Debugging djcelery's celeryd via pdb

Question

Have anybody tried debugging celeryd worker using pdb? Whenever a breakpoint is encountered (either by running celeryd via pdb, or by pdb.set_trace()), I hit the following error:

Error while handling action event.
Traceback (most recent call last):
  File "/home/jeeyo/workspace3/uwcr/subscriptions/tasks.py", line 79, in process_action_event
    func(action_event)
  File "/home/jeeyo/workspace3/uwcr/subscriptions/tasks.py", line 36, in new_user_email
    send_registration_email(username, new_user.get_profile().plaintext_password)
  File "/home/jeeyo/workspace3/uwcr/looers/email.py", line 18, in send_registration_email
    'Your password from UWCoopRankings', user
  File "/home/jeeyo/workspace3/uwcr/looers/email.py", line 61, in send_email
    if isinstance(to, basestring):
  File "/home/jeeyo/workspace3/uwcr/looers/email.py", line 61, in send_email
    if isinstance(to, basestring):
  File "/usr/lib/python2.6/bdb.py", line 46, in trace_dispatch
    return self.dispatch_line(frame)
  File "/usr/lib/python2.6/bdb.py", line 65, in dispatch_line
    if self.quitting: raise BdbQuit
BdbQuit

Any solution to this?

Answer 1

I had the same problem. Try using Celery's remote debugger rdb instead:

from celery import task
from celery.contrib import rdb

@task()
def add(x, y):
    result = x + y
    rdb.set_trace()  # <- set break-point
    return result

See the user guide (link update 2017/5).