Refactor API error handling

Refactor the API error handling to ensure error messages are translated.
Since wsme 0.5b6, the error message doesn't need to be converted to
unicode, wsme handles it for us.

Related bug #1200518

Change-Id: Iec396f045cd3afe817301f0d00917c42c7587b55

ceilometer/api/controllers/v2.py

@@ -67,7 +67,13 @@ state_kind_enum = wtypes.Enum(str, *state_kind)
 operation_kind = wtypes.Enum(str, 'lt', 'le', 'eq', 'ne', 'ge', 'gt')
 
 
-class EntityNotFound(wsme.exc.ClientSideError):
+class ClientSideError(wsme.exc.ClientSideError):
+    def __init__(self, error, status_code=400):
+        pecan.response.translatable_error = error
+        super(ClientSideError, self).__init__(error, status_code)
+
+
+class EntityNotFound(ClientSideError):
     def __init__(self, entity, id):
         super(EntityNotFound, self).__init__(
             _("%(entity)s %(id)s Not Found") % {'entity': entity,
@@ -99,14 +105,12 @@ class BoundedInt(wtypes.UserType):
         if self.min is not None and value < self.min:
             error = _('Value %(value)s is invalid (should be greater or equal '
                       'to %(min)s)') % dict(value=value, min=self.min)
-            pecan.response.translatable_error = error
+            raise ClientSideError(error)
-            raise wsme.exc.ClientSideError(unicode(error))
 
         if self.max is not None and value > self.max:
             error = _('Value %(value)s is invalid (should be lower or equal '
                       'to %(max)s)') % dict(value=value, max=self.max)
-            pecan.response.translatable_error = error
+            raise ClientSideError(error)
-            raise wsme.exc.ClientSideError(unicode(error))
         return value
 
 
@@ -262,21 +266,21 @@ class Query(_Base):
             msg = _('Failed to convert the metadata value %(value)s'
                     ' to the expected data type %(type)s.') % \
                 {'value': self.value, 'type': type}
-            raise wsme.exc.ClientSideError(unicode(msg))
+            raise ClientSideError(msg)
         except TypeError:
             msg = _('The data type %s is not supported. The supported'
                     ' data type list is: integer, float, boolean and'
                     ' string.') % (type)
-            raise wsme.exc.ClientSideError(unicode(msg))
+            raise ClientSideError(msg)
         except Exception:
             msg = _('Unexpected exception converting %(value)s to'
                     ' the expected data type %(type)s.') % \
                 {'value': self.value, 'type': type}
-            raise wsme.exc.ClientSideError(unicode(msg))
+            raise ClientSideError(msg)
         return converted_value
 
 
-class ProjectNotAuthorized(wsme.exc.ClientSideError):
+class ProjectNotAuthorized(ClientSideError):
     def __init__(self, id):
         super(ProjectNotAuthorized, self).__init__(
             _("Not Authorized to access project %s") % id,
@@ -787,9 +791,7 @@ class MeterController(rest.RestController):
                        period long of that number of seconds.
         """
         if period and period < 0:
-            error = _("Period must be positive.")
+            raise ClientSideError(_("Period must be positive."))
-            pecan.response.translatable_error = error
-            raise wsme.exc.ClientSideError(unicode(error))
 
         kwargs = _query_to_kwargs(q, storage.SampleFilter.__init__)
         kwargs['meter'] = self._id
@@ -1158,14 +1160,12 @@ class Alarm(_Base):
                 and alarm.combination_rule == wtypes.Unset):
             error = _("either threshold_rule or combination_rule "
                       "must be set")
-            pecan.response.translatable_error = error
+            raise ClientSideError(error)
-            raise wsme.exc.ClientSideError(unicode(error))
 
         if alarm.threshold_rule and alarm.combination_rule:
             error = _("threshold_rule and combination_rule "
                       "cannot be set at the same time")
-            pecan.response.translatable_error = error
+            raise ClientSideError(error)
-            raise wsme.exc.ClientSideError(unicode(error))
 
         if alarm.threshold_rule:
             # ensure an implicit constraint on project_id is added to
@@ -1183,9 +1183,7 @@ class Alarm(_Base):
                 alarms = list(pecan.request.storage_conn.get_alarms(
                     alarm_id=id, project=project))
                 if not alarms:
-                    error = _("Alarm %s doesn't exist") % id
+                    raise ClientSideError(_("Alarm %s doesn't exist") % id)
-                    pecan.response.translatable_error = error
-                    raise wsme.exc.ClientSideError(unicode(error))
 
         return alarm
 
@@ -1350,9 +1348,7 @@ class AlarmController(rest.RestController):
             alarm_in = storage.models.Alarm(**updated_alarm)
         except Exception:
             LOG.exception("Error while putting alarm: %s" % updated_alarm)
-            error = _("Alarm incorrect")
+            raise ClientSideError(_("Alarm incorrect"))
-            pecan.response.translatable_error = error
-            raise wsme.exc.ClientSideError(unicode(error))
 
         alarm = self.conn.update_alarm(alarm_in)
 
@@ -1402,10 +1398,7 @@ class AlarmController(rest.RestController):
         # note(sileht): body are not validated by wsme
         # Workaround for https://bugs.launchpad.net/wsme/+bug/1227229
         if state not in state_kind:
-            error = _("state invalid")
+            raise ClientSideError(_("state invalid"))
-            pecan.response.translatable_error = error
-            raise wsme.exc.ClientSideError(unicode(error))
-
         now = timeutils.utcnow()
         alarm = self._alarm()
         alarm.state = state
@@ -1488,17 +1481,13 @@ class AlarmsController(rest.RestController):
         alarms = list(conn.get_alarms(name=data.name,
                                       project=data.project_id))
         if len(alarms) > 0:
-            error = _("Alarm with that name exists")
+            raise ClientSideError(_("Alarm with that name exists"))
-            pecan.response.translatable_error = error
-            raise wsme.exc.ClientSideError(unicode(error))
 
         try:
             alarm_in = storage.models.Alarm(**change)
         except Exception:
             LOG.exception("Error while posting alarm: %s" % change)
-            error = _("Alarm incorrect")
+            raise ClientSideError(_("Alarm incorrect"))
-            pecan.response.translatable_error = error
-            raise wsme.exc.ClientSideError(unicode(error))
 
         alarm = conn.create_alarm(alarm_in)
         self._record_creation(conn, change, alarm.alarm_id, now)

ceilometer/tests/api/v2/test_query.py

@@ -16,6 +16,7 @@
 """Test the methods related to query."""
 import datetime
 
+import fixtures
 import mock
 import wsme
 
@@ -29,6 +30,10 @@ from ceilometer.tests import base as tests_base
 
 
 class TestQuery(test.BaseTestCase):
+    def setUp(self):
+        super(TestQuery, self).setUp()
+        self.useFixture(fixtures.MonkeyPatch(
+            'pecan.response', mock.MagicMock()))
 
     def test_get_value_as_type_with_integer(self):
         query = Query(field='metadata.size',