Handle EndpointNotFound in nova notifier

Currently if the nova endpoint do not exist
exception is raised. Even the endpoint gets created
notification keeps on failing until the session
expires.
If the endpoint not exist the session is not useful
so marking it as invalid, this will ensure if endpoint is
created later the notification do not fail.

Closes-Bug: #2081174
Change-Id: I1f7fd1d1371ca0a3c4edb409cffd2177d44a1f23
(cherry picked from commit 7d1a20e)

Author: karelyatin

neutron/notifiers/nova.py

@@ -281,6 +281,9 @@ def send_events(self, batched_events):
         try:
             response = novaclient.server_external_events.create(
                 batched_events)
+        except ks_exceptions.EndpointNotFound:
+            LOG.exception("Nova endpoint not found, invalidating the session")
+            self.session.invalidate()
         except nova_exceptions.NotFound:
             LOG.debug("Nova returned NotFound for event: %s",
                       batched_events)

neutron/tests/unit/notifiers/test_nova.py

@@ -237,6 +237,16 @@ def test_no_notification_notify_nova_on_port_data_changes_false(self):
                                                    {}, {})
             self.assertFalse(send_events.called)
 
+    @mock.patch('novaclient.client.Client')
+    def test_nova_send_events_noendpoint_invalidate_session(self, mock_client):
+        create = mock_client().server_external_events.create
+        create.side_effect = ks_exc.EndpointNotFound
+        with mock.patch.object(self.nova_notifier.session,
+                               'invalidate', return_value=True) as mock_sess:
+            self.nova_notifier.send_events([])
+            create.assert_called()
+            mock_sess.assert_called()
+
     @mock.patch('novaclient.client.Client')
     def test_nova_send_events_returns_bad_list(self, mock_client):
         create = mock_client().server_external_events.create