Aborting a thread pool executor using events. Some threads will never run (that's what we want to demonstrate)

abortable-threadpoolexectuor.py

import concurrent.futures
import logging
import threading

import time
import random

def return_after_5_secs(num, stop):
    threading.current_thread().name = f"banane{num}"
    logging.debug(f"from inside {num}")
    if not stop.isSet():
        print(f'{num:4d} a) started')
        if stop.wait(random.randint(1, 5)):
            print(f'{num:4d} b) cancelled')
    else:
        return f'{num:4d} c) never started'
    
    return f"{num:4d} c) returned"


def main():
    stop = threading.Event()
    pool = concurrent.futures.ThreadPoolExecutor(5)
    futures = []
    for x in range(15):
        futures.append(pool.submit(return_after_5_secs, x, stop))

    try:
        count = 0
        for x in concurrent.futures.as_completed(futures, timeout=5):
            count = count + 1
            print(x.result())
            if count > 3:
                stop.set()
    except concurrent.futures.TimeoutError as te:
        print(f'Timeout {te}')
        stop.set()
        pool.shutdown(False)


if __name__ == '__main__':
    logging.basicConfig(format='%(asctime)s %(levelname)s t:%(threadName)s %(message)s [%(filename)s:%(lineno)d]', level=logging.DEBUG)
    main()