Using zeromq together with Python multiprocessing

Question

I found this example code that shows the usage of Python's multiprocessing together with ZeroMQ:

import zmq
import time
from multiprocessing import Process


def server():
    port="5556"
    context = zmq.Context()
    socket = context.socket(zmq.REP)
    socket.bind("tcp://*:%s" % port)
    print("Running server on port: ", port)
    # serves only 5 request and dies
    for reqnum in range(5):
        # Wait for next request from client
        message = socket.recv()
        print("Received request #%s: %s" % (reqnum, message))
        socket.send_string("World from %s" % port)


def client():
    port="5556"
    context = zmq.Context()
    print("Connecting to server with port %s" % port)
    socket = context.socket(zmq.REQ)
    socket.connect("tcp://localhost:%s" % port)
    for request in range(20):
        print("Sending request ", request, "...")
        socket.send_string("Hello")
        message = socket.recv()
        print("Received reply ", request, "[", message, "]")
        time.sleep(1)


if __name__ == "__main__":
    Process(target=server).start()
    Process(target=client).start()

This works well, but I would like to encapsulate the functions in classes, like so:

import zmq
import time
from multiprocessing import Process


class Server:
    def run(self, socket):
        port = "5556"
        # serves only 5 request and dies
        for reqnum in range(5):
            # Wait for next request from client
            message = socket.recv()
            print("Received request #%s: %s" % (reqnum, message))
            socket.send_string("World from %s" % port)


class Client:
    def run(self, socket):
        for request in range(20):
            print("Sending request ", request, "...")
            socket.send_string("Hello")
            message = socket.recv()
            print("Received reply ", request, "[", message, "]")
            time.sleep(1)


if __name__ == "__main__":
    port = "5556"
    
    server = Server()
    client = Client()
    
    context = zmq.Context()
    server_socket = context.socket(zmq.REP)
    server_socket.bind("tcp://*:%s" % port)
    print("Running server on port: ", port)
    
    context = zmq.Context()
    print("Connecting to server with port %s" % port)
    client_socket = context.socket(zmq.REQ)
    client_socket.connect("tcp://localhost:%s" % port)

    Process(target=server.run, args=(server_socket,)).start()

    Process(target=client.run, args=(client_socket,)).start()

But this results in following error message: TypeError: no default __reduce__ due to non-trivial __cinit__

I researched a little bit and thought it would be because I don't share variables between processes, but I actually don't share anything. The processes should be independent to each other and all communications should run using ZeroMQ.

Answer 1

等待大神答复