Thread and BoundedSemaphore

test_thread.py

import time
from threading import Thread, BoundedSemaphore

MAX_CONCURRENT_THREADS = 3
thread_limiter = BoundedSemaphore(value=MAX_CONCURRENT_THREADS)


class MyThread(Thread):
    def run(self):
        thread_limiter.acquire()
        try:
            time.sleep(3)
            print(f'hello: {time.time()}')
        finally:
            thread_limiter.release()


if __name__ == '__main__':
    for _ in range(10):
        MyThread().start()

hello: 1557495011.279253
hello: 1557495011.279388
hello: 1557495011.2799518
hello: 1557495014.285185
hello: 1557495014.285435
hello: 1557495014.285822
hello: 1557495017.285931
hello: 1557495017.2861922
hello: 1557495017.286457
hello: 1557495020.2913122

import time
from threading import Thread, BoundedSemaphore



class MyThread(Thread):

    MAX_CONCURRENT_THREADS = 3
    thread_limiter = BoundedSemaphore(value=MAX_CONCURRENT_THREADS)

    def run(self):
        self.thread_limiter.acquire()
        try:
            time.sleep(3)
            print(f'hello: {time.time()}')
        finally:
            self.thread_limiter.release()


if __name__ == '__main__':
    for _ in range(10):
        MyThread().start()