python loging 文件是空的问题

不知道怎么回事，一个日志本地Macbook没问题，线上centos就输出了一个空文件：

原来代码

logHandler = TimedRotatingFileHandler(log_file, when='midnight', interval=1)
logHandler.setLevel(level=logging.INFO)
logging.basicConfig(level=logging.INFO,
                    format='%(asctime)s %(pathname)s %(filename)s %(funcName)s %(lineno)d %(levelname)s - %(message)s',
                    handlers=[logHandler])
print("__name__ is " + str(__name__))
logger = logging.getLogger(__name__)
logger.setLevel(logging.INFO)

这里用了basicConfig，结果logging file是个空文件

改成下面，去掉basicConfig就好了，原因未知

logger = logging.getLogger(__name__)
logger.setLevel(logging.INFO)
log_format = logging.Formatter('%(asctime)s %(pathname)s %(filename)s %(funcName)s %(lineno)d %(levelname)s - %(message)s')
logHandler = TimedRotatingFileHandler(log_file, when='midnight', interval=1)
logHandler.setLevel(level=logging.INFO)
logHandler.setFormatter(log_format)
logger.addHandler(logHandler)