I want to run a function every 5 minutes, it must be at a "round" intervals, for example :
12:05:00, 12:10:00, 12:15:00...
It cannot be like this:
12:06:00, 12:11:00, 12:16:00...
Or like this:
12:05:14, 12:10:14, 12:15:14...
What is the most accurate way to do this in python?
You could use a threading.Timer. You have to do some math to calculate the next run time. datetime has a handy replace method for that.
from datetime import datetime, timedelta
from threading import Timer
from time import sleep
import random
def schedule_next_run():
sleep_time = get_sleep_time()
t = Timer(sleep_time, do_work)
t.daemon = True
t.start()
print(f'sleeping for {sleep_time} seconds')
def get_sleep_time():
now = datetime.now()
last_run_time = now.replace(minute=now.minute // 5 * 5, second=0, microsecond=0)
next_run_time = last_run_time + timedelta(minutes=5)
return (next_run_time - now).total_seconds()
def do_work():
now = datetime.now()
print('Doing some work at', now)
sleep(random.uniform(0, 29))
print('Work complete. Scheduling next run.')
schedule_next_run()
print('Starting work schedule')
schedule_next_run()
input('Doing work every 5 minutes. Press enter to exit:\n')
On my system, the function fires within a half millisecond of the target time
Note that the time calculation rounds down and then adds a timedelta to carefully wrap around the end of each hour. You would want to ponder how this will behave around daylight savings changes.
Suggestion: move all this logic to a class to clean it up.