zeromq pub/sub/FORWARDER实现 FORWARDER模式

参考： https://learning-0mq-with-pyzmq.readthedocs.io/en/latest/pyzmq/devices/forwarder.html
1）forwarder_device.py

import zmq

def main():
    try:
        context = zmq.Context(1)
        # Socket facing clients
        frontend = context.socket(zmq.SUB)
        frontend.bind("tcp://*:5559")

        frontend.setsockopt(zmq.SUBSCRIBE, "".encode('ascii'))

        # Socket facing services
        backend = context.socket(zmq.PUB)
        backend.bind("tcp://*:5560")

        zmq.device(zmq.FORWARDER, frontend, backend)
    except Exception as e:
        print (e)
        print ("bringing down zmq device")
    finally:
        pass
        frontend.close()
        backend.close()
        context.term()

if __name__ == "__main__":
    main()

2）forwarder_subscriber.py

import sys
import zmq

port = "5560"
# Socket to talk to server
context = zmq.Context()
socket = context.socket(zmq.SUB)
print ("Collecting updates from server...")
socket.connect ("tcp://localhost:%s" % port)
topicfilter = "9".encode('ascii')
socket.setsockopt(zmq.SUBSCRIBE, topicfilter)

for update_nbr in range(10):
    string = socket.recv()
    topic, messagedata = string.split()
    print (topic, messagedata)

3）forwarder_server.py

import zmq
import random
import sys
import time

port = "5559"
context = zmq.Context()
socket = context.socket(zmq.PUB)
socket.connect("tcp://localhost:%s" % port)
publisher_id = random.randrange(0,9999)
while True:
    topic = random.randrange(1,10)
    messagedata = "server#%s" % publisher_id
    print ("%s %s" % (topic, messagedata))
    socket.send( ("%d %s" % (topic, messagedata)).encode('ascii') )
    time.sleep(1)

#python3 forwarder_device.py
#python3 forwarder_subscriber.py
#python3 forwarder_server.py
#python3 forwarder_server.py