[FIXED] While loop waits without stopping until the time.sleep finishes

Issue

I have a while loop in a thread which checks a webstream every 10 minutes.

while not stop_event.is_set():
    time.sleep(600)
    response = requests.get(api_url, headers=headers, params=params)
    if response.status_code==200:
        print("UPDATED")
    else:
        print("NOT UPDATED")

But if the not stop_event.is_set() changed to False before 10 minutes, Still the while loop waits 10 minutes and executes the rest of the code and then exits

    response = requests.get(api_url, headers=headers, params=params)
    if response.status_code==200:
        print("UPDATED")
    else:
        print("NOT UPDATED")

I want to quit immediately as the not stop_event.is_set() changed to False without witing time.sleep(600) to finish

Thanks in advance

Solution

Instead of time.sleep, which is blocking, you could use threading.Event.wait which will return immediately if the internal flag is set:

while not stop_event.is_set():
    if stop_event.wait(600):
        break # or use "return" if you want the entire function to end
    response = requests.get(api_url, headers=headers, params=params)
    if response.status_code == 200:
        print("UPDATED")
    else:
        print("NOT UPDATED")

A reproducible example:

import time
import threading


def run_in_thread(stop_event):
    while not stop_event.is_set():
        if stop_event.wait(5):
            print(f"{time.strftime('%H:%M:%S', time.localtime())}: Stopped.")
            return
        print(f"{time.strftime('%H:%M:%S', time.localtime())}: Running.")


if __name__ == '__main__':
    stop_event = threading.Event()
    t = threading.Thread(target=run_in_thread, args=(stop_event,))
    t.start()
    time.sleep(16)
    stop_event.set()

Answered By - FJSevilla