Wednesday, March 16, 2022

[SOLVED] APScheduler jobs run several times when jobs are set to be run at the same time

Issue

I want to schedule and run jobs using APScheduler and the cron format.

from apscheduler.schedulers.background import BackgroundScheduler

def test_func():
    print("Test job func")

scheduler = BackgroundScheduler()

today_str = datetime.today().strftime('%Y-%m-%d')
today_with_time = datetime.strptime(today_str + " " + "12:07:00", "%Y-%m-%d %H:%M:%S")

scheduler.add_job(
                test_func,
                "cron",
                id="test",
                name="test",
                day_of_week="2",
                hour=today_with_time.hour,
                minute=today_with_time.minute,
                replace_existing=False)

Let's say I do this twice, with two different job IDs. There are two jobs, set to run at the exact same time. With one job, it runs once as expected. With two jobs, it runs 4 times. The same happens with other triggers such as DateTrigger.

Note that this is set-up within a Flask app. Normally, the app makes a call to another API to fetch jobs, then schedules them one by one.

EDIT: my actual app fetches 3 jobs and schedules them, all at the same time. When I fetch 1 job instead of 3, the bug does not occur. When I have 3 jobs, the function is run 9 times. With 1 job, it is run once.


Solution

It turns out I was a genius and initialized a scheduler every time a job was fetched. :-]

So now, I changed the class that manages scheduling (and initializes the scheduler) to a singleton and it works as expected.



Answered By - Konrad
Answer Checked By - Mary Flores (WPSolving Volunteer)
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