如何等待python中的multiprocessing.connection.Client可用？

Question

我有一个

process.py

脚本：

from multiprocessing.connection import Listener

with Listener(('localhost', 6000)) as listener:
    with listener.accept() as connection:
        message = connection.recv()
        # [...]
        connection.send(message)

我在线程中启动此脚本（以避免阻塞主线程）：

import threading, subprocess
threading.Thread(target=lambda: subprocess.run(['python', 'process.py'])).start()

但有时我想等待（阻塞主线程）直到我的进程启动。

这就是我所做的：

from multiprocessing.connection import Client

nAttempts = 0
while True:
    try:
        with Client(('localhost', 6000)) as connection:
            connection.send(nAttempts)
            message = connection.recv()
            # [...]
            break
    except ConnectionRefusedError:
        nAttempts += 1
        pass

有更好的方法吗？

程序在能够连接之前尝试了约 282 个连接，这会是一个问题吗？

Answer 1

首先修改

process.py

，这样就可以导入你需要的东西了：

from multiprocessing.connection import Listener

def listen(listening_event=None):
    with Listener(('localhost', 6000)) as listener:
        if listening_event:
            listening_event.set()  # Signal that we are now listening
    
        with listener.accept() as connection:
            message = connection.recv()
            # [...]
            connection.send(message)

if __name__ == '__main__':
    listen()

那么你的主要脚本将是：

import threading

from process import listen

listening_event = threading.Event()
t = Thread(target=listener, args=(listening_event,))
t.start()
listening_event.wait()  # Wait for this notification
...
t.join()  #  Wait for thread to terminate (if it ever does)