Returns 503 if the NVP cluster is in maintenance mode

If the NVP cluster is in 'readonly-mode' during a maintenance
window, some NVP operations may raise a Forbidden error. This
is not currently handled correctly, and Neutron server ends up
returning 500. This patch addresses the problem by ensuring
the right error code is returned.

Fixes bug 1204715

Change-Id: Ibd2cac8286a0978a95f9006142c2a405053dfa00

neutron/common/exceptions.py

@@ -59,7 +59,7 @@ class NotAuthorized(NeutronException):
 
 
 class ServiceUnavailable(NeutronException):
-    message = _("The service is unailable")
+    message = _("The service is unavailable")
 
 
 class AdminRequired(NotAuthorized):

neutron/plugins/nicira/NeutronPlugin.py

@@ -757,7 +757,9 @@ class NvpPluginV2(db_base_plugin_v2.NeutronDbPluginV2,
         base.FAULT_MAP.update({nvp_exc.NvpInvalidNovaZone:
                                webob.exc.HTTPBadRequest,
                                nvp_exc.NvpNoMorePortsException:
-                               webob.exc.HTTPBadRequest})
+                               webob.exc.HTTPBadRequest,
+                               nvp_exc.MaintenanceInProgress:
+                               webob.exc.HTTPServiceUnavailable})
 
     def _handle_provider_create(self, context, attrs):
         # NOTE(salvatore-orlando): This method has been borrowed from

neutron/plugins/nicira/NvpApiClient.py

@@ -147,7 +147,7 @@ class NVPApiHelper(client_eventlet.NvpApiClientEventlet):
         if status in self.error_codes:
             LOG.error(_("Received error code: %s"), status)
             LOG.error(_("Server Error Message: %s"), response.body)
-            self.error_codes[status](self)
+            self.error_codes[status](self, response)
 
         # Continue processing for non-error condition.
         if (status != httplib.OK and status != httplib.CREATED
@@ -174,19 +174,22 @@ class NVPApiHelper(client_eventlet.NvpApiClientEventlet):
                           'Plugin might not work as expected.'))
         return self._nvp_version
 
-    def fourZeroFour(self):
+    def fourZeroFour(self, response=None):
         raise ResourceNotFound()
 
-    def fourZeroNine(self):
+    def fourZeroNine(self, response=None):
         raise Conflict()
 
-    def fiveZeroThree(self):
+    def fiveZeroThree(self, response=None):
         raise ServiceUnavailable()
 
-    def fourZeroThree(self):
-        raise Forbidden()
+    def fourZeroThree(self, response=None):
+        if 'read-only' in response.body:
+            raise ReadOnlyMode()
+        else:
+            raise Forbidden()
 
-    def zero(self):
+    def zero(self, response=None):
         raise NvpApiException()
 
     # TODO(del): ensure error_codes are handled/raised appropriately
@@ -247,5 +250,9 @@ class Forbidden(NvpApiException):
                 "referenced resource.")
 
 
+class ReadOnlyMode(Forbidden):
+    message = _("Create/Update actions are forbidden when in read-only mode.")
+
+
 class RequestTimeout(NvpApiException):
     message = _("The request has timed out.")

neutron/plugins/nicira/common/exceptions.py

@@ -56,3 +56,9 @@ class NvpNatRuleMismatch(NvpPluginException):
 
 class NvpInvalidAttachmentType(NvpPluginException):
     message = _("Invalid NVP attachment type '%(attachment_type)s'")
+
+
+class MaintenanceInProgress(NvpPluginException):
+    message = _("The networking backend is currently in maintenance mode and "
+                "therefore unable to accept requests which modify its state. "
+                "Please try later.")

neutron/plugins/nicira/nvplib.py

@@ -950,6 +950,8 @@ def do_request(*args, **kwargs):
             return json.loads(res)
     except NvpApiClient.ResourceNotFound:
         raise exception.NotFound()
+    except NvpApiClient.ReadOnlyMode:
+        raise nvp_exc.MaintenanceInProgress()
 
 
 def mk_body(**kwargs):

neutron/tests/unit/nicira/test_nicira_plugin.py

@@ -30,6 +30,7 @@ from neutron.extensions import providernet as pnet
 from neutron.extensions import securitygroup as secgrp
 from neutron import manager
 from neutron.openstack.common import uuidutils
+from neutron.plugins.nicira.common import exceptions as nvp_exc
 from neutron.plugins.nicira.dbexts import nicira_db
 from neutron.plugins.nicira.dbexts import nicira_qos_db as qos_db
 from neutron.plugins.nicira.extensions import nvp_networkgw
@@ -192,6 +193,22 @@ class TestNiciraPortsV2(NiciraPluginV2TestCase,
                                   webob.exc.HTTPInternalServerError.code)
                 self._verify_no_orphan_left(net_id)
 
+    def test_create_port_maintenance_returns_503(self):
+        with self.network() as net:
+            with mock.patch.object(nvplib, 'do_request',
+                                   side_effect=nvp_exc.MaintenanceInProgress):
+                data = {'port': {'network_id': net['network']['id'],
+                                 'admin_state_up': False,
+                                 'fixed_ips': [],
+                                 'tenant_id': self._tenant_id}}
+                plugin = manager.NeutronManager.get_plugin()
+                with mock.patch.object(plugin, 'get_network',
+                                       return_value=net['network']):
+                    port_req = self.new_create_request('ports', data, self.fmt)
+                    res = port_req.get_response(self.api)
+                    self.assertEqual(webob.exc.HTTPServiceUnavailable.code,
+                                     res.status_int)
+
 
 class TestNiciraNetworksV2(test_plugin.TestNetworksV2,
                            NiciraPluginV2TestCase):
@@ -276,6 +293,17 @@ class TestNiciraNetworksV2(test_plugin.TestNetworksV2,
             # Assert neutron name is not truncated
             self.assertEqual(net['network']['name'], name)
 
+    def test_create_network_maintenance_returns_503(self):
+        data = {'network': {'name': 'foo',
+                            'admin_state_up': True,
+                            'tenant_id': self._tenant_id}}
+        with mock.patch.object(nvplib, 'do_request',
+                               side_effect=nvp_exc.MaintenanceInProgress):
+            net_req = self.new_create_request('networks', data, self.fmt)
+            res = net_req.get_response(self.api)
+            self.assertEqual(webob.exc.HTTPServiceUnavailable.code,
+                             res.status_int)
+
 
 class NiciraPortSecurityTestCase(psec.PortSecurityDBTestCase):
 
@@ -615,6 +643,23 @@ class TestNiciraL3NatTestCase(test_l3_plugin.L3NatDBTestCase,
                 self.assertIsNone(body['floatingip']['port_id'])
                 self.assertIsNone(body['floatingip']['fixed_ip_address'])
 
+    def test_create_router_maintenance_returns_503(self):
+        with self._create_l3_ext_network() as net:
+            with self.subnet(network=net) as s:
+                with mock.patch.object(
+                    nvplib,
+                    'do_request',
+                    side_effect=nvp_exc.MaintenanceInProgress):
+                    data = {'router': {'tenant_id': 'whatever'}}
+                    data['router']['name'] = 'router1'
+                    data['router']['external_gateway_info'] = {
+                        'network_id': s['subnet']['network_id']}
+                    router_req = self.new_create_request(
+                        'routers', data, self.fmt)
+                    res = router_req.get_response(self.ext_api)
+                    self.assertEqual(webob.exc.HTTPServiceUnavailable.code,
+                                     res.status_int)
+
 
 class NvpQoSTestExtensionManager(object):
 

neutron/tests/unit/nicira/test_nvplib.py

@@ -1318,7 +1318,7 @@ class TestNvplibLogicalPorts(NvplibTestCase):
             self.assertIn(res_port['uuid'], switch_port_uuids)
 
 
-class TestNvplibClusterVersion(NvplibTestCase):
+class TestNvplibClusterManagement(NvplibTestCase):
 
     def test_get_cluster_version(self):
 
@@ -1330,7 +1330,6 @@ class TestNvplibClusterVersion(NvplibTestCase):
                 return {'result_count': 1,
                         'results': [{'uuid': 'xyz'}]}
 
-        # mock do_request
         with mock.patch.object(nvplib, 'do_request', new=fakedorequest):
             version = nvplib.get_cluster_version('whatever')
             self.assertEqual(version, '3.0')
@@ -1341,11 +1340,17 @@ class TestNvplibClusterVersion(NvplibTestCase):
             if 'node' in uri:
                 return {'result_count': 0}
 
-        # mock do_request
         with mock.patch.object(nvplib, 'do_request', new=fakedorequest):
             version = nvplib.get_cluster_version('whatever')
             self.assertIsNone(version)
 
+    def test_cluster_in_readonly_mode(self):
+        with mock.patch.object(self.fake_cluster.api_client,
+                               'request',
+                               side_effect=NvpApiClient.ReadOnlyMode):
+            self.assertRaises(nvp_exc.MaintenanceInProgress,
+                              nvplib.do_request, cluster=self.fake_cluster)
+
 
 def _nicira_method(method_name, module_name='nvplib'):
     return '%s.%s.%s' % ('neutron.plugins.nicira', module_name, method_name)