Allow filtering of instances by tags in GCE dynamic inventory (#35770)

* Allow filtering of instances by tags in GCE dynamic inventory

* Optimize instance tags configuration

* Fix for PEP8

contrib/inventory/gce.ini

@@ -46,10 +46,14 @@ gce_service_account_pem_file_path =
 gce_project_id =
 gce_zone =
 
-# Filter inventory based on on state. Leave undefined to return instances regardless of state.
+# Filter inventory based on state. Leave undefined to return instances regardless of state.
 # example: Uncomment to only return inventory in the running or provisioning state
 #instance_states = RUNNING,PROVISIONING
 
+# Filter inventory based on instance tags. Leave undefined to return instances regardless of tags.
+# example: Uncomment to only return inventory with the http-server or https-server tag
+#instance_tags = http-server,https-server
+
 
 [inventory]
 # The 'inventory_ip_type' parameter specifies whether 'ansible_ssh_host' should

contrib/inventory/gce.py

@@ -222,6 +222,7 @@ class GceInventory(object):
             'gce_project_id': '',
             'gce_zone': '',
             'libcloud_secrets': '',
+            'instance_tags': '',
             'inventory_ip_type': '',
             'cache_path': '~/.ansible/tmp',
             'cache_max_age': '300'
@@ -247,6 +248,16 @@ class GceInventory(object):
             if states:
                 self.instance_states = states.split(',')
 
+        # Set the instance_tags filter, env var overrides config from file
+        # and cli param overrides all
+        if self.args.instance_tags:
+            self.instance_tags = self.args.instance_tags
+        else:
+            self.instance_tags = os.environ.get(
+                'GCE_INSTANCE_TAGS', config.get('gce', 'instance_tags'))
+        if self.instance_tags:
+            self.instance_tags = self.instance_tags.split(',')
+
         # Caching
         cache_path = config.get('cache', 'cache_path')
         cache_max_age = config.getint('cache', 'cache_max_age')
@@ -338,6 +349,8 @@ class GceInventory(object):
                             help='List instances (default: True)')
         parser.add_argument('--host', action='store',
                             help='Get all information about an instance')
+        parser.add_argument('--instance-tags', action='store',
+                            help='Only include instances with this tags, separated by comma')
         parser.add_argument('--pretty', action='store_true', default=False,
                             help='Pretty format (default: False)')
         parser.add_argument(
@@ -430,6 +443,18 @@ class GceInventory(object):
             if self.instance_states and not node.extra['status'] in self.instance_states:
                 continue
 
+            # This check filters on the desired instance tags defined in the
+            # config file with the instance_tags config option, env var GCE_INSTANCE_TAGS,
+            # or as the cli param --instance-tags.
+            #
+            # If the instance_tags list is _empty_ then _ALL_ instances are returned.
+            #
+            # If the instance_tags list is _populated_ then check the current
+            # instance tags against the instance_tags list. If the instance has
+            # at least one tag from the instance_tags list, it is returned.
+            if self.instance_tags and not set(self.instance_tags) & set(node.extra['tags']):
+                continue
+
             name = node.name
 
             meta["hostvars"][name] = self.node_to_dict(node)