Add caching for nova extensions

This patch adds caching for nova extensions.

Change-Id: I6170f1075a923b7fb2dfb50d4008ff9722fcee48
Partial-Bug: #1506875

heat/engine/clients/os/__init__.py

@@ -0,0 +1,21 @@
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from oslo_cache import core
+from oslo_config import cfg
+
+from heat.common import cache
+
+MEMOIZE = core.get_memoization_decorator(conf=cfg.CONF,
+                                         region=cache.get_cache_region(),
+                                         group="service_extension_cache")

heat/engine/clients/os/neutron/__init__.py

@@ -14,18 +14,11 @@
 from neutronclient.common import exceptions
 from neutronclient.neutron import v2_0 as neutronV20
 from neutronclient.v2_0 import client as nc
-from oslo_cache import core
-from oslo_config import cfg
 from oslo_utils import uuidutils
 
-from heat.common import cache
 from heat.common import exception
 from heat.engine.clients import client_plugin
-
-
-MEMOIZE = core.get_memoization_decorator(conf=cfg.CONF,
-                                         region=cache.get_cache_region(),
-                                         group="service_extension_cache")
+from heat.engine.clients import os as os_client
 
 
 class NeutronClientPlugin(client_plugin.ClientPlugin):
@@ -79,7 +72,7 @@ class NeutronClientPlugin(client_plugin.ClientPlugin):
         return neutronV20.find_resourceid_by_name_or_id(
             self.client(), key_type, props.get(key))
 
-    @MEMOIZE
+    @os_client.MEMOIZE
     def _list_extensions(self):
         extensions = self.client().list_extensions().get('extensions')
         return set(extension.get('alias') for extension in extensions)

heat/engine/clients/os/nova.py

@@ -33,6 +33,7 @@ from heat.common.i18n import _
 from heat.common.i18n import _LI
 from heat.common.i18n import _LW
 from heat.engine.clients import client_plugin
+from heat.engine.clients import os as os_client
 from heat.engine import constraints
 
 LOG = logging.getLogger(__name__)
@@ -656,10 +657,14 @@ echo -e '%s\tALL=(ALL)\tNOPASSWD: ALL' >> /etc/sudoers
         else:
             return False
 
-    def has_extension(self, alias):
-        """Check if extension is present."""
+    @os_client.MEMOIZE
+    def _list_extensions(self):
         extensions = self.client().list_extensions.show_all()
-        return alias in [extension.alias for extension in extensions]
+        return set(extension.alias for extension in extensions)
+
+    def has_extension(self, alias):
+        """Check if specific extension is present."""
+        return alias in self._list_extensions()
 
 
 class ServerConstraint(constraints.BaseCustomConstraint):