Merge "libvirt: ignore conflict when defining network filters"

nova/tests/unit/virt/libvirt/test_firewall.py

@@ -713,3 +713,40 @@ class NWFilterTestCase(test.NoDBTestCase):
         self.assertEqual(2, debug.call_count)
         self.assertEqual(u"Cannot find UUID for filter '%(name)s': '%(e)s'",
                          debug.call_args_list[0][0][0])
+
+    def test_define_filter_already_exists(self):
+        """Tests that we ignore a libvirt error when the nw filter already
+        exists for a given name.
+        """
+        error = fakelibvirt.libvirtError('already exists')
+        error.err = (fakelibvirt.VIR_ERR_OPERATION_FAILED, None,
+                     "filter 'nova-no-nd-reflection' already exists with uuid "
+                     "e740c5ec-c715-4f73-9874-630cc73d4ac2",)
+        with mock.patch.object(self.fw._conn, 'nwfilterDefineXML',
+                               side_effect=error) as define:
+            self.fw._define_filter(mock.sentinel.xml)
+        define.assert_called_once_with(mock.sentinel.xml)
+
+    def test_define_filter_fails_wrong_message(self):
+        """Tests that we reraise the libvirt error for an operational failure
+        if the error message is something unexpected.
+        """
+        error = fakelibvirt.libvirtError('already exists')
+        error.err = (fakelibvirt.VIR_ERR_OPERATION_FAILED, None, 'oops',)
+        with mock.patch.object(self.fw._conn, 'nwfilterDefineXML',
+                               side_effect=error) as define:
+            self.assertRaises(fakelibvirt.libvirtError,
+                              self.fw._define_filter, mock.sentinel.xml)
+        define.assert_called_once_with(mock.sentinel.xml)
+
+    def test_define_filter_fails_wrong_code(self):
+        """Tests that we reraise the libvirt error for an operational failure
+        if the error code is something unexpected.
+        """
+        error = fakelibvirt.libvirtError('already exists')
+        error.err = (fakelibvirt.VIR_ERR_OPERATION_TIMEOUT, None, 'timeout',)
+        with mock.patch.object(self.fw._conn, 'nwfilterDefineXML',
+                               side_effect=error) as define:
+            self.assertRaises(fakelibvirt.libvirtError,
+                              self.fw._define_filter, mock.sentinel.xml)
+        define.assert_called_once_with(mock.sentinel.xml)

nova/virt/libvirt/firewall.py

@@ -20,6 +20,7 @@ import uuid
 from eventlet import greenthread
 from lxml import etree
 from oslo_log import log as logging
+from oslo_utils import excutils
 from oslo_utils import importutils
 
 from nova.cloudpipe import pipelib
@@ -259,7 +260,20 @@ class NWFilterFirewall(base_firewall.FirewallDriver):
     def _define_filter(self, xml):
         if callable(xml):
             xml = xml()
-        self._conn.nwfilterDefineXML(xml)
+        try:
+            self._conn.nwfilterDefineXML(xml)
+        except libvirt.libvirtError as ex:
+            with excutils.save_and_reraise_exception() as ctxt:
+                errcode = ex.get_error_code()
+                if errcode == libvirt.VIR_ERR_OPERATION_FAILED:
+                    # Since libvirt 1.2.7 this operation can fail if the filter
+                    # with the same name already exists for the given uuid.
+                    # Unfortunately there is not a specific error code for this
+                    # so we have to parse the error message to see if that was
+                    # the failure.
+                    errmsg = ex.get_error_message()
+                    if 'already exists with uuid' in errmsg:
+                        ctxt.reraise = False
 
     def unfilter_instance(self, instance, network_info):
         """Clear out the nwfilter rules."""