[ovn]: Fix l3_plugin.add_router_interface to comply with RouterPluginBase

OVNL3RouterPlugin inherits from L3_NAT_dbonly_mixin, which inherits
from neutron.extensions.l3.RouterPluginBase

As maintenance task expects OVNL3RouterPlugin to behave as
RouterPluginBase, the add_router_interface should have the signature:

  add_router_interface(self, context, router_id, interface_info)

Note: With this change, the default behavior of OVNL3RouterPlugin's
_add_neutron_router_interface becomes idem-potent: multiple calls to add
the same interface will not fail. Because of that, the unit test
test_router_add_interface_dup_port no longer makes sense and is being
removed.

Closes-Bug: #1876148
Change-Id: I8010113b4d8c66ecbccf3126f322a8836d92e7ba
Signed-off-by: Flavio Fernandes <flaviof@redhat.com>

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

@@ -398,7 +398,7 @@ class DBInconsistenciesPeriodics(SchemaAwarePeriodicsBase):
     def _create_lrouter_port(self, context, port):
         router_id = port['device_id']
         self._ovn_client._l3_plugin.add_router_interface(
-            context, router_id, {'port_id': port['id']}, may_exist=True)
+            context, router_id, {'port_id': port['id']})
 
     def _check_subnet_global_dhcp_opts(self):
         inconsistent_subnets = []

neutron/services/ovn_l3/plugin.py

@@ -159,14 +159,12 @@ class OVNL3RouterPlugin(service_base.ServicePluginBase,
                     context, {'router': original_router})
 
     def _add_neutron_router_interface(self, context, router_id,
-                                      interface_info, may_exist=False):
+                                      interface_info):
         try:
             router_interface_info = (
                 super(OVNL3RouterPlugin, self).add_router_interface(
                     context, router_id, interface_info))
         except n_exc.PortInUse:
-            if not may_exist:
-                raise
             # NOTE(lucasagomes): If the port is already being used it means
             # the interface has been created already, let's just fetch it from
             # the database. Perhaps the code below should live in Neutron
@@ -183,10 +181,9 @@ class OVNL3RouterPlugin(service_base.ServicePluginBase,
 
         return router_interface_info
 
-    def add_router_interface(self, context, router_id, interface_info,
-                             may_exist=False):
+    def add_router_interface(self, context, router_id, interface_info=None):
         router_interface_info = self._add_neutron_router_interface(
-            context, router_id, interface_info, may_exist=may_exist)
+            context, router_id, interface_info)
         try:
             self._ovn_client.create_router_port(
                 context, router_id, router_interface_info)

neutron/tests/unit/extensions/test_l3.py

@@ -1457,38 +1457,6 @@ class L3NatTestCaseBase(L3NatTestCaseMixin):
                                               exc.HTTPBadRequest.code)
                 self.assertFalse(plugin.get_ports(context.get_admin_context()))
 
-    def test_router_add_interface_dup_port(self):
-        '''This tests that if multiple routers add one port as their
-        interfaces. Only the first router's interface would be added
-        to this port. All the later requests would return exceptions.
-        '''
-        with self.router() as r1, self.router() as r2, self.network() as n:
-            with self.subnet(network=n) as s:
-                with self.port(subnet=s) as p:
-                    self._router_interface_action('add',
-                                                  r1['router']['id'],
-                                                  None,
-                                                  p['port']['id'])
-                    # mock out the sequential check
-                    plugin = 'neutron.db.l3_db.L3_NAT_dbonly_mixin'
-                    check_p = mock.patch(plugin + '._check_router_port',
-                                         port_id=p['port']['id'],
-                                         device_id=r2['router']['id'],
-                                         return_value=p['port'])
-                    checkport = check_p.start()
-                    # do regular checkport after first skip
-                    checkport.side_effect = check_p.stop()
-                    self._router_interface_action('add',
-                                                  r2['router']['id'],
-                                                  None,
-                                                  p['port']['id'],
-                                                  exc.HTTPConflict.code)
-                    # clean-up
-                    self._router_interface_action('remove',
-                                                  r1['router']['id'],
-                                                  None,
-                                                  p['port']['id'])
-
     def _assert_body_port_id_and_update_port(self, body, mock_update_port,
                                              port_id, device_id):
         self.assertNotIn('port_id', body)

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

@@ -276,8 +276,7 @@ class TestDBInconsistenciesPeriodics(testlib_api.SqlTestCaseLight,
         self.periodic._create_lrouter_port(self.ctx, port)
         l3_mock = self.periodic._ovn_client._l3_plugin
         l3_mock.add_router_interface.assert_called_once_with(
-            self.ctx, port['device_id'], {'port_id': port['id']},
-            may_exist=True)
+            self.ctx, port['device_id'], {'port_id': port['id']})
 
     @mock.patch.object(maintenance.LOG, 'debug')
     def test__log_maintenance_inconsistencies(self, mock_log):