Python 创建进程的三种方式

最新推荐文章于 2024-11-19 15:48:23 发布

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第一种方式：使用os模块中的fork方式实现多进程

Python

# -*- coding: utf-8 -*- """ @Time: 2018/1/20 @Author: songhao @微信公众号: zero<a href="https://www.168seo.cn/tag/python" title="View all posts in python" target="_blank">python</a> @File: jincheng.py """ # 第一种方式：使用<a href="https://www.168seo.cn/tag/os" title="View all posts in os" target="_blank">os</a>模块中的fork方式实现多进程 import <a href="https://www.168seo.cn/tag/os" title="View all posts in os" target="_blank">os</a> if __name__ == '__main__': print('current Process ({}) start ...'.format(<a href="https://www.168seo.cn/tag/os" title="View all posts in os" target="_blank">os</a>.getpid())) pid = os.fork() if pid < 0: print('error in fork') elif pid == 0: print('I am child process({0}) and my parent process is ({1})'.format(os.getpid(), os.getppid())) else: print('I({0}) created a chlid process ({1}).'.format(os.getpid(),pid))

# -*- coding: utf-8 -*-

"""

@Time: 2018/1/20

@Author: songhao

@微信公众号: zeropython

@File: jincheng.py

"""

# 第一种方式：使用os模块中的fork方式实现多进程

import os

if __name__ == '__main__' :

print ( 'current Process ({}) start ...' . format ( os . getpid ( ) ) )

pid = os . fork ( )

if pid < 0 :

print ( 'error in fork' )

elif pid == 0 :

print ( 'I am child process({0}) and my parent process is ({1})' . format ( os . getpid ( ) , os . getppid ( ) ) )

else :

print ( 'I({0}) created a chlid process ({1}).' . format ( os . getpid ( ) , pid ) )

输出：

第二种方法：使用multiprocessing模块创建多进程

Python

import os from <a href="https://www.168seo.cn/tag/multiprocessing" title="View all posts in multiprocessing" target="_blank">multiprocessing</a> import Process # 子进程要执行的代码 def run_proc(name): print('Child process {0} ({1}) Running...'.format(name, os.getpid())) if __name__ == '__main__': print('Parent process %s.' % os.getpid()) p_list=[] for i in range(5): p = Process(target=run_proc, args=(str(i),)) p_list.append(p) print('Process will start.') p_list[i].start() for p in p_list: p.join() print('Process end.')

import os

from multiprocessing import Process

# 子进程要执行的代码

def run_proc ( name ) :

print ( 'Child process {0} ({1}) Running...' . format ( name , os . getpid ( ) ) )

if __name__ == '__main__' :

print ( 'Parent process %s.' % os . getpid ( ) )

p_list = [ ]

for i in range ( 5 ) :

p = Process ( target = run_proc , args = ( str ( i ) , ) )

p_list . append ( p )

print ( 'Process will start.' )

p_list [ i ] . start ( )

for p in p_list :

p . join ( )

print ( 'Process end.' )

输出结果：

multiprocessing模块提供了一个Pool类来代表进程池对象

Python

from multiprocessing import Pool import os, time, random def run_task(name): print 'Task %s (pid = %s) is running...' % (name, os.getpid()) time.sleep(random.random() * 3) print 'Task %s end.' % name if __name__=='__main__': print 'Current process %s.' % os.getpid() p = Pool(processes=3) for i in range(5): p.apply_async(run_task, args=(i,)) print 'Waiting for all subprocesses done...' p.close() p.join() print 'All subprocesses done.'

from multiprocessing import Pool

import os , time , random

def run_task ( name ) :

print 'Task %s (pid = %s) is running...' % ( name , os . getpid ( ) )

time . sleep ( random . random ( ) * 3 )

print 'Task %s end.' % name

if __name__ == '__main__' :

print 'Current process %s.' % os . getpid ( )

p = Pool ( processes = 3 )

for i in range ( 5 ) :

p . apply_async ( run_task , args = ( i , ) )

print 'Waiting for all subprocesses done...'

p . close ( )

p . join ( )

print 'All subprocesses done.'

# Queue进程间通信

Python

Queue进程间通信 from multiprocessing import Process, Queue import os, time, random # 写数据进程执行的代码: def proc_write(q,urls): print('Process(%s) is writing...' % os.getpid()) for url in urls: q.put(url) print('Put %s to queue...' % url) time.sleep(random.random()) # 读数据进程执行的代码: def proc_read(q): print('Process(%s) is reading...' % os.getpid()) while True: url = q.get(True) print('Get %s from queue.' % url) if __name__=='__main__': # 父进程创建Queue，并传给各个子进程： q = Queue() proc_writer1 = Process(target=proc_write, args=(q,['url_1', 'url_2', 'url_3'])) proc_writer2 = Process(target=proc_write, args=(q,['url_4','url_5','url_6'])) proc_reader = Process(target=proc_read, args=(q,)) # 启动子进程proc_writer，写入: proc_writer1.start() proc_writer2.start() # 启动子进程proc_reader，读取: proc_reader.start() # 等待proc_writer结束: proc_writer1.join() proc_writer2.join() # proc_reader进程里是死循环，无法等待其结束，只能强行终止: proc_reader.terminate()

Queue进程间通信

from multiprocessing import Process , Queue

import os , time , random

# 写数据进程执行的代码:

def proc_write ( q , urls ) :

print ( 'Process(%s) is writing...' % os . getpid ( ) )

for url in urls :

q . put ( url )

print ( 'Put %s to queue...' % url )

time . sleep ( random . random ( ) )

# 读数据进程执行的代码:

def proc_read ( q ) :

print ( 'Process(%s) is reading...' % os . getpid ( ) )

while True :

url = q . get ( True )

print ( 'Get %s from queue.' % url )

if __name__ == '__main__' :

# 父进程创建Queue，并传给各个子进程：

q = Queue ( )

proc_writer1 = Process ( target = proc_write , args = ( q , [ 'url_1' , 'url_2' , 'url_3' ] ) )

proc_writer2 = Process ( target = proc_write , args = ( q , [ 'url_4' , 'url_5' , 'url_6' ] ) )

proc_reader = Process ( target = proc_read , args = ( q , ) )

# 启动子进程proc_writer，写入:

proc_writer1 . start ( )

proc_writer2 . start ( )

# 启动子进程proc_reader，读取:

proc_reader . start ( )

# 等待proc_writer结束:

proc_writer1 . join ( )

proc_writer2 . join ( )

# proc_reader进程里是死循环，无法等待其结束，只能强行终止:

proc_reader . terminate ( )

pipe进程间通信

Python

import multiprocessing import random import time,os def proc_send(pipe,urls): for url in urls: print "Process(%s) send: %s" %(os.getpid(),url) pipe.send(url) time.sleep(random.random()) def proc_recv(pipe): while True: print "Process(%s) rev:%s" %(os.getpid(),pipe.recv()) time.sleep(random.random())