Fix AXFR loop when updating secondary zone

When a secondary zone is created or updated we trigger an AXFR,
this AXFR then goes ahead and updates the zone. This then causes
the AXFR code to get triggered again as it thinks the masters
has changed.

We fix this by ensuring that when we update the zone from the AXFR
code that we always reset the masters field.

Partial-Bug: #1856442
Change-Id: Ifc2efb5a6d1091ff16373f3cbe3846f5e4371272

designate/central/service.py

@@ -819,9 +819,7 @@ class Service(service.RPCService):
         self.worker_api.create_zone(context, zone)
 
         if zone.type == constants.ZONE_SECONDARY:
-            xfr_zone = copy.deepcopy(zone)
-            xfr_zone.obj_reset_changes(recursive=True)
-            self.worker_api.perform_zone_xfr(context, xfr_zone)
+            self.worker_api.perform_zone_xfr(context, zone)
 
         # If zone is a superzone, update subzones
         # with new parent IDs

designate/tests/unit/test_central/test_basic.py

@@ -1622,42 +1622,6 @@ class CentralZoneTestCase(CentralBasic):
             refresh_time = central_service._generate_soa_refresh_interval()
             self.assertEqual(3563, refresh_time)
 
-    @patch.object(objects.Zone, 'obj_reset_changes')
-    def test_create_secondary_zone(self, mock_obj_reset_changes):
-        self.service._enforce_zone_quota = mock.Mock()
-        self.service._create_zone_in_storage = mock.Mock(
-            return_value=objects.Zone(name='example.com.', type='SECONDARY'))
-        self.service._is_valid_zone_name = mock.Mock()
-        self.service._is_valid_ttl = mock.Mock()
-        self.service._is_subzone = mock.Mock(return_value=False)
-        self.service._is_superzone = mock.Mock(return_value=[])
-        self.service.storage.get_pool.return_value = RoObject(
-            ns_records=[RoObject()])
-        self.useFixture(
-            fixtures.MockPatchObject(
-                self.service.storage,
-                'find_pools',
-                return_value=objects.PoolList.from_list(
-                    [
-                        {'id': '94ccc2c1-d751-44fe-b57f-8894c9f5c842'}
-                    ]
-                )
-            )
-        )
-        output = self.service.create_zone(
-            self.context,
-            objects.Zone(
-                tenant_id='1',
-                name='example.com.',
-                ttl=60,
-                pool_id=CentralZoneTestCase.pool__id,
-                refresh=0,
-                type='SECONDARY'
-            )
-        )
-        self.assertEqual('example.com.', output.name)
-        mock_obj_reset_changes.assert_called_once_with(recursive=True)
-
 
 class IsSubzoneTestCase(CentralBasic):
     def setUp(self):

designate/tests/unit/workers/test_xfr.py

@@ -60,6 +60,38 @@ class TestXfr(oslotest.base.BaseTestCase):
             self.assertIn('transferred_at', zone.obj_what_changed())
             self.assertNotIn('name', zone.obj_what_changed())
 
+    @mock.patch.object(dnsutils, 'do_axfr', mock.Mock())
+    def test_zone_sync_not_change_masters(self):
+        recordset = objects.RecordSet(
+            name='www.example.test.', type='TXT',
+            records=objects.RecordList(objects=[
+                objects.Record(data='foo bar'),
+            ])
+        )
+        zone = objects.Zone(
+            id='7592878e-4ade-40de-8b8d-699b871ee6fa',
+            name='example.com.',
+            serial=1,
+            masters=objects.ZoneMasterList.from_list(
+                [{'host': '127.0.0.1', 'port': 53}, ]
+            ),
+            type=constants.ZONE_SECONDARY,
+            recordsets=objects.RecordSetList(objects=[]),
+        )
+
+        self.xfr = worker_zone.ZoneXfr(mock.Mock(), self.context, zone)
+        self.xfr._central_api = mock.Mock()
+
+        with mock.patch.object(dnsutils, 'from_dnspython_zone') as mock_dns:
+            zone.recordsets = objects.RecordSetList(objects=[recordset])
+            zone.masters = objects.ZoneMasterList()
+            mock_dns.return_value = zone
+
+            self.xfr()
+
+            self.assertIn('transferred_at', zone.obj_what_changed())
+            self.assertNotIn('masters', zone.obj_what_changed())
+
     @mock.patch.object(dnsutils, 'do_axfr', mock.Mock())
     def test_zone_sync_using_list_of_servers(self):
         zone = objects.Zone(

designate/worker/tasks/zone.py

@@ -183,7 +183,7 @@ class ZoneXfr(base.Task):
 
         self.zone.update(dnsutils.from_dnspython_zone(dnspython_zone))
         self.zone.transferred_at = timeutils.utcnow()
-        self.zone.obj_reset_changes(['name'])
+        self.zone.obj_reset_changes(['name', 'masters'], recursive=True)
         self.central_api.update_zone(
             self.context, self.zone, increment_serial=False
         )