在进程中创建线程，并在线程之间共享队列

Question

我试图在两个进程中的每一个进程中创建3个线程，并在所有线程之间共享multiprocessing.JoinableQueue类型的队列。worker_func函数只是创建线程，而thread_func函数打印出它从队列中获得的值。程序卡在time.sleep或queue的get()方法中。我做错了什么？我在Windows计算机上运行。

import threading
from multiprocessing import Pool, Manager, JoinableQueue
import multiprocessing
from threading import Thread
import time

def thread_func(q, disp_lock):
with disp_lock:
print('thread ', threading.current_thread().name, ' in process ', multiprocessing.current_process().name ,
' reporting for duty')
while True:
time.sleep(0.1)
try:
val = q.get_nowait()
with disp_lock:
print('thread ', threading.current_thread().name, ' in process ', multiprocessing.current_process().name , ' got value: ',val)
q.task_done()
except:
with disp_lock:
print('queue is empty: ', q.qsize())
def worker_func(num_threads, q, disp_lock):
threads = []
for i in range(num_threads):
thread = Thread(target= thread_func, args=( q, disp_lock,))
thread.daemon = True
thread.start()
if __name__ == "__main__":
manager = Manager()
lock    = manager.Lock()
q1 = JoinableQueue()#manager.Queue()
q1_length = 20
for i in range(q1_length):
q1.put(i)

processes = []
num_processes = 2   # 2 processes
num_threads = 3
for _ in range(num_processes):
p = multiprocessing.Process(target=worker_func, args=( num_threads, q1, lock, )) # create a new Process
p.daemon = True
p.start()
processes.append(p)
q1.join()

Answer 1

您不允许线程完成它们的工作。要么将它们设置为非守护进程，要么明确等待它们加入：

def worker_func(num_threads, q, disp_lock):
threads = []
for i in range(num_threads):
thread = Thread(target=thread_func, args=(q, disp_lock,))
thread.daemon = True
thread.start()

threads.append(thread)
# Wait for them to finish
for thread in threads:
thread.join()