本文實(shí)例講述了python 協(xié)程 gevent原理與用法。分享給大家供大家參考，具體如下：

gevent

greenlet已經(jīng)實(shí)現(xiàn)了協(xié)程，但是這個(gè)還的人工切換，是不是覺(jué)得太麻煩了，不要捉急，python還有一個(gè)比greenlet更強(qiáng)大的并且能夠自動(dòng)切換任務(wù)的模塊gevent

其原理是當(dāng)一個(gè)greenlet遇到IO(指的是input output 輸入輸出，比如網(wǎng)絡(luò)、文件操作等)操作時(shí)，比如訪問(wèn)網(wǎng)絡(luò)，就自動(dòng)切換到其他的greenlet，等到IO操作完成，再在適當(dāng)?shù)臅r(shí)候切換回來(lái)繼續(xù)執(zhí)行。

由于IO操作非常耗時(shí)，經(jīng)常使程序處于等待狀態(tài)，有了gevent為我們自動(dòng)切換協(xié)程，就保證總有g(shù)reenlet在運(yùn)行，而不是等待IO

安裝

pip3 install gevent

1. gevent的使用

import geventdef f(n):  for i in range(n):    print(gevent.getcurrent(), i)g1 = gevent.spawn(f, 5)g2 = gevent.spawn(f, 5)g3 = gevent.spawn(f, 5)g1.join()g2.join()g3.join()

運(yùn)行結(jié)果

<Greenlet at 0x10e49f550: f(5)> 0
<Greenlet at 0x10e49f550: f(5)> 1
<Greenlet at 0x10e49f550: f(5)> 2
<Greenlet at 0x10e49f550: f(5)> 3
<Greenlet at 0x10e49f550: f(5)> 4
<Greenlet at 0x10e49f910: f(5)> 0
<Greenlet at 0x10e49f910: f(5)> 1
<Greenlet at 0x10e49f910: f(5)> 2
<Greenlet at 0x10e49f910: f(5)> 3
<Greenlet at 0x10e49f910: f(5)> 4
<Greenlet at 0x10e49f4b0: f(5)> 0
<Greenlet at 0x10e49f4b0: f(5)> 1
<Greenlet at 0x10e49f4b0: f(5)> 2
<Greenlet at 0x10e49f4b0: f(5)> 3
<Greenlet at 0x10e49f4b0: f(5)> 4

可以看到，3個(gè)greenlet是依次運(yùn)行而不是交替運(yùn)行

2. gevent切換執(zhí)行

import geventdef f(n):  for i in range(n):    print(gevent.getcurrent(), i)    #用來(lái)模擬一個(gè)耗時(shí)操作，注意不是time模塊中的sleep    gevent.sleep(1)g1 = gevent.spawn(f, 5)g2 = gevent.spawn(f, 5)g3 = gevent.spawn(f, 5)g1.join()g2.join()g3.join()

運(yùn)行結(jié)果

<Greenlet at 0x7fa70ffa1c30: f(5)> 0
<Greenlet at 0x7fa70ffa1870: f(5)> 0
<Greenlet at 0x7fa70ffa1eb0: f(5)> 0
<Greenlet at 0x7fa70ffa1c30: f(5)> 1
<Greenlet at 0x7fa70ffa1870: f(5)> 1
<Greenlet at 0x7fa70ffa1eb0: f(5)> 1
<Greenlet at 0x7fa70ffa1c30: f(5)> 2
<Greenlet at 0x7fa70ffa1870: f(5)> 2
<Greenlet at 0x7fa70ffa1eb0: f(5)> 2
<Greenlet at 0x7fa70ffa1c30: f(5)> 3
<Greenlet at 0x7fa70ffa1870: f(5)> 3
<Greenlet at 0x7fa70ffa1eb0: f(5)> 3
<Greenlet at 0x7fa70ffa1c30: f(5)> 4
<Greenlet at 0x7fa70ffa1870: f(5)> 4
<Greenlet at 0x7fa70ffa1eb0: f(5)> 4

3. 給程序打補(bǔ)丁

from gevent import monkeyimport geventimport randomimport timedef coroutine_work(coroutine_name):  for i in range(10):    print(coroutine_name, i)    time.sleep(random.random())gevent.joinall([    gevent.spawn(coroutine_work, "work1"),    gevent.spawn(coroutine_work, "work2")])