CODEWITHSUNDEEP
pythoncelery
resolvewang
resolvewang

Reputation: 103

how can celery execute a periodic task immediately？

I want to use celery to execute a periodic task.
According to the documentation: http://docs.celeryproject.org/en/latest/userguide/periodic-tasks.html#entries, I wrote down the following code:

app.conf.beat_schedule = {
    'test_celery': {
        'task': 'tasks.login.test_timertask',
        'schedule': 60.0,
    }
}

but when I run it as follows:

celery beat -A tasks.login --loglevel=info

the first task is executed after 60s.
I want to start the task once the worker starts rather than with 60 seconds delay. What should I do?

Upvotes: 1

Views: 2243

Answers (2)

bluppfisk
bluppfisk

Reputation: 2652

It's pretty daft that there's no setting to start periodic tasks immediately, so I guess the only true solution is to just start the task manually before adding it as a periodic task, or using your own scheduler class that sets the last time started before now.

Upvotes: 0

John Moutafis
John Moutafis

Reputation: 23134

You can use crontab schedules for this:

from celery.schedules import crontab

app.conf.beat_schedule = {
    'test_celery': {
        'task': 'tasks.login.test_timertask',
        'schedule': crontab(), # default, executes every minute
    }
}

But you must be aware of the following (as the docs state):

A Crontab like schedule also exists, see the section on Crontab schedules.

Like with cron, the tasks may overlap if the first task doesn’t complete before the next. If that’s a concern you should use a locking strategy to ensure only one instance can run at a time (see for example Ensuring a task is only executed one at a time).

Upvotes: 2

Related Questions