Python Scheduled Task Execution Methods: sleep loops, threading.Timer, sched, and schedule library

This article demonstrates several ways to execute periodic tasks in Python, including using a while‑True loop with time.sleep() , the threading.Timer class, the sched module, and the third‑party schedule library.

1. Loop with sleep()

from datetime import datetime
import time

def timedTask():
    while True:
        print(datetime.now().strftime("%Y-%m-%d %H:%M:%S"))
        time.sleep(10)

if __name__ == '__main__':
    timedTask()

This method prints the current time every 10 seconds but keeps the loop active, which may block other operations.

2. threading.Timer

from datetime import datetime
from threading import Timer
import time

def task():
    print(datetime.now().strftime("%Y-%m-%d %H:%M:%S"))

Timer(10, task).start()

Timer schedules a single execution after a delay; repeated execution can be achieved by re‑creating the timer inside the task.

3. sched module

import datetime, sched, time

def task():
    print(datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"))

scheduler = sched.scheduler(time.time, time.sleep)
scheduler.enter(10, 1, task)
scheduler.run()

The sched.scheduler accepts a time function and a delay function, allowing precise control over task ordering and priority.

4. schedule library

import schedule, time

def job():
    print("I'm working...")

schedule.every(10).minutes.do(job)          # every 10 minutes
schedule.every().hour.do(job)              # every hour
schedule.every().day.at("10:30").do(job)   # daily at 10:30

while True:
    schedule.run_pending()
    time.sleep(1)

The library provides a readable DSL for common intervals and also supports passing arguments to the job function.