python 多进程使用Queue通信的例子

import time
from multiprocessing import Process,Queue

MSG_QUEUE = Queue(5)

def startA(msgQueue):
    while True:
        if msgQueue.empty() > 0:
            print 'queue is empty %d' % (msgQueue.qsize())
        else:
            msg = msgQueue.get()
            print 'get msg %s' % (msg,)
        time.sleep(1)

def startB(msgQueue):
    while True:
        msgQueue.put('hello world')
        print 'put hello world queue size is %d' % (msgQueue.qsize(),)
        time.sleep(3)

if __name__ == '__main__':
    processA = Process(target=startA,args=(MSG_QUEUE,))
    processB = Process(target=startB,args=(MSG_QUEUE,))

    processA.start()
    print 'processA start..'

    processB.start()
    print 'processB start..'

python2.6 test.py
processA start..
queue is empty 0
processB start..
put hello world queue size is 1
get msg hello world
queue is empty 0
queue is empty 0
put hello world queue size is 1
get msg hello world
queue is empty 0
queue is empty 0
put hello world queue size is 1
get msg hello world
queue is empty 0
queue is empty 0
put hello world queue size is 1
get msg hello world
queue is empty 0
queue is empty 0
put hello world queue size is 1
get msg hello world
queue is empty 0
queue is empty 0
put hello world queue size is 1
get msg hello world
queue is empty 0
queue is empty 0
put hello world queue size is 1
get msg hello world
queue is empty 0
queue is empty 0

主进程定义了一个Queue类型的变量，并作为Process的args参数传给子进程processA和processB，两个进程一个向队列中写数据，一个读数据。

其打印的结果如下：

python2.6 test.py
processA start..
queue is empty 0
processB start..
put hello world queue size is 1
get msg hello world
queue is empty 0
queue is empty 0
put hello world queue size is 1
get msg hello world
queue is empty 0
queue is empty 0
put hello world queue size is 1
get msg hello world
queue is empty 0
queue is empty 0
put hello world queue size is 1
get msg hello world
queue is empty 0
queue is empty 0
put hello world queue size is 1
get msg hello world
queue is empty 0
queue is empty 0
put hello world queue size is 1
get msg hello world
queue is empty 0
queue is empty 0
put hello world queue size is 1
get msg hello world
queue is empty 0
queue is empty 0