python:多进程，多进程队列，多进程管道,Manager,进程锁,进程池

Posted 2020-10-22 CanSun

#!usr/bin/env python
# -*- coding:utf-8 -*-

__author__ = "Samson"

import multiprocessing
import time

def run(name):
    time.sleep(2)
    print("process start...%s" % name)
if __name__ == "__main__":
    for i in range(10):
        p = multiprocessing.Process(target=run,args=("bob",))
        p.start()

多进程队列

#!usr/bin/env python
# -*- coding:utf-8 -*-

__author__ = "Samson"

from multiprocessing import Process,Queue

def f(q):
    q.put([1,"ss",None])
if __name__ == "__main__":
    q = Queue()#进程队列，通过它可以使得子进程访问主进程的数据
    p = Process(target=f,args=(q,))
    p.start()
    print(q.get())
    p.join()

多进程管道

#!usr/bin/env python
# -*- coding:utf-8 -*-

__author__ = "Samson"
from multiprocessing import Pipe,Process

def fun(conn,data):
    conn.send(data)
    conn.send(data)
    print(conn.recv())

if __name__ == "__main__":
    data = "hello"
    parent_conn,child_conn = Pipe()#接收管道的两个对象
    p = Process(target=fun,args=(child_conn,data,))
    p.start()
    print(parent_conn.recv())
    print(parent_conn.recv())
    parent_conn.send("word")
    p.join()

多进程manager

#!usr/bin/env python
# -*- coding:utf-8 -*-

__author__ = "Samson"

from multiprocessing import Process,Manager
import os
def f(d, l):
    d[os.getpid()] =os.getppid()#存储相应进程的pid
    l.append(os.getpid())
    print(l)

if __name__ == "__main__":
    with Manager() as manager:
        d = manager.dict()#生成一个字典
        l = manager.list(range(5))#生成一个列表，默认值为0,1,2,3,4
        pro_obj = []#用于存储子进程
        for i in range(10):#生成十个子进程
            p = Process(target=f,args=(d,l))
            p.start()
            pro_obj.append(p)
        for pro in pro_obj:
            pro.join()

        print(d)
        print(l)

进程锁

#!usr/bin/env python
# -*- coding:utf-8 -*-

__author__ = "Samson"

from multiprocessing import Lock,Process
#进程锁可以防止一个进程在打印数据时，另一个进程插队进来打印数据
def f(l,d):
    l.acquire()
    print("hello %s" %d)
    l.release()
if __name__ == "__main__":
    lock = Lock()
    for i in range(10):
        p = Process(target=f,args=(lock,i))#注意，得把锁也传进去
        p.start()

进程池

#!usr/bin/env python
# -*- coding:utf-8 -*-

__author__ = "Samson"

from multiprocessing import Pool,Process
import time,os

def Foo(i):
    time.sleep(2)
    print("in process",os.getpid())
    return i + 100

def Bar(arg):
    print("--exec done:",arg,os.getpid())

if __name__ == "__main__":
    pool = Pool(processes=5)#允许进程池同时放入5个进程
    print("主进程:",os.getpid())
    for i in range(10):
        # pool.apply(func=Foo,args=(i,))#串行
        # pool.apply_async(func=Foo,args=(i,))#并行
        pool.apply_async(func=Foo,args=(i,),callback=Bar)#并行同时调用回掉函数Bar(),注意该回掉函数是由主进程调用的
    print("end")
    pool.close()#关闭进程池
    pool.join()#进程池中进程执行完毕后再关闭，如果注释，那么程序直接关闭；注意，该方法必须放在pool.close()函数后面