Add keyed_groups feature (#52045)

This implements:
- Allow creating keyed group parents

changelogs/fragments/52045-keyed-group-features.yaml

@@ -0,0 +1,2 @@
+minor_changes:
+- keyed_groups now has a 'parent_group' keyword that allows assigning all generated groups to the same parent group

lib/ansible/plugins/inventory/__init__.py

@@ -335,7 +335,6 @@ class Constructable(object):
     def _add_host_to_keyed_groups(self, keys, variables, host, strict=False):
         ''' helper to create groups for plugins based on variable values and add the corresponding hosts to it'''
         if keys and isinstance(keys, list):
-            groups = []
             for keyed in keys:
                 if keyed and isinstance(keyed, dict):
 
@@ -349,26 +348,33 @@ class Constructable(object):
                     if key:
                         prefix = keyed.get('prefix', '')
                         sep = keyed.get('separator', '_')
+                        raw_parent_name = keyed.get('parent_group', None)
 
+                        new_raw_group_names = []
                         if isinstance(key, string_types):
-                            groups.append('%s%s%s' % (prefix, sep, key))
+                            new_raw_group_names.append(key)
                         elif isinstance(key, list):
                             for name in key:
-                                groups.append('%s%s%s' % (prefix, sep, name))
+                                new_raw_group_names.append(name)
                         elif isinstance(key, Mapping):
                             for (gname, gval) in key.items():
                                 name = '%s%s%s' % (gname, sep, gval)
-                                groups.append('%s%s%s' % (prefix, sep, name))
+                                new_raw_group_names.append(name)
                         else:
                             raise AnsibleParserError("Invalid group name format, expected a string or a list of them or dictionary, got: %s" % type(key))
+
+                        for bare_name in new_raw_group_names:
+                            gname = to_safe_group_name('%s%s%s' % (prefix, sep, bare_name))
+                            self.inventory.add_group(gname)
+                            self.inventory.add_child(gname, host)
+
+                            if raw_parent_name:
+                                parent_name = to_safe_group_name(raw_parent_name)
+                                self.inventory.add_group(parent_name)
+                                self.inventory.add_child(parent_name, gname)
+
                     else:
                         if strict:
                             raise AnsibleParserError("No key or key resulted empty, invalid entry")
                 else:
                     raise AnsibleParserError("Invalid keyed group entry, it must be a dictionary: %s " % keyed)
-
-            # now actually add any groups
-            for group_name in groups:
-                gname = to_safe_group_name(group_name)
-                self.inventory.add_group(gname)
-                self.inventory.add_child(gname, host)

lib/ansible/plugins/inventory/constructed.py

@@ -53,9 +53,19 @@ EXAMPLES = r'''
         - prefix: distro
           key: ansible_distribution
 
+        # the following examples assume the first inventory is from contrib/inventory/ec2.py
         # this creates a group per ec2 architecture and assign hosts to the matching ones (arch_x86_64, arch_sparc, etc)
         - prefix: arch
           key: ec2_architecture
+
+        # this creates a group per ec2 region like "us_west_1"
+        - prefix: ""
+          separator: ""
+          key: ec2_region
+
+        # this creates a common parent group for all ec2 availability zones
+        - key: ec2_placement
+          parent_group: all_ec2_zones
 '''
 
 import os

test/units/plugins/inventory/test_constructed.py

@@ -0,0 +1,104 @@
+# -*- coding: utf-8 -*-
+
+# Copyright 2019 Alan Rominger <arominge@redhat.net>
+#
+# 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 pytest
+
+from ansible.plugins.inventory.constructed import InventoryModule
+from ansible.inventory.data import InventoryData
+from ansible.template import Templar
+
+
+@pytest.fixture(scope="module")
+def inventory_module():
+    r = InventoryModule()
+    r.inventory = InventoryData()
+    r.templar = Templar(None)
+    return r
+
+
+def test_group_by_value_only(inventory_module):
+    inventory_module.inventory.add_host('foohost')
+    inventory_module.inventory.set_variable('foohost', 'bar', 'my_group_name')
+    host = inventory_module.inventory.get_host('foohost')
+    keyed_groups = [
+        {
+            'prefix': '',
+            'separator': '',
+            'key': 'bar'
+        }
+    ]
+    inventory_module._add_host_to_keyed_groups(
+        keyed_groups, host.vars, host.name, strict=False
+    )
+    assert 'my_group_name' in inventory_module.inventory.groups
+    group = inventory_module.inventory.groups['my_group_name']
+    assert group.hosts == [host]
+
+
+def test_keyed_group_separator(inventory_module):
+    inventory_module.inventory.add_host('farm')
+    inventory_module.inventory.set_variable('farm', 'farmer', 'mcdonald')
+    inventory_module.inventory.set_variable('farm', 'barn', {'cow': 'betsy'})
+    host = inventory_module.inventory.get_host('farm')
+    keyed_groups = [
+        {
+            'prefix': 'farmer',
+            'separator': '_old_',
+            'key': 'farmer',
+            'unsafe': True
+        },
+        {
+            'separator': 'mmmmmmmmmm',
+            'key': 'barn',
+            'unsafe': True
+        }
+    ]
+    inventory_module._add_host_to_keyed_groups(
+        keyed_groups, host.vars, host.name, strict=False
+    )
+    for group_name in ('farmer_old_mcdonald', 'mmmmmmmmmmcowmmmmmmmmmmbetsy'):
+        assert group_name in inventory_module.inventory.groups
+        group = inventory_module.inventory.groups[group_name]
+        assert group.hosts == [host]
+
+
+def test_keyed_parent_groups(inventory_module):
+    inventory_module.inventory.add_host('web1')
+    inventory_module.inventory.add_host('web2')
+    inventory_module.inventory.set_variable('web1', 'region', 'japan')
+    inventory_module.inventory.set_variable('web2', 'region', 'japan')
+    host1 = inventory_module.inventory.get_host('web1')
+    host2 = inventory_module.inventory.get_host('web2')
+    keyed_groups = [
+        {
+            'prefix': 'region',
+            'key': 'region',
+            'parent_group': 'region_list'
+        }
+    ]
+    for host in [host1, host2]:
+        inventory_module._add_host_to_keyed_groups(
+            keyed_groups, host.vars, host.name, strict=False
+        )
+    assert 'region_japan' in inventory_module.inventory.groups
+    assert 'region_list' in inventory_module.inventory.groups
+    region_group = inventory_module.inventory.groups['region_japan']
+    all_regions = inventory_module.inventory.groups['region_list']
+    assert all_regions.child_groups == [region_group]
+    assert region_group.hosts == [host1, host2]