零mq：socket.recv（）调用被阻止

零mq：socket.recv（）调用被阻止

如果传递

zmq.NOBLOCK

flag参数，zmq.Socket.recv将不会阻塞。

文档说：

If NOBLOCK is set, this method will raise a ZMQError with EAGAIN if a message is not ready.

zmq会将接收到的消息放入队列中，并且每次recv（）调用都会返回一条消息，直到此队列耗尽为止，之后引发ZMQError。

下面示例中使用的zmq.Again是一个

wrapperfor zmq.EAGAIN

。

例如：

while True:    try:        #check for a message, this will not block        message = socket.recv(flags=zmq.NOBLOCK)        #a message has been received        print "Message received:", message    except zmq.Again as e:        print "No message received yet"    # perform other important stuff    time.sleep(10)

该

sub_client.py

示例可能被编写为使用如下非阻塞行为：

import sys, timeimport zmqport = "5556"if len(sys.argv) > 1:    port =  sys.argv[1]    int(port)# Socket to talk to servercontext = zmq.Context()socket = context.socket(zmq.SUB)print "Collecting updates from weather server..."socket.connect ("tcp://localhost:%s" % port)# Subscribe to zippre, default is NYC, 10001topicfilter = "10001"socket.setsockopt(zmq.SUBSCRIBE, topicfilter)# Process 5 updatestotal_value = 0received_value_count = 0do_receive_loop = Truewhile do_receive_loop:    try:        #process all messages waiting on subscribe socket        while True: #check for a message, this will not block string = socket.recv(flags=zmq.NOBLOCK) #message received, process it topic, messagedata = string.split() total_value += int(messagedata) print ('{} {}'.format(topic, messagedata)) #check if we have all the messages we want received_value_count += 1 if received_value_count > 4:     do_receive_loop = False     break    except zmq.Again as e:        #No messages waiting to be processed        pass    #Here we can do other stuff while waiting for messages    #contemplate answer to 'The Last Question'    time.sleep(15)    print "INSUFFICIENT DATA FOR MEANINGFUL ANSWER"print('Avg data value for topic {} was {}'.format(topicfilter, (total_value/5)))