Handle over quota exception from Neutron

When using the floating IP in Nova with Neutron, and
a quota limit is exceeded in Neutron, the exception from
the Neutron client results in Nova generating a 500 error.
This is unhelpful to user, and not consistent with nova-networking
Return FloatingIPExceedLimit exception when quota exceeded.

Change I8788993578ac872da9f676fe3e2fb8f98414289d at neutronclient
add OverQuotaClient exception and it is used in this patch

Change-Id: Ieb90521cf231acae8b5a9920acf6c77f2e34ef67
Closes-Bug: #1210598
Closes-Bug: #1301117

nova/api/openstack/compute/contrib/floating_ips.py

@@ -163,6 +163,12 @@ class FloatingIPController(object):
             else:
                 msg = _("No more floating ips available.")
             raise webob.exc.HTTPNotFound(explanation=msg)
+        except exception.FloatingIpLimitExceeded:
+            if pool:
+                msg = _("IP allocation over quota in pool %s.") % pool
+            else:
+                msg = _("IP allocation over quota.")
+            raise webob.exc.HTTPForbidden(explanation=msg)
 
         return _translate_floating_ip_view(ip)
 

nova/network/neutronv2/api.py

@@ -975,15 +975,15 @@ class API(base_api.NetworkAPI):
         pool = pool or CONF.default_floating_pool
         pool_id = self._get_floating_ip_pool_id_by_name_or_id(client, pool)
 
-        # TODO(amotoki): handle exception during create_floatingip()
-        # At this timing it is ensured that a network for pool exists.
-        # quota error may be returned.
         param = {'floatingip': {'floating_network_id': pool_id}}
         try:
             fip = client.create_floatingip(param)
         except (neutron_client_exc.IpAddressGenerationFailureClient,
                 neutron_client_exc.ExternalIpAddressExhaustedClient) as e:
             raise exception.NoMoreFloatingIps(unicode(e))
+        except neutron_client_exc.OverQuotaClient as e:
+            raise exception.FloatingIpLimitExceeded(unicode(e))
+
         return fip['floatingip']['floating_ip_address']
 
     def _get_floating_ip_by_address(self, client, address):

nova/tests/api/openstack/compute/contrib/test_floating_ips.py

@@ -325,6 +325,25 @@ class FloatingIpTest(test.TestCase):
         self.assertIn('No more floating ips in pool non_existent_pool',
                       ex.explanation)
 
+    @mock.patch('nova.network.api.API.allocate_floating_ip',
+                side_effect=exception.FloatingIpLimitExceeded())
+    def test_floating_ip_allocate_over_quota(self, allocate_mock):
+        req = fakes.HTTPRequest.blank('/v2/fake/os-floating-ips')
+        ex = self.assertRaises(webob.exc.HTTPForbidden,
+                               self.controller.create, req)
+
+        self.assertIn('IP allocation over quota', ex.explanation)
+
+    @mock.patch('nova.network.api.API.allocate_floating_ip',
+                side_effect=exception.FloatingIpLimitExceeded())
+    def test_floating_ip_allocate_quota_exceed_in_pool(self, allocate_mock):
+        req = fakes.HTTPRequest.blank('/v2/fake/os-floating-ips')
+        ex = self.assertRaises(webob.exc.HTTPForbidden,
+            self.controller.create, req, {'pool': 'non_existent_pool'})
+
+        self.assertIn('IP allocation over quota in pool non_existent_pool.',
+                      ex.explanation)
+
     def test_floating_ip_allocate(self):
         def fake1(*args, **kwargs):
             pass

nova/tests/network/test_neutronv2.py

@@ -2311,6 +2311,21 @@ class TestNeutronv2WithMock(test.TestCase):
 
             list_ports_mock.assert_called_once_with(**list_port_mock_params)
 
+    def test_allocate_floating_ip_exceed_limit(self):
+        # Verify that the correct exception is thrown when quota exceed
+        pool_name = 'dummy'
+        api = neutronapi.API()
+        with contextlib.nested(
+            mock.patch.object(client.Client, 'create_floatingip'),
+            mock.patch.object(api,
+                '_get_floating_ip_pool_id_by_name_or_id')) as (
+            create_mock, get_mock):
+            create_mock.side_effect = neutronv2.exceptions.OverQuotaClient()
+
+            self.assertRaises(exception.FloatingIpLimitExceeded,
+                          api.allocate_floating_ip,
+                          self.context, pool_name)
+
 
 class TestNeutronv2ModuleMethods(test.TestCase):