Handle conflict from neutron when addFloatingIP fails

Neutron can raise a Conflict exception when attempting
to associate a floating IP to a server when the fixed
address is already associated to another floating IP.
This has always resulted in a 400 response, however, it
would also trace an ERROR in the nova-api logs, which is
something we shouldn't be doing for an expected type of
failure.

This handles the Conflict in the neutronv2 API client code
and re-raises an exception that the REST API controller code
can handle and return as a 400 without the stacktrace in the
logs.

Change-Id: I27d3241300f75e2aa79a32348a3843e09123cb10
Closes-Bug: #1693576

2 files changed, 39 insertions, 0 deletions

diff --git a/nova/tests/unit/api/openstack/compute/test_floating_ips.py b/nova/tests/unit/api/openstack/compute/test_floating_ips.py
index 1cb214142d..0fc45b6f72 100644
--- a/nova/tests/unit/api/openstack/compute/test_floating_ips.py
+++ b/nova/tests/unit/api/openstack/compute/test_floating_ips.py
@@ -634,6 +634,15 @@ class FloatingIpTestV21(test.TestCase):
                           self.manager._add_floating_ip, self.fake_req,
                           TEST_INST, body=body)
 
+    @mock.patch.object(network.api.API, 'associate_floating_ip',
+                       side_effect=exception.FloatingIpAssociateFailed(
+                           address='10.10.10.11'))
+    def test_associate_floating_ip_failed(self, associate_mock):
+        body = dict(addFloatingIp=dict(address='10.10.10.11'))
+        self.assertRaises(webob.exc.HTTPBadRequest,
+                          self.manager._add_floating_ip, self.fake_req,
+                          TEST_INST, body=body)
+
     def test_associate_floating_ip_bad_address_key(self):
         body = dict(addFloatingIp=dict(bad_address='10.10.10.11'))
         req = fakes.HTTPRequest.blank('/v2/fake/servers/test_inst/action')
diff --git a/nova/tests/unit/network/test_neutronv2.py b/nova/tests/unit/network/test_neutronv2.py
index 18bb9c0aa2..9f99638bd8 100644
--- a/nova/tests/unit/network/test_neutronv2.py
+++ b/nova/tests/unit/network/test_neutronv2.py
@@ -4783,6 +4783,36 @@ class TestNeutronv2WithMock(test.TestCase):
             self.context, pci_requests, requested_networks)
         self.assertFalse(getclient.called)
 
+    @mock.patch.object(neutronapi, 'get_client')
+    def test_associate_floating_ip_conflict(self, mock_get_client):
+        """Tests that if Neutron raises a Conflict we handle it and re-raise
+        as a nova-specific exception.
+        """
+        mock_get_client.return_value.update_floatingip.side_effect = (
+            exceptions.Conflict(
+                "Cannot associate floating IP 172.24.5.15 "
+                "(60a8f00b-4404-4518-ad66-00448a155904) with port "
+                "95ee1ffb-6d41-447d-a90e-b6ce5d9c92fa using fixed IP "
+                "10.1.0.9, as that fixed IP already has a floating IP on "
+                "external network bdcda645-f612-40ab-a956-0d95af42cf7c.")
+        )
+        with test.nested(
+            mock.patch.object(
+                self.api, '_get_port_id_by_fixed_address',
+                return_value='95ee1ffb-6d41-447d-a90e-b6ce5d9c92fa'),
+            mock.patch.object(
+                self.api, '_get_floating_ip_by_address',
+                return_value={'id': uuids.floating_ip_id})
+        ) as (
+            _get_floating_ip_by_address, _get_port_id_by_fixed_address
+        ):
+            instance = fake_instance.fake_instance_obj(
+                self.context, uuid='2a2200ec-02fe-484e-885b-9bae7b21ecba')
+            self.assertRaises(exception.FloatingIpAssociateFailed,
+                              self.api.associate_floating_ip,
+                              self.context, instance,
+                              '172.24.5.15', '10.1.0.9')
+
 
 class TestNeutronv2ModuleMethods(test.NoDBTestCase):