Make Executor an abstract class

Author: lw

cms/io/triggeredservice.py

@@ -28,9 +28,11 @@
 from __future__ import unicode_literals
 from future.builtins.disabled import *  # noqa
 from future.builtins import *  # noqa
+from six import with_metaclass
 
 import logging
 import time
+from abc import ABCMeta, abstractmethod
 
 import gevent
 from gevent.event import Event
@@ -42,7 +44,7 @@
 logger = logging.getLogger(__name__)
 
 
-class Executor(object):  # pylint: disable=R0921
+class Executor(with_metaclass(ABCMeta, object)):  # pylint: disable=R0921
 
     """A class taking care of executing operations.
 
@@ -170,6 +172,7 @@ def max_operations_per_batch(self):
         """
         return 0
 
+    @abstractmethod
     def execute(self, entry):
         """Perform a single operation.
 
@@ -183,7 +186,7 @@ def execute(self, entry):
             re-enqueue the item.
 
         """
-        raise NotImplementedError("Please use a subclass.")
+        pass
 
 
 class TriggeredService(Service):