celery beat schedule: run task instantly when start celery beat?

Question

If I create a celery beat schedule, using timedelta(days=1), the first task will be carried out after 24 hours, quote celery beat documentation:

Answer 1

The best idea is create an implementation which schedules the task itself after completing the task. Also, create an entrance lock so the task cannot be executed multiple times per moment. Trigger the execution once.

In this case,

• you don't need a celerybeat process
• the task is guaranteed to execute

Answer 2

I decide I could just declare a instance of every task, and execute them at celery launch. I don't like this at all because it makes starting celery beat extremely slow (if you have slow PeriodicTask), but it does what I want.

simply add this to the end of tasks.py:

########### spawn all tasks at launch! ############
localmess = locals().values()
for obj in localmess:
    if isclass(obj):
        if obj is not PeriodicTask and issubclass(obj, PeriodicTask):
            instance = obj()
            logger.info('running {0}'.format(obj))
            try:
                instance.run()
            except:
                logger.warn('task fail: {0}'.format(obj))
                pass

######## all tasks must be decleared above! ########