Ensure that 404's are returned as JSON

Overide default Pecan 404 behaviour, and return a error from middleware
like all other errors

Change-Id: Idd2a051f5ce298f7cc5327ceb2946cfc30fe68ac
Closes-Bug: #1333347
(cherry picked from commit 047f94c178)

designate/api/middleware.py

@@ -223,8 +223,9 @@ class FaultWrapperMiddleware(wsgi.Middleware):
             return self._handle_exception(request, e)
 
     def _handle_exception(self, request, e, status=500, response={}):
-        # Log the exception ASAP
-        LOG.exception(e)
+        # Log the exception ASAP unless it is a 404 Not Found
+        if not getattr(e, 'expected', False):
+            LOG.exception(e)
 
         headers = [
             ('Content-Type', 'application/json'),

designate/api/v2/__init__.py

@@ -33,7 +33,11 @@ def factory(global_config, **local_conf):
     conf = {
         'app': {
             'root': 'designate.api.v2.controllers.root.RootController',
-            'modules': ['designate.api.v2']
+            'modules': ['designate.api.v2'],
+            'errors': {
+                404: '/not_found',
+                '__force_dict__' : True
+            }
         }
     }
 

designate/api/v2/controllers/root.py

@@ -13,6 +13,7 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations
 # under the License.
+from designate import exceptions
 from designate.openstack.common import log as logging
 from designate.api.v2.controllers import limits
 from designate.api.v2.controllers import reverse
@@ -21,6 +22,8 @@ from designate.api.v2.controllers import tlds
 from designate.api.v2.controllers import zones
 from designate.api.v2.controllers import blacklists
 
+from pecan import expose
+
 LOG = logging.getLogger(__name__)
 
 
@@ -35,3 +38,9 @@ class RootController(object):
     tlds = tlds.TldsController()
     zones = zones.ZonesController()
     blacklists = blacklists.BlacklistsController()
+
+    @expose(content_type='text/plain')
+    @expose(content_type='text/dns')
+    @expose(content_type='application/json')
+    def not_found(self):
+        raise exceptions.NotFound

designate/exceptions.py

@@ -197,6 +197,7 @@ class DuplicateBlacklist(Duplicate):
 
 
 class NotFound(Base):
+    expected = True
     error_code = 404
     error_type = 'not_found'