multiprocessing.Queue

• q = multiprocessing.Queue()
• q.put(x) # 向隊(duì)列中放入一個(gè)值
• q.get() # 從隊(duì)列中取一個(gè)值
• q.empty() # 判斷隊(duì)列是否為空
• q.full() # 判斷隊(duì)列是否滿了
• q.get_nowait() # 從隊(duì)列中取值魂角，如果隊(duì)列為空丛忆，則拋出異常。普通get()方法為空時(shí)堵塞
• q.qsize() # 求取隊(duì)列長(zhǎng)度

生產(chǎn)者消費(fèi)者模型

用來解決數(shù)據(jù)供需的平衡問題

• 生產(chǎn)者 -- 進(jìn)程
• 消費(fèi)者 -- 進(jìn)程

import multiprocessing
import time
import random


def consumer(q, name):
    while True:
        food = q.get()
        if food is None:
            print("%s 拿到一個(gè)空" % name)
            break
        print("\033[31m%s 消費(fèi)了 %s\033[0m" %(name, food))
        time.sleep(random.randint(1, 3))


def producer(name, food, q):
    for i in range(10):
        f = "%s生產(chǎn)的 %s %s" % (name, food, i)
        print(f)
        q.put(f)
        time.sleep(1)


if __name__ == "__main__":
    q = multiprocessing.Queue(20)
    p = multiprocessing.Process(target=producer, args=("Sun", "包子", q))
    p.start()
    p2 = multiprocessing.Process(target=producer, args=("Wang", "泔水", q))
    p2.start()
    c1 = multiprocessing.Process(target=consumer, args=(q, "1號(hào)"))
    c1.start()
    c2 = multiprocessing.Process(target=consumer, args=(q, "2號(hào)"))
    c2.start()
    p.join()
    p2.join()
    q.put(None)
    q.put(None)

JoinableQueue

使用阻塞方式等待隊(duì)列空閑后退出

import multiprocessing
import time
import random

def consumer(q, name):
    while True:
        food = q.get()
        print("\033[31m%s 消費(fèi)了 %s\033[0m" %(name, food))
        time.sleep(random.randint(1, 3))
        q.task_done()


def producer(name, food, q):
    for i in range(10):
        f = "%s生產(chǎn)的 %s %s" % (name, food, i)
        print(f)
        q.put(f)
        time.sleep(1)
    q.join()


if __name__ == "__main__":
    q = multiprocessing.JoinableQueue(20)
    p1 = multiprocessing.Process(target=producer, args=("Sun", "包子", q))
    p1.start()
    p2 = multiprocessing.Process(target=producer, args=("Wang", "泔水", q))
    p2.start()
    c1 = multiprocessing.Process(target=consumer, args=(q, "1號(hào)"))
    c2 = multiprocessing.Process(target=consumer, args=(q, "2號(hào)"))

    c1.daemon = True
    c2.daemon = True

    c1.start()
    c2.start()

    p1.join()
    p2.join()