多进程multiprocessing

多进程实现简易版的抢票工具

实现：多个进程共享同一文件，把文件当数据库，用多个进程模拟多个人执行抢票任务
关键词：多进程，锁
1） 多进程

import json
import os
import time
from multiprocessing import Process, Lock, set_start_method

FILE_PATH = os.path.join(os.getcwd(), 'data.json')


class BuyTickets:
    def search(self, name):
        with open(FILE_PATH, 'r') as f:
            dic = json.loads(f.read())
            time.sleep(1)
            print(f"{name}用户查看剩余余票数为：{dic['count']}")

    def get(self, name):
        with open(FILE_PATH, 'r') as f_read:
            dic = json.loads(f_read.read())
            if dic.get('count') > 0:
                dic['count'] -= 1
                time.sleep(1)
                with open(FILE_PATH, 'w') as f_write:
                    json.dump(dic, f_write)
                    print(f'{name}购票成功!')
                    print(f'剩余票数为：{dic["count"]}')
            else:
                print('没票了')

    def task(self, name, lock):
        self.search(name)
        with lock:
            self.get(name)


if __name__ == '__main__':
    set_start_method('fork')
    _buy = BuyTickets()
    mutex = Lock()
    for i in range(10):
        p = Process(target=_buy.task, args=("路人%s" % i, mutex))
        p.start()

2. 进程池

from multiprocessing import Pool,Manager

class BuyTickets:
    def search(self, name):
        with open(FILE_PATH, 'r') as f:
            dic = json.loads(f.read())
            time.sleep(1)
            print(f"{name}用户查看剩余余票数为：{dic['count']}")

    def get(self, name):
        with open(FILE_PATH, 'r') as f_read:
            dic = json.loads(f_read.read())
            if dic.get('count') > 0:
                dic['count'] -= 1
                time.sleep(1)
                with open(FILE_PATH, 'w') as f_write:
                    json.dump(dic, f_write)
                    print(f'{name}购票成功!')
                    print(f'剩余票数为：{dic["count"]}')
            else:
                print('没票了')

    def task(self, name, lock):
        self.search(name)
        with lock:
            self.get(name)


if __name__ == '__main__':
    p = Pool(5)
    set_start_method('forkserver', force=True)
    _buy = BuyTickets()
    mutex = Manager().Lock()
    for i in range(10):
        res = p.apply_async(_buy.task, args=("路人%s" % i, mutex))
    p.close()
    p.join()