python - celery如何立即执行周期性任务？

Question

我想使用 celery 执行周期性任务。
根据文档:http://docs.celeryproject.org/en/latest/userguide/periodic-tasks.html#entries ，我写下了以下代码:

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

但是当我按如下方式运行时:

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

第一个任务在 60 秒后执行。
我想在工作人员启动后立即启动任务，而不是延迟 60 秒。我该怎么办？

Answer 1

您可以使用crontab schedules为此:

from celery.schedules import crontab

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

但您必须了解以下内容(如文档所述):

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).