etc.
The term functional refers to a specific package management discipline. In Guix, the package build and installation process is seen as a function, in the mathematical sense. That function takes inputs, such as build scripts, a compiler, and libraries, and returns an installed package. As a pure function, its result depends solely on its inputs—for instance, it cannot refer to software or scripts that were not explicitly passed as inputs. A build function always produces the same result when passed a given set of inputs. It cannot alter the system's environment in any way; for instance, it cannot create, modify, or delete files outside of its build and installation directories. This is achieved by running build processes in isolated environments (or containers), where only their explicit inputs are visible.
The result of package build functions is cached in the file system, in a special directory called the store (see The Store). Each package is installed in a directory of its own, in the store—by default under /nix/store. The directory name contains a hash of all the inputs used to build that package; thus, changing an input yields a different directory name.
This approach is the foundation of Guix's salient features: support for transactional package upgrade and rollback, per-user installation, and garbage collection of packages (see Features).
Guix has a command-line interface, which allows users to build, install, upgrade, and remove packages, as well as a Scheme programming interface.
Last but not least, Guix is used to build a distribution of the GNU system, with many GNU and non-GNU free software packages. See GNU Distribution.
Next: Package Management, Previous: Introduction, Up: Top [Contents][Index]
GNU Guix is available for download from its website at http://www.gnu.org/software/guix/. This section describes the software requirements of Guix, as well as how to install it and get ready to use it.
The build procedure for Guix is the same as for other GNU software, and is not covered here. Please see the files README and INSTALL in the Guix source tree for additional details.
• Requirements: | Software needed to build and run Guix. | |
• Setting Up the Daemon: | Preparing the build daemon's environment. | |
• Invoking guix-daemon: | Running the build daemon. |
Next: Setting Up the Daemon, Up: Installation [Contents][Index]
GNU Guix depends on the following packages:
Unless --disable-daemon
was passed to configure
, the
following packages are also needed:
When a working installation of the Nix package
manager is available, you
can instead configure Guix with --disable-daemon
. In that case,
Nix replaces the three dependencies above.
Guix is compatible with Nix, so it is possible to share the same store
between both. To do so, you must pass configure
not only the
same --with-store-dir
value, but also the same
value. The latter is essential because it
specifies where the database that stores metadata about the store is
located, among other things. The default values are
and --localstatedir=/nix/var
Note that --disable-daemon
is not required if
your goal is to share the store with Nix.
Next: Invoking guix-daemon, Previous: Requirements, Up: Installation [Contents][Index]
Operations such as building a package or running the garbage collector
are all performed by a specialized process, the Guix daemon, on
behalf of clients. Only the daemon may access the store and its
associated database. Thus, any operation that manipulates the store
goes through the daemon. For instance, command-line tools such as
guix package
and guix build
communicate with the
daemon (via remote procedure calls) to instruct it what to do.
In a standard multi-user setup, Guix and its daemon—the
program—are installed by the system
administrator; /nix/store is owned by root
runs as root
. Unprivileged users may use
Guix tools to build packages or otherwise access the store, and the
daemon will do it on their behalf, ensuring that the store is kept in a
consistent state, and allowing built packages to be shared among users.
When guix-daemon
runs as root
, you may not want package
build processes themselves to run as root
too, for obvious
security reasons. To avoid that, a special pool of build users
should be created for use by build processes started by the daemon.
These build users need not have a shell and a home directory: they will
just be used when the daemon drops root
privileges in build
processes. Having several such users allows the daemon to launch
distinct build processes under separate UIDs, which guarantees that they
do not interfere with each other—an essential feature since builds are
regarded as pure functions (see Introduction).
On a GNU/Linux system, a build user pool may be created like this (using
Bash syntax and the shadow
# groupadd guix-builder # for i in `seq 1 10`; do useradd -g guix-builder -G guix-builder \ -d /var/empty -s `which nologin` \ -c "Guix build user $i" guix-builder$i; done
The guix-daemon
program may then be run as root
# guix-daemon --build-users-group=guix-builder
This way, the daemon starts build processes in a chroot, under one of
the guix-builder
users. On GNU/Linux, by default, the chroot
environment contains nothing but the /dev
and /proc
Guix may also be used in a single-user setup, with guix-daemon
running as an unprivileged user. However, to maximize non-interference
of build processes, the daemon still needs to perform certain operations
that are restricted to root
on GNU/Linux: it should be able to
run build processes in a chroot, and to run them under different UIDs.
To that end, the nix-setuid-helper
program is provided; it is
a small C program (less than 300 lines) that, if it is made setuid
, can be executed by the daemon to perform these operations
on its behalf. The root
-owned /etc/nix-setuid.conf file
is read by nix-setuid-helper
; it should contain exactly two
words: the user name under which the authorized guix-daemon
runs, and the name of the build users group.
If you are installing Guix as an unprivileged user and do not have the
ability to make nix-setuid-helper setuid-root
, it is still
possible to run guix-daemon
. However, build processes will
not be isolated from one another, and not from the rest of the system.
Thus, build processes may interfere with each other, and may access
programs, libraries, and other files available on the system—making it
much harder to view them as pure functions.
Previous: Setting Up the Daemon, Up: Installation [Contents][Index]
The guix-daemon
program implements all the functionality to
access the store. This includes launching build processes, running the
garbage collector, querying the availability of a build result, etc. It
is normally run as root
like this:
# guix-daemon --build-users-group=guix-builder
For details on how to set it up, Setting Up the Daemon.
By default, guix-daemon
launches build processes under
different UIDs, taken from the build group specified with
. In addition, each build process is run in a
chroot environment that only contains the subset of the store that the
build process depends on, as specified by its derivation
(see derivation), plus a set of specific
system directories. By default, the latter contains /dev and
/dev/pts. Furthermore, on GNU/Linux, the build environment is a
container: in addition to having its own file system tree, it has
a separate mount name space, its own PID name space, network name space,
etc. This helps achieve reproducible builds (see Features).
The following command-line options are supported:
Take users from group to run build processes (see build users).
Do not use substitutes for build products. That is, always build things locally instead of allowing downloads of pre-built binaries.
By default substitutes are used, unless the client—such as the
guix package
command—is explicitly invoked with
When the daemon runs with --no-substitutes
, clients can still
explicitly enable substitution via the set-build-options
remote procedure call (see The Store).
Cache build failures. By default, only successful builds are cached.
-c n
Use n CPU cores to build each derivation; 0
means as many
as available.
The default value is 1
, but it may be overridden by clients, such
as the --cores
option of guix build
(see Invoking guix build).
The effect is to define the NIX_BUILD_CORES
environment variable
in the build process, which can then use it to exploit internal
parallelism—for instance, by running make -j$NIX_BUILD_CORES
-M n
Allow at most n build jobs in parallel. The default value is
Produce debugging output.
This is useful to debug daemon start-up issues, but then it may be
overridden by clients, for example the --verbosity
option of
guix build
(see Invoking guix build).
Add dir to the build chroot.
Doing this may change the result of build processes—for instance if they use optional dependencies found in dir when it is available, and not otherwise. For that reason, it is not recommended to do so. Instead, make sure that each derivation declares all the inputs that it needs.
Disable chroot builds.
Using this option is not recommended since, again, it would allow build processes to gain access to undeclared dependencies.
Disable compression of the build logs.
Unless --lose-logs
is used, all the build logs are kept in the
localstatedir. To save space, the daemon automatically compresses
them with bzip2 by default. This option disables that.
Disable automatic file "deduplication" in the store.
By default, files added to the store are automatically "deduplicated": if a newly added file is identical as another one found in the store, the daemon makes the new file a hard link to the other file. This slightly increases the input/output load at the end of a build process. This option disables this.
On Linux-based systems, impersonate Linux 2.6. This means that the
kernel's uname
system call will report 2.6 as the release number.
This might be helpful to build programs that (usually wrongfully) depend on the kernel version number.
Do not keep build logs. By default they are kept under
Assume system as the current system type. By default it is the
architecture/kernel pair found at configure time, such as
Listen for connections on socket, the file name of a Unix-domain socket. The default socket is localstatedir/daemon-socket/socket. This option is only useful in exceptional circumstances, such as if you need to run several daemons on the same machine.
Next: Programming Interface, Previous: Installation, Up: Top [Contents][Index]
The purpose of GNU Guix is to allow users to easily install, upgrade, and remove software packages, without having to know about their build procedure or dependencies. Guix also goes beyond this obvious set of features.
This chapter describes the main features of Guix, as well as the package management tools it provides.
• Features: | How Guix will make your life brighter. | |
• Invoking guix package: | Package installation, removal, etc. | |
• Packages with Multiple Outputs: | Single source package, multiple outputs. | |
• Invoking guix gc: | Running the garbage collector. | |
• Invoking guix pull: | Fetching the latest Guix and distribution. |
Next: Invoking guix package, Up: Package Management [Contents][Index]
When using Guix, each package ends up in the package store, in its
own directory—something that resembles
/nix/store/xxx-package-1.2, where xxx
is a base32 string.
Instead of referring to these directories, users have their own
profile, which points to the packages that they actually want to
use. These profiles are stored within each user's home directory, at
For example, alice
installs GCC 4.7.2. As a result,
/home/alice/.guix-profile/bin/gcc points to
/nix/store/…-gcc-4.7.2/bin/gcc. Now, on the same machine,
had already installed GCC 4.8.0. The profile of bob
simply continues to point to
/nix/store/…-gcc-4.8.0/bin/gcc—i.e., both versions of GCC
coexist on the same system without any interference.
The guix package
command is the central tool to manage
packages (see Invoking guix package). It operates on those per-user
profiles, and can be used with normal user privileges.
The command provides the obvious install, remove, and upgrade
operations. Each invocation is actually a transaction: either
the specified operation succeeds, or nothing happens. Thus, if the
guix package
process is terminated during the transaction,
or if a power outage occurs during the transaction, then the user's
profile remains in its previous state, and remains usable.
In addition, any package transaction may be rolled back. So, if, for example, an upgrade installs a new version of a package that turns out to have a serious bug, users may roll back to the previous instance of their profile, which was known to work well. Similarly, the global system configuration is subject to transactional upgrades and roll-back (see Using the Configuration System).
All those packages in the package store may be garbage-collected. Guix can determine which packages are still referenced by the user profiles, and remove those that are provably no longer referenced (see Invoking guix gc). Users may also explicitly remove old generations of their profile so that the packages they refer to can be collected.
Finally, Guix takes a purely functional approach to package management, as described in the introduction (see Introduction). Each /nix/store package directory name contains a hash of all the inputs that were used to build that package—compiler, libraries, build scripts, etc. This direct correspondence allows users to make sure a given package installation matches the current state of their distribution. It also helps maximize build reproducibility: thanks to the isolated build environments that are used, a given build is likely to yield bit-identical files when performed on different machines (see container).
This foundation allows Guix to support transparent binary/source deployment. When a pre-built binary for a /nix/store path is available from an external source—a substitute, Guix just downloads it3; otherwise, it builds the package from source, locally.
Next: Packages with Multiple Outputs, Previous: Features, Up: Package Management [Contents][Index]
guix package
The guix package
command is the tool that allows users to
install, upgrade, and remove packages, as well as rolling back to
previous configurations. It operates only on the user's own profile,
and works with normal user privileges (see Features). Its syntax
guix package options
Primarily, options specifies the operations to be performed during the transaction. Upon completion, a new profile is created, but previous generations of the profile remain available, should the user want to roll back.
For each user, a symlink to the user's default profile is automatically
created in $HOME/.guix-profile. This symlink always points to the
current generation of the user's default profile. Thus, users can add
$HOME/.guix-profile/bin to their PATH
variable, and so on.
In a multi-user setup, user profiles must be stored in a place
registered as a garbage-collector root, which
$HOME/.guix-profile points to (see Invoking guix gc). That
directory is normally
, where
localstatedir is the value passed to configure
, and user is the user name. It must be
created by root
, with user as the owner. When it does not
exist, or is not owned by user, guix package
emits an
error about it.
The options can be among the following:
-i package
Install package.
package may specify either a simple package name, such as
, or a package name followed by a hyphen and version number,
such as guile-1.8.8
. If no version number is specified, the
newest available version will be selected. In addition, package
may contain a colon, followed by the name of one of the outputs of the
package, as in gcc:doc
or binutils-2.22:lib
(see Packages with Multiple Outputs).
Sometimes packages have propagated inputs: these are dependencies that automatically get installed along with the required package.
An example is the GNU MPC library: its C header files refer to those of the GNU MPFR library, which in turn refer to those of the GMP library. Thus, when installing MPC, the MPFR and GMP libraries also get installed in the profile; removing MPC also removes MPFR and GMP—unless they had also been explicitly installed independently.
Besides, packages sometimes rely on the definition of environment
variables for their search paths (see explanation of
below). Any missing or possibly incorrect
environment variable definitions are reported here.
Finally, when installing a GNU package, the tool reports the availability of a newer upstream version. In the future, it may provide the option of installing directly from the upstream version, even if that version is not yet in the distribution.
-e exp
Install the package exp evaluates to.
exp must be a Scheme expression that evaluates to a
object. This option is notably useful to disambiguate
between same-named variants of a package, with expressions such as
(@ (gnu packages base) guile-final)
Note that this option installs the first output of the specified package, which may be insufficient when needing a specific output of a multiple-output package.
-r package
Remove package.
As for --install
, package may specify a version number
and/or output name in addition to the package name. For instance,
-r glibc:debug
would remove the debug
output of
-u [regexp]
Upgrade all the installed packages. When regexp is specified, upgrade only installed packages whose name matches regexp.
Note that this upgrades package to the latest version of packages found
in the distribution currently installed. To update your distribution,
you should regularly run guix pull
(see Invoking guix pull).
Roll back to the previous generation of the profile—i.e., undo the last transaction.
When combined with options such as --install
, roll back occurs
before any other actions.
When rolling back from the first generation that actually contains installed packages, the profile is made to point to the zeroth generation, which contains no files apart from its own meta-data.
Installing, removing, or upgrading packages from a generation that has been rolled back to overwrites previous future generations. Thus, the history of a profile's generations is always linear.
Report environment variable definitions, in Bash syntax, that may be needed in order to use the set of installed packages. These environment variables are used to specify search paths for files used by some of the installed packages.
For example, GCC needs the CPATH
and LIBRARY_PATH
environment variables to be defined so it can look for headers and
libraries in the user's profile (see Environment Variables in Using the GNU Compiler Collection (GCC)). If GCC and, say, the C
library are installed in the profile, then --search-paths
suggest setting these variables to profile/include
, respectively.
-p profile
Use profile instead of the user's default profile.
Show what would be done without actually doing it.
When substituting a pre-built binary fails, fall back to building packages locally.
Do not use substitutes for build products. That is, always build things locally instead of allowing downloads of pre-built binaries.
Same as for guix build
(see Invoking guix build).
Produce verbose output. In particular, emit the environment's build log on the standard error port.
Use the bootstrap Guile to build the profile. This option is only useful to distribution developers.
In addition to these actions guix package
supports the
following options to query the current state of a profile, or the
availability of packages:
List the available packages whose synopsis or description matches
regexp. Print all the meta-data of matching packages in
format (see GNU recutils databases in GNU recutils manual).
This allows specific fields to be extracted using the recsel
command, for instance:
$ guix package -s malloc | recsel -p name,version name: glibc version: 2.17 name: libgc version: 7.2alpha6
List the currently installed packages in the specified profile, with the most recently installed packages shown last. When regexp is specified, list only installed packages whose name matches regexp.
For each installed package, print the following items, separated by
tabs: the package name, its version string, the part of the package that
is installed (for instance, out
for the default output,
for its headers, etc.), and the path of this package in
the store.
List packages currently available in the software distribution (see GNU Distribution). When regexp is specified, list only installed packages whose name matches regexp.
For each package, print the following items separated by tabs: its name, its version string, the parts of the package (see Packages with Multiple Outputs), and the source location of its definition.
Return a list of generations along with their creation dates; for each generation, show the installed packages, with the most recently installed packages shown last. Note that the zeroth generation is never shown.
For each installed package, print the following items, separated by tabs: the name of a package, its version string, the part of the package that is installed (see Packages with Multiple Outputs), and the location of this package in the store.
When pattern is used, the command returns only matching generations. Valid patterns include:
the first one.
And --list-generations=1,8,2
outputs three generations in the
specified order. Neither spaces nor trailing commas are allowed.
prints the
specified generations and everything in between. Note that the start of
a range must be lesser than its end.
It is also possible to omit the endpoint. For example,
, returns all generations starting from the
second one.
lists generations
that are up to 20 days old.
When pattern is omitted, delete all generations except the current one.
This command accepts the same patterns as --list-generations.
When pattern is specified, delete the matching generations. When
pattern specifies a duration, generations older than the
specified duration match. For instance, --delete-generations=1m
deletes generations that are more than one month old.
If the current generation matches, it is deleted atomically—i.e., by switching to the previous available generation. Note that the zeroth generation is never deleted.
Note that deleting generations prevents roll-back to them. Consequently, this command must be used with care.
Next: Invoking guix gc, Previous: Invoking guix package, Up: Package Management [Contents][Index]
Often, packages defined in Guix have a single output—i.e., the
source package leads exactly one directory in the store. When running
guix package -i glibc
, one installs the default output of the
GNU libc package; the default output is called out
, but its name
can be omitted as shown in this command. In this particular case, the
default output of glibc
contains all the C header files, shared
libraries, static libraries, Info documentation, and other supporting
Sometimes it is more appropriate to separate the various types of files
produced from a single source package into separate outputs. For
instance, the GLib C library (used by GTK+ and related packages)
installs more than 20 MiB of reference documentation as HTML pages.
To save space for users who do not need it, the documentation goes to a
separate output, called doc
. To install the main GLib output,
which contains everything but the documentation, one would run:
guix package -i glib
The command to install its documentation is:
guix package -i glib:doc
Some packages install programs with different "dependency footprints". For instance, the WordNet package install both command-line tools and graphical user interfaces (GUIs). The former depend solely on the C library, whereas the latter depend on Tcl/Tk and the underlying X libraries. In this case, we leave the command-line tools in the default output, whereas the GUIs are in a separate output. This allows users who do not need the GUIs to save space.
There are several such multiple-output packages in the GNU distribution.
Other conventional output names include lib
for libraries and
possibly header files, bin
for stand-alone programs, and
for debugging information (see Installing Debugging Files). The outputs of a packages are listed in the third column of
the output of guix package --list-available
(see Invoking guix package).
Next: Invoking guix pull, Previous: Packages with Multiple Outputs, Up: Package Management [Contents][Index]
guix gc
Packages that are installed but not used may be garbage-collected.
The guix gc
command allows users to explicitly run the garbage
collector to reclaim space from the /nix/store directory.
The garbage collector has a set of known roots: any file under
/nix/store reachable from a root is considered live and
cannot be deleted; any other file is considered dead and may be
deleted. The set of garbage collector roots includes default user
profiles, and may be augmented with guix build --root
, for
example (see Invoking guix build).
Prior to running guix gc --collect-garbage
to make space, it is
often useful to remove old generations from user profiles; that way, old
package builds referenced by those generations can be reclaimed. This
is achieved by running guix package --delete-generations
(see Invoking guix package).
The guix gc
command has three modes of operation: it can be
used to garbage-collect any dead files (the default), to delete specific
files (the --delete
option), or to print garbage-collector
information. The available options are listed below:
-C [min]
Collect garbage—i.e., unreachable /nix/store files and sub-directories. This is the default operation when no option is specified.
When min is given, stop once min bytes have been collected.
min may be a number of bytes, or it may include a unit as a
suffix, such as MiB
for mebibytes and GB
for gigabytes.
When min is omitted, collect all the garbage.
Attempt to delete all the store files and directories specified as arguments. This fails if some of the files are not in the store, or if they are still live.
Show the list of dead files and directories still present in the store—i.e., files and directories no longer reachable from any root.
Show the list of live store files and directories.
In addition, the references among existing store files can be queried:
List the references (respectively, the referrers) of store files given as arguments.
List the requisites of the store files passed as arguments. Requisites include the store files themselves, their references, and the references of these, recursively. In other words, the returned list is the transitive closure of the store files.
Previous: Invoking guix gc, Up: Package Management [Contents][Index]
guix pull
Packages are installed or upgraded to the latest version available in
the distribution currently available on your local machine. To update
that distribution, along with the Guix tools, you must run guix
: the command downloads the latest Guix source code and package
descriptions, and deploys it.
On completion, guix package
will use packages and package
versions from this just-retrieved copy of Guix. Not only that, but all
the Guix commands and Scheme modules will also be taken from that latest
version. New guix
sub-commands added by the update also
become available.
The guix pull
command is usually invoked with no arguments,
but it supports the following options:
Produce verbose output, writing build logs to the standard error output.
Download the source tarball of Guix from url.
By default, the tarball is taken from its canonical address at
, for the stable branch of Guix.
Use the bootstrap Guile to build the latest Guix. This option is only useful to Guix developers.
Next: Utilities, Previous: Package Management, Up: Top [Contents][Index]
GNU Guix provides several Scheme programming interfaces (APIs) to define, build, and query packages. The first interface allows users to write high-level package definitions. These definitions refer to familiar packaging concepts, such as the name and version of a package, its build system, and its dependencies. These definitions can then be turned into concrete build actions.
Build actions are performed by the Guix daemon, on behalf of users. In a standard setup, the daemon has write access to the store—the /nix/store directory—whereas users do not. The recommended setup also has the daemon perform builds in chroots, under a specific build users, to minimize interference with the rest of the system.
Lower-level APIs are available to interact with the daemon and the store. To instruct the daemon to perform a build action, users actually provide it with a derivation. A derivation is a low-level representation of the build actions to be taken, and the environment in which they should occur—derivations are to package definitions what assembly is to C programs.
This chapter describes all these APIs in turn, starting from high-level package definitions.
• Defining Packages: | Defining new packages. | |
• The Store: | Manipulating the package store. | |
• Derivations: | Low-level interface to package derivations. | |
• The Store Monad: | Purely functional interface to the store. |
Next: The Store, Up: Programming Interface [Contents][Index]
The high-level interface to package definitions is implemented in the
(guix packages)
and (guix build-system)
modules. As an
example, the package definition, or recipe, for the GNU Hello
package looks like this:
(use-modules (guix packages) (guix download) (guix build-system gnu) (guix licenses)) (define hello (package (name "hello") (version "2.8") (source (origin (method url-fetch) (uri (string-append "mirror://gnu/hello/hello-" version ".tar.gz")) (sha256 (base32 "0wqd8sjmxfskrflaxywc7gqw7sfawrfvdxd9skxawzfgyy0pzdz6")))) (build-system gnu-build-system) (inputs `(("gawk" ,gawk))) (synopsis "GNU Hello") (description "Yeah...") (home-page "http://www.gnu.org/software/hello/") (license gpl3+)))
Without being a Scheme expert, the reader may have guessed the meaning
of the various fields here. This expression binds variable hello
to a <package>
object, which is essentially a record
(see Scheme records in GNU Guile Reference Manual).
This package object can be inspected using procedures found in the
(guix packages)
module; for instance, (package-name hello)
There are a few points worth noting in the above package definition:
field of the package is an <origin>
Here, the url-fetch
method from (guix download)
is used,
meaning that the source is a file to be downloaded over FTP or HTTP.
The mirror://gnu
prefix instructs url-fetch
to use one of
the GNU mirrors defined in (guix download)
The sha256
field specifies the expected SHA256 hash of the file
being downloaded. It is mandatory, and allows Guix to check the
integrity of the file. The (base32 …)
form introduces the
base32 representation of the hash. You can obtain this information with
guix download
(see Invoking guix download) and guix
(see Invoking guix hash).
When needed, the origin
form can also have a patches
listing patches to be applied, and a snippet
field giving a
Scheme expression to modify the source code.
field is set to gnu-build-system. The
gnu-build-system variable is defined in the (guix
build-system gnu)
module, and is bound to a <build-system>
Naturally, gnu-build-system represents the familiar GNU Build
System, and variants thereof (see configuration and
makefile conventions in GNU Coding Standards). In a
nutshell, packages using the GNU Build System may be configured, built,
and installed with the usual ./configure && make && make check &&
make install
command sequence. This is what gnu-build-system
In addition, gnu-build-system ensures that the "standard" environment for GNU packages is available. This includes tools such as GCC, Coreutils, Bash, Make, Diffutils, and Patch.
field specifies inputs to the build process—i.e.,
build-time or run-time dependencies of the package. Here, we define an
input called "gawk"
whose value is that of the gawk
variable; gawk is itself bound to a <package>
Note that GCC, Coreutils, Bash, and other essential tools do not need to be specified as inputs here. Instead, gnu-build-system takes care of ensuring that they are present.
However, any other dependencies need to be specified in the
field. Any dependency not specified here will simply be
unavailable to the build process, possibly leading to a build failure.
There are other fields that package definitions may provide. Of
particular interest is the arguments
field. When specified, it
must be bound to a list of additional arguments to be passed to the
build system. For instance, the above definition could be augmented
with the following field initializer:
(arguments `(#:tests? #f #:configure-flags '("--enable-silent-rules")))
These are keyword arguments (see keyword
arguments in Guile in GNU Guile Reference Manual). They are
passed to gnu-build-system, which interprets them as meaning "do
not run make check
", and "run configure with the
flag". The value of these keyword
parameters is actually evaluated in the build stratum—i.e., by a
Guile process launched by the daemon (see Derivations).
Once a package definition is in place4, the
package may actually be built using the guix build
tool (see Invoking guix build). Eventually, updating the package
definition to a new upstream version can be partly automated by the
guix refresh
command (see Invoking guix refresh).
Behind the scenes, a derivation corresponding to the <package>
object is first computed by the package-derivation
That derivation is stored in a .drv
file under /nix/store.
The build actions it prescribes may then be realized by using the
procedure (see The Store).
Return the <derivation>
object of package for system
(see Derivations).
package must be a valid <package>
object, and system
must be a string denoting the target system type—e.g.,
for an x86_64 Linux-based GNU system. store
must be a connection to the daemon, which operates on the store
(see The Store).
Similarly, it is possible to compute a derivation that cross-builds a package for some other system:
Return the <derivation>
object of package cross-built from
system to target.
target must be a valid GNU triplet denoting the target hardware
and operating system, such as "mips64el-linux-gnu"
(see GNU configuration triplets in GNU
Configure and Build System).
Next: Derivations, Previous: Defining Packages, Up: Programming Interface [Contents][Index]
Conceptually, the store is where derivations that have been successfully built are stored—by default, under /nix/store. Sub-directories in the store are referred to as store paths. The store has an associated database that contains information such has the store paths referred to by each store path, and the list of valid store paths—paths that result from a successful build.
The store is always accessed by the daemon on behalf of its clients (see Invoking guix-daemon). To manipulate the store, clients connect to the daemon over a Unix-domain socket, send it requests, and read the result—these are remote procedure calls, or RPCs.
The (guix store)
module provides procedures to connect to the
daemon, and to perform RPCs. These are described below.
Connect to the daemon over the Unix-domain socket at file. When reserve-space? is true, instruct it to reserve a little bit of extra space on the file system so that the garbage collector can still operate, should the disk become full. Return a server object.
file defaults to %default-socket-path, which is the normal
location given the options that were passed to configure
Close the connection to server.
This variable is bound to a SRFI-39 parameter, which refers to the port where build and error logs sent by the daemon should be written.
Procedures that make RPCs all take a server object as their first argument.
Return #t
when path is a valid store path.
Add text under file name in the store, and return its store path. references is the list of store paths referred to by the resulting store path.
Build derivations (a list of <derivation>
objects or
derivation paths), and return when the worker is done building them.
Return #t
on success.
Note that the (guix monads)
module provides a monad as well as
monadic versions of the above procedures, with the goal of making it
more convenient to work with code that accesses the store (see The Store Monad).
This section is currently incomplete.
Next: The Store Monad, Previous: The Store, Up: Programming Interface [Contents][Index]
Low-level build actions and the environment in which they are performed are represented by derivations. A derivation contain the following pieces of information:
Derivations allow clients of the daemon to communicate build actions to
the store. They exist in two forms: as an in-memory representation,
both on the client- and daemon-side, and as files in the store whose
name end in .drv
—these files are referred to as derivation
paths. Derivations paths can be passed to the build-derivations
procedure to perform the build actions they prescribe (see The Store).
The (guix derivations)
module provides a representation of
derivations as Scheme objects, along with procedures to create and
otherwise manipulate derivations. The lowest-level primitive to create
a derivation is the derivation
Build a derivation with the given arguments, and return the resulting
When hash, hash-algo, and hash-mode are given, a fixed-output derivation is created—i.e., one whose result is known in advance, such as a file download.
When references-graphs is true, it must be a list of file name/store path pairs. In that case, the reference graph of each store path is exported in the build environment in the corresponding file, in a simple text format.
Here's an example with a shell script as its builder, assuming store is an open connection to the daemon, and bash points to a Bash executable in the store:
(use-modules (guix utils) (guix store) (guix derivations)) (let ((builder ; add the Bash script to the store (add-text-to-store store "my-builder.sh" "echo hello world > $out\n" '()))) (derivation store "foo" bash `("-e" ,builder) #:env-vars '(("HOME" . "/homeless")))) ⇒ #<derivation /nix/store/…-foo.drv => /nix/store/…-foo>
As can be guessed, this primitive is cumbersome to use directly. An
improved variant is build-expression->derivation
, which allows
the caller to directly pass a Guile expression as the build script:
Return a derivation that executes Scheme expression exp as a
builder for derivation name. inputs must be a list of
(name drv-path sub-drv)
tuples; when sub-drv is omitted,
is assumed. modules is a list of names of Guile
modules from the current search path to be copied in the store,
compiled, and made available in the load path during the execution of
exp—e.g., ((guix build utils) (guix build
exp is evaluated in an environment where %outputs
is bound
to a list of output/path pairs, and where %build-inputs
is bound
to a list of string/output-path pairs made from inputs.
Optionally, env-vars is a list of string pairs specifying the name
and value of environment variables visible to the builder. The builder
terminates by passing the result of exp to exit
; thus, when
exp returns #f
, the build is considered to have failed.
exp is built using guile-for-build (a derivation). When
guile-for-build is omitted or is #f
, the value of the
fluid is used instead.
See the derivation
procedure for the meaning of references-graphs.
Here's an example of a single-output derivation that creates a directory containing one file:
(let ((builder '(let ((out (assoc-ref %outputs "out"))) (mkdir out) ; create /nix/store/…-goo (call-with-output-file (string-append out "/test") (lambda (p) (display '(hello guix) p)))))) (build-expression->derivation store "goo" builder)) ⇒ #<derivation /nix/store/…-goo.drv => …>
Remember that the build expression passed to
is run by a separate Guile process
than the one that calls build-expression->derivation
: it is run
by a Guile process launched by the daemon, typically in a chroot. So,
while there is a single language for both the host and the build
side, there are really two strata of code: the host-side, and the
build-side code5.
This distinction is important to keep in mind, notably when using
higher-level constructs such as gnu-build-system (see Defining Packages). For this reason, Guix modules that are meant to be used in
the build stratum are kept in the (guix build …)
Previous: Derivations, Up: Programming Interface [Contents][Index]
The procedures that operate on the store described in the previous sections all take an open connection to the build daemon as their first argument. Although the underlying model is functional, they either have side effects or depend on the current state of the store.
The former is inconvenient: the connection to the build daemon has to be carried around in all those functions, making it impossible to compose functions that do not take that parameter with functions that do. The latter can be problematic: since store operations have side effects and/or depend on external state, they have to be properly sequenced.
This is where the (guix monads)
module comes in. This module
provides a framework for working with monads, and a particularly
useful monad for our uses, the store monad. Monads are a
construct that allows two things: associating "context" with values
(in our case, the context is the store), and building sequences of
computations (here computations includes accesses to the store.) Values
in a monad—values that carry this additional context—are called
monadic values; procedures that return such values are called
monadic procedures.
Consider this "normal" procedure:
(define (profile.sh store) ;; Return the name of a shell script in the store that ;; initializes the 'PATH' environment variable. (let* ((drv (package-derivation store coreutils)) (out (derivation->output-path drv))) (add-text-to-store store "profile.sh" (format #f "export PATH=~a/bin" out))))
Using (guix monads)
, it may be rewritten as a monadic function:
(define (profile.sh) ;; Same, but return a monadic value. (mlet %store-monad ((bin (package-file coreutils "bin"))) (text-file "profile.sh" (string-append "export PATH=" bin))))
There are two things to note in the second version: the store
parameter is now implicit, and the monadic value returned by
—a wrapper around package-derivation
—is bound using mlet
instead of plain let
Calling the monadic profile.sh
has no effect. To get the desired
effect, one must use run-with-store
(run-with-store (open-connection) (profile.sh)) ⇒ /nix/store/...-profile.sh
The main syntactic forms to deal with monads in general are described below.
Evaluate any >>=
or return
forms in body as being
in monad.
Return a monadic value that encapsulates val.
Bind monadic value mval, passing its "contents" to monadic procedure mproc6.
Bind the variables var to the monadic values mval in
body. The form (var -> val) binds var to the
"normal" value val, as per let
is to mlet
what let*
is to let
(see Local Bindings in GNU Guile Reference Manual).
The interface to the store monad provided by (guix monads)
is as
The store monad. Values in the store monad encapsulate accesses to the
store. When its effect is needed, a value of the store monad must be
"evaluated" by passing it to the run-with-store
procedure (see
Run mval, a monadic value in the store monad, in store, an open store connection.
Return as a monadic value the absolute file name in the store of the file containing text.
value in the absolute file name of file within the output directory of package. When file is omitted, return the name of the output directory of package.
Monadic version of build-expression->derivation
(see Derivations).
Monadic version of package-derivation
(see Defining Packages).
Next: GNU Distribution, Previous: Programming Interface, Up: Top [Contents][Index]
This section describes tools primarily targeted at developers and users who write new package definitions. They complement the Scheme programming interface of Guix in a convenient way.
• Invoking guix build: | Building packages from the command line. | |
• Invoking guix download: | Downloading a file and printing its hash. | |
• Invoking guix hash: | Computing the cryptographic hash of a file. | |
• Invoking guix refresh: | Updating package definitions. |
Next: Invoking guix download, Up: Utilities [Contents][Index]
guix build
The guix build
command builds packages or derivations and
their dependencies, and prints the resulting store paths. Note that it
does not modify the user's profile—this is the job of the
guix package
command (see Invoking guix package). Thus,
it is mainly useful for distribution developers.
The general syntax is:
guix build options package-or-derivation…
package-or-derivation may be either the name of a package found in
the software distribution such as coreutils
, or a derivation such as
/nix/store/…-coreutils-8.19.drv. Alternatively, the
option may be used to specify a Scheme expression
that evaluates to a package; this is useful when disambiguation among
several same-named packages or package variants is needed.
The options may be zero or more of the following:
-e expr
Build the package or derivation expr evaluates to.
For example, expr may be (@ (gnu packages guile)
, which unambiguously designates this specific variant of
version 1.8 of Guile.
Alternately, expr may refer to a zero-argument monadic procedure
(see The Store Monad). The procedure must return a derivation as a
monadic value, which is then passed through run-with-store
Build the packages' source derivations, rather than the packages themselves.
For instance, guix build -S gcc
returns something like
/nix/store/…-gcc-4.7.2.tar.bz2, which is GCC's source tarball.
The returned source tarball is the result of applying any patches and
code snippets specified in the package's origin
(see Defining Packages).
-s system
Attempt to build for system—e.g., i686-linux
—instead of
the host's system type.
An example use of this is on Linux-based systems, which can emulate
different personalities. For instance, passing
on an x86_64-linux
system allows users
to build packages in a complete 32-bit environment.
Cross-build for triplet, which must be a valid GNU triplet, such
as "mips64el-linux-gnu"
(see GNU
configuration triplets in GNU Configure and Build System).
Return the derivation paths, not the output paths, of the given packages.
Keep the build tree of failed builds. Thus, if a build fail, its build tree is kept under /tmp, in a directory whose name is shown at the end of the build log. This is useful when debugging build issues.
Do not build the derivations.
When substituting a pre-built binary fails, fall back to building packages locally.
Do not use substitutes for build products. That is, always build things locally instead of allowing downloads of pre-built binaries.
When the build or substitution process remains silent for more than seconds, terminate it and report a build failure.
-c n
Allow the use of up to n CPU cores for the build. The special
value 0
means to use as many CPU cores as available.
-r file
Make file a symlink to the result, and register it as a garbage collector root.
Use the given verbosity level. level must be an integer between 0 and 5; higher means more verbose output. Setting a level of 4 or more may be helpful when debugging setup issues with the build daemon.
Return the build log file names for the given package-or-derivations, or raise an error if build logs are missing.
This works regardless of how packages or derivations are specified. For instance, the following invocations are equivalent:
guix build --log-file `guix build -d guile` guix build --log-file `guix build guile` guix build --log-file guile guix build --log-file -e '(@ (gnu packages guile) guile-2.0)'
Behind the scenes, guix build
is essentially an interface to
the package-derivation
procedure of the (guix packages)
module, and to the build-derivations
procedure of the (guix
Next: Invoking guix hash, Previous: Invoking guix build, Up: Utilities [Contents][Index]
guix download
When writing a package definition, developers typically need to download
the package's source tarball, compute its SHA256 hash, and write that
hash in the package definition (see Defining Packages). The
guix download
tool helps with this task: it downloads a file
from the given URI, adds it to the store, and prints both its file name
in the store and its SHA256 hash.
The fact that the downloaded file is added to the store saves bandwidth:
when the developer eventually tries to build the newly defined package
with guix build
, the source tarball will not have to be
downloaded again because it is already in the store. It is also a
convenient way to temporarily stash files, which may be deleted
eventually (see Invoking guix gc).
The guix download
command supports the same URIs as used in
package definitions. In particular, it supports mirror://
URIs (HTTP over TLS) are supported provided the
Guile bindings for GnuTLS are available in the user's environment; when
they are not available, an error is raised.
The following option is available:
-f fmt
Write the hash in the format specified by fmt. For more information on the valid values for fmt, Invoking guix hash.
Next: Invoking guix refresh, Previous: Invoking guix download, Up: Utilities [Contents][Index]
guix hash
The guix hash
command computes the SHA256 hash of a file.
It is primarily a convenience tool for anyone contributing to the
distribution: it computes the cryptographic hash of a file, which can be
used in the definition of a package (see Defining Packages).
The general syntax is:
guix hash option file
guix hash
has the following option:
-f fmt
Write the hash in the format specified by fmt.
Supported formats: nix-base32
, base32
, base16
and hexadecimal
can be used as well).
If the --format option is not specified, guix hash
will output the hash in nix-base32
. This representation is used
in the definitions of packages.
Previous: Invoking guix hash, Up: Utilities [Contents][Index]
guix refresh
The primary audience of the guix refresh
command is developers
of the GNU software distribution. By default, it reports any packages
provided by the distribution that are outdated compared to the latest
upstream version, like this:
$ guix refresh gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
It does so by browsing each package's FTP directory and determining the highest version number of the source tarballs therein7.
When passed --update
, it modifies distribution source files to
update the version numbers and source tarball hashes of those packages'
recipes (see Defining Packages). This is achieved by downloading
each package's latest source tarball and its associated OpenPGP
signature, authenticating the downloaded tarball against its signature
using gpg
, and finally computing its hash. When the public
key used to sign the tarball is missing from the user's keyring, an
attempt is made to automatically retrieve it from a public key server;
when it's successful, the key is added to the user's keyring; otherwise,
guix refresh
reports an error.
The following options are supported:
Update distribution source files (package recipes) in place. Defining Packages, for more information on package definitions.
-s subset
Select all the packages in subset, one of core
The core
subset refers to all the packages at the core of the
distribution—i.e., packages that are used to build "everything
else". This includes GCC, libc, Binutils, Bash, etc. Usually,
changing one of these packages in the distribution entails a rebuild of
all the others. Thus, such updates are an inconvenience to users in
terms of build time or bandwidth used to achieve the upgrade.
The non-core
subset refers to the remaining packages. It is
typically useful in cases where an update of the core packages would be
In addition, guix refresh
can be passed one or more package
names, as in this example:
guix refresh -u emacs idutils
The command above specifically updates the emacs
packages. The --select
option would have no
effect in this case.
The following options can be used to customize GnuPG operation:
Use host as the OpenPGP key server when importing a public key.
Use command as the GnuPG 2.x command. command is searched
for in $PATH
Next: Contributing, Previous: Utilities, Up: Top [Contents][Index]
Guix comes with a distribution of free software8 that forms the basis of the GNU system. This
includes core GNU packages such as GNU libc, GCC, and Binutils, as well
as many GNU and non-GNU applications. The complete list of available
packages can be browsed
on-line or by
running guix package
(see Invoking guix package):
guix package --list-available
Our goal is to build a practical 100% free software distribution of Linux-based and other variants of GNU, with a focus on the promotion and tight integration of GNU components, and an emphasis on programs and tools that help users exert that freedom.
The GNU distribution is currently available on the following platforms:
Intel/AMD x86_64
architecture, Linux-Libre kernel;
Intel 32-bit architecture (IA32), Linux-Libre kernel;
little-endian 64-bit MIPS processors, specifically the Loongson series, n32 application binary interface (ABI), and Linux-Libre kernel.
For information on porting to other architectures or kernels, See Porting.
• Installing Debugging Files: | Feeding the debugger. | |
• Package Modules: | Packages from the programmer's viewpoint. | |
• Packaging Guidelines: | Growing the distribution. | |
• Bootstrapping: | GNU/Linux built from scratch. | |
• Porting: | Targeting another platform or kernel. | |
• System Configuration: | Configuring a GNU system. |
Building this distribution is a cooperative effort, and you are invited to join! Contributing, for information about how you can help.
Next: Package Modules, Up: GNU Distribution [Contents][Index]
Program binaries, as produced by the GCC compilers for instance, are typically written in the ELF format, with a section containing debugging information. Debugging information is what allows the debugger, GDB, to map binary code to source code; it is required to debug a compiled program in good conditions.
The problem with debugging information is that is takes up a fair amount of disk space. For example, debugging information for the GNU C Library weighs in at more than 60 MiB. Thus, as a user, keeping all the debugging info of all the installed programs is usually not an option. Yet, space savings should not come at the cost of an impediment to debugging—especially in the GNU system, which should make it easier for users to exert their computing freedom (see GNU Distribution).
Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a mechanism that allows users to get the best of both worlds: debugging information can be stripped from the binaries and stored in separate files. GDB is then able to load debugging information from those files, when they are available (see Separate Debug Files in Debugging with GDB).
The GNU distribution takes advantage of this by storing debugging
information in the lib/debug
sub-directory of a separate package
output unimaginatively called debug
(see Packages with Multiple Outputs). Users can choose to install the debug
of a package when they need it. For instance, the following command
installs the debugging information for the GNU C Library and for GNU
guix package -i glibc:debug -i guile:debug
GDB must then be told to look for debug files in the user's profile, by
setting the debug-file-directory
variable (consider setting it
from the ~/.gdbinit file, see Startup in Debugging with
(gdb) set debug-file-directory ~/.guix-profile/lib/debug
From there on, GDB will pick up debugging information from the
files under ~/.guix-profile/lib/debug.
The debug
output mechanism in Guix is implemented by the
(see Defining Packages). Currently, it is
opt-in—debugging information is available only for those packages
whose definition explicitly declares a debug
output. This may be
changed to opt-out in the future, if our build farm servers can handle
the load. To check whether a package has a debug
output, use
guix package --list-available
(see Invoking guix package).
Next: Packaging Guidelines, Previous: Installing Debugging Files, Up: GNU Distribution [Contents][Index]
From a programming viewpoint, the package definitions of the
distribution are provided by Guile modules in the (gnu packages
name space (see Guile modules in GNU Guile
Reference Manual). For instance, the (gnu packages emacs)
module exports a variable named emacs
, which is bound to a
object (see Defining Packages). The (gnu
module provides facilities for searching for packages.
The distribution is fully bootstrapped and self-contained:
each package is built based solely on other packages in the
distribution. The root of this dependency graph is a small set of
bootstrap binaries, provided by the (gnu packages
module. For more information on bootstrapping,
Next: Bootstrapping, Previous: Package Modules, Up: GNU Distribution [Contents][Index]
The GNU distribution is nascent and may well lack some of your favorite packages. This section describes how you can help make the distribution grow. See Contributing, for additional information on how you can help.
Free software packages are usually distributed in the form of source code tarballs—typically tar.gz files that contain all the source files. Adding a package to the distribution means essentially two things: adding a recipe that describes how to build the package, including a list of other packages required to build it, and adding package meta-data along with that recipe, such as a description and licensing information.
In Guix all this information is embodied in package definitions. Package definitions provide a high-level view of the package. They are written using the syntax of the Scheme programming language; in fact, for each package we define a variable bound to the package definition, and export that variable from a module (see Package Modules). However, in-depth Scheme knowledge is not a prerequisite for creating packages. For more information on package definitions, Defining Packages.
Once a package definition is in place, stored in a file in the Guix
source tree, it can be tested using the guix build
(see Invoking guix build). For example, assuming the new package is
called gnew
, you may run this command from the Guix build tree:
./pre-inst-env guix build gnew --keep-failed
Using --keep-failed
makes it easier to debug build failures since
it provides access to the failed build tree.
Once your package builds correctly, please send us a patch (see Contributing). Well, if you need help, we will be happy to help you too. Once the patch is committed in the Guix repository, the new package automatically gets built on the supported platforms by our continuous integration system.
Users can obtain the new package definition simply by running
guix pull
(see Invoking guix pull). When
is done building the package, installing the
package automatically downloads binaries from there (except when using
). The only place where human intervention is
needed is to review and apply the patch.
• Software Freedom: | What may go into the distribution. | |
• Package Naming: | What's in a name? | |
• Version Numbers: | When the name is not enough. | |
• Python Modules: | Taming the snake. |
Next: Package Naming, Up: Packaging Guidelines [Contents][Index]
The GNU operating system has been developed so that users can have freedom in their computing. GNU is free software, meaning that users have the four essential freedoms: to run the program, to study and change the program in source code form, to redistribute exact copies, and to distribute modified versions. Packages found in the GNU distribution provide only software that conveys these four freedoms.
In addition, the GNU distribution follow the free software distribution guidelines. Among other things, these guidelines reject non-free firmware, recommendations of non-free software, and discuss ways to deal with trademarks and patents.
Some packages contain a small and optional subset that violates the
above guidelines, for instance because this subset is itself non-free
code. When that happens, the offending items are removed with
appropriate patches or code snippets in the package definition's
form (see Defining Packages). That way, guix
build --source
returns the "freed" source rather than the unmodified
upstream source.
Next: Version Numbers, Previous: Software Freedom, Up: Packaging Guidelines [Contents][Index]
A package has actually two names associated with it:
First, there is the name of the Scheme variable, the one following
. By this name, the package can be made known in the
Scheme code, for instance as input to another package. Second, there is
the string in the name
field of a package definition. This name
is used by package management commands such as
guix package
and guix build
Both are usually the same and correspond to the lowercase conversion of the
project name chosen upstream. For instance, the GNUnet project is packaged
as gnunet
. We do not add lib
prefixes for library packages,
unless these are already part of the official project name. But see
Python Modules for special rules concerning modules for
the Python language.
Next: Python Modules, Previous: Package Naming, Up: Packaging Guidelines [Contents][Index]
We usually package only the latest version of a given free software
project. But sometimes, for instance for incompatible library versions,
two (or more) versions of the same package are needed. These require
different Scheme variable names. We use the name as defined
in Package Naming
for the most recent version; previous versions use the same name, suffixed
by -
and the smallest prefix of the version number that may
distinguish the two versions.
The name inside the package definition is the same for all versions of a package and does not contain any version number.
For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
(define-public gtk+ (package (name "gtk+") (version "3.9.12") ...)) (define-public gtk+-2 (package (name "gtk+") (version "2.24.20") ...))
If we also wanted GTK+ 3.8.2, this would be packaged as
(define-public gtk+-3.8 (package (name "gtk+") (version "3.8.2") ...))
Previous: Version Numbers, Up: Packaging Guidelines [Contents][Index]
We currently package Python 2 and Python 3, under the Scheme variable names
and python
as explained in Version Numbers.
To avoid confusion and naming clashes with other programming languages, it
seems desirable that the name of a package for a Python module contains
the word python
Some modules are compatible with only one version of Python, others with both.
If the package Foo compiles only with Python 3, we name it
; if it compiles only with Python 2, we name it
. If it is compatible with both versions, we create two
packages with the corresponding names.
If a project already contains the word python
, we drop this;
for instance, the module python-dateutil is packaged under the names
and python2-dateutil
Next: Porting, Previous: Packaging Guidelines, Up: GNU Distribution [Contents][Index]
Bootstrapping in our context refers to how the distribution gets built "from nothing". Remember that the build environment of a derivation contains nothing but its declared inputs (see Introduction). So there's an obvious chicken-and-egg problem: how does the first package get built? How does the first compiler get compiled? Note that this is a question of interest only to the curious hacker, not to the regular user, so you can shamelessly skip this section if you consider yourself a "regular user".
The GNU system is primarily made of C code, with libc at its core. The
GNU build system itself assumes the availability of a Bourne shell and
command-line tools provided by GNU Coreutils, Awk, Findutils, 'sed', and
'grep'. Furthermore, build programs—programs that run
, make
, etc.—are written in Guile Scheme
(see Derivations). Consequently, to be able to build anything at
all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
Binutils, libc, and the other packages mentioned above—the
bootstrap binaries.
These bootstrap binaries are "taken for granted", though we can also re-create them if needed (more on that later).
The figure above shows the very beginning of the dependency graph of the
distribution, corresponding to the package definitions of the (gnu
packages bootstrap)
module. At this level of detail, things are
slightly complex. First, Guile itself consists of an ELF executable,
along with many source and compiled Scheme files that are dynamically
loaded when it runs. This gets stored in the guile-2.0.7.tar.xz
tarball shown in this graph. This tarball is part of Guix's "source"
distribution, and gets inserted into the store with add-to-store
(see The Store).
But how do we write a derivation that unpacks this tarball and adds it
to the store? To solve this problem, the guile-bootstrap-2.0.drv
derivation—the first one that gets built—uses bash
as its
builder, which runs build-bootstrap-guile.sh
, which in turn calls
to unpack the tarball. Thus, bash, tar,
xz, and mkdir are statically-linked binaries, also part of
the Guix source distribution, whose sole purpose is to allow the Guile
tarball to be unpacked.
Once guile-bootstrap-2.0.drv
is built, we have a functioning
Guile that can be used to run subsequent build programs. Its first task
is to download tarballs containing the other pre-built binaries—this
is what the .tar.xz.drv
derivations do. Guix modules such as
are used for this purpose. The
derivations import those modules in a directory
in the store, using the original layout. The
derivations compile those modules, and
write them in an output directory with the right layout. This
corresponds to the #:modules
argument of
(see Derivations).
Finally, the various tarballs are unpacked by the
derivations gcc-bootstrap-0.drv
, glibc-bootstrap-0.drv
etc., at which point we have a working C tool chain.
Bootstrapping is complete when we have a full tool chain that does not
depend on the pre-built bootstrap tools discussed above. This
no-dependency requirement is verified by checking whether the files of
the final tool chain contain references to the /nix/store
directories of the bootstrap inputs. The process that leads to this
"final" tool chain is described by the package definitions found in
the (gnu packages base)
The first tool that gets built with the bootstrap binaries is GNU Make, which is a prerequisite for all the following packages. From there Findutils and Diffutils get built.
Then come the first-stage Binutils and GCC, built as pseudo cross
tools—i.e., with --target
equal to --host
. They are
used to build libc. Thanks to this cross-build trick, this libc is
guaranteed not to hold any reference to the initial tool chain.
From there the final Binutils and GCC are built. GCC uses ld
from the final Binutils, and links programs against the just-built libc.
This tool chain is used to build the other packages used by Guix and by
the GNU Build System: Guile, Bash, Coreutils, etc.
And voilà! At this point we have the complete set of build tools that
the GNU Build System expects. These are in the %final-inputs
variables of the (gnu packages base)
module, and are implicitly
used by any package that uses gnu-build-system
(see Defining Packages).
Because the final tool chain does not depend on the bootstrap binaries,
those rarely need to be updated. Nevertheless, it is useful to have an
automated way to produce them, should an update occur, and this is what
the (gnu packages make-bootstrap)
module provides.
The following command builds the tarballs containing the bootstrap binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture of Coreutils and other basic command-line tools):
guix build bootstrap-tarballs
The generated tarballs are those that should be referred to in the
(gnu packages bootstrap)
module mentioned at the beginning of
this section.
Still here? Then perhaps by now you've started to wonder: when do we reach a fixed point? That is an interesting question! The answer is unknown, but if you would like to investigate further (and have significant computational and storage resources to do so), then let us know.
Next: System Configuration, Previous: Bootstrapping, Up: GNU Distribution [Contents][Index]
As discussed above, the GNU distribution is self-contained, and
self-containment is achieved by relying on pre-built "bootstrap
binaries" (see Bootstrapping). These binaries are specific to an
operating system kernel, CPU architecture, and application binary
interface (ABI). Thus, to port the distribution to a platform that is
not yet supported, one must build those bootstrap binaries, and update
the (gnu packages bootstrap)
module to use them on that platform.
Fortunately, Guix can cross compile those bootstrap binaries. When everything goes well, and assuming the GNU tool chain supports the target platform, this can be as simple as running a command like this one:
guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
Once these are built, the (gnu packages bootstrap)
module needs
to be updated to refer to these binaries on the target platform. In
addition, the glibc-dynamic-linker
procedure in that module must
be augmented to return the right file name for libc's dynamic linker on
that platform; likewise, system->linux-architecture
in (gnu
packages linux)
must be taught about the new platform.
In practice, there may be some complications. First, it may be that the
extended GNU triplet that specifies an ABI (like the eabi
above) is not recognized by all the GNU tools. Typically, glibc
recognizes some of these, whereas GCC uses an extra --with-abi
configure flag (see gcc.scm
for examples of how to handle this).
Second, some of the required packages could fail to build for that
platform. Lastly, the generated binaries could be broken for some
Previous: Porting, Up: GNU Distribution [Contents][Index]
This section documents work-in-progress. As such it may be incomplete, outdated, or open to discussions. Please discuss it on email@example.com.
The GNU system supports a consistent whole-system configuration mechanism. By that we mean that all aspects of the global system configuration—such as the available system services, timezone and locale settings, user accounts—are declared in a single place. Such a system configuration can be instantiated—i.e., effected.
One of the advantages of putting all the system configuration under the control of Guix is that it supports transactional system upgrades, and makes it possible to roll-back to a previous system instantiation, should something go wrong with the new one (see Features). Another one is that it makes it easy to replicate the exact same configuration across different machines, or at different points in time, without having to resort to additional administration tools layered on top of the system's own tools.
This section describes this mechanism. First we focus on the system administrator's viewpoint—explaining how the system is configured and instantiated. Then we show how this mechanism can be extended, for instance to support new system services.
• Using the Configuration System: | Customizing your GNU system. | |
• Defining Services: | Adding new service definitions. |
Next: Defining Services, Up: System Configuration [Contents][Index]
The operating system is configured by filling in an
structure, as defined by the (gnu system)
module. A simple setup, with the default system services, the default
Linux-Libre kernel, initial RAM disk, and boot loader looks like this:
(use-modules (gnu system) (gnu system shadow) ; for 'user-account' (gnu system service) ; for 'lsh-service' (gnu packages base) ; Coreutils, grep, etc. (gnu packages bash) ; Bash (gnu packages system) ; dmd, Inetutils (gnu packages zile) ; Zile (gnu packages less) ; less (gnu packages guile) ; Guile (gnu packages linux)) ; procps, psmisc (define komputilo (operating-system (host-name "komputilo") (timezone "Europe/Paris") (locale "fr_FR.UTF-8") (users (list (user-account (name "alice") (password "") (uid 1000) (gid 100) (comment "Bob's sister") (home-directory "/home/alice")))) (packages (list coreutils bash guile-2.0 guix dmd inetutils findutils grep sed procps psmisc zile less)) (services (cons (lsh-service #:port 2222 #:allow-root-login? #t) %standard-services))))
This example should be self-describing. The packages
field lists
packages provided by the various (gnu packages ...)
modules above
(see Package Modules). These are the packages that will be globally
visible on the system, for all user accounts—i.e., in every user's
environment variable—in addition to the per-user profiles
(see Invoking guix package).
The services
field lists system services to be made
available when the system starts. The %standard-services list,
from the (gnu system)
module, provides the basic services one
would expect from a GNU system: a login service (mingetty) on each tty,
syslogd, libc's name service cache daemon (nscd), etc.
The operating-system
declaration above specifies that, in
addition to those services, we want the lshd
secure shell
daemon listening on port 2222, and allowing remote root
(see Invoking lshd in GNU lsh Manual). Under the hood,
arranges so that lshd
is started with the
right command-line options, possibly with supporting configuration files
generated as needed (see Defining Services).
Assuming the above snippet is stored in the my-system-config.scm
file, the (yet unwritten!) guix system --boot
command instantiates that configuration, and makes
it the default GRUB boot entry. The normal way to change the system's
configuration is by updating this file and re-running the guix
At the Scheme level, the bulk of an operating-system
is instantiated with the following monadic procedure (see The Store Monad):
Return a derivation that builds os, an operating-system
object (see Derivations).
The output of the derivation is a single directory that refers to all the packages, configuration files, and other supporting files needed to instantiate os.
Previous: Using the Configuration System, Up: System Configuration [Contents][Index]
The (gnu system dmd)
module defines several procedures that allow
users to declare the operating system's services (see Using the Configuration System). These procedures are monadic
procedures—i.e., procedures that return a monadic value in the store
monad (see The Store Monad). Examples of such procedures include:
return the definition of a service that runs mingetty
offer a login service on the given console tty;
return a definition for libc's name service cache daemon (nscd);
return a definition for a service that runs guix-daemon
(see Invoking guix-daemon).
The monadic value returned by those procedures is a service
definition—a structure as returned by the service
Service definitions specifies the inputs the service depends on, and an
expression to start and stop the service. Behind the scenes, service
definitions are "translated" into the form suitable for the
configuration file of dmd, the init system (see Services in GNU
dmd Manual).
As an example, here is what the nscd-service
procedure looks
(define (nscd-service) (mlet %store-monad ((nscd (package-file glibc "sbin/nscd"))) (return (service (documentation "Run libc's name service cache daemon.") (provision '(nscd)) (start `(make-forkexec-constructor ,nscd "-f" "/dev/null" "--foreground")) (stop `(make-kill-destructor)) (respawn? #f) (inputs `(("glibc" ,glibc)))))))
The inputs
field specifies that this service depends on the
glibc package—the package that contains the nscd
program. The start
and stop
fields are expressions that
make use of dmd's facilities to start and stop processes (see Service
De- and Constructors in GNU dmd Manual). The provision
field specifies the name under which this service is known to dmd, and
specifies on-line documentation. Thus, the
commands deco start ncsd
, deco stop nscd
, and
deco doc nscd
will do what you would expect (see Invoking
deco in GNU dmd Manual).
Next: Acknowledgments, Previous: GNU Distribution, Up: Top [Contents][Index]
This project is a cooperative effort, and we need your help to make it grow! Please get in touch with us on firstname.lastname@example.com. We welcome ideas, bug reports, patches, and anything that may be helpful to the project. We particularly welcome help on packaging (see Packaging Guidelines).
Please see the HACKING file that comes with the Guix source code for practical details about contributions.
Next: GNU Free Documentation License, Previous: Contributing, Up: Top [Contents][Index]
Guix is based on the Nix package manager, which was designed and implemented by Eelco Dolstra. Nix pioneered functional package management, and promoted unprecedented features, such as transactional package upgrades and rollbacks, per-user profiles, and referentially transparent build processes. Without this work, Guix would not exist.
The Nix-based software distributions, Nixpkgs and NixOS, have also been an inspiration for Guix.
Next: Concept Index, Previous: Acknowledgments, Up: Top [Contents][Index]
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Next: Function Index, Previous: GNU Free Documentation License, Up: Top [Contents][Index]
Jump to: | B C D F G M P R S |
Jump to: | B C D F G M P R S |
Previous: Concept Index, Up: Top [Contents][Index]
Jump to: | >
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"Guix" is pronounced like "geeks", or "ɡiːks" using the international phonetic alphabet (IPA).
On some systems /dev/shm
, which supports
shared memory, is a symlink to another directory such as
, that is not is the chroot. When that is the
case, shared memory support is unavailable in the chroot environment.
The workaround is to make sure that /dev/shm is directly a
mount point.
As of version 0.6, substitutes are downloaded from
http://hydra.gnu.org/ but are not authenticated—i.e.,
Guix cannot tell whether binaries it downloaded have been tampered with,
nor whether they come from the genuine gnu.org
build farm. This
will be fixed in future versions. In the meantime, concerned users can
opt for --no-substitutes
(see Invoking guix-daemon).
Simple package
definitions like the one above may be automatically converted from the
Nixpkgs distribution using the guix import
The term stratum in this context was coined by Manuel Serrano et al. in the context of their work on Hop.
This operation is commonly referred to as "bind", but that name denotes an unrelated procedure in Guile. Thus we use this somewhat cryptic symbol inherited from the Haskell language.
Currently, this only works for GNU packages.
The term "free" here refers to the freedom provided to users of that software.