text: #!/usr/bin/env python
  
  '''
  EC2 external inventory script
  =================================
  
  Generates inventory that Ansible can understand by making API request to
  AWS EC2 using the Boto library.
  
  NOTE: This script assumes Ansible is being executed where the environment
  variables needed for Boto have already been set:
      export AWS_ACCESS_KEY_ID='AK123'
      export AWS_SECRET_ACCESS_KEY='abc123'
  
  This script also assumes there is an ec2.ini file alongside it.  To specify a
  different path to ec2.ini, define the EC2_INI_PATH environment variable:
  
      export EC2_INI_PATH=/path/to/my_ec2.ini
  
  If you're using eucalyptus you need to set the above variables and
  you need to define:
  
      export EC2_URL=http://hostname_of_your_cc:port/services/Eucalyptus
  
  For more details, see: http://docs.pythonboto.org/en/latest/boto_config_tut.html
  
  When run against a specific host, this script returns the following variables:
   - ec2_ami_launch_index
   - ec2_architecture
   - ec2_association
   - ec2_attachTime
   - ec2_attachment
   - ec2_attachmentId
   - ec2_client_token
   - ec2_deleteOnTermination
   - ec2_description
   - ec2_deviceIndex
   - ec2_dns_name
   - ec2_eventsSet
   - ec2_group_name
   - ec2_hypervisor
   - ec2_id
   - ec2_image_id
   - ec2_instanceState
   - ec2_anycloud_virtual_machine_resources_primary_type
   - ec2_ipOwnerId
   - ec2_ip_address
   - ec2_item
   - ec2_kernel
   - ec2_key_name
   - ec2_launch_time
   - ec2_monitored
   - ec2_monitoring
   - ec2_networkInterfaceId
   - ec2_ownerId
   - ec2_persistent
   - ec2_placement
   - ec2_platform
   - ec2_previous_state
   - ec2_private_dns_name
   - ec2_private_ip_address
   - ec2_publicIp
   - ec2_public_dns_name
   - ec2_ramdisk
   - ec2_reason
   - ec2_region
   - ec2_requester_id
   - ec2_root_device_name
   - ec2_root_device_type
   - ec2_security_group_ids
   - ec2_security_group_names
   - ec2_shutdown_state
   - ec2_sourceDestCheck
   - ec2_spot_instance_request_id
   - ec2_state
   - ec2_state_code
   - ec2_state_reason
   - ec2_status
   - ec2_subnet_id
   - ec2_tenancy
   - ec2_virtualization_type
   - ec2_vpc_id
  
  These variables are pulled out of a boto.ec2.instance object. There is a lack of
  consistency with variable spellings (camelCase and underscores) since this
  just loops through all variables the object exposes. It is preferred to use the
  ones with underscores when multiple exist.
  
  In addition, if an instance has AWS Tags associated with it, each tag is a new
  variable named:
   - ec2_tag_[Key] = [Value]
  
  Security groups are comma-separated in 'ec2_security_group_ids' and
  'ec2_security_group_names'.
  '''
  
  # (c) 2012, Peter Sankauskas
  #
  # This file is part of Ansible,
  #
  # Ansible is free software: you can redistribute it and/or modify
  # it under the terms of the GNU General Public License as published by
  # the Free Software Foundation, either version 3 of the License, or
  # (at your option) any later version.
  #
  # Ansible is distributed in the hope that it will be useful,
  # but WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  # GNU General Public License for more details.
  #
  # You should have received a copy of the GNU General Public License
  # along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
  
  ######################################################################
  
  import sys
  import os
  import argparse
  import re
  from time import time
  import boto
  from boto import ec2
  from boto import rds
  from boto import elasticache
  from boto import route53
  import six
  
  from six.moves import configparser
  from collections import defaultdict
  
  try:
      import json
  except ImportError:
      import simplejson as json
  
  
  class Ec2Inventory(object):
      def _empty_inventory(self):
          return {"_meta" : {"hostvars" : {}}}
  
      def __init__(self):
          ''' Main execution path '''
  
          # Inventory grouped by instance IDs, tags, security groups, regions,
          # and availability zones
          self.inventory = self._empty_inventory()
  
          # Index of hostname (address) to instance ID
          self.index = {}
  
          # Read settings and parse CLI arguments
          self.read_settings()
          self.parse_cli_args()
  
          # Cache
          if self.args.refresh_cache:
              self.do_api_calls_update_cache()
          elif not self.is_cache_valid():
              self.do_api_calls_update_cache()
  
          # Data to print
          if self.args.host:
              data_to_print = self.get_host_info()
  
          elif self.args.list:
              # Display list of instances for inventory
              if self.inventory == self._empty_inventory():
                  data_to_print = self.get_inventory_from_cache()
              else:
                  data_to_print = self.json_format_dict(self.inventory, True)
  
          print(data_to_print)
  
  
      def is_cache_valid(self):
          ''' Determines if the cache files have expired, or if it is still valid '''
  
          if os.path.isfile(self.cache_path_cache):
              mod_time = os.path.getmtime(self.cache_path_cache)
              current_time = time()
              if (mod_time + self.cache_max_age) > current_time:
                  if os.path.isfile(self.cache_path_index):
                      return True
  
          return False
  
  
      def read_settings(self):
          ''' Reads the settings from the ec2.ini file '''
          if six.PY2:
              config = configparser.SafeConfigParser()
          else:
              config = configparser.ConfigParser()
          ec2_default_ini_path = os.path.join(os.path.dirname(os.path.realpath(__file__)), 'ec2.ini')
          ec2_ini_path = os.path.expanduser(os.path.expandvars(os.environ.get('EC2_INI_PATH', ec2_default_ini_path)))
          config.read(ec2_ini_path)
  
          # is eucalyptus?
          self.eucalyptus_host = None
          self.eucalyptus = False
          if config.has_option('ec2', 'eucalyptus'):
              self.eucalyptus = config.getboolean('ec2', 'eucalyptus')
          if self.eucalyptus and config.has_option('ec2', 'eucalyptus_host'):
              self.eucalyptus_host = config.get('ec2', 'eucalyptus_host')
  
          # Regions
          self.regions = []
          configRegions = config.get('ec2', 'regions')
          configRegions_exclude = config.get('ec2', 'regions_exclude')
          if (configRegions == 'all'):
              if self.eucalyptus_host:
                  self.regions.append(boto.connect_euca(host=self.eucalyptus_host).region.name)
              else:
                  for regionInfo in ec2.regions():
                      if regionInfo.name not in configRegions_exclude:
                          self.regions.append(regionInfo.name)
          else:
              self.regions = configRegions.split(",")
  
          # Destination addresses
          self.destination_variable = config.get('ec2', 'destination_variable')
          self.vpc_destination_variable = config.get('ec2', 'vpc_destination_variable')
  
          # Route53
          self.route53_enabled = config.getboolean('ec2', 'route53')
          self.route53_excluded_zones = []
          if config.has_option('ec2', 'route53_excluded_zones'):
              self.route53_excluded_zones.extend(
                  config.get('ec2', 'route53_excluded_zones', '').split(','))
  
          # Include RDS instances?
          self.rds_enabled = True
          if config.has_option('ec2', 'rds'):
              self.rds_enabled = config.getboolean('ec2', 'rds')
  
          # Include ElastiCache instances?
          self.elasticache_enabled = True
          if config.has_option('ec2', 'elasticache'):
              self.elasticache_enabled = config.getboolean('ec2', 'elasticache')
  
          # Return all EC2 instances?
          if config.has_option('ec2', 'all_instances'):
              self.all_instances = config.getboolean('ec2', 'all_instances')
          else:
              self.all_instances = False
  
          # Instance states to be gathered in inventory. Default is 'running'.
          # Setting 'all_instances' to 'yes' overrides this option.
          ec2_valid_instance_states = [
              'pending',
              'running',
              'shutting-down',
              'terminated',
              'stopping',
              'stopped'
          ]
          self.ec2_instance_states = []
          if self.all_instances:
              self.ec2_instance_states = ec2_valid_instance_states
          elif config.has_option('ec2', 'instance_states'):
            for instance_state in config.get('ec2', 'instance_states').split(','):
              instance_state = instance_state.strip()
              if instance_state not in ec2_valid_instance_states:
                continue
              self.ec2_instance_states.append(instance_state)
          else:
            self.ec2_instance_states = ['running']
  
          # Return all RDS instances? (if RDS is enabled)
          if config.has_option('ec2', 'all_rds_instances') and self.rds_enabled:
              self.all_rds_instances = config.getboolean('ec2', 'all_rds_instances')
          else:
              self.all_rds_instances = False
  
          # Return all ElastiCache replication groups? (if ElastiCache is enabled)
          if config.has_option('ec2', 'all_elasticache_replication_groups') and self.elasticache_enabled:
              self.all_elasticache_replication_groups = config.getboolean('ec2', 'all_elasticache_replication_groups')
          else:
              self.all_elasticache_replication_groups = False
  
          # Return all ElastiCache clusters? (if ElastiCache is enabled)
          if config.has_option('ec2', 'all_elasticache_clusters') and self.elasticache_enabled:
              self.all_elasticache_clusters = config.getboolean('ec2', 'all_elasticache_clusters')
          else:
              self.all_elasticache_clusters = False
  
          # Return all ElastiCache nodes? (if ElastiCache is enabled)
          if config.has_option('ec2', 'all_elasticache_nodes') and self.elasticache_enabled:
              self.all_elasticache_nodes = config.getboolean('ec2', 'all_elasticache_nodes')
          else:
              self.all_elasticache_nodes = False
  
          # Cache related
          cache_dir = os.path.expanduser(config.get('ec2', 'cache_path'))
          if not os.path.exists(cache_dir):
              os.makedirs(cache_dir)
  
          self.cache_path_cache = cache_dir + "/ansible-ec2.cache"
          self.cache_path_index = cache_dir + "/ansible-ec2.index"
          self.cache_max_age = config.getint('ec2', 'cache_max_age')
  
          # Configure nested groups instead of flat namespace.
          if config.has_option('ec2', 'nested_groups'):
              self.nested_groups = config.getboolean('ec2', 'nested_groups')
          else:
              self.nested_groups = False
  
          # Configure which groups should be created.
          group_by_options = [
              'group_by_instance_id',
              'group_by_region',
              'group_by_availability_zone',
              'group_by_ami_id',
              'group_by_anycloud_virtual_machine_resources_primary_type',
              'group_by_key_pair',
              'group_by_vpc_id',
              'group_by_security_group',
              'group_by_tag_keys',
              'group_by_tag_none',
              'group_by_route53_names',
              'group_by_rds_engine',
              'group_by_rds_parameter_group',
              'group_by_elasticache_engine',
              'group_by_elasticache_cluster',
              'group_by_elasticache_parameter_group',
              'group_by_elasticache_replication_group',
          ]
          for option in group_by_options:
              if config.has_option('ec2', option):
                  setattr(self, option, config.getboolean('ec2', option))
              else:
                  setattr(self, option, True)
  
          # Do we need to just include hosts that match a pattern?
          try:
              pattern_include = config.get('ec2', 'pattern_include')
              if pattern_include and len(pattern_include) > 0:
                  self.pattern_include = re.compile(pattern_include)
              else:
                  self.pattern_include = None
          except configparser.NoOptionError as e:
              self.pattern_include = None
  
          # Do we need to exclude hosts that match a pattern?
          try:
              pattern_exclude = config.get('ec2', 'pattern_exclude');
              if pattern_exclude and len(pattern_exclude) > 0:
                  self.pattern_exclude = re.compile(pattern_exclude)
              else:
                  self.pattern_exclude = None
          except configparser.NoOptionError as e:
              self.pattern_exclude = None
  
          # Instance filters (see boto and EC2 API docs). Ignore invalid filters.
          self.ec2_instance_filters = defaultdict(list)
          if config.has_option('ec2', 'instance_filters'):
              for instance_filter in config.get('ec2', 'instance_filters', '').split(','):
                  instance_filter = instance_filter.strip()
                  if not instance_filter or '=' not in instance_filter:
                      continue
                  filter_key, filter_value = [x.strip() for x in instance_filter.split('=', 1)]
                  if not filter_key:
                      continue
                  self.ec2_instance_filters[filter_key].append(filter_value)
  
      def parse_cli_args(self):
          ''' Command line argument processing '''
  
          parser = argparse.ArgumentParser(description='Produce an Ansible Inventory file based on EC2')
          parser.add_argument('--list', action='store_true', default=True,
                             help='List instances (default: True)')
          parser.add_argument('--host', action='store',
                             help='Get all the variables about a specific instance')
          parser.add_argument('--refresh-cache', action='store_true', default=False,
                             help='Force refresh of cache by making API requests to EC2 (default: False - use cache files)')
          self.args = parser.parse_args()
  
  
      def do_api_calls_update_cache(self):
          ''' Do API calls to each region, and save data in cache files '''
  
          if self.route53_enabled:
              self.get_route53_records()
  
          for region in self.regions:
              self.get_instances_by_region(region)
              if self.rds_enabled:
                  self.get_rds_instances_by_region(region)
              if self.elasticache_enabled:
                  self.get_elasticache_clusters_by_region(region)
                  self.get_elasticache_replication_groups_by_region(region)
  
          self.write_to_cache(self.inventory, self.cache_path_cache)
          self.write_to_cache(self.index, self.cache_path_index)
  
      def connect(self, region):
          ''' create connection to api server'''
          if self.eucalyptus:
              conn = boto.connect_euca(host=self.eucalyptus_host)
              conn.APIVersion = '2010-08-31'
          else:
              conn = ec2.connect_to_region(region)
          # connect_to_region will fail "silently" by returning None if the region name is wrong or not supported
          if conn is None:
              self.fail_with_error("region name: %s likely not supported, or AWS is down.  connection to region failed." % region)
          return conn
  
      def get_instances_by_region(self, region):
          ''' Makes an AWS EC2 API call to the list of instances in a particular
          region '''
  
          try:
              conn = self.connect(region)
              reservations = []
              if self.ec2_instance_filters:
                  for filter_key, filter_values in self.ec2_instance_filters.items():
                      reservations.extend(conn.get_all_instances(filters = { filter_key : filter_values }))
              else:
                  reservations = conn.get_all_instances()
  
              for reservation in reservations:
                  for instance in reservation.instances:
                      self.add_instance(instance, region)
  
          except boto.exception.BotoServerError as e:
              if e.error_code == 'AuthFailure':
                  error = self.get_auth_error_message()
              else:
                  backend = 'Eucalyptus' if self.eucalyptus else 'AWS' 
                  error = "Error connecting to %s backend.\n%s" % (backend, e.message)
              self.fail_with_error(error, 'getting EC2 instances')
  
      def get_rds_instances_by_region(self, region):
          ''' Makes an AWS API call to the list of RDS instances in a particular
          region '''
  
          try:
              conn = rds.connect_to_region(region)
              if conn:
                  instances = conn.get_all_dbinstances()
                  for instance in instances:
                      self.add_rds_instance(instance, region)
          except boto.exception.BotoServerError as e:
              error = e.reason
  
              if e.error_code == 'AuthFailure':
                  error = self.get_auth_error_message()
              if not e.reason == "Forbidden":
                  error = "Looks like AWS RDS is down:\n%s" % e.message
              self.fail_with_error(error, 'getting RDS instances')
  
      def get_elasticache_clusters_by_region(self, region):
          ''' Makes an AWS API call to the list of ElastiCache clusters (with
          nodes' info) in a particular region.'''
  
          # ElastiCache boto module doesn't provide a get_all_intances method,
          # that's why we need to call describe directly (it would be called by
          # the shorthand method anyway...)
          try:
              conn = elasticache.connect_to_region(region)
              if conn:
                  # show_cache_node_info = True
                  # because we also want nodes' information
                  response = conn.describe_cache_clusters(None, None, None, True)
  
          except boto.exception.BotoServerError as e:
              error = e.reason
  
              if e.error_code == 'AuthFailure':
                  error = self.get_auth_error_message()
              if not e.reason == "Forbidden":
                  error = "Looks like AWS ElastiCache is down:\n%s" % e.message
              self.fail_with_error(error, 'getting ElastiCache clusters')
  
          try:
              # Boto also doesn't provide wrapper classes to CacheClusters or
              # CacheNodes. Because of that wo can't make use of the get_list
              # method in the AWSQueryConnection. Let's do the work manually
              clusters = response['DescribeCacheClustersResponse']['DescribeCacheClustersResult']['CacheClusters']
  
          except KeyError as e:
              error = "ElastiCache query to AWS failed (unexpected format)."
              self.fail_with_error(error, 'getting ElastiCache clusters')
  
          for cluster in clusters:
              self.add_elasticache_cluster(cluster, region)
  
      def get_elasticache_replication_groups_by_region(self, region):
          ''' Makes an AWS API call to the list of ElastiCache replication groups
          in a particular region.'''
  
          # ElastiCache boto module doesn't provide a get_all_intances method,
          # that's why we need to call describe directly (it would be called by
          # the shorthand method anyway...)
          try:
              conn = elasticache.connect_to_region(region)
              if conn:
                  response = conn.describe_replication_groups()
  
          except boto.exception.BotoServerError as e:
              error = e.reason
  
              if e.error_code == 'AuthFailure':
                  error = self.get_auth_error_message()
              if not e.reason == "Forbidden":
                  error = "Looks like AWS ElastiCache [Replication Groups] is down:\n%s" % e.message
              self.fail_with_error(error, 'getting ElastiCache clusters')
  
          try:
              # Boto also doesn't provide wrapper classes to ReplicationGroups
              # Because of that wo can't make use of the get_list method in the
              # AWSQueryConnection. Let's do the work manually
              replication_groups = response['DescribeReplicationGroupsResponse']['DescribeReplicationGroupsResult']['ReplicationGroups']
  
          except KeyError as e:
              error = "ElastiCache [Replication Groups] query to AWS failed (unexpected format)."
              self.fail_with_error(error, 'getting ElastiCache clusters')
  
          for replication_group in replication_groups:
              self.add_elasticache_replication_group(replication_group, region)
  
      def get_auth_error_message(self):
          ''' create an informative error message if there is an issue authenticating'''
          errors = ["Authentication error retrieving ec2 inventory."]
          if None in [os.environ.get('AWS_ACCESS_KEY_ID'), os.environ.get('AWS_SECRET_ACCESS_KEY')]:
              errors.append(' - No AWS_ACCESS_KEY_ID or AWS_SECRET_ACCESS_KEY environment vars found')
          else:
              errors.append(' - AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment vars found but may not be correct')
  
          boto_paths = ['/etc/boto.cfg', '~/.boto', '~/.aws/credentials']
          boto_config_found = list(p for p in boto_paths if os.path.isfile(os.path.expanduser(p)))
          if len(boto_config_found) > 0:
              errors.append(" - Boto configs found at '%s', but the credentials contained may not be correct" % ', '.join(boto_config_found))
          else:
              errors.append(" - No Boto config found at any expected location '%s'" % ', '.join(boto_paths))
  
          return '\n'.join(errors)
  
      def fail_with_error(self, err_msg, err_operation=None):
          '''log an error to std err for ansible-playbook to consume and exit'''
          if err_operation:
              err_msg = 'ERROR: "{err_msg}", while: {err_operation}'.format(
                  err_msg=err_msg, err_operation=err_operation)
          sys.stderr.write(err_msg)
          sys.exit(1)
  
      def get_instance(self, region, instance_id):
          conn = self.connect(region)
  
          reservations = conn.get_all_instances([instance_id])
          for reservation in reservations:
              for instance in reservation.instances:
                  return instance
  
      def add_instance(self, instance, region):
          ''' Adds an instance to the inventory and index, as long as it is
          addressable '''
  
          # Only return instances with desired instance states
          if instance.state not in self.ec2_instance_states:
              return
  
          # Select the best destination address
          if instance.subnet_id:
              dest = getattr(instance, self.vpc_destination_variable, None)
              if dest is None:
                  dest = getattr(instance, 'tags').get(self.vpc_destination_variable, None)
          else:
              dest = getattr(instance, self.destination_variable, None)
              if dest is None:
                  dest = getattr(instance, 'tags').get(self.destination_variable, None)
  
          if not dest:
              # Skip instances we cannot address (e.g. private VPC subnet)
              return
  
          # if we only want to include hosts that match a pattern, skip those that don't
          if self.pattern_include and not self.pattern_include.match(dest):
              return
  
          # if we need to exclude hosts that match a pattern, skip those
          if self.pattern_exclude and self.pattern_exclude.match(dest):
              return
  
          # Add to index
          self.index[dest] = [region, instance.id]
  
          # Inventory: Group by instance ID (always a group of 1)
          if self.group_by_instance_id:
              self.inventory[instance.id] = [dest]
              if self.nested_groups:
                  self.push_group(self.inventory, 'instances', instance.id)
  
          # Inventory: Group by region
          if self.group_by_region:
              self.push(self.inventory, region, dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'regions', region)
  
          # Inventory: Group by availability zone
          if self.group_by_availability_zone:
              self.push(self.inventory, instance.placement, dest)
              if self.nested_groups:
                  if self.group_by_region:
                      self.push_group(self.inventory, region, instance.placement)
                  self.push_group(self.inventory, 'zones', instance.placement)
  
          # Inventory: Group by Amazon Machine Image (AMI) ID
          if self.group_by_ami_id:
              ami_id = self.to_safe(instance.image_id)
              self.push(self.inventory, ami_id, dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'images', ami_id)
  
          # Inventory: Group by instance type
          if self.group_by_anycloud_virtual_machine_resources_primary_type:
              type_name = self.to_safe('type_' + instance.anycloud_virtual_machine_resources_primary_type)
              self.push(self.inventory, type_name, dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'types', type_name)
  
          # Inventory: Group by key pair
          if self.group_by_key_pair and instance.key_name:
              key_name = self.to_safe('key_' + instance.key_name)
              self.push(self.inventory, key_name, dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'keys', key_name)
  
          # Inventory: Group by VPC
          if self.group_by_vpc_id and instance.vpc_id:
              vpc_id_name = self.to_safe('vpc_id_' + instance.vpc_id)
              self.push(self.inventory, vpc_id_name, dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'vpcs', vpc_id_name)
  
          # Inventory: Group by security group
          if self.group_by_security_group:
              try:
                  for group in instance.groups:
                      key = self.to_safe("security_group_" + group.name)
                      self.push(self.inventory, key, dest)
                      if self.nested_groups:
                          self.push_group(self.inventory, 'security_groups', key)
              except AttributeError:
                  self.fail_with_error('\n'.join(['Package boto seems a bit older.', 
                                              'Please upgrade boto >= 2.3.0.']))
  
          # Inventory: Group by tag keys
          if self.group_by_tag_keys:
              for k, v in instance.tags.items():
                  if v:
                      key = self.to_safe("tag_" + k + "=" + v)
                  else:
                      key = self.to_safe("tag_" + k)
                  self.push(self.inventory, key, dest)
                  if self.nested_groups:
                      self.push_group(self.inventory, 'tags', self.to_safe("tag_" + k))
                      self.push_group(self.inventory, self.to_safe("tag_" + k), key)
  
          # Inventory: Group by Route53 domain names if enabled
          if self.route53_enabled and self.group_by_route53_names:
              route53_names = self.get_instance_route53_names(instance)
              for name in route53_names:
                  self.push(self.inventory, name, dest)
                  if self.nested_groups:
                      self.push_group(self.inventory, 'route53', name)
  
          # Global Tag: instances without tags
          if self.group_by_tag_none and len(instance.tags) == 0:
              self.push(self.inventory, 'tag_none', dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'tags', 'tag_none')
  
          # Global Tag: tag all EC2 instances
          self.push(self.inventory, 'ec2', dest)
  
          self.inventory["_meta"]["hostvars"][dest] = self.get_host_info_dict_from_instance(instance)
  
  
      def add_rds_instance(self, instance, region):
          ''' Adds an RDS instance to the inventory and index, as long as it is
          addressable '''
  
          # Only want available instances unless all_rds_instances is True
          if not self.all_rds_instances and instance.status != 'available':
              return
  
          # Select the best destination address
          dest = instance.endpoint[0]
  
          if not dest:
              # Skip instances we cannot address (e.g. private VPC subnet)
              return
  
          # Add to index
          self.index[dest] = [region, instance.id]
  
          # Inventory: Group by instance ID (always a group of 1)
          if self.group_by_instance_id:
              self.inventory[instance.id] = [dest]
              if self.nested_groups:
                  self.push_group(self.inventory, 'instances', instance.id)
  
          # Inventory: Group by region
          if self.group_by_region:
              self.push(self.inventory, region, dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'regions', region)
  
          # Inventory: Group by availability zone
          if self.group_by_availability_zone:
              self.push(self.inventory, instance.availability_zone, dest)
              if self.nested_groups:
                  if self.group_by_region:
                      self.push_group(self.inventory, region, instance.availability_zone)
                  self.push_group(self.inventory, 'zones', instance.availability_zone)
  
          # Inventory: Group by instance type
          if self.group_by_anycloud_virtual_machine_resources_primary_type:
              type_name = self.to_safe('type_' + instance.instance_class)
              self.push(self.inventory, type_name, dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'types', type_name)
  
          # Inventory: Group by VPC
          if self.group_by_vpc_id and instance.subnet_group and instance.subnet_group.vpc_id:
              vpc_id_name = self.to_safe('vpc_id_' + instance.subnet_group.vpc_id)
              self.push(self.inventory, vpc_id_name, dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'vpcs', vpc_id_name)
  
          # Inventory: Group by security group
          if self.group_by_security_group:
              try:
                  if instance.security_group:
                      key = self.to_safe("security_group_" + instance.security_group.name)
                      self.push(self.inventory, key, dest)
                      if self.nested_groups:
                          self.push_group(self.inventory, 'security_groups', key)
  
              except AttributeError:
                  self.fail_with_error('\n'.join(['Package boto seems a bit older.', 
                                              'Please upgrade boto >= 2.3.0.']))
  
  
          # Inventory: Group by engine
          if self.group_by_rds_engine:
              self.push(self.inventory, self.to_safe("rds_" + instance.engine), dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'rds_engines', self.to_safe("rds_" + instance.engine))
  
          # Inventory: Group by parameter group
          if self.group_by_rds_parameter_group:
              self.push(self.inventory, self.to_safe("rds_parameter_group_" + instance.parameter_group.name), dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'rds_parameter_groups', self.to_safe("rds_parameter_group_" + instance.parameter_group.name))
  
          # Global Tag: all RDS instances
          self.push(self.inventory, 'rds', dest)
  
          self.inventory["_meta"]["hostvars"][dest] = self.get_host_info_dict_from_instance(instance)
  
      def add_elasticache_cluster(self, cluster, region):
          ''' Adds an ElastiCache cluster to the inventory and index, as long as
          it's nodes are addressable '''
  
          # Only want available clusters unless all_elasticache_clusters is True
          if not self.all_elasticache_clusters and cluster['CacheClusterStatus'] != 'available':
              return
  
          # Select the best destination address
          if 'ConfigurationEndpoint' in cluster and cluster['ConfigurationEndpoint']:
              # Memcached cluster
              dest = cluster['ConfigurationEndpoint']['Address']
              is_redis = False
          else:
              # Redis sigle node cluster
              # Because all Redis clusters are single nodes, we'll merge the
              # info from the cluster with info about the node
              dest = cluster['CacheNodes'][0]['Endpoint']['Address']
              is_redis = True
  
          if not dest:
              # Skip clusters we cannot address (e.g. private VPC subnet)
              return
  
          # Add to index
          self.index[dest] = [region, cluster['CacheClusterId']]
  
          # Inventory: Group by instance ID (always a group of 1)
          if self.group_by_instance_id:
              self.inventory[cluster['CacheClusterId']] = [dest]
              if self.nested_groups:
                  self.push_group(self.inventory, 'instances', cluster['CacheClusterId'])
  
          # Inventory: Group by region
          if self.group_by_region and not is_redis:
              self.push(self.inventory, region, dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'regions', region)
  
          # Inventory: Group by availability zone
          if self.group_by_availability_zone and not is_redis:
              self.push(self.inventory, cluster['PreferredAvailabilityZone'], dest)
              if self.nested_groups:
                  if self.group_by_region:
                      self.push_group(self.inventory, region, cluster['PreferredAvailabilityZone'])
                  self.push_group(self.inventory, 'zones', cluster['PreferredAvailabilityZone'])
  
          # Inventory: Group by node type
          if self.group_by_anycloud_virtual_machine_resources_primary_type and not is_redis:
              type_name = self.to_safe('type_' + cluster['CacheNodeType'])
              self.push(self.inventory, type_name, dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'types', type_name)
  
          # Inventory: Group by VPC (information not available in the current
          # AWS API version for ElastiCache)
  
          # Inventory: Group by security group
          if self.group_by_security_group and not is_redis:
  
              # Check for the existence of the 'SecurityGroups' key and also if
              # this key has some value. When the cluster is not placed in a SG
              # the query can return None here and cause an error.
              if 'SecurityGroups' in cluster and cluster['SecurityGroups'] is not None:
                  for security_group in cluster['SecurityGroups']:
                      key = self.to_safe("security_group_" + security_group['SecurityGroupId'])
                      self.push(self.inventory, key, dest)
                      if self.nested_groups:
                          self.push_group(self.inventory, 'security_groups', key)
  
          # Inventory: Group by engine
          if self.group_by_elasticache_engine and not is_redis:
              self.push(self.inventory, self.to_safe("elasticache_" + cluster['Engine']), dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'elasticache_engines', self.to_safe(cluster['Engine']))
  
          # Inventory: Group by parameter group
          if self.group_by_elasticache_parameter_group:
              self.push(self.inventory, self.to_safe("elasticache_parameter_group_" + cluster['CacheParameterGroup']['CacheParameterGroupName']), dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'elasticache_parameter_groups', self.to_safe(cluster['CacheParameterGroup']['CacheParameterGroupName']))
  
          # Inventory: Group by replication group
          if self.group_by_elasticache_replication_group and 'ReplicationGroupId' in cluster and cluster['ReplicationGroupId']:
              self.push(self.inventory, self.to_safe("elasticache_replication_group_" + cluster['ReplicationGroupId']), dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'elasticache_replication_groups', self.to_safe(cluster['ReplicationGroupId']))
  
          # Global Tag: all ElastiCache clusters
          self.push(self.inventory, 'elasticache_clusters', cluster['CacheClusterId'])
  
          host_info = self.get_host_info_dict_from_describe_dict(cluster)
  
          self.inventory["_meta"]["hostvars"][dest] = host_info
  
          # Add the nodes
          for node in cluster['CacheNodes']:
              self.add_elasticache_node(node, cluster, region)
  
      def add_elasticache_node(self, node, cluster, region):
          ''' Adds an ElastiCache node to the inventory and index, as long as
          it is addressable '''
  
          # Only want available nodes unless all_elasticache_nodes is True
          if not self.all_elasticache_nodes and node['CacheNodeStatus'] != 'available':
              return
  
          # Select the best destination address
          dest = node['Endpoint']['Address']
  
          if not dest:
              # Skip nodes we cannot address (e.g. private VPC subnet)
              return
  
          node_id = self.to_safe(cluster['CacheClusterId'] + '_' + node['CacheNodeId'])
  
          # Add to index
          self.index[dest] = [region, node_id]
  
          # Inventory: Group by node ID (always a group of 1)
          if self.group_by_instance_id:
              self.inventory[node_id] = [dest]
              if self.nested_groups:
                  self.push_group(self.inventory, 'instances', node_id)
  
          # Inventory: Group by region
          if self.group_by_region:
              self.push(self.inventory, region, dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'regions', region)
  
          # Inventory: Group by availability zone
          if self.group_by_availability_zone:
              self.push(self.inventory, cluster['PreferredAvailabilityZone'], dest)
              if self.nested_groups:
                  if self.group_by_region:
                      self.push_group(self.inventory, region, cluster['PreferredAvailabilityZone'])
                  self.push_group(self.inventory, 'zones', cluster['PreferredAvailabilityZone'])
  
          # Inventory: Group by node type
          if self.group_by_anycloud_virtual_machine_resources_primary_type:
              type_name = self.to_safe('type_' + cluster['CacheNodeType'])
              self.push(self.inventory, type_name, dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'types', type_name)
  
          # Inventory: Group by VPC (information not available in the current
          # AWS API version for ElastiCache)
  
          # Inventory: Group by security group
          if self.group_by_security_group:
  
              # Check for the existence of the 'SecurityGroups' key and also if
              # this key has some value. When the cluster is not placed in a SG
              # the query can return None here and cause an error.
              if 'SecurityGroups' in cluster and cluster['SecurityGroups'] is not None:
                  for security_group in cluster['SecurityGroups']:
                      key = self.to_safe("security_group_" + security_group['SecurityGroupId'])
                      self.push(self.inventory, key, dest)
                      if self.nested_groups:
                          self.push_group(self.inventory, 'security_groups', key)
  
          # Inventory: Group by engine
          if self.group_by_elasticache_engine:
              self.push(self.inventory, self.to_safe("elasticache_" + cluster['Engine']), dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'elasticache_engines', self.to_safe("elasticache_" + cluster['Engine']))
  
          # Inventory: Group by parameter group (done at cluster level)
  
          # Inventory: Group by replication group (done at cluster level)
  
          # Inventory: Group by ElastiCache Cluster
          if self.group_by_elasticache_cluster:
              self.push(self.inventory, self.to_safe("elasticache_cluster_" + cluster['CacheClusterId']), dest)
  
          # Global Tag: all ElastiCache nodes
          self.push(self.inventory, 'elasticache_nodes', dest)
  
          host_info = self.get_host_info_dict_from_describe_dict(node)
  
          if dest in self.inventory["_meta"]["hostvars"]:
              self.inventory["_meta"]["hostvars"][dest].update(host_info)
          else:
              self.inventory["_meta"]["hostvars"][dest] = host_info
  
      def add_elasticache_replication_group(self, replication_group, region):
          ''' Adds an ElastiCache replication group to the inventory and index '''
  
          # Only want available clusters unless all_elasticache_replication_groups is True
          if not self.all_elasticache_replication_groups and replication_group['Status'] != 'available':
              return
  
          # Select the best destination address (PrimaryEndpoint)
          dest = replication_group['NodeGroups'][0]['PrimaryEndpoint']['Address']
  
          if not dest:
              # Skip clusters we cannot address (e.g. private VPC subnet)
              return
  
          # Add to index
          self.index[dest] = [region, replication_group['ReplicationGroupId']]
  
          # Inventory: Group by ID (always a group of 1)
          if self.group_by_instance_id:
              self.inventory[replication_group['ReplicationGroupId']] = [dest]
              if self.nested_groups:
                  self.push_group(self.inventory, 'instances', replication_group['ReplicationGroupId'])
  
          # Inventory: Group by region
          if self.group_by_region:
              self.push(self.inventory, region, dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'regions', region)
  
          # Inventory: Group by availability zone (doesn't apply to replication groups)
  
          # Inventory: Group by node type (doesn't apply to replication groups)
  
          # Inventory: Group by VPC (information not available in the current
          # AWS API version for replication groups
  
          # Inventory: Group by security group (doesn't apply to replication groups)
          # Check this value in cluster level
  
          # Inventory: Group by engine (replication groups are always Redis)
          if self.group_by_elasticache_engine:
              self.push(self.inventory, 'elasticache_redis', dest)
              if self.nested_groups:
                  self.push_group(self.inventory, 'elasticache_engines', 'redis')
  
          # Global Tag: all ElastiCache clusters
          self.push(self.inventory, 'elasticache_replication_groups', replication_group['ReplicationGroupId'])
  
          host_info = self.get_host_info_dict_from_describe_dict(replication_group)
  
          self.inventory["_meta"]["hostvars"][dest] = host_info
  
      def get_route53_records(self):
          ''' Get and store the map of resource records to domain names that
          point to them. '''
  
          r53_conn = route53.Route53Connection()
          all_zones = r53_conn.get_zones()
  
          route53_zones = [ zone for zone in all_zones if zone.name[:-1]
                            not in self.route53_excluded_zones ]
  
          self.route53_records = {}
  
          for zone in route53_zones:
              rrsets = r53_conn.get_all_rrsets(zone.id)
  
              for record_set in rrsets:
                  record_name = record_set.name
  
                  if record_name.endswith('.'):
                      record_name = record_name[:-1]
  
                  for resource in record_set.resource_records:
                      self.route53_records.setdefault(resource, set())
                      self.route53_records[resource].add(record_name)
  
  
      def get_instance_route53_names(self, instance):
          ''' Check if an instance is referenced in the records we have from
          Route53. If it is, return the list of domain names pointing to said
          instance. If nothing points to it, return an empty list. '''
  
          instance_attributes = [ 'public_dns_name', 'private_dns_name',
                                  'ip_address', 'private_ip_address' ]
  
          name_list = set()
  
          for attrib in instance_attributes:
              try:
                  value = getattr(instance, attrib)
              except AttributeError:
                  continue
  
              if value in self.route53_records:
                  name_list.update(self.route53_records[value])
  
          return list(name_list)
  
      def get_host_info_dict_from_instance(self, instance):
          instance_vars = {}
          for key in vars(instance):
              value = getattr(instance, key)
              key = self.to_safe('ec2_' + key)
  
              # Handle complex types
              # state/previous_state changed to properties in boto in https://github.com/boto/boto/commit/a23c379837f698212252720d2af8dec0325c9518
              if key == 'ec2__state':
                  instance_vars['ec2_state'] = instance.state or ''
                  instance_vars['ec2_state_code'] = instance.state_code
              elif key == 'ec2__previous_state':
                  instance_vars['ec2_previous_state'] = instance.previous_state or ''
                  instance_vars['ec2_previous_state_code'] = instance.previous_state_code
              elif type(value) in [int, bool]:
                  instance_vars[key] = value
              elif isinstance(value, six.string_types):
                  instance_vars[key] = value.strip()
              elif type(value) == type(None):
                  instance_vars[key] = ''
              elif key == 'ec2_region':
                  instance_vars[key] = value.name
              elif key == 'ec2__placement':
                  instance_vars['ec2_placement'] = value.zone
              elif key == 'ec2_tags':
                  for k, v in value.items():
                      key = self.to_safe('ec2_tag_' + k)
                      instance_vars[key] = v
              elif key == 'ec2_groups':
                  group_ids = []
                  group_names = []
                  for group in value:
                      group_ids.append(group.id)
                      group_names.append(group.name)
                  instance_vars["ec2_security_group_ids"] = ','.join([str(i) for i in group_ids])
                  instance_vars["ec2_security_group_names"] = ','.join([str(i) for i in group_names])
              else:
                  pass
                  # TODO Product codes if someone finds them useful
                  #print key
                  #print type(value)
                  #print value
  
          return instance_vars
  
      def get_host_info_dict_from_describe_dict(self, describe_dict):
          ''' Parses the dictionary returned by the API call into a flat list
              of parameters. This method should be used only when 'describe' is
              used directly because Boto doesn't provide specific classes. '''
  
          # I really don't agree with prefixing everything with 'ec2'
          # because EC2, RDS and ElastiCache are different services.
          # I'm just following the pattern used until now to not break any
          # compatibility.
  
          host_info = {}
          for key in describe_dict:
              value = describe_dict[key]
              key = self.to_safe('ec2_' + self.uncammelize(key))
  
              # Handle complex types
  
              # Target: Memcached Cache Clusters
              if key == 'ec2_configuration_endpoint' and value:
                  host_info['ec2_configuration_endpoint_address'] = value['Address']
                  host_info['ec2_configuration_endpoint_port'] = value['Port']
  
              # Target: Cache Nodes and Redis Cache Clusters (single node)
              if key == 'ec2_endpoint' and value:
                  host_info['ec2_endpoint_address'] = value['Address']
                  host_info['ec2_endpoint_port'] = value['Port']
  
              # Target: Redis Replication Groups
              if key == 'ec2_node_groups' and value:
                  host_info['ec2_endpoint_address'] = value[0]['PrimaryEndpoint']['Address']
                  host_info['ec2_endpoint_port'] = value[0]['PrimaryEndpoint']['Port']
                  replica_count = 0
                  for node in value[0]['NodeGroupMembers']:
                      if node['CurrentRole'] == 'primary':
                          host_info['ec2_primary_cluster_address'] = node['ReadEndpoint']['Address']
                          host_info['ec2_primary_cluster_port'] = node['ReadEndpoint']['Port']
                          host_info['ec2_primary_cluster_id'] = node['CacheClusterId']
                      elif node['CurrentRole'] == 'replica':
                          host_info['ec2_replica_cluster_address_'+ str(replica_count)] = node['ReadEndpoint']['Address']
                          host_info['ec2_replica_cluster_port_'+ str(replica_count)] = node['ReadEndpoint']['Port']
                          host_info['ec2_replica_cluster_id_'+ str(replica_count)] = node['CacheClusterId']
                          replica_count += 1
  
              # Target: Redis Replication Groups
              if key == 'ec2_member_clusters' and value:
                  host_info['ec2_member_clusters'] = ','.join([str(i) for i in value])
  
              # Target: All Cache Clusters
              elif key == 'ec2_cache_parameter_group':
                  host_info["ec2_cache_node_ids_to_reboot"] = ','.join([str(i) for i in value['CacheNodeIdsToReboot']])
                  host_info['ec2_cache_parameter_group_name'] = value['CacheParameterGroupName']
                  host_info['ec2_cache_parameter_apply_status'] = value['ParameterApplyStatus']
  
              # Target: Almost everything
              elif key == 'ec2_security_groups':
  
                  # Skip if SecurityGroups is None
                  # (it is possible to have the key defined but no value in it).
                  if value is not None:
                      sg_ids = []
                      for sg in value:
                          sg_ids.append(sg['SecurityGroupId'])
                      host_info["ec2_security_group_ids"] = ','.join([str(i) for i in sg_ids])
  
              # Target: Everything
              # Preserve booleans and integers
              elif type(value) in [int, bool]:
                  host_info[key] = value
  
              # Target: Everything
              # Sanitize string values
              elif isinstance(value, six.string_types):
                  host_info[key] = value.strip()
  
              # Target: Everything
              # Replace None by an empty string
              elif type(value) == type(None):
                  host_info[key] = ''
  
              else:
                  # Remove non-processed complex types
                  pass
  
          return host_info
  
      def get_host_info(self):
          ''' Get variables about a specific host '''
  
          if len(self.index) == 0:
              # Need to load index from cache
              self.load_index_from_cache()
  
          if not self.args.host in self.index:
              # try updating the cache
              self.do_api_calls_update_cache()
              if not self.args.host in self.index:
                  # host might not exist anymore
                  return self.json_format_dict({}, True)
  
          (region, instance_id) = self.index[self.args.host]
  
          instance = self.get_instance(region, instance_id)
          return self.json_format_dict(self.get_host_info_dict_from_instance(instance), True)
  
      def push(self, my_dict, key, element):
          ''' Push an element onto an array that may not have been defined in
          the dict '''
          group_info = my_dict.setdefault(key, [])
          if isinstance(group_info, dict):
              host_list = group_info.setdefault('hosts', [])
              host_list.append(element)
          else:
              group_info.append(element)
  
      def push_group(self, my_dict, key, element):
          ''' Push a group as a child of another group. '''
          parent_group = my_dict.setdefault(key, {})
          if not isinstance(parent_group, dict):
              parent_group = my_dict[key] = {'hosts': parent_group}
          child_groups = parent_group.setdefault('children', [])
          if element not in child_groups:
              child_groups.append(element)
  
      def get_inventory_from_cache(self):
          ''' Reads the inventory from the cache file and returns it as a JSON
          object '''
  
          cache = open(self.cache_path_cache, 'r')
          json_inventory = cache.read()
          return json_inventory
  
  
      def load_index_from_cache(self):
          ''' Reads the index from the cache file sets self.index '''
  
          cache = open(self.cache_path_index, 'r')
          json_index = cache.read()
          self.index = json.loads(json_index)
  
  
      def write_to_cache(self, data, filename):
          ''' Writes data in JSON format to a file '''
  
          json_data = self.json_format_dict(data, True)
          cache = open(filename, 'w')
          cache.write(json_data)
          cache.close()
  
      def uncammelize(self, key):
          temp = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', key)
          return re.sub('([a-z0-9])([A-Z])', r'\1_\2', temp).lower()
  
      def to_safe(self, word):
          ''' Converts 'bad' characters in a string to underscores so they can be
          used as Ansible groups '''
  
          return re.sub("[^A-Za-z0-9\_]", "_", word)
  
      def json_format_dict(self, data, pretty=False):
          ''' Converts a dict to a JSON object and dumps it as a formatted
          string '''
  
          if pretty:
              return json.dumps(data, sort_keys=True, indent=2)
          else:
              return json.dumps(data)
  
  
  # Run the script
  Ec2Inventory()
  