Handle NetworkInUse exception in api layer

In nova-network, if we delete an existing network with port already
associated, a 500 error will be reported and this is not helpful for
end user. This patch catch the network in use exception and raise
an HTTPConflict exception with formatted message.

Change-Id: I7361e461e0eecc0ef6e47fa8ef9a48a24b7d5dfd
Closes-Bug: #1294920

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

@@ -100,6 +100,8 @@ class NetworkController(wsgi.Controller):
         LOG.info(_("Deleting network with id %s") % id)
         try:
             self.network_api.delete(context, id)
+        except exception.NetworkInUse as e:
+            raise exc.HTTPConflict(explanation=e.format_message())
         except exception.NetworkNotFound:
             msg = _("Network not found")
             raise exc.HTTPNotFound(explanation=msg)

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

@@ -131,6 +131,8 @@ class NetworkController(object):
             response = exc.HTTPAccepted()
         except exception.PolicyNotAuthorized as e:
             raise exc.HTTPForbidden(explanation=str(e))
+        except exception.NetworkInUse as e:
+            raise exc.HTTPConflict(explanation=e.format_message())
         except exception.NetworkNotFound:
             msg = _("Network not found")
             raise exc.HTTPNotFound(explanation=msg)

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

@@ -106,6 +106,8 @@ class FakeNetworkAPI(object):
         self._vlan_is_disabled = True
 
     def delete(self, context, network_id):
+        if network_id == -1:
+            raise exception.NetworkInUse(network_id=network_id)
         for i, network in enumerate(self.networks):
             if network['id'] == network_id:
                 del self.networks[0]
@@ -304,6 +306,11 @@ class NetworksTest(test.NoDBTestCase):
         self.assertRaises(webob.exc.HTTPNotFound,
                           self.controller.delete, req, 100)
 
+    def test_network_delete_in_use(self):
+        req = fakes.HTTPRequest.blank('/v2/1234/os-networks/-1')
+        self.assertRaises(webob.exc.HTTPConflict,
+                          self.controller.delete, req, -1)
+
     def test_network_add_vlan_disabled(self):
         self.fake_network_api.disable_vlan()
         uuid = FAKE_NETWORKS[1]['uuid']

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

@@ -0,0 +1,36 @@
+# Copyright 2014 IBM Corp.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import mock
+import webob
+
+from nova.api.openstack.compute.contrib import os_tenant_networks as networks
+from nova import exception
+from nova import test
+from nova.tests.api.openstack import fakes
+
+
+class NetworksTest(test.NoDBTestCase):
+
+    def setUp(self):
+        super(NetworksTest, self).setUp()
+        self.controller = networks.NetworkController()
+
+    @mock.patch('nova.network.api.API.delete',
+                side_effect=exception.NetworkInUse(network_id=1))
+    def test_network_delete_in_use(self, mock_delete):
+        req = fakes.HTTPRequest.blank('/v2/1234/os-tenant-networks/1')
+
+        self.assertRaises(webob.exc.HTTPConflict,
+                          self.controller.delete, req, 1)