I am trying to run something at the exact time to the second everyday. I have tried Schedule and used a sleep time of 1 second but it runs twice sometimes so I want to switch to APScheduler. But I have never used anything Cron like before and their webpage's "User Guide" thing doesn't resemble a detailed documentation at all so I don't know where to start. Googled but there's only answers for intervals. I want to specify a time not interval.
For example run a function at 03:00:05 everyday. How would you do that?
Thank you.
I believe what you want is the BackgroundScheduler from APScheduler using a CronTrigger.
A minimal example of the program would be the following:
from time import sleep
from apscheduler.schedulers.background import BackgroundScheduler
from apscheduler.triggers.cron import CronTrigger
def foo(bar):
print(bar)
def main():
scheduler = BackgroundScheduler()
scheduler.start()
trigger = CronTrigger(
year="*", month="*", day="*", hour="3", minute="0", second="5"
)
scheduler.add_job(
foo,
trigger=trigger,
args=["hello world"],
name="daily foo",
)
while True:
sleep(5)
if __name__ == "__main__":
main()
This would run the function foo with argument bar equal to the string "hello world" every day at 03:00:05.
The background scheduler is not blocking, therefore the while loop is needed to keep the program running forever.
To change the function to call you would just need to change the first argument of scheduler.add_job to the function you want to call and change the args keyword argument to a list containing the arguments you want your function to be called with.
The arguments to CronTrigger form a cron string, this is a well-known format used by the crontab utility in Linux (i find the following site quite useful for testing those strings.)