python协程

有耗时操作，网络请求，IO，文件的读写

from time import sleep


def task1():
    for i in range(3):
        print("1-------->{}".format(i))
        yield i
        sleep(2)


def task2():
    for i in range(3):
        print("2-------->{}".format(i))
        yield i
        sleep(1)


if __name__ == '__main__':
    t1 = task1()
    t2 = task2()
    while True:
        try:
            next(t1)
            next(t2)
        except:
            print("任务结束")
            break

greenlet

import time
from greenlet import greenlet


def a():
    for i in range(5):
        print("A" + str(i))
        gb.switch()
        time.sleep(2)


def b():
    for i in range(5):
        print("B" + str(i))
        gc.switch()
        time.sleep(2)


def c():
    for i in range(5):
        print("C" + str(i))
        ga.switch()
        time.sleep(2)


if __name__ == '__main__':
    ga = greenlet(a)
    gb = greenlet(b)
    gc = greenlet(c)
    ga.switch()

猴子补丁

import time

import gevent
from gevent import monkey

monkey.patch_all()


def a():
    for i in range(5):
        print("A" + str(i))
        time.sleep(1)


def b():
    for i in range(5):
        print("B" + str(i))
        time.sleep(1)


def c():
    for i in range(5):
        print("C" + str(i))
        time.sleep(1)


if __name__ == '__main__':
    ga = gevent.spawn(a)
    gb = gevent.spawn(b)
    gc = gevent.spawn(c)

    ga.join()
    gb.join()
    gc.join()

猴子补丁模拟下载

import urllib.request
import gevent
from gevent import monkey

monkey.patch_all()


def download(url):
    # 网络请求耗时操作
    response = urllib.request.urlopen(url)
    text = response.read()
    print("下载了{}网站的数据".format(url))


if __name__ == '__main__':
    urls = ['http://www.163.com', 'http://www.qq.com', 'http://www.baidu.com']
    try:
        g1 = gevent.spawn(download, urls[0])
        g2 = gevent.spawn(download, urls[1])
        g3 = gevent.spawn(download, urls[2])
        g1.join()
        g2.join()
        g3.join()
    except:
        print("报错了")