Conditionally check for service extensions

Currently we always check for service extensions, even when the endpoint
doesn't exist, which leads to a spurious backtrace in the logs.

Change-Id: I0b7b6c1ed4ce39602b3745408e059a0d7a453130
Closes-Bug: #1515215

heat/engine/resource.py

@@ -564,12 +564,13 @@ class Resource(object):
                 endpoint_exists = client_plugin.does_endpoint_exist(
                     service_type=service_type,
                     service_name=cls.default_client_name)
-                req_extension = cls.required_service_extension
-                is_ext_available = (
-                    not req_extension or client_plugin.has_extension(
-                        req_extension))
-                if endpoint_exists and is_ext_available:
-                    return True
+                if endpoint_exists:
+                    req_extension = cls.required_service_extension
+                    is_ext_available = (
+                        not req_extension or client_plugin.has_extension(
+                            req_extension))
+                    if is_ext_available:
+                        return True
         except Exception as ex:
             LOG.exception(ex)
 

heat/tests/generic_resource.py

@@ -235,6 +235,11 @@ class ResourceWithDefaultClientName(resource.Resource):
     default_client_name = 'sample'
 
 
+class ResourceWithDefaultClientNameExt(resource.Resource):
+    default_client_name = 'sample'
+    required_service_extension = 'foo'
+
+
 class ResourceWithFnGetAttType(GenericResource):
     def FnGetAtt(self, name):
         pass

heat/tests/test_resource.py

@@ -2955,6 +2955,108 @@ class ResourceAvailabilityTest(common.HeatTestCase):
                           .default_client_name)
         )
 
+    @mock.patch.object(clients.OpenStackClients, 'client_plugin')
+    def test_service_deployed_required_extension_true(
+            self,
+            mock_client_plugin_method):
+        """Test availability of resource with a required extension. """
+
+        mock_service_types, mock_client_plugin = self._mock_client_plugin(
+            ['test_type']
+        )
+        mock_client_plugin.has_extension = mock.Mock(
+            return_value=True)
+        mock_client_plugin_method.return_value = mock_client_plugin
+
+        self.assertTrue(
+            generic_rsrc.ResourceWithDefaultClientNameExt.is_service_available(
+                context=mock.Mock()))
+        mock_client_plugin_method.assert_called_once_with(
+            generic_rsrc.ResourceWithDefaultClientName.default_client_name)
+        mock_service_types.assert_called_once_with()
+        mock_client_plugin.does_endpoint_exist.assert_called_once_with(
+            service_type='test_type',
+            service_name=(generic_rsrc.ResourceWithDefaultClientName
+                          .default_client_name))
+        mock_client_plugin.has_extension.assert_called_once_with('foo')
+
+    @mock.patch.object(clients.OpenStackClients, 'client_plugin')
+    def test_service_deployed_required_extension_false(
+            self,
+            mock_client_plugin_method):
+        """Test availability of resource with a required extension. """
+
+        mock_service_types, mock_client_plugin = self._mock_client_plugin(
+            ['test_type']
+        )
+        mock_client_plugin.has_extension = mock.Mock(
+            return_value=False)
+        mock_client_plugin_method.return_value = mock_client_plugin
+
+        self.assertFalse(
+            generic_rsrc.ResourceWithDefaultClientNameExt.is_service_available(
+                context=mock.Mock()))
+        mock_client_plugin_method.assert_called_once_with(
+            generic_rsrc.ResourceWithDefaultClientName.default_client_name)
+        mock_service_types.assert_called_once_with()
+        mock_client_plugin.does_endpoint_exist.assert_called_once_with(
+            service_type='test_type',
+            service_name=(generic_rsrc.ResourceWithDefaultClientName
+                          .default_client_name))
+        mock_client_plugin.has_extension.assert_called_once_with('foo')
+
+    @mock.patch.object(clients.OpenStackClients, 'client_plugin')
+    def test_service_deployed_required_extension_exception(
+            self,
+            mock_client_plugin_method):
+        """Test availability of resource with a required extension. """
+
+        mock_service_types, mock_client_plugin = self._mock_client_plugin(
+            ['test_type']
+        )
+        mock_client_plugin.has_extension = mock.Mock(
+            side_effect=Exception("error"))
+        mock_client_plugin_method.return_value = mock_client_plugin
+
+        self.assertFalse(
+            generic_rsrc.ResourceWithDefaultClientNameExt.is_service_available(
+                context=mock.Mock()))
+        mock_client_plugin_method.assert_called_once_with(
+            generic_rsrc.ResourceWithDefaultClientName.default_client_name)
+        mock_service_types.assert_called_once_with()
+        mock_client_plugin.does_endpoint_exist.assert_called_once_with(
+            service_type='test_type',
+            service_name=(generic_rsrc.ResourceWithDefaultClientName
+                          .default_client_name))
+        mock_client_plugin.has_extension.assert_called_once_with('foo')
+
+    @mock.patch.object(clients.OpenStackClients, 'client_plugin')
+    def test_service_not_deployed_required_extension(
+            self,
+            mock_client_plugin_method):
+        """Test availability of resource when the service is not deployed.
+
+        When the service is not deployed, resource is considered as
+        unavailable.
+        """
+
+        mock_service_types, mock_client_plugin = self._mock_client_plugin(
+            ['test_type_un_deployed'],
+            False
+        )
+        mock_client_plugin_method.return_value = mock_client_plugin
+
+        self.assertFalse(
+            generic_rsrc.ResourceWithDefaultClientNameExt.is_service_available(
+                context=mock.Mock()))
+        mock_client_plugin_method.assert_called_once_with(
+            generic_rsrc.ResourceWithDefaultClientName.default_client_name)
+        mock_service_types.assert_called_once_with()
+        mock_client_plugin.does_endpoint_exist.assert_called_once_with(
+            service_type='test_type_un_deployed',
+            service_name=(generic_rsrc.ResourceWithDefaultClientName
+                          .default_client_name))
+
     def test_service_not_deployed_throws_exception(self):
         """Test raising exception when the service is not deployed.