为根记录器配置格式

Question

I use this code to configure the given logger, or the root logger:

def configure_logging(level='INFO', logger=None):
    """Configures a simple console logger with the givel level"""
    formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
    console = logging.StreamHandler()
    console.setFormatter(formatter)
    console.setLevel(level)
    logger = logger or logging.getLogger()  # either the given logger or the root logger
    logger.setLevel(level)
    logger.addHandler(console)

Log messages are then duplicated when configuring the root logger. It seems that both the newly configured console handler and the default handler are active for the root logger.

How can I disable / remove the default handler of the root logger, and enable exclusively the console handler?

Or alternatively, how can I setup formatting of the default handler for the root logger?

Answer 1

This more or less solves my problem:

def configure_logging(level='INFO', logger=None):
    """
    Configures a simple console logger with the givel level.
    A usecase is to change the formatting of the default handler of the root logger
    """
    formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
    logger = logger or logging.getLogger()  # either the given logger or the root logger
    logger.setLevel(level)
    # If the logger has handlers, we configure the first one. Otherwise we add a handler and configure it
    if logger.handlers:
        console = logger.handlers[0]  # we assume the first handler is the one we want to configure
    else:
        console = logging.StreamHandler()
        logger.addHandler(console)
    console.setFormatter(formatter)
    console.setLevel(level)

Answer 2

The logging module has a default setup 'built in'. If you just want to change the format of the root logger you can use dictConfig and continue customizing from there.

Here is a snippet from my logger configuration

 cfg = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'standard': {
            'format': _format
        },
    },
    'handlers': {},
    'loggers': {
        '': {
            'handlers': [],
            'level': level.upper(),
            'propagate': True

        }
    }
}

if console:
    cfg['handlers']['console'] = {
        'class': 'logging.StreamHandler',
        'level': level.upper(),
        'formatter': 'standard',
    }
    # noinspection PyUnresolvedReferences
    cfg['loggers']['']['handlers'].append('console')