Python classes that inherit threads cannot end threads through flag bits

Question

I encountered such a problem when testing the producer-consumer model. After inheriting the thread, I added a mark mark

class Consumer(threading.Thread):
    def __init__(self, queue):
        threading.Thread.__init__(self)
        self._queue = queue
        self.mark = True

    def run(self):
        while self.mark:
            msg = self._queue.get()
            if isinstance(msg, str) and msg == 'quit':
                break
            print("I'm a thread, and I received %s!!" % msg)

        print('Bye byes!')

def producer():
    q = queue.Queue()
    worker = Consumer(q)
    worker.start()  # 开启消费者线程
    start_time = time.time()
    while time.time() - start_time < 5:
        q.put('something at %s' % time.time())
        time.sleep(1)
    worker.mark = Flese
    worker.join()

I originally expected to use this flag to achieve thread end control, but the actual effect is that the program is stuck in worker.join()
and does not exit at all.

Excuse me, what is the reason for this?

Answer 1

class Consumer(threading.Thread):
    def __init__(self, queue):
        threading.Thread.__init__(self)
        self._queue = queue
        self.mark = True

    def run(self):
        while self.mark:
            try:
                msg = self._queue.get(block=False) # 非阻塞
                print("I'm a thread, and I received %s!!" % msg)
            except:pass
            
        print('self.mark',self.mark)
        print('Bye byes!')
        
def producer():
    q = queue.Queue()
    worker = Consumer(q)
    worker.start()  # 开启消费者线程
    start_time = time.time()
    while time.time() - start_time < 5:
        q.put('something at %s' % time.time())
        time.sleep(1)
    worker.mark = False
    worker.join()