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diff --git a/lib/ansible/plugins/inventory/constructed.py b/lib/ansible/plugins/inventory/constructed.py
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+++ b/lib/ansible/plugins/inventory/constructed.py
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+# 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)