CODEWITHSUNDEEP
pythonmultithreading
Cody
Cody

Reputation: 2649

Python ThreadPoolExecutor: Not working as expected?

According to realpython:

The end of the with block causes the ThreadPoolExecutor to do a .join() on each of the threads in the pool. It is strongly recommended that you use ThreadPoolExecutor as a context manager when you can so that you never forget to .join() the threads.

import logging
# import threading
import time
import concurrent.futures

def thread_function(name):
    logging.info("Thread %s: starting", name)
    time.sleep(2)
    logging.info("Thread %s: finishing", name)


if __name__ == "__main__":
    format = "%(asctime)s: %(message)s"
    logging.basicConfig(format=format, level=logging.INFO,
                        datefmt="%H:%M:%S")

    with concurrent.futures.ThreadPoolExecutor(max_workers=3) as executor:
        executor.map(thread_function, range(3))

    print("all done")

In the given code snippet, I was expecting that the last line - print("all done") to be executed at the end (i.e. after all the threads are done executing). However, it is not? what am I missing?

Upvotes: 0

Views: 1226

Answers (1)

Ron Serruya
Ron Serruya

Reputation: 4446

I think it has something to do with the way the Pycharm console buffers output (that you showed in your screenshot)

I run it several times in pycharm and it worked sometimes, while not working other times. However, when you run it in the terminal (or tell pycharm to "emulate terminal output") I don't see it anymore

Upvotes: 1

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