[OVN] Fix the revision number retrieval method

The "ovn_revision_numbers" table has a unique constraint that is a
combination of the "resource_uuid" and the "resource_type". There is
a case where the resource_uuid can be the same for two registers.
A router interface will create a single Neutron DB register ("ports")
but it will require two OVN DB registers ("Logical_Switch_Port" and
"Logical_Router_Ports"). In this case is needed to define the
"resource_type" when retrieving the revision number.

The exception "RevisionNumberNotDefined" will be thrown if only the
"resource_uuid" is provided in the related case.

Closes-Bug: #2085946
Change-Id: I12079de78773f7409503392d4791848aea90cb7b
(cherry picked from commit a298a37fe7ee41d25db02fdde36e134b01ef5d9a)

neutron/db/ovn_revision_numbers_db.py

@@ -92,6 +92,12 @@ class UnknownResourceType(n_exc.NeutronException):
     message = 'Uknown resource type: %(resource_type)s'
 
 
+# NOTE(ralonsoh): to be moved to neutron-lib
+class RevisionNumberNotDefined(n_exc.NeutronException):
+    message = ('Unique revision number not found for %(resource_uuid)s, '
+               'the resource type is required in query')
+
+
 def _get_standard_attr_id(context, resource_uuid, resource_type):
     try:
         row = context.session.query(STD_ATTR_MAP[resource_type]).filter_by(
@@ -155,14 +161,26 @@ def _ensure_revision_row_exist(context, resource, resource_type, std_attr_id):
 
 
 @db_api.retry_if_session_inactive()
-def get_revision_row(context, resource_uuid):
+@db_api.CONTEXT_READER
+def get_revision_row(context, resource_uuid, resource_type=None):
+    """Retrieve the resource revision number
+
+    Only the Neutron ports can have two revision number registers, one for the
+    Logical_Switch_Port and another for the Logical_Router_Port, if this port
+    is a router interface. It is not strictly needed to filter by resource_type
+    if the resource is not a port.
+    """
     try:
-        with db_api.CONTEXT_READER.using(context):
+        filters = {'resource_uuid': resource_uuid}
-            return context.session.query(
+        if resource_type:
-                ovn_models.OVNRevisionNumbers).filter_by(
+            filters['resource_type'] = resource_type
-                    resource_uuid=resource_uuid).one()
+        return context.session.query(
+            ovn_models.OVNRevisionNumbers).filter_by(
+            **filters).one()
     except exc.NoResultFound:
         pass
+    except exc.MultipleResultsFound:
+        raise RevisionNumberNotDefined(resource_uuid=resource_uuid)
 
 
 @db_api.retry_if_session_inactive()

neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovn_client.py

@@ -838,7 +838,8 @@ class OVNClient(object):
             # to allow at least one maintenance cycle  before we delete the
             # revision number so that the port doesn't stale and eventually
             # gets deleted by the maintenance task.
-            rev_row = db_rev.get_revision_row(context, port_id)
+            rev_row = db_rev.get_revision_row(
+                context, port_id, resource_type=ovn_const.TYPE_PORTS)
             time_ = (timeutils.utcnow() - datetime.timedelta(
                 seconds=ovn_const.DB_CONSISTENCY_CHECK_INTERVAL + 30))
             if rev_row and rev_row.created_at >= time_:

neutron/tests/functional/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_maintenance.py

@@ -380,7 +380,8 @@ class TestMaintenance(_TestMaintenanceHelper):
         # Assert the revision number no longer exists
         self.assertIsNone(db_rev.get_revision_row(
             self.context,
-            neutron_obj['id']))
+            neutron_obj['id'],
+            resource_type=ovn_const.TYPE_PORTS))
 
     def test_subnet_global_dhcp4_opts(self):
         obj_name = 'globaltestsubnet'

neutron/tests/unit/db/test_ovn_revision_numbers_db.py

@@ -24,6 +24,7 @@ from oslo_db import exception as db_exc
 
 from neutron.api import extensions
 from neutron.common import config
+from neutron.common.ovn import constants as ovn_const
 from neutron.db.models import ovn as ovn_models
 from neutron.db import ovn_revision_numbers_db as ovn_rn_db
 import neutron.extensions
@@ -32,7 +33,6 @@ from neutron.tests.unit.db import test_db_base_plugin_v2
 from neutron.tests.unit.extensions import test_l3
 from neutron.tests.unit.extensions import test_securitygroup
 
-
 EXTENSIONS_PATH = ':'.join(neutron.extensions.__path__)
 PLUGIN_CLASS = (
     'neutron.tests.unit.db.test_ovn_revision_numbers_db.TestMaintenancePlugin')
@@ -123,6 +123,24 @@ class TestRevisionNumber(test_db_base_plugin_v2.NeutronDbPluginV2TestCase):
                 self.fail("create_initial_revision shouldn't raise "
                           "DBDuplicateEntry when may_exist is True")
 
+    def test_get_revision_row_ports(self):
+        res = self._create_port(self.fmt, self.net['id'])
+        port = self.deserialize(self.fmt, res)['port']
+        with db_api.CONTEXT_WRITER.using(self.ctx):
+            for resource_type in (ovn_const.TYPE_PORTS,
+                                  ovn_const.TYPE_ROUTER_PORTS):
+                self._create_initial_revision(port['id'], resource_type)
+
+        for resource_type in (ovn_const.TYPE_PORTS,
+                              ovn_const.TYPE_ROUTER_PORTS):
+            row = ovn_rn_db.get_revision_row(
+                self.ctx, port['id'], resource_type=resource_type)
+            self.assertEqual(resource_type, row.resource_type)
+            self.assertEqual(port['id'], row.resource_uuid)
+
+        self.assertRaises(ovn_rn_db.RevisionNumberNotDefined,
+                          ovn_rn_db.get_revision_row, self.ctx, port['id'])
+
 
 class TestMaintenancePlugin(test_securitygroup.SecurityGroupTestPlugin,
                             test_l3.TestL3NatBasePlugin):