Events: repr complex objects sent as event fields.

It's a bad idea to sent pickled objects with the events, as the receiving
part may even not have the classes installed.

And anyway, the events are meant for information not deep introspection.

Closes #106. Thanks to dfdeshom. Please verify.

celery/worker/job.py

@@ -346,7 +346,7 @@ class TaskWrapper(object):
 
         runtime = time.time() - self.time_start
         self.send_event("task-succeeded", uuid=self.task_id,
-                        result=ret_value, runtime=runtime)
+                        result=repr(ret_value), runtime=runtime)
 
         msg = self.success_msg.strip() % {
                 "id": self.task_id,
@@ -361,7 +361,7 @@ class TaskWrapper(object):
             self.acknowledge()
 
         self.send_event("task-failed", uuid=self.task_id,
-                                       exception=exc_info.exception,
+                                       exception=repr(exc_info.exception),
                                        traceback=exc_info.traceback)
 
         context = {

celery/worker/listener.py

@@ -113,8 +113,8 @@ class CarrotListener(object):
             return task.on_ack()
 
         self.event_dispatcher.send("task-received", uuid=task.task_id,
-                name=task.task_name, args=task.args, kwargs=task.kwargs,
-                retries=task.retries, eta=eta)
+                name=task.task_name, args=repr(task.args),
+                kwargs=repr(task.kwargs), retries=task.retries, eta=eta)
 
         if eta:
             if not isinstance(eta, datetime):