Python synchronization management mechanism-semaphore

import multiprocessing,time
'''
    测试多进程
    使用Semaphore
'''
def worker(sema):
    # 获取信号量,如果没有可用信号量则进入到组赛队列;
    if sema.acquire():
        # 输出提示信息
        print("{}进程开始进行业务办理".format(multiprocessing.current_process().name));
        # 模拟业务逻辑处理时间
        time.sleep(2);
        # 释放资源,一般放在finally中
        sema.release();
def main():
    # 创建只允许有三个进程并发执行
    sema = multiprocessing.Semaphore(3);
    # 创建10个进程模拟操作
    job_process = [multiprocessing.Process(target=worker,args=(sema,),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();

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