logging.py 文件源码

def reconfigure_rootlogger(cls,
            use_stderr=False, use_file='', verbose=False):

        cls._configured = True
        level = logging.DEBUG if verbose else logging.INFO

        # Clear out current handlers to allow re-use of basicConfig.
        rootlogger = logging.root       # old school: logging.getLogger('')
        cls._remove_handlers(rootlogger)

        if use_stderr:                  # does logging.RootLogger.addHandler()
            logging.basicConfig(        # only the first call matters
                stream=sys.stderr,
                format=cls._format,
                datefmt=cls._datefmt,
                level=level)

        if use_file:
            h = cls._setup_filehandler(use_file, backupCount=3)
            rootlogger.addHandler(h)
            rootlogger.setLevel(level)