logging.py 文件源码

def _extract_handlers(handlers_dict):
    handlers = []
    if not handlers_dict:
        raise ConfigurationError('no handlers are defined for logger')

    for filename, handler_config in handlers_dict.items():
        if not isinstance(handler_config, collections.abc.Mapping):
            raise ConfigurationError(
                'handler %s is not a dictionary' % filename
            )

        level = handler_config.get('level', 'debug').lower()
        fmt   = handler_config.get('format', '%(message)s')
        datefmt = handler_config.get('datefmt', '%FT%T')
        append  = handler_config.get('append', False)
        timestamp = handler_config.get('timestamp', None)

        if filename == '&1':
            hdlr = StreamHandler(stream=sys.stdout)
        elif filename == '&2':
            hdlr = StreamHandler(stream=sys.stderr)
        else:
            if timestamp:
                basename, ext = os.path.splitext(filename)
                filename = '%s_%s%s' % (
                    basename, datetime.now().strftime(timestamp), ext
                )

            hdlr = RotatingFileHandler(filename, mode='a+' if append else 'w+')

        hdlr.setFormatter(logging.Formatter(fmt=fmt, datefmt=datefmt))
        hdlr.setLevel(level)
        handlers.append(hdlr)

    return handlers