Django signal 信号量 参考博客：方法发及使用场景：https://my.oschina.net/linktime/blog/151871 部分源码解析：https://www.cnblogs.com/shizhengwen/p/7716178.html https://www.jianshu.com/p/b8cb3d295f8f https://blog.csdn.net/u013007900/article/details/78110891