Change MQ targeting to honor only what is in the context

Previously we had aimed to make things like compute RPC automatically
look up the InstanceMapping or HostMapping for the call being performed
to target appropriately. However, we cannot do that within the cell,
and even trying incurs some overhead. For now, just deprecate the
by_instance() and by_host() methods and honor what is in the context
(if set) and otherwise fall back to the default client. Make the context
target routines create and store the RPC transport and remove the caching
logic from the ClientRouter since we're removing its ability to do that.

Related to blueprint cells-aware-api
Change-Id: I10f374adca672576058c4dbab708c040d166df47

1 files changed, 22 insertions, 132 deletions

diff --git a/nova/tests/unit/test_rpc.py b/nova/tests/unit/test_rpc.py
index a265d45cbd..0c49762c9e 100644
--- a/nova/tests/unit/test_rpc.py
+++ b/nova/tests/unit/test_rpc.py
@@ -12,18 +12,15 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 import copy
-import datetime
 
 import fixtures
 import mock
 import oslo_messaging as messaging
 from oslo_messaging.rpc import dispatcher
 from oslo_serialization import jsonutils
-from oslo_utils import fixture as utils_fixture
 import testtools
 
 from nova import context
-from nova import exception
 from nova import objects
 from nova import rpc
 from nova import test
@@ -445,179 +442,72 @@ class TestProfilerRequestContextSerializer(test.NoDBTestCase):
 
 
 class TestClientRouter(test.NoDBTestCase):
-    @mock.patch('nova.objects.InstanceMapping.get_by_instance_uuid')
-    @mock.patch('nova.rpc.create_transport')
     @mock.patch('oslo_messaging.RPCClient')
-    def test_by_instance(self, mock_rpcclient, mock_create, mock_get):
+    def test_by_instance(self, mock_rpcclient):
         default_client = mock.Mock()
         cell_client = mock.Mock()
         mock_rpcclient.return_value = cell_client
         ctxt = mock.Mock()
-        cm = objects.CellMapping(uuid=uuids.cell_mapping,
-                                 transport_url='fake:///')
-        mock_get.return_value = objects.InstanceMapping(cell_mapping=cm)
+        ctxt.mq_connection = mock.sentinel.transport
         instance = objects.Instance(uuid=uuids.instance)
 
         router = rpc.ClientRouter(default_client)
         client = router.by_instance(ctxt, instance)
 
-        mock_get.assert_called_once_with(ctxt, instance.uuid)
         # verify a client was created by ClientRouter
         mock_rpcclient.assert_called_once_with(
-                mock_create.return_value, default_client.target,
+                mock.sentinel.transport, default_client.target,
                 version_cap=default_client.version_cap,
                 serializer=default_client.serializer)
         # verify cell client was returned
         self.assertEqual(cell_client, client)
 
-        # reset and check that cached client is returned the second time
-        mock_rpcclient.reset_mock()
-        mock_create.reset_mock()
-        mock_get.reset_mock()
+    @mock.patch('oslo_messaging.RPCClient')
+    def test_by_instance_untargeted(self, mock_rpcclient):
+        default_client = mock.Mock()
+        cell_client = mock.Mock()
+        mock_rpcclient.return_value = cell_client
+        ctxt = mock.Mock()
+        ctxt.mq_connection = None
+        instance = objects.Instance(uuid=uuids.instance)
 
+        router = rpc.ClientRouter(default_client)
         client = router.by_instance(ctxt, instance)
-        mock_get.assert_called_once_with(ctxt, instance.uuid)
-        mock_rpcclient.assert_not_called()
-        mock_create.assert_not_called()
-        self.assertEqual(cell_client, client)
 
-    @mock.patch('nova.objects.HostMapping.get_by_host')
-    @mock.patch('nova.rpc.create_transport')
+        self.assertEqual(router.default_client, client)
+        self.assertFalse(mock_rpcclient.called)
+
     @mock.patch('oslo_messaging.RPCClient')
-    def test_by_host(self, mock_rpcclient, mock_create, mock_get):
+    def test_by_host(self, mock_rpcclient):
         default_client = mock.Mock()
         cell_client = mock.Mock()
         mock_rpcclient.return_value = cell_client
         ctxt = mock.Mock()
-        cm = objects.CellMapping(uuid=uuids.cell_mapping,
-                                 transport_url='fake:///')
-        mock_get.return_value = objects.HostMapping(cell_mapping=cm)
+        ctxt.mq_connection = mock.sentinel.transport
         host = 'fake-host'
 
         router = rpc.ClientRouter(default_client)
         client = router.by_host(ctxt, host)
 
-        mock_get.assert_called_once_with(ctxt, host)
         # verify a client was created by ClientRouter
         mock_rpcclient.assert_called_once_with(
-                mock_create.return_value, default_client.target,
+                mock.sentinel.transport, default_client.target,
                 version_cap=default_client.version_cap,
                 serializer=default_client.serializer)
         # verify cell client was returned
         self.assertEqual(cell_client, client)
 
-        # reset and check that cached client is returned the second time
-        mock_rpcclient.reset_mock()
-        mock_create.reset_mock()
-        mock_get.reset_mock()
-
-        client = router.by_host(ctxt, host)
-        mock_get.assert_called_once_with(ctxt, host)
-        mock_rpcclient.assert_not_called()
-        mock_create.assert_not_called()
-        self.assertEqual(cell_client, client)
-
-    @mock.patch('nova.objects.InstanceMapping.get_by_instance_uuid',
-            side_effect=exception.InstanceMappingNotFound(uuid=uuids.instance))
-    @mock.patch('nova.rpc.create_transport')
     @mock.patch('oslo_messaging.RPCClient')
-    def test_by_instance_not_found(self, mock_rpcclient, mock_create,
-                                   mock_get):
-        default_client = mock.Mock()
-        cell_client = mock.Mock()
-        mock_rpcclient.return_value = cell_client
-        ctxt = mock.Mock()
-        instance = objects.Instance(uuid=uuids.instance)
-
-        router = rpc.ClientRouter(default_client)
-        client = router.by_instance(ctxt, instance)
-
-        mock_get.assert_called_once_with(ctxt, instance.uuid)
-        mock_rpcclient.assert_not_called()
-        mock_create.assert_not_called()
-        # verify default client was returned
-        self.assertEqual(default_client, client)
-
-    @mock.patch('nova.objects.HostMapping.get_by_host',
-            side_effect=exception.HostMappingNotFound(name='fake-host'))
-    @mock.patch('nova.rpc.create_transport')
-    @mock.patch('oslo_messaging.RPCClient')
-    def test_by_host_not_found(self, mock_rpcclient, mock_create, mock_get):
+    def test_by_host_untargeted(self, mock_rpcclient):
         default_client = mock.Mock()
         cell_client = mock.Mock()
         mock_rpcclient.return_value = cell_client
         ctxt = mock.Mock()
+        ctxt.mq_connection = None
         host = 'fake-host'
 
         router = rpc.ClientRouter(default_client)
         client = router.by_host(ctxt, host)
 
-        mock_get.assert_called_once_with(ctxt, host)
-        mock_rpcclient.assert_not_called()
-        mock_create.assert_not_called()
-        # verify default client was returned
-        self.assertEqual(default_client, client)
-
-    @mock.patch('nova.objects.InstanceMapping.get_by_instance_uuid')
-    @mock.patch('nova.rpc.create_transport')
-    @mock.patch('oslo_messaging.RPCClient')
-    def test_remove_stale_clients(self, mock_rpcclient, mock_create, mock_get):
-        t0 = datetime.datetime(2016, 8, 9, 0, 0, 0)
-        time_fixture = self.useFixture(utils_fixture.TimeFixture(t0))
-
-        default_client = mock.Mock()
-        ctxt = mock.Mock()
-
-        cm1 = objects.CellMapping(uuid=uuids.cell_mapping1,
-                                  transport_url='fake:///')
-        cm2 = objects.CellMapping(uuid=uuids.cell_mapping2,
-                                  transport_url='fake:///')
-        cm3 = objects.CellMapping(uuid=uuids.cell_mapping3,
-                                  transport_url='fake:///')
-        mock_get.side_effect = [objects.InstanceMapping(cell_mapping=cm1),
-                                objects.InstanceMapping(cell_mapping=cm2),
-                                objects.InstanceMapping(cell_mapping=cm3),
-                                objects.InstanceMapping(cell_mapping=cm3)]
-        instance1 = objects.Instance(uuid=uuids.instance1)
-        instance2 = objects.Instance(uuid=uuids.instance2)
-        instance3 = objects.Instance(uuid=uuids.instance3)
-
-        router = rpc.ClientRouter(default_client)
-        cell1_client = router.by_instance(ctxt, instance1)
-        cell2_client = router.by_instance(ctxt, instance2)
-
-        # default client, cell1 client, cell2 client
-        self.assertEqual(3, len(router.clients))
-        expected = {'default': default_client,
-                    uuids.cell_mapping1: cell1_client,
-                    uuids.cell_mapping2: cell2_client}
-        for client_id, client in expected.items():
-            self.assertEqual(client, router.clients[client_id].client)
-
-        # expire cell1 client and cell2 client
-        time_fixture.advance_time_seconds(80)
-
-        # add cell3 client
-        cell3_client = router.by_instance(ctxt, instance3)
-
-        router._remove_stale_clients(ctxt)
-
-        # default client, cell3 client
-        expected = {'default': default_client,
-                    uuids.cell_mapping3: cell3_client}
-        self.assertEqual(2, len(router.clients))
-        for client_id, client in expected.items():
-            self.assertEqual(client, router.clients[client_id].client)
-
-        # expire cell3 client
-        time_fixture.advance_time_seconds(80)
-
-        # access cell3 client to refresh it
-        cell3_client = router.by_instance(ctxt, instance3)
-
-        router._remove_stale_clients(ctxt)
-
-        # default client and cell3 client should be there
-        self.assertEqual(2, len(router.clients))
-        for client_id, client in expected.items():
-            self.assertEqual(client, router.clients[client_id].client)
+        self.assertEqual(router.default_client, client)
+        self.assertFalse(mock_rpcclient.called)