Python学习 之 协程

---

gevent 模块

from gevent import monkey;monkey.patch_all()
import gevent
import time
import random


# 定义使用协程执行的两个函数
# 间隔随机时间, 打印下一个(模拟 io)
# 因为 io 阻塞时间不同, 所以输出结果也不同
def myprint1(i):
    print(i)
    time.sleep(random.randint(1,3))
    print(i+1)
    time.sleep(random.randint(1,3))
    print(i+2)


def myprint2():
    print("x")
    time.sleep(random.randint(1,3))
    print("y")
    time.sleep(random.randint(1,3))
    print("z")
    

if __name__ == "__main__":
    gevent.joinall([
    	# 参数依次写在 spawn 后边即可
        gevent.spawn(myprint1, 10),
        gevent.spawn(myprint2),
    ])

    # 等同于
    # g1 = gevent.spawn(myprint1, 10)
    # g2 = gevent.spawn(myprint2)

    # g1.join()
    # g2.join()

---

greenlet 模块

""" - 比较简单粗暴, 声明切换过程 """
import greenlet 

def eat(name):
    print("%s eat 1" % name)
    # No. 2
    gp.switch("Tim")
    print("%s eat 2" % name)
    # No. 4
    gp.switch()

def play(name):
    print("%s play 1" % name)
    # No. 3
    ge.switch()
    print("%s play 2" % name)

# greenlet 对象
ge = greenlet.greenlet(eat)
gp = greenlet.greenlet(play)

# No. 1
# 第一次使用需要传参, 之后的使用不需要
ge.switch("Tim")

---

示例 - 使用协程单线程实现并发

• server.py

  from gevent import monkey, spawn;monkey.patch_all()
  from socket import socket,AF_INET,SOCK_STREAM
  from threading import Thread,current_thread
  
  def communicat(conn):
      print("子线程: %s" % current_thread().getName())
      while True:
          try:
              data = conn.recv(1024)
              if not data:break
              conn.send(data.upper())
          except ConnectionRefusedError:
              break
      conn.close()
  
  
  def server(ip, port):
      print("主线程: %s" % current_thread().getName())
      s = socket(AF_INET, SOCK_STREAM)
      s.bind((ip, port))
      s.listen(5)
  
      while 1:
          conn, addr = s.accept()
          print(addr)
          # t = Thread(target=communicat, args=(conn,))
          # t.start()
          spawn(communicat, conn)
      s.close()
  
  if __name__ == "__main__":
      g = spawn(server, "127.0.0.1", 8081)
      g.join()
  
  

• client.py

  from socket import socket,AF_INET,SOCK_STREAM
  from threading import Thread, current_thread
  
  def client():
      c = socket(AF_INET, SOCK_STREAM)
      c.connect(("127.0.0.1", 8081))
  
      while 1:
          msg = "%s say hello" % current_thread().getName()
          c.send(msg.encode("utf-8"))
          r = c.recv(1024)
          print(r.decode("utf-8"))
  
      c.close()
  
  
  if __name__ == "__main__":
      for i in range(500):
          t = Thread(target=client)
          t.start()