class MyDLock(object):

    def __init__(self, lockID,timeout):

        self.connection = redis.Redis(host=cfg.REDIS_SERVER_IP, port=cfg.REDIS_SERVER_PORT, password=cfg.REDIS_SERVER_PWD, db=cfg.REDIS_SERVER_DB_NUM,decode_responses=True)

        self.__lockID = lockID

        self.__timeout  = timeout

    def tryLock(self, appid):

        #To_Main

        try:

            val=self.connection.get(self.__lockID)

            if val is None:

                logging.info("The app(%s) try lock(%s) ok." % (appid, self.__lockID));

                self.connection.set(self.__lockID, appid, ex=self.__timeout)

                return True

            else:

                logging.info("The owner of lock(%s) is %s. you(%s) can not get it"%(self.__lockID, val, appid));

                return False

        except Exception as e:

            logging.error("Warning: Can't write log. (%s)" % e)

            return False

    def activeLock(self, appid):

        #心跳，定期激活

        val = self.connection.get(self.__lockID)

        if val is None:

            logging.info("There is no lock(%s)." % (self.__lockID));

            return False

        else:

            if appid == val:

                #只能激活自己的锁

                logging.info("Application(%s) active lock(%s) ok." % (appid, self.__lockID));

                self.connection.set(self.__lockID, appid, ex=self.__timeout)

                return True

            else:

                #不能激活非自己的锁

                logging.info("Application(%s) can not active lock(%s). The owner is (%s)" % (appid, self.__lockID, val));

                return False

    def releaseLock(self, key, appid):

        val = self.connection.get(self.__lockID)

        if val is None:

            return False

        else:

            if appid == val:

                # 只能删除自己的锁

                self.connection.delete(self.__lockID)

                return True

            else:

                # 不能删除非自己的锁

                return False