python 协程
2020-12-13 16:10
标签：目的 table string 服务端 enc tom top 客户 pip3 单线程实现并发,在应用程序里控制多个任务的切换+保存状态 greenlet只是提供了一种比generator更加便捷的切换方式，当切到一个任务执行时如果遇到io，那就原地阻塞，仍然是没有解决遇到IO自动切换来提升效率的问题。 遇到IO阻塞时会自动切换任务 from gevent import monkey;monkey.patch_all()一定要放到导入socket模块之前，否则gevent无法识别socket的阻塞 python 协程 标签：目的 table string 服务端 enc tom top 客户 pip3 原文地址：https://www.cnblogs.com/kingforn/p/11618298.html协程
一、协程的本质：
二、协程的目的：
三、补充：
四、优点
五、缺点
注意：单纯地切换反而会降低运行效率
#并发执行 import time
def producer():
g=consumer()
next(g)
for i in range(100):
g.send(i)
def consumer():
while True:
res=yield
start_time=time.time()
producer()stop_time=time.time()
print(stop_time-start_time)
#串行import time
def producer():
res=[]
for i in range(10000000):
res.append(i)
return res
def consumer(res):
pass
start_time=time.time()
res=producer()
consumer(res)stop_time=time.time()
print(stop_time-start_time)
greenlet
注意：单纯的切换（在没有io的情况下或者没有重复开辟内存空间的操作），反而会降低程序的执行速度
#pip3 install greenlet from greenlet import greenlet
import time
def eat(name):
print(‘%s eat 1‘ %name)
time.sleep(2)
g2.switch(‘tom‘)
print(‘%s eat 2‘ %name)
g2.switch()
def play(name):
print(‘%s play 1‘ %name )
g1.switch()
print(‘%s play 2‘ %name )
g1=greenlet(eat)
g2=greenlet(play)
g1.switch(‘tom‘)
"""tom eat 1tom play 1tom eat 2tom play 2"""gevent
一、用法：
二、补充：
#pip3 install geventfrom gevent import monkey;monkey.patch_all()
import gevent
import time
def eat(name):
print(‘%s eat 1‘ % name)
time.sleep(3)
print(‘%s eat 2‘ % name)
def play(name):
print(‘%s play 1‘ % name)
time.sleep(2)
print(‘%s play 2‘ % name)
start_time=time.time()
g1=gevent.spawn(eat,‘tom‘)
g2=gevent.spawn(play,‘rose‘)
g1.join()g2.join()stop_time=time.time()
print(stop_time-start_time)
"""tom eat 1rose play 1rose play 2tom eat 23.003171920776367"""from gevent import monkey;monkey.patch_all()
import gevent
import time
def eat(name):
print(‘%s eat 1‘ % name)
time.sleep(3)
print(‘%s eat 2‘ % name)
def play(name):
print(‘%s play 1‘ % name)
time.sleep(2)
print(‘%s play 2‘ % name)
g1=gevent.spawn(eat,‘tom‘)
g2=gevent.spawn(play,‘rose‘)
# g1.join()# g2.join()gevent.joinall([g1,g2])三、通过gevent实现单线程下的socket并发
"""服务端#基于gevent实现"""from gevent import monkey,spawn;monkey.patch_all()
from socket import *
def communicate(conn):
while True:
try:
data=conn.recv(1024)
if not data:break
conn.send(data.upper())
except ConnectionResetError:
break
conn.close()
def server(ip,port):
server = socket(AF_INET, SOCK_STREAM)
server.bind((ip,port))
server.listen(5)
while True:
conn, addr = server.accept()
spawn(communicate,conn)
server.close()
if __name__ == ‘__main__‘:
g=spawn(server,‘127.0.0.1‘,8090)
g.join()
"""客户端"""from socket import *
from threading import Thread,currentThread
def client():
client=socket(AF_INET,SOCK_STREAM)
client.connect((‘127.0.0.1‘,8090))
while True:
client.send((‘%s hello‘ %currentThread().getName()).encode(‘utf-8‘))
data=client.recv(1024)
print(data.decode(‘utf-8‘))
client.close()
if __name__ == ‘__main__‘:
for i in range(500):
t=Thread(target=client)
t.start()