python学习笔记(57) 进程间通信

IPC(Inter-Process Communication)

队列：

队列是进程安全的：同时只能被一个进程取值

q = Queue(5)

q.put()

q.full()

q.get()　　# 无值阻塞

q.empty()　　# 如果其他进程正在添加项目，那么结果不准确

q.get_nowait()　　# 无值报错

import time
import random
from multiprocessing import Process,Queue

def consumer(q,name):
    while True:
        food = q.get()
        if food is None:
            print('%s啥也没拿到'%name)
            break
        print('%s吃了%s'%(name,food))
        time.sleep(random.randint(1,3))


def producer(name,food,q):
    for i in range(4):
        time.sleep(random.randint(1,3))
        print('%s生产了%s'%(name,food))
        q.put(food)


if __name__ == '__main__':
    q = Queue(20)
    p1 = Process(target=producer,args=('汤姆','包子',q))
    p2 = Process(target=producer, args=('杰瑞','沙琪玛',q))
    c1 = Process(target=consumer,args=(q,'狗狗'))
    c2 = Process(target=consumer, args=(q, '小鸟'))
    p1.start()
    p2.start()
    c1.start()
    c2.start()
    p1.join()
    p2.join()
    q.put(None)
    q.put(None)

################################################

JoinableQueue

多了

q.join(),

q.task_done()

方法

import time
import random
from multiprocessing import Process,JoinableQueue

def consumer(q,name):
    while True:
        food = q.get()
        print('%s吃了%s'%(name,food))
        time.sleep(random.randint(1,3))
        q.task_done()


def producer(name,food,q):
    for i in range(4):
        time.sleep(random.randint(1,3))
        print('%s生产了%s%s'%(name,food,i))
        q.put(food)
    q.join()


if __name__ == '__main__':
    q = JoinableQueue(20)
    p1 = Process(target=producer,args=('汤姆','包子',q))
    p2 = Process(target=producer, args=('杰瑞','沙琪玛',q))
    c1 = Process(target=consumer,args=(q,'狗狗'))
    c2 = Process(target=consumer, args=(q, '小鸟'))
    p1.start()
    p2.start()
    c1.daemon = True
    c2.daemon = True
    c1.start()
    c2.start()
    p1.join()
    p2.join()