生产者消费者模型

生产者+消息队列+消费者模型

q = JoinQueue()

JoinableQueue: 每当你往该队列中存入数据的时候，内部有一个计数器+1，每当调用task_done()时候，计数器-1

q.join(): 当计数器为0时，才往下执行代码。

未使用JoinableQueue案例一：

from multiprocessing import Process, Queue
import time
import random

def producer(name,food,q):
    for i in range(1,5):
        data = "%s produce %s no. %s" % (name,food,i)
        time.sleep(random.randint(1,3))
        q.put(data)
        print(data)

def customer(name,q):
    while True:
        data = q.get()
        if data is None:break      #检测到取到了标志位后循环停止
        time.sleep(random.randint(1,3))
        print("%s 吃了 %s" % (name,data))

if __name__ == '__main__':
    q = Queue()
    p1 = Process(target=producer,args=("hector",'brade',q))
    p2 = Process(target=producer,args=("nico","rice",q))
    c1 = Process(target=customer,args=("tom",q))
    c2 = Process(target=customer,args=("lily",q))
    p1.start()
    p2.start()
    c1.start()
    c2.start()
    p1.join()
    p2.join().  
    q.put(None).  #在队列之后插入None标志位
    q.put(None)。 #有几个消费者就要插入几个None

使用JoinableQueue模块案例二：标准的生产者消费者模型

from multiprocessing import Process, JoinableQueue
import time
import random

def producer(name,food,q):
    for i in range(1,5):
        data = "%s produce %s no. %s" % (name,food,i)
        time.sleep(random.randint(1,3))
        q.put(data)
        print(data)

def customer(name,q):
    while True:
        data = q.get()
        # if data is None:break
        time.sleep(random.randint(1,3))
        print("%s 吃了 %s" % (name,data))
        q.task_done()

if __name__ == '__main__':
    q = JoinableQueue()
    p1 = Process(target=producer,args=("hector",'brade',q))
    p2 = Process(target=producer,args=("nico","rice",q))
    c1 = Process(target=customer,args=("tom",q))
    c2 = Process(target=customer,args=("lily",q))
    p1.start()
    p2.start()
    c1.daemon = True
    c2.daemon = True     #定义为守护进程，当q.join()执行时表示数据已被取完，那么主进程结束，那么守护进程将被杀死。
    c1.start()
    c2.start()
    p1.join()
    p2.join()
    q.join()   # 直到队列中的数据全部取完为0时，才往下执行代码