Merge "Return 503 if engine overloaded/unresponsive"

congress/dse2/dse_node.py

@@ -334,7 +334,7 @@ class DseNode(object):
         except (messaging_exceptions.MessagingTimeout,
                 messaging_exceptions.MessageDeliveryFailure):
             msg = "Request to service '%s' timed out"
-            raise exception.NotFound(msg % service_id)
+            raise exception.Unavailable(msg % service_id)
         LOG.trace("<%s> RPC call returned: %s", self.node_id, result)
         return result
 

congress/exception.py

@@ -132,6 +132,11 @@ class NotFound(CongressException):
     code = 404
 
 
+class Unavailable(CongressException):
+    msg_fmt = _("Service Unavailable.")
+    code = 503
+
+
 class PolicyNotAuthorized(Forbidden):
     msg_fmt = _("Policy doesn't allow %(action)s to be performed.")