Perform fault wrapping in the openstack WSGI controller. This allows

us to just raise webob Exceptions in OS API controllers with the
appropriate explanations set. This resolves some inconsistencies
with exception raising and returning that could cause HTML output
to occur when an exception was raised.

14 files changed, 89 insertions, 101 deletions

diff --git a/nova/api/openstack/accounts.py b/nova/api/openstack/accounts.py
index e3201b14f..a13a758ab 100644
--- a/nova/api/openstack/accounts.py
+++ b/nova/api/openstack/accounts.py
@@ -47,10 +47,10 @@ class Controller(object):
             raise exception.AdminRequired()
 
     def index(self, req):
-        raise faults.Fault(webob.exc.HTTPNotImplemented())
+        raise webob.exc.HTTPNotImplemented()
 
     def detail(self, req):
-        raise faults.Fault(webob.exc.HTTPNotImplemented())
+        raise webob.exc.HTTPNotImplemented()
 
     def show(self, req, id):
         """Return data about the given account id"""
@@ -65,7 +65,7 @@ class Controller(object):
     def create(self, req, body):
         """We use update with create-or-update semantics
            because the id comes from an external source"""
-        raise faults.Fault(webob.exc.HTTPNotImplemented())
+        raise webob.exc.HTTPNotImplemented()
 
     def update(self, req, id, body):
         """This is really create or update."""
diff --git a/nova/api/openstack/backup_schedules.py b/nova/api/openstack/backup_schedules.py
index 3e95aedf3..7ff0d999e 100644
--- a/nova/api/openstack/backup_schedules.py
+++ b/nova/api/openstack/backup_schedules.py
@@ -19,7 +19,6 @@ import time
 
 from webob import exc
 
-from nova.api.openstack import faults
 from nova.api.openstack import wsgi
 
 
@@ -36,20 +35,20 @@ class Controller(object):
 
     def index(self, req, server_id, **kwargs):
         """ Returns the list of backup schedules for a given instance """
-        return faults.Fault(exc.HTTPNotImplemented())
+        raise exc.HTTPNotImplemented()
 
     def show(self, req, server_id, id, **kwargs):
         """ Returns a single backup schedule for a given instance """
-        return faults.Fault(exc.HTTPNotImplemented())
+        raise exc.HTTPNotImplemented()
 
     def create(self, req, server_id, **kwargs):
         """ No actual update method required, since the existing API allows
         both create and update through a POST """
-        return faults.Fault(exc.HTTPNotImplemented())
+        raise exc.HTTPNotImplemented()
 
     def delete(self, req, server_id, id, **kwargs):
         """ Deletes an existing backup schedule """
-        return faults.Fault(exc.HTTPNotImplemented())
+        raise exc.HTTPNotImplemented()
 
 
 def create_resource():
diff --git a/nova/api/openstack/common.py b/nova/api/openstack/common.py
index 8e12ce0c0..f41d25537 100644
--- a/nova/api/openstack/common.py
+++ b/nova/api/openstack/common.py
@@ -53,10 +53,10 @@ def get_pagination_params(request):
             params[param] = int(request.GET[param])
         except ValueError:
             msg = _('%s param must be an integer') % param
-            raise webob.exc.HTTPBadRequest(msg)
+            raise webob.exc.HTTPBadRequest(explanation=msg)
         if params[param] < 0:
             msg = _('%s param must be positive') % param
-            raise webob.exc.HTTPBadRequest(msg)
+            raise webob.exc.HTTPBadRequest(explanation=msg)
 
     return params
 
@@ -77,18 +77,22 @@ def limited(items, request, max_limit=FLAGS.osapi_max_limit):
     try:
         offset = int(request.GET.get('offset', 0))
     except ValueError:
-        raise webob.exc.HTTPBadRequest(_('offset param must be an integer'))
+        msg =  _('offset param must be an integer')
+        raise webob.exc.HTTPBadRequest(explanation=msg)
 
     try:
         limit = int(request.GET.get('limit', max_limit))
     except ValueError:
-        raise webob.exc.HTTPBadRequest(_('limit param must be an integer'))
+        msg = _('limit param must be an integer')
+        raise webob.exc.HTTPBadRequest(explanation=msg)
 
     if limit < 0:
-        raise webob.exc.HTTPBadRequest(_('limit param must be positive'))
+        msg = _('limit param must be positive')
+        raise webob.exc.HTTPBadRequest(explanation=msg)
 
     if offset < 0:
-        raise webob.exc.HTTPBadRequest(_('offset param must be positive'))
+        msg = _('offset param must be positive')
+        raise webob.exc.HTTPBadRequest(explanation=msg)
 
     limit = min(max_limit, limit or max_limit)
     range_end = offset + limit
@@ -111,7 +115,8 @@ def limited_by_marker(items, request, max_limit=FLAGS.osapi_max_limit):
                 start_index = i + 1
                 break
         if start_index < 0:
-            raise webob.exc.HTTPBadRequest(_('marker [%s] not found' % marker))
+            msg = _('marker [%s] not found' % marker)
+            raise webob.exc.HTTPBadRequest(explanation=msg)
     range_end = start_index + limit
     return items[start_index:range_end]
 
diff --git a/nova/api/openstack/consoles.py b/nova/api/openstack/consoles.py
index 9c7b37f0d..d2655acfa 100644
--- a/nova/api/openstack/consoles.py
+++ b/nova/api/openstack/consoles.py
@@ -20,7 +20,6 @@ import webob
 
 from nova import console
 from nova import exception
-from nova.api.openstack import faults
 from nova.api.openstack import wsgi
 
 
@@ -72,12 +71,12 @@ class Controller(object):
                                         int(server_id),
                                         int(id))
         except exception.NotFound:
-            return faults.Fault(exc.HTTPNotFound())
+            raise exc.HTTPNotFound()
         return _translate_detail_keys(console)
 
     def update(self, req, server_id, id):
         """You can't update a console"""
-        raise faults.Fault(exc.HTTPNotImplemented())
+        raise exc.HTTPNotImplemented()
 
     def delete(self, req, server_id, id):
         """Deletes a console"""
@@ -86,7 +85,7 @@ class Controller(object):
                                             int(server_id),
                                             int(id))
         except exception.NotFound:
-            return faults.Fault(exc.HTTPNotFound())
+            raise exc.HTTPNotFound()
         return webob.Response(status_int=202)
 
 
diff --git a/nova/api/openstack/create_instance_helper.py b/nova/api/openstack/create_instance_helper.py
index 2654e3c40..7784a3e81 100644
--- a/nova/api/openstack/create_instance_helper.py
+++ b/nova/api/openstack/create_instance_helper.py
@@ -28,7 +28,6 @@ from nova import quota
 from nova import utils
 
 from nova.compute import instance_types
-from nova.api.openstack import faults
 from nova.api.openstack import wsgi
 from nova.auth import manager as auth_manager
 
@@ -70,7 +69,7 @@ class CreateInstanceHelper(object):
         return type from this method is left to the caller.
         """
         if not body:
-            raise faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
 
         context = req.environ['nova.context']
 
@@ -94,7 +93,7 @@ class CreateInstanceHelper(object):
         except Exception, e:
             msg = _("Cannot find requested image %(image_href)s: %(e)s" %
                                                                     locals())
-            raise faults.Fault(exc.HTTPBadRequest(explanation=msg))
+            raise exc.HTTPBadRequest(explanation=msg)
 
         personality = body['server'].get('personality')
 
@@ -153,7 +152,7 @@ class CreateInstanceHelper(object):
             self._handle_quota_error(error)
         except exception.ImageNotFound as error:
             msg = _("Can not find requested image")
-            raise faults.Fault(exc.HTTPBadRequest(explanation=msg))
+            raise exc.HTTPBadRequest(explanation=msg)
 
         # Let the caller deal with unhandled exceptions.
 
diff --git a/nova/api/openstack/image_metadata.py b/nova/api/openstack/image_metadata.py
index 4f33844fa..c0fc8c09b 100644
--- a/nova/api/openstack/image_metadata.py
+++ b/nova/api/openstack/image_metadata.py
@@ -22,7 +22,6 @@ from nova import flags
 from nova import image
 from nova import quota
 from nova import utils
-from nova.api.openstack import faults
 from nova.api.openstack import wsgi
 
 
@@ -62,7 +61,7 @@ class Controller(object):
         if id in metadata:
             return {'meta': {id: metadata[id]}}
         else:
-            return faults.Fault(exc.HTTPNotFound())
+            raise exc.HTTPNotFound()
 
     def create(self, req, image_id, body):
         context = req.environ['nova.context']
@@ -105,7 +104,7 @@ class Controller(object):
         img = self.image_service.show(context, image_id)
         metadata = self._get_metadata(context, image_id)
         if not id in metadata:
-            return faults.Fault(exc.HTTPNotFound())
+            raise exc.HTTPNotFound()
         metadata.pop(id)
         img['properties'] = metadata
         self.image_service.update(context, image_id, img, None)
diff --git a/nova/api/openstack/images.py b/nova/api/openstack/images.py
index d0317583e..96c5cd3fa 100644
--- a/nova/api/openstack/images.py
+++ b/nova/api/openstack/images.py
@@ -25,7 +25,6 @@ from nova import flags
 import nova.image
 from nova import log
 from nova.api.openstack import common
-from nova.api.openstack import faults
 from nova.api.openstack import image_metadata
 from nova.api.openstack import servers
 from nova.api.openstack.views import images as images_view
@@ -78,7 +77,7 @@ class Controller(object):
             image = self._image_service.show(context, id)
         except (exception.NotFound, exception.InvalidImageRef):
             explanation = _("Image not found.")
-            raise faults.Fault(webob.exc.HTTPNotFound(explanation=explanation))
+            raise webob.exc.HTTPNotFound(explanation=explanation)
 
         return dict(image=self.get_builder(req).build(image, detail=True))
 
diff --git a/nova/api/openstack/ips.py b/nova/api/openstack/ips.py
index 1ebfdb831..2996b032d 100644
--- a/nova/api/openstack/ips.py
+++ b/nova/api/openstack/ips.py
@@ -20,7 +20,6 @@ import time
 from webob import exc
 
 import nova
-from nova.api.openstack import faults
 import nova.api.openstack.views.addresses
 from nova.api.openstack import wsgi
 from nova import db
@@ -37,14 +36,14 @@ class Controller(object):
             instance = self.compute_api.get(
                 req.environ['nova.context'], server_id)
         except nova.exception.NotFound:
-            return faults.Fault(exc.HTTPNotFound())
+            raise exc.HTTPNotFound()
         return instance
 
     def create(self, req, server_id, body):
-        return faults.Fault(exc.HTTPNotImplemented())
+        raise exc.HTTPNotImplemented()
 
     def delete(self, req, server_id, id):
-        return faults.Fault(exc.HTTPNotImplemented())
+        raise exc.HTTPNotImplemented()
 
 
 class ControllerV10(Controller):
@@ -63,7 +62,7 @@ class ControllerV10(Controller):
             view = builder.build_public_parts(instance)
         else:
             msg = _("Only private and public networks available")
-            return faults.Fault(exc.HTTPNotFound(explanation=msg))
+            raise exc.HTTPNotFound(explanation=msg)
 
         return {id: view}
 
@@ -86,7 +85,7 @@ class ControllerV11(Controller):
 
         if network is None:
             msg = _("Instance is not a member of specified network")
-            return faults.Fault(exc.HTTPNotFound(explanation=msg))
+            raise exc.HTTPNotFound(explanation=msg)
 
         return network
 
diff --git a/nova/api/openstack/server_metadata.py b/nova/api/openstack/server_metadata.py
index 3b9169f81..d4f42bbf5 100644
--- a/nova/api/openstack/server_metadata.py
+++ b/nova/api/openstack/server_metadata.py
@@ -18,7 +18,6 @@
 from webob import exc
 
 from nova import compute
-from nova.api.openstack import faults
 from nova.api.openstack import wsgi
 from nova import exception
 from nova import quota
diff --git a/nova/api/openstack/servers.py b/nova/api/openstack/servers.py
index 3b3d0685d..7bef1d9b2 100644
--- a/nova/api/openstack/servers.py
+++ b/nova/api/openstack/servers.py
@@ -27,7 +27,6 @@ from nova import log as logging
 from nova import utils
 from nova.api.openstack import common
 from nova.api.openstack import create_instance_helper as helper
-from nova.api.openstack import faults
 import nova.api.openstack.views.addresses
 import nova.api.openstack.views.flavors
 import nova.api.openstack.views.images
@@ -102,17 +101,14 @@ class Controller(object):
                 req.environ['nova.context'], id)
             return self._build_view(req, instance, is_detail=True)
         except exception.NotFound:
-            return faults.Fault(exc.HTTPNotFound())
+            raise exc.HTTPNotFound()
 
     def create(self, req, body):
         """ Creates a new server for a given user """
         extra_values = None
         result = None
-        try:
-            extra_values, instances = self.helper.create_instance(
-                    req, body, self.compute_api.create)
-        except faults.Fault, f:
-            return f
+        extra_values, instances = self.helper.create_instance(
+                req, body, self.compute_api.create)
 
         # We can only return 1 instance via the API, if we happen to
         # build more than one...  instances is a list, so we'll just
@@ -132,7 +128,7 @@ class Controller(object):
             raise exc.HTTPUnprocessableEntity()
 
         if not body:
-            return faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
 
         ctxt = req.environ['nova.context']
         update_dict = {}
@@ -147,7 +143,7 @@ class Controller(object):
         try:
             self.compute_api.update(ctxt, id, **update_dict)
         except exception.NotFound:
-            return faults.Fault(exc.HTTPNotFound())
+            raise exc.HTTPNotFound()
 
         return exc.HTTPNoContent()
 
@@ -171,7 +167,7 @@ class Controller(object):
         for key in actions.keys():
             if key in body:
                 return actions[key](body, req, id)
-        return faults.Fault(exc.HTTPNotImplemented())
+        raise exc.HTTPNotImplemented()
 
     def _action_change_password(self, input_dict, req, id):
         return exc.HTTPNotImplemented()
@@ -181,7 +177,7 @@ class Controller(object):
             self.compute_api.confirm_resize(req.environ['nova.context'], id)
         except Exception, e:
             LOG.exception(_("Error in confirm-resize %s"), e)
-            return faults.Fault(exc.HTTPBadRequest())
+            raise exc.HTTPBadRequest()
         return exc.HTTPNoContent()
 
     def _action_revert_resize(self, input_dict, req, id):
@@ -189,7 +185,7 @@ class Controller(object):
             self.compute_api.revert_resize(req.environ['nova.context'], id)
         except Exception, e:
             LOG.exception(_("Error in revert-resize %s"), e)
-            return faults.Fault(exc.HTTPBadRequest())
+            raise exc.HTTPBadRequest()
         return webob.Response(status_int=202)
 
     def _action_resize(self, input_dict, req, id):
@@ -200,14 +196,14 @@ class Controller(object):
             reboot_type = input_dict['reboot']['type']
         else:
             LOG.exception(_("Missing argument 'type' for reboot"))
-            return faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
         try:
             # TODO(gundlach): pass reboot_type, support soft reboot in
             # virt driver
             self.compute_api.reboot(req.environ['nova.context'], id)
         except Exception, e:
             LOG.exception(_("Error in reboot %s"), e)
-            return faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
         return webob.Response(status_int=202)
 
     def _action_migrate(self, input_dict, req, id):
@@ -215,7 +211,7 @@ class Controller(object):
             self.compute_api.resize(req.environ['nova.context'], id)
         except Exception, e:
             LOG.exception(_("Error in migrate %s"), e)
-            return faults.Fault(exc.HTTPBadRequest())
+            raise exc.HTTPBadRequest()
         return webob.Response(status_int=202)
 
     @scheduler_api.redirect_handler
@@ -231,7 +227,7 @@ class Controller(object):
         except:
             readable = traceback.format_exc()
             LOG.exception(_("Compute.api::lock %s"), readable)
-            return faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
         return webob.Response(status_int=202)
 
     @scheduler_api.redirect_handler
@@ -247,7 +243,7 @@ class Controller(object):
         except:
             readable = traceback.format_exc()
             LOG.exception(_("Compute.api::unlock %s"), readable)
-            return faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
         return webob.Response(status_int=202)
 
     @scheduler_api.redirect_handler
@@ -262,7 +258,7 @@ class Controller(object):
         except:
             readable = traceback.format_exc()
             LOG.exception(_("Compute.api::get_lock %s"), readable)
-            return faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
         return webob.Response(status_int=202)
 
     @scheduler_api.redirect_handler
@@ -277,7 +273,7 @@ class Controller(object):
         except:
             readable = traceback.format_exc()
             LOG.exception(_("Compute.api::reset_network %s"), readable)
-            return faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
         return webob.Response(status_int=202)
 
     @scheduler_api.redirect_handler
@@ -292,7 +288,7 @@ class Controller(object):
         except:
             readable = traceback.format_exc()
             LOG.exception(_("Compute.api::inject_network_info %s"), readable)
-            return faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
         return webob.Response(status_int=202)
 
     @scheduler_api.redirect_handler
@@ -304,7 +300,7 @@ class Controller(object):
         except:
             readable = traceback.format_exc()
             LOG.exception(_("Compute.api::pause %s"), readable)
-            return faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
         return webob.Response(status_int=202)
 
     @scheduler_api.redirect_handler
@@ -316,7 +312,7 @@ class Controller(object):
         except:
             readable = traceback.format_exc()
             LOG.exception(_("Compute.api::unpause %s"), readable)
-            return faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
         return webob.Response(status_int=202)
 
     @scheduler_api.redirect_handler
@@ -328,7 +324,7 @@ class Controller(object):
         except:
             readable = traceback.format_exc()
             LOG.exception(_("compute.api::suspend %s"), readable)
-            return faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
         return webob.Response(status_int=202)
 
     @scheduler_api.redirect_handler
@@ -340,7 +336,7 @@ class Controller(object):
         except:
             readable = traceback.format_exc()
             LOG.exception(_("compute.api::resume %s"), readable)
-            return faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
         return webob.Response(status_int=202)
 
     @scheduler_api.redirect_handler
@@ -352,7 +348,7 @@ class Controller(object):
         except:
             readable = traceback.format_exc()
             LOG.exception(_("compute.api::rescue %s"), readable)
-            return faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
         return webob.Response(status_int=202)
 
     @scheduler_api.redirect_handler
@@ -364,7 +360,7 @@ class Controller(object):
         except:
             readable = traceback.format_exc()
             LOG.exception(_("compute.api::unrescue %s"), readable)
-            return faults.Fault(exc.HTTPUnprocessableEntity())
+            raise exc.HTTPUnprocessableEntity()
         return webob.Response(status_int=202)
 
     @scheduler_api.redirect_handler
@@ -374,7 +370,7 @@ class Controller(object):
             self.compute_api.get_ajax_console(req.environ['nova.context'],
                 int(id))
         except exception.NotFound:
-            return faults.Fault(exc.HTTPNotFound())
+            raise exc.HTTPNotFound()
         return webob.Response(status_int=202)
 
     @scheduler_api.redirect_handler
@@ -384,7 +380,7 @@ class Controller(object):
             self.compute_api.get_vnc_console(req.environ['nova.context'],
                                              int(id))
         except exception.NotFound:
-            return faults.Fault(exc.HTTPNotFound())
+            raise exc.HTTPNotFound()
         return webob.Response(status_int=202)
 
     @scheduler_api.redirect_handler
@@ -416,7 +412,7 @@ class ControllerV10(Controller):
         try:
             self.compute_api.delete(req.environ['nova.context'], id)
         except exception.NotFound:
-            return faults.Fault(exc.HTTPNotFound())
+            raise exc.HTTPNotFound()
         return webob.Response(status_int=202)
 
     def _image_ref_from_req_data(self, data):
@@ -440,17 +436,13 @@ class ControllerV10(Controller):
 
     def _action_resize(self, input_dict, req, id):
         """ Resizes a given instance to the flavor size requested """
-        try:
-            if 'resize' in input_dict and 'flavorId' in input_dict['resize']:
-                flavor_id = input_dict['resize']['flavorId']
-                self.compute_api.resize(req.environ['nova.context'], id,
-                        flavor_id)
-            else:
-                LOG.exception(_("Missing 'flavorId' argument for resize"))
-                return faults.Fault(exc.HTTPUnprocessableEntity())
-        except Exception, e:
-            LOG.exception(_("Error in resize %s"), e)
-            return faults.Fault(exc.HTTPBadRequest())
+        if 'resize' in input_dict and 'flavorId' in input_dict['resize']:
+            flavor_id = input_dict['resize']['flavorId']
+            self.compute_api.resize(req.environ['nova.context'], id,
+                    flavor_id)
+        else:
+            LOG.exception(_("Missing 'flavorId' argument for resize"))
+            raise exc.HTTPUnprocessableEntity()
         return webob.Response(status_int=202)
 
     def _action_rebuild(self, info, request, instance_id):
@@ -462,14 +454,14 @@ class ControllerV10(Controller):
         except (KeyError, TypeError):
             msg = _("Could not parse imageId from request.")
             LOG.debug(msg)
-            return faults.Fault(exc.HTTPBadRequest(explanation=msg))
+            raise exc.HTTPBadRequest(explanation=msg)
 
         try:
             self.compute_api.rebuild(context, instance_id, image_id)
         except exception.BuildInProgress:
             msg = _("Instance %d is currently being rebuilt.") % instance_id
             LOG.debug(msg)
-            return faults.Fault(exc.HTTPConflict(explanation=msg))
+            raise exc.HTTPConflict(explanation=msg)
 
         return webob.Response(status_int=202)
 
@@ -486,7 +478,7 @@ class ControllerV11(Controller):
         try:
             self.compute_api.delete(req.environ['nova.context'], id)
         except exception.NotFound:
-            return faults.Fault(exc.HTTPNotFound())
+            raise exc.HTTPNotFound()
 
     def _image_ref_from_req_data(self, data):
         return data['server']['imageRef']
@@ -530,7 +522,7 @@ class ControllerV11(Controller):
         except AttributeError as ex:
             msg = _("Unable to parse metadata key/value pairs.")
             LOG.debug(msg)
-            raise faults.Fault(exc.HTTPBadRequest(explanation=msg))
+            raise exc.HTTPBadRequest(explanation=msg)
 
     def _decode_personalities(self, personalities):
         """Decode the Base64-encoded personalities."""
@@ -541,14 +533,14 @@ class ControllerV11(Controller):
             except (KeyError, TypeError):
                 msg = _("Unable to parse personality path/contents.")
                 LOG.info(msg)
-                raise faults.Fault(exc.HTTPBadRequest(explanation=msg))
+                raise exc.HTTPBadRequest(explanation=msg)
 
             try:
                 personality["contents"] = base64.b64decode(contents)
             except TypeError:
                 msg = _("Personality content could not be Base64 decoded.")
                 LOG.info(msg)
-                raise faults.Fault(exc.HTTPBadRequest(explanation=msg))
+                raise exc.HTTPBadRequest(explanation=msg)
 
     def _action_resize(self, input_dict, req, id):
         """ Resizes a given instance to the flavor size requested """
@@ -560,10 +552,10 @@ class ControllerV11(Controller):
                         flavor_id)
             else:
                 LOG.exception(_("Missing 'flavorRef' argument for resize"))
-                return faults.Fault(exc.HTTPUnprocessableEntity())
+                raise exc.HTTPUnprocessableEntity()
         except Exception, e:
             LOG.exception(_("Error in resize %s"), e)
-            return faults.Fault(exc.HTTPBadRequest())
+            raise exc.HTTPBadRequest()
         return webob.Response(status_int=202)
 
     def _action_rebuild(self, info, request, instance_id):
@@ -575,7 +567,7 @@ class ControllerV11(Controller):
         except (KeyError, TypeError):
             msg = _("Could not parse imageRef from request.")
             LOG.debug(msg)
-            return faults.Fault(exc.HTTPBadRequest(explanation=msg))
+            raise exc.HTTPBadRequest(explanation=msg)
 
         personalities = info["rebuild"].get("personality", [])
         metadata = info["rebuild"].get("metadata")
@@ -591,7 +583,7 @@ class ControllerV11(Controller):
         except exception.BuildInProgress:
             msg = _("Instance %d is currently being rebuilt.") % instance_id
             LOG.debug(msg)
-            return faults.Fault(exc.HTTPConflict(explanation=msg))
+            raise exc.HTTPConflict(explanation=msg)
 
         return webob.Response(status_int=202)
 
diff --git a/nova/api/openstack/shared_ip_groups.py b/nova/api/openstack/shared_ip_groups.py
index cf2ddbabb..54d0a8334 100644
--- a/nova/api/openstack/shared_ip_groups.py
+++ b/nova/api/openstack/shared_ip_groups.py
@@ -17,7 +17,6 @@
 
 from webob import exc
 
-from nova.api.openstack import faults
 from nova.api.openstack import wsgi
 
 
@@ -26,27 +25,27 @@ class Controller(object):
 
     def index(self, req, **kwargs):
         """ Returns a list of Shared IP Groups for the user """
-        raise faults.Fault(exc.HTTPNotImplemented())
+        raise exc.HTTPNotImplemented()
 
     def show(self, req, id, **kwargs):
         """ Shows in-depth information on a specific Shared IP Group """
-        raise faults.Fault(exc.HTTPNotImplemented())
+        raise exc.HTTPNotImplemented()
 
     def update(self, req, id, **kwargs):
         """ You can't update a Shared IP Group """
-        raise faults.Fault(exc.HTTPNotImplemented())
+        raise exc.HTTPNotImplemented()
 
     def delete(self, req, id, **kwargs):
         """ Deletes a Shared IP Group """
-        raise faults.Fault(exc.HTTPNotImplemented())
+        raise exc.HTTPNotImplemented()
 
     def detail(self, req, **kwargs):
         """ Returns a complete list of Shared IP Groups """
-        raise faults.Fault(exc.HTTPNotImplemented())
+        raise exc.HTTPNotImplemented()
 
     def create(self, req, **kwargs):
         """ Creates a new Shared IP group """
-        raise faults.Fault(exc.HTTPNotImplemented())
+        raise exc.HTTPNotImplemented()
 
 
 def create_resource():
diff --git a/nova/api/openstack/users.py b/nova/api/openstack/users.py
index 6ae1eaf2a..8dd72d559 100644
--- a/nova/api/openstack/users.py
+++ b/nova/api/openstack/users.py
@@ -19,7 +19,6 @@ from nova import exception
 from nova import flags
 from nova import log as logging
 from nova.api.openstack import common
-from nova.api.openstack import faults
 from nova.api.openstack import wsgi
 from nova.auth import manager
 
@@ -69,7 +68,7 @@ class Controller(object):
             user = None
 
         if user is None:
-            raise faults.Fault(exc.HTTPNotFound())
+            raise exc.HTTPNotFound()
 
         return dict(user=_translate_keys(user))
 
diff --git a/nova/api/openstack/wsgi.py b/nova/api/openstack/wsgi.py
index c3f841aa5..05767da19 100644
--- a/nova/api/openstack/wsgi.py
+++ b/nova/api/openstack/wsgi.py
@@ -441,7 +441,11 @@ class Resource(wsgi.Application):
             msg = _("Malformed request body")
             return faults.Fault(webob.exc.HTTPBadRequest(explanation=msg))
 
-        action_result = self.dispatch(request, action, args)
+        try:
+            action_result = self.dispatch(request, action, args)
+        except webob.exc.HTTPException as ex:
+            LOG.info(_("HTTP exception thrown: %s"), unicode(ex))
+            action_result = faults.Fault(ex)
 
         #TODO(bcwaldon): find a more elegant way to pass through non-dict types
         if type(action_result) is dict or action_result is None:
diff --git a/nova/api/openstack/zones.py b/nova/api/openstack/zones.py
index 2e02ec380..f7fd87bcd 100644
--- a/nova/api/openstack/zones.py
+++ b/nova/api/openstack/zones.py
@@ -27,7 +27,6 @@ from nova.scheduler import api
 
 from nova.api.openstack import create_instance_helper as helper
 from nova.api.openstack import common
-from nova.api.openstack import faults
 from nova.api.openstack import wsgi
 
 
@@ -127,11 +126,8 @@ class Controller(object):
         Returns a reservation ID (a UUID).
         """
         result = None
-        try:
-            extra_values, result = self.helper.create_instance(req, body,
-                                    self.compute_api.create_all_at_once)
-        except faults.Fault, f:
-            return f
+        extra_values, result = self.helper.create_instance(req, body,
+                                self.compute_api.create_all_at_once)
 
         reservation_id = result
         return {'reservation_id': reservation_id}