Set result when lswitch port exist

A TypeError was thrown during a synchronization
command(neutron-ovn-db-sync-util) execution. From the code[1][2], it
can be seen. The result of the AddLSwitchPortCommand command will be
passed as a parameter to the UpdateLSwitchPortQosOptionsCommand. But
if the logical switch port exists, the result will not be set. Therefore,
when the UpdateLSwitchPortQosOptionsCommand is executed, the port_id
will not be obtained, thereby throwing an exception TypeError.
This patch sets the result when the logical switch port exists.

[1] https://opendev.org/openstack/neutron/src/commit/b71f7ceb3e97e021cb9aeda757a7ffdeeff80e8e/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovn_client.py#L488
[2] https://opendev.org/openstack/neutron/src/commit/b71f7ceb3e97e021cb9aeda757a7ffdeeff80e8e/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovn_client.py#L505

Closes-Bug: #2025202

Change-Id: Ie09d9d3e5efa8a57ad11655c2eb31d2604bab326
(cherry picked from commit 65bbbce)

Author: zhouhenglc

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

@@ -124,6 +124,7 @@ def run_idl(self, txn):
                                          'Logical_Switch_Port', 'name',
                                          self.lport, None)
             if port:
+                self.result = port.uuid
                 return
 
         port = txn.insert(self.api._tables['Logical_Switch_Port'])

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

@@ -66,3 +66,21 @@ def check_metadata_port(enable_dhcp):
             # because it checks first if the metadata port exists.
             ovn_client.create_metadata_port(self.context, network)
             check_metadata_port(enable_dhcp)
+
+    def test_create_port(self):
+        with self.network('test-ovn-client') as net:
+            with self.subnet(net) as subnet:
+                with self.port(subnet) as port:
+                    port_data = port['port']
+                    nb_ovn = self.mech_driver.nb_ovn
+                    lsp = nb_ovn.lsp_get(port_data['id']).execute()
+                    # The logical switch port has been created during the
+                    # port creation.
+                    self.assertIsNotNone(lsp)
+                    ovn_client = self.mech_driver._ovn_client
+                    port_data = self.plugin.get_port(self.context,
+                                                     port_data['id'])
+                    # Call the create_port again to ensure that the create
+                    # command automatically checks for existing logical
+                    # switch ports
+                    ovn_client.create_port(self.context, port_data)

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

@@ -105,7 +105,7 @@ def test_lswitch_not_found(self):
 
     def test_lswitch_port_exists(self):
         with mock.patch.object(idlutils, 'row_by_value',
-                               return_value=mock.ANY):
+                               return_value=mock.Mock()):
             cmd = commands.AddLSwitchPortCommand(
                 self.ovn_api, 'fake-lsp', 'fake-lswitch', may_exist=True)
             cmd.run_idl(self.transaction)