# Copyright (c) 2017 Ansible Project # GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt) from __future__ import (absolute_import, division, print_function) __metaclass__ = type DOCUMENTATION = ''' name: constructed version_added: "2.4" short_description: Uses Jinja2 to construct vars and groups based on existing inventory. description: - Uses a YAML configuration file with a valid YAML or C(.config) extension to define var expressions and group conditionals - The Jinja2 conditionals that qualify a host for membership. - The Jinja2 expressions are calculated and assigned to the variables - Only variables already available from previous inventories or the fact cache can be used for templating. - When I(strict) is False, failed expressions will be ignored (assumes vars were missing). options: plugin: description: token that ensures this is a source file for the 'constructed' plugin. required: True choices: ['ansible.builtin.constructed', 'constructed'] use_vars_plugins: description: - Normally, for performance reasons, vars plugins get executed after the inventory sources complete the base inventory, this option allows for getting vars related to hosts/groups from those plugins. - The host_group_vars (enabled by default) 'vars plugin' is the one responsible for reading host_vars/ and group_vars/ directories. - This will execute all vars plugins, even those that are not supposed to execute at the 'inventory' stage. See vars plugins docs for details on 'stage'. required: false default: false type: boolean version_added: '2.11' extends_documentation_fragment: - constructed ''' EXAMPLES = r''' # inventory.config file in YAML format plugin: ansible.builtin.constructed strict: False compose: var_sum: var1 + var2 # this variable will only be set if I have a persistent fact cache enabled (and have non expired facts) # `strict: False` will skip this instead of producing an error if it is missing facts. server_type: "ansible_hostname | regex_replace ('(.{6})(.{2}).*', '\\2')" groups: # simple name matching webservers: inventory_hostname.startswith('web') # using ec2 'tags' (assumes aws inventory) development: "'devel' in (ec2_tags|list)" # using other host properties populated in inventory private_only: not (public_dns_name is defined or ip_address is defined) # complex group membership multi_group: (group_names | intersect(['alpha', 'beta', 'omega'])) | length >= 2 keyed_groups: # this creates a group per distro (distro_CentOS, distro_Debian) and assigns the hosts that have matching values to it, # using the default separator "_" - prefix: distro key: ansible_distribution # the following examples assume the first inventory is from the `aws_ec2` plugin # this creates a group per ec2 architecture and assign hosts to the matching ones (arch_x86_64, arch_sparc, etc) - prefix: arch key: architecture # this creates a group per ec2 region like "us_west_1" - prefix: "" separator: "" key: placement.region # this creates a common parent group for all ec2 availability zones - key: placement.availability_zone parent_group: all_ec2_zones ''' import os from ansible import constants as C from ansible.errors import AnsibleParserError, AnsibleOptionsError from ansible.inventory.helpers import get_group_vars from ansible.plugins.inventory import BaseInventoryPlugin, Constructable from ansible.module_utils._text import to_native from ansible.utils.vars import combine_vars from ansible.vars.fact_cache import FactCache from ansible.vars.plugins import get_vars_from_inventory_sources class InventoryModule(BaseInventoryPlugin, Constructable): """ constructs groups and vars using Jinja2 template expressions """ NAME = 'constructed' def __init__(self): super(InventoryModule, self).__init__() self._cache = FactCache() def verify_file(self, path): valid = False if super(InventoryModule, self).verify_file(path): file_name, ext = os.path.splitext(path) if not ext or ext in ['.config'] + C.YAML_FILENAME_EXTENSIONS: valid = True return valid def get_all_host_vars(self, host, loader, sources): ''' requires host object ''' return combine_vars(self.host_groupvars(host, loader, sources), self.host_vars(host, loader, sources)) def host_groupvars(self, host, loader, sources): ''' requires host object ''' gvars = get_group_vars(host.get_groups()) if self.get_option('use_vars_plugins'): gvars = combine_vars(gvars, get_vars_from_inventory_sources(loader, sources, host.get_groups(), 'all')) return gvars def host_vars(self, host, loader, sources): ''' requires host object ''' hvars = host.get_vars() if self.get_option('use_vars_plugins'): hvars = combine_vars(hvars, get_vars_from_inventory_sources(loader, sources, [host], 'all')) return hvars def parse(self, inventory, loader, path, cache=False): ''' parses the inventory file ''' super(InventoryModule, self).parse(inventory, loader, path, cache=cache) self._read_config_data(path) sources = [] try: sources = inventory.processed_sources except AttributeError: if self.get_option('use_vars_plugins'): raise AnsibleOptionsError("The option use_vars_plugins requires ansible >= 2.11.") strict = self.get_option('strict') fact_cache = FactCache() try: # Go over hosts (less var copies) for host in inventory.hosts: # get available variables to templar hostvars = self.get_all_host_vars(inventory.hosts[host], loader, sources) if host in fact_cache: # adds facts if cache is active hostvars = combine_vars(hostvars, fact_cache[host]) # create composite vars self._set_composite_vars(self.get_option('compose'), hostvars, host, strict=strict) # refetch host vars in case new ones have been created above hostvars = self.get_all_host_vars(inventory.hosts[host], loader, sources) if host in self._cache: # adds facts if cache is active hostvars = combine_vars(hostvars, self._cache[host]) # constructed groups based on conditionals self._add_host_to_composed_groups(self.get_option('groups'), hostvars, host, strict=strict, fetch_hostvars=False) # constructed groups based variable values self._add_host_to_keyed_groups(self.get_option('keyed_groups'), hostvars, host, strict=strict, fetch_hostvars=False) except Exception as e: raise AnsibleParserError("failed to parse %s: %s " % (to_native(path), to_native(e)), orig_exc=e)