OVSInterfaceDriver.plug_new should catch correct exceptions

Now that "IPWrapper.add_device_to_namespace" is implemented with
Pyroute2, the function should catch the correct exceptions:
- NetlinkError in case of duplicated interface
- OSError in case of corrupted namespace

Change-Id: I12b5710dc3bfdcc4c6b1e96bbfbfab9e59684065
Closes-Bug: #1856853

neutron/agent/linux/interface.py

@@ -21,6 +21,7 @@ from neutron_lib import constants
 from neutron_lib import exceptions
 from oslo_log import log as logging
 from oslo_utils import excutils
+from pyroute2.netlink import exceptions as pyroute2_exc
 import six
 
 from neutron.agent.common import ovs_lib
@@ -379,13 +380,11 @@ class OVSInterfaceDriver(LinuxInterfaceDriver):
             try:
                 namespace_obj = ip.ensure_namespace(namespace)
                 namespace_obj.add_device_to_namespace(ns_dev)
-            except exceptions.ProcessExecutionError:
-                # To prevent the namespace failure from blasting
-                # ovs, the ovs port created should be reverted
-                # When the namespace is corrupted, the ProcessExecutionError
-                # has execption message as:
-                # Exit code: 2; Stdin: ; Stdout: ; Stderr: RTNETLINK
-                # answers: Invalid argument
+            except (pyroute2_exc.NetlinkError, OSError):
+                # To prevent the namespace failure from blasting OVS, the OVS
+                # port creation should be reverted. Possible exceptions:
+                # - NetlinkError in case of duplicated interface
+                # - OSError in case of corrupted namespace
                 LOG.warning("Failed to plug interface %s into bridge %s, "
                             "cleaning up", device_name, bridge)
                 with excutils.save_and_reraise_exception():

neutron/tests/unit/agent/linux/test_interface.py

@@ -15,8 +15,8 @@
 
 import mock
 from neutron_lib import constants
-from neutron_lib import exceptions
 from oslo_utils import excutils
+from pyroute2.netlink import exceptions as pyroute2_exc
 
 from neutron.agent.common import ovs_lib
 from neutron.agent.linux import interface
@@ -476,20 +476,22 @@ class TestOVSInterfaceDriver(TestBase):
                     reraise = mock.patch.object(
                         excutils, 'save_and_reraise_exception')
                     reraise.start()
-                    proEr = exceptions.ProcessExecutionError('', 2)
-                    processExecutionError = mock.Mock(side_effect=proEr)
-                    ip = self.ip.return_value
-                    ip.ensure_namespace.side_effect = processExecutionError
-                    ovs.plug_new(
-                        '01234567-1234-1234-99',
-                        'port-1234',
-                        'tap0',
-                        'aa:bb:cc:dd:ee:ff',
-                        bridge=bridge,
-                        namespace=namespace,
-                        prefix='veth',
-                        mtu=9000)
-                    delete_port.assert_called_once_with('tap0')
+                    ip_wrapper = mock.Mock()
+                    for exception in (OSError(),
+                                      pyroute2_exc.NetlinkError(22)):
+                        ip_wrapper.ensure_namespace.side_effect = exception
+                        self.ip.return_value = ip_wrapper
+                        delete_port.reset_mock()
+                        ovs.plug_new(
+                            '01234567-1234-1234-99',
+                            'port-1234',
+                            'tap0',
+                            'aa:bb:cc:dd:ee:ff',
+                            bridge=bridge,
+                            namespace=namespace,
+                            prefix='veth',
+                            mtu=9000)
+                        delete_port.assert_called_once_with('tap0')
 
     def test_unplug(self):
         with mock.patch('neutron.agent.common.ovs_lib.OVSBridge') as ovs_br: