Fix incorrect exception raised during evacuate

This change creates a new exception 'ComputeServiceInUse'
to better represent the error when trying to evacuate
an instance with a running compute service. Also, it adds
a missing test for evacuate API v3.

Closes-Bug: #1230282

Change-Id: I1c4edb01e84cd2a89879bca9c99f5e38f47e16fb

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

@@ -84,7 +84,7 @@ class Controller(wsgi.Controller):
                     'evacuate')
         except exception.InstanceNotFound as e:
             raise exc.HTTPNotFound(explanation=e.format_message())
-        except exception.ComputeServiceUnavailable as e:
+        except exception.ComputeServiceInUse as e:
             raise exc.HTTPBadRequest(explanation=e.format_message())
 
         if password:

nova/api/openstack/compute/plugins/v3/evacuate.py

@@ -86,7 +86,7 @@ class EvacuateController(wsgi.Controller):
                     'evacuate')
         except exception.InstanceNotFound as e:
             raise exc.HTTPNotFound(explanation=e.format_message())
-        except exception.ComputeServiceUnavailable as e:
+        except exception.ComputeServiceInUse as e:
             raise exc.HTTPBadRequest(explanation=e.format_message())
 
         return {'admin_password': password}

nova/compute/api.py

@@ -2899,7 +2899,7 @@ class API(base.Base):
             msg = (_('Instance compute service state on %s '
                      'expected to be down, but it was up.') % inst_host)
             LOG.error(msg)
-            raise exception.ComputeServiceUnavailable(msg)
+            raise exception.ComputeServiceInUse(host=inst_host)
 
         instance = self.update(context, instance, expected_task_state=None,
                                task_state=task_states.REBUILDING)

nova/exception.py

@@ -393,6 +393,10 @@ class ComputeServiceUnavailable(ServiceUnavailable):
     msg_fmt = _("Compute service of %(host)s is unavailable at this time.")
 
 
+class ComputeServiceInUse(NovaException):
+    msg_fmt = _("Compute service of %(host)s is still in use.")
+
+
 class UnableToMigrateToSelf(Invalid):
     msg_fmt = _("Unable to migrate instance (%(instance_id)s) "
                 "to current host (%(host)s).")

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

@@ -126,7 +126,7 @@ class EvacuateTest(test.NoDBTestCase):
             })
 
         def fake_evacuate(*args, **kwargs):
-            raise exception.ComputeServiceUnavailable("Service Unavailable")
+            raise exception.ComputeServiceInUse("Service still in use")
 
         self.stubs.Set(compute_api.API, 'evacuate', fake_evacuate)
 

nova/tests/api/openstack/compute/plugins/v3/test_evacuate.py

@@ -140,6 +140,19 @@ class EvacuateTest(test.NoDBTestCase):
         resp_json = jsonutils.loads(res.body)
         self.assertEqual(resp_json['admin_password'], None)
 
+    def test_evacuate_with_active_service(self):
+        req, app = self._gen_request_with_app({'host': 'my_host',
+                                               'on_shared_storage': 'false',
+                                               'admin_password': 'MyNewPass'})
+
+        def fake_evacuate(*args, **kwargs):
+            raise exception.ComputeServiceInUse("Service still in use")
+
+        self.stubs.Set(compute_api.API, 'evacuate', fake_evacuate)
+
+        res = req.get_response(app)
+        self.assertEqual(res.status_int, 400)
+
     def test_not_admin(self):
         req, app = self._gen_request_with_app({'host': 'my_host',
                                                'on_shared_storage': 'True'},

nova/tests/compute/test_compute.py

@@ -8057,7 +8057,7 @@ class ComputeAPITestCase(BaseTestCase):
         self.stubs.Set(self.compute_api.servicegroup_api, 'service_is_up',
                 fake_service_is_up)
 
-        self.assertRaises(exception.ComputeServiceUnavailable,
+        self.assertRaises(exception.ComputeServiceInUse,
                 self.compute_api.evacuate, self.context.elevated(), instance,
                 host='fake_dest_host', on_shared_storage=True,
                 admin_password=None)