协程

协程
    Coroutine,用户自己控制的轻量级线程
    好处:
        无须线程上下文切换的开销
        无须院子操作锁定和同步的开销
        方便切换控制流,简化编程模型
        高并发,高扩展,低成本

    缺点:
        无法利用多核资源

    遇到IO操作就切换下一个协程

#!/usr/bin/env python3
# -*- coding:utf-8 -*-
# -*- Author:Hinimix -*-
# yield实现类似效果

def consumer(name):
    print("start eating baozi")
    while True:
        new_baozi = yield
        print("%s is eating baozi %s" % (name, new_baozi))


def producer():
    conn1.__next__()
    conn2.__next__()
    n = 0
    while n < 5:
        conn1.send(n)
        conn2.send(n)
        print("making baozi, ", n)
        n += 1


if __name__ == '__main__':
    conn1 = consumer('hinimix')
    conn2 = consumer('annie')
    p = producer()

 greenlet 协程

#!/usr/bin/env python3
# -*- coding:utf-8 -*-
# -*- Author:Hinimix -*-
from greenlet import greenlet
# 封装好的协程库
# gevent是对greenlet再次封装而成的,可以自动切换协程

def t1():
    print(12)
    gr2.switch()
    print(34)
    gr2.switch()


def t2():
    print(56)
    gr1.switch()
    print(78)


gr1 = greenlet(t1)
gr2 = greenlet(t2)

gr1.switch()

 gevent

#!/usr/bin/env python3
# -*- coding:utf-8 -*-
# -*- Author:Hinimix -*-
import gevent

def t1():
    print('in t1')
    gevent.sleep(2)
    print('done t1')

def t2():
    print('in t2')
    gevent.sleep(.5)
    print('done t2')

def t3():
    print('in t3')
    gevent.sleep(0)
    print('done t3')
gevent.joinall([
    gevent.spawn(t1),
    gevent.spawn(t2),
    gevent.spawn(t3)
])

gevent并行和串行对比

并行:

#!/usr/bin/env python3
# -*- coding:utf-8 -*-
# -*- Author:Hinimix -*-

import urllib.request
import gevent
from gevent import monkey
import time

monkey.patch_all()      #把当前程序所有的IO单独做标记

def get_url(url):
    print('get url %s' % url)
    response = urllib.request.urlopen(url)
    print('done! size: ', len(response.read()))
    return response.read()


# print(get_url("https://blog.csdn.net/woainishifu/article/details/76105667"))
atime = time.time()
gevent.joinall([
    gevent.spawn(get_url, 'https://blog.csdn.net/woainishifu/article/details/76105667'),
    gevent.spawn(get_url, 'http://www.sina.com.cn/'),
    gevent.spawn(get_url, 'https://www.openssl.org/source/')
])
btime = time.time()
print(btime-atime)

串行:

#!/usr/bin/env python3
# -*- coding:utf-8 -*-
# -*- Author:Hinimix -*-

import urllib.request
import gevent
import time

def get_url(url):
    print('get url %s' % url)
    response = urllib.request.urlopen(url)
    print('done! size: ', len(response.read()))
    return response.read()

list_address = [
'https://blog.csdn.net/woainishifu/article/details/76105667',
'http://www.sina.com.cn/',
'https://www.openssl.org/source/',
]

# print(get_url("https://blog.csdn.net/woainishifu/article/details/76105667"))
atime = time.time()
for i in list_address:
    get_url(i)
btime = time.time()
print(btime-atime)