How to make worker threads quit after work is finished in a multithreaded producer-consumer pattern?

Question

I am trying to implement a multithreaded producer-consumer pattern using Queue.Queue in Python 2.7. I am trying to figure out how to make the consumers, i.e. the worker threads,

Answer 1

Don't call it a special case for a task.

Use an Event instead, with non-blocking implementation for your workers.

stopping = threading.Event()

def worker(n, q, timeout=1):
    # run until the master thread indicates we're done
    while not stopping.is_set():
        try:
            # don't block indefinitely so we can return to the top
            # of the loop and check the stopping event
            data = q.get(True, timeout)
        # raised by q.get if we reach the timeout on an empty queue
        except queue.Empty:
            continue
        q.task_done()

def master():
    ...

    print 'waiting for workers to finish'
    q.join()
    stopping.set()
    print 'done'