python进程同步 使用lock锁

多进程数据不同步

import multiprocessing,time
'''
    测试多进程抢票
    并发执行,或导致数据不同步,那么我们需要做的是进程同步,进行加锁
'''
def worker(dict):
    while True:
        number = dict.get("ticket");
        if number > 0:
            # 模拟网络延迟
            time.sleep(1);
            number -= 1;
            print("{},ticket = {}".format(multiprocessing.current_process().name,number));
            dict.update({
    
    "ticket":number});
        else:
            break;
def main():
    # 创建贡献数据
    manager = multiprocessing.Manager();
    # 创建共享的字典对象
    manager_dict = manager.dict(ticket = 5);
    # 创建10个进程模拟操作
    job_process = [multiprocessing.Process(target=worker,args=(manager_dict,),name = "售票员：{}".format(item)) for item in range(10)];
    # 启动
    for process in job_process:
        process.start();
    for process in job_process:
        process.join();

    print("所有进程执行完毕,字典最终数据为：{}".format(manager_dict))


if __name__ == '__main__':
    main();

使用lock进行同步的处理 和Java一样,但是这样加锁的话,会导致性能的下降;

import multiprocessing,time
'''
    测试多进程抢票
    并发执行,或导致数据不同步,那么我们需要做的是进程同步,进行加锁
    使用lock进行加锁和解锁
'''
def worker(dict,lock):
    while True:
        # 加锁 设置5秒的加锁时间,超时放弃加锁
        lock.acquire(timeout = 5);
        number = dict.get("ticket");
        if number > 0:
            # 模拟网络延迟
            time.sleep(1);
            number -= 1;
            print("{},ticket = {}".format(multiprocessing.current_process().name,number));
            dict.update({
    
    "ticket":number});
        else:
            break;
        # 解锁
        lock.release();
def main():
    # 创建锁
    lock = multiprocessing.Lock();
    # 创建贡献数据
    manager = multiprocessing.Manager();
    # 创建共享的字典对象
    manager_dict = manager.dict(ticket = 5);
    # 创建10个进程模拟操作
    job_process = [multiprocessing.Process(target=worker,args=(manager_dict,lock,),name = "售票员：{}".format(item)) for item in range(10)];
    # 启动
    for process in job_process:
        process.start();
    for process in job_process:
        process.join();

    print("所有进程执行完毕,字典最终数据为：{}".format(manager_dict))


if __name__ == '__main__':
    main();