随笔记录zmq中的poller()用法

              一个线程中如果有多个sokect,同时需要收发数据时,zmq提供polling sockets实现，不用在send()或者recv()时阻塞socket。

下面是一个在recv（）端接受信息的poller()轮询接受代码。

#!/usr/bin/python# -*- coding: utf-8import zmqimport randomimport timefrom  multiprocessing import Processdef server_push(port="5556"):    context = zmq.Context()    socket = context.socket(zmq.PUSH)    socket.bind("tcp://*:%s" % port)    print "Running server on port: ", port    # serves only 5 request and dies    for reqnum in range(10):        if reqnum < 6:            socket.send("Continue")        else:            socket.send("Exit")            break        time.sleep (1)def server_pub(port="5558"):    context = zmq.Context()    socket = context.socket(zmq.PUB)    socket.bind("tcp://*:%s" % port)    publisher_id = random.randrange(0,9999)    print "Running server on port: ", port    # serves only 5 request and dies    for reqnum in range(10):        # Wait for next request from client        topic = random.randrange(8,10)        messagedata = "server#%s" % publisher_id        print "%s %s" % (topic, messagedata)        socket.send("%d %s" % (topic, messagedata))        time.sleep(1)def client(port_push, port_sub):    context = zmq.Context()    socket_pull = context.socket(zmq.PULL)    socket_pull.connect ("tcp://localhost:%s" % port_push)    print "Connected to server with port %s" % port_push    socket_sub = context.socket(zmq.SUB)    socket_sub.connect ("tcp://localhost:%s" % port_sub)    socket_sub.setsockopt(zmq.SUBSCRIBE, "9")    #zmq.SUBSCRIBE创建一个消息过滤标志，订阅以9为前缀的消息    print "Connected to publisher with port %s" % port_sub    # 初始化Poller    poller = zmq.Poller()    poller.register(socket_pull, zmq.POLLIN)    poller.register(socket_sub, zmq.POLLIN)    # Work on requests from both server and publisher    #如果设置为POLLIN则刷新recv,与之对应的是POLLOUT刷新send发送事件，也可以同时设置两个标志    should_continue = True    while should_continue:        socks = dict(poller.poll())        if socket_pull in socks and socks[socket_pull] == zmq.POLLIN:            message = socket_pull.recv()            print "Recieved control command: %s" % message            if message == "Exit":                print "Recieved exit command, client will stop recieving messages"                should_continue = False        if socket_sub in socks and socks[socket_sub] == zmq.POLLIN:            string = socket_sub.recv()            topic, messagedata = string.split()            #Python split()通过指定分隔符对字符串进行切片，如果参数num 有指定值，则仅分隔 num 个子字符串            #str.split(str="", num=string.count(str)).            # str -- 分隔符，默认为所有的空字符，包括空格、换行(\n)、制表符(\t)等,num -- 分割次数            print "Processing ... ", topic, messagedataif __name__ == "__main__":    # Now we can run a few servers    server_push_port = "5556"    server_pub_port = "5558"    Process(target=server_push, args=(server_push_port,)).start()    Process(target=server_pub, args=(server_pub_port,)).start()    Process(target=client, args=(server_push_port,server_pub_port,)).start()

在poller中POLLIN和POLLOUT的区别是pollin在recv（）端，负责刷新recv端口，来接受信息，POLLOUT在send()端口，负责刷新send端，来发送消息。

 

flag (int, default=POLLIN|POLLOUT) – 0MQpoll flags. If flag|POLLIN, recv events will be flushed. If flag|POLLOUT, sendevents will be flushed. Both flags can be set at once, which is the default.

这是程序运行结果。

Running server on port:  5556Running server on port:  55588 server#5230Connected to server with port 5556Connected to publisher with port 5558Recieved control command: Continue8 server#5230Recieved control command: Continue9 server#5230Processing ...  9 server#5230Recieved control command: Continue9 server#5230Processing ...  9 server#5230Recieved control command: Continue9 server#5230Processing ...  9 server#5230Recieved control command: Continue9 server#5230Processing ...  9 server#5230Recieved control command: Continue9 server#5230Processing ...  9 server#5230Recieved control command: ExitRecieved exit command, client will stop recieving messages8 server#52309 server#52309 server#5230Process finished with exit code 0