Create GCE Service outside Neutron service start path

Creating gce client inside Neutron service start causes neutron-server
crash if service_key is not there at mentioned path. Neutron service
should not crash at start if service key is not there.

Change-Id: I8e0f8b150c60d55d71846face217d5213b5df9b7
Closes-Bug: #1707872

neutron/neutron/common/gceutils.py

@@ -11,6 +11,7 @@ License for the specific language governing permissions and limitations
 under the License.
 """
 
+import os
 import time
 import uuid
 
@@ -75,6 +76,10 @@ class GceResourceNotFound(e.NotFound):
     message = _("GCE Resource %(name)s %(identifier)s was not found")
 
 
+class GceServiceKeyNotFound(e.NotFound):
+    message = _("GCE service key was not found at %(path)s location")
+
+
 def list_instances(compute, project, zone):
     """Returns list of GCE instance resources for specified project
 
@@ -151,6 +156,9 @@ def get_gce_service(service_key):
     :return: :class:`Resource <Resource>` object
     :rtype: googleapiclient.discovery.Resource
     """
+    if not os.path.exists(service_key):
+        raise GceServiceKeyNotFound(path=service_key)
+
     credentials = GoogleCredentials.from_stream(service_key)
     service = build('compute', 'v1', credentials=credentials)
     return service

neutron/neutron/plugins/ml2/drivers/gce/mech_gce.py

@@ -48,13 +48,19 @@ class GceMechanismDriver(api.MechanismDriver):
         self.gce_region = gceconf.region
         self.gce_project = gceconf.project_id
         self.gce_svc_key = gceconf.service_key_path
+        self._gce_svc = None
 
     def initialize(self):
-        self.gce_svc = gceutils.get_gce_service(self.gce_svc_key)
         LOG.info("GCE Mechanism driver init with %s project, %s region" %
                  (self.gce_project, self.gce_region))
         self._subscribe_events()
 
+    @property
+    def gce_svc(self):
+        if self._gce_svc is None:
+            self._gce_svc = gceutils.get_gce_service(self.gce_svc_key)
+        return self._gce_svc
+
     def _subscribe_events(self):
         registry.subscribe(self.secgroup_callback, resources.SECURITY_GROUP,
                            events.BEFORE_DELETE)

neutron/neutron/services/l3_router/gce_router_plugin.py

@@ -75,10 +75,16 @@ class GceRouterPlugin(
         self.gce_region = gceconf.region
         self.gce_project = gceconf.project_id
         self.gce_svc_key = gceconf.service_key_path
-        self.gce_svc = gceutils.get_gce_service(self.gce_svc_key)
+        self._gce_svc = None
         LOG.info("GCE Router plugin init with %s project, %s region" %
                  (self.gce_project, self.gce_region))
 
+    @property
+    def gce_svc(self):
+        if self._gce_svc is None:
+            self._gce_svc = gceutils.get_gce_service(self.gce_svc_key)
+        return self._gce_svc
+
     def get_plugin_type(self):
         return plugin_type
 

neutron/tests/plugins/ml2/drivers/gce/test_gce.py

@@ -35,10 +35,13 @@ else:
 
 
 class GCENeutronTestCase(test_sg.SecurityGroupsTestCase, base.BaseTestCase):
-    @mock.patch('neutron.common.gceutils.get_gce_service')
-    def setUp(self, mock_service):
-        mock_service.side_effect = gce_mock.get_gce_service
+    def setUp(self):
         super(GCENeutronTestCase, self).setUp()
+        self.service_patcher = mock.patch(
+            'neutron.common.gceutils.get_gce_service').start()
+        mock_service = self.service_patcher.start()
+        mock_service.side_effect = gce_mock.get_gce_service
+        self.addCleanup(self.service_patcher.stop)
         self._driver = GceMechanismDriver()
         self._driver.gce_zone = 'us-central1-c'
         self._driver.gce_region = 'us-central1'