中文
devexamples

Python Logging Rotating File Handler

Configure Python logging with rotation by size and backups, per-module loggers, structured formatting, and a root-level filter guard.

PythonResilience

Code

snippet
import logging
import logging.config

CONFIG = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'standard': {
            'format': '%(asctime)s %(levelname)s %(name)s %(message)s',
            'datefmt': '%Y-%m-%dT%H:%M:%S',
        },
    },
    'handlers': {
        'app_file': {
            'class': 'logging.handlers.RotatingFileHandler',
            'filename': 'logs/app.log',
            'maxBytes': 10 * 1024 * 1024,
            'backupCount': 5,
            'encoding': 'utf-8',
            'formatter': 'standard',
            'level': 'INFO',
        },
        'errors_file': {
            'class': 'logging.handlers.RotatingFileHandler',
            'filename': 'logs/errors.log',
            'maxBytes': 5 * 1024 * 1024,
            'backupCount': 3,
            'formatter': 'standard',
            'level': 'ERROR',
        },
        'console': {
            'class': 'logging.StreamHandler',
            'formatter': 'standard',
            'level': 'WARNING',
        },
    },
    'root': {
        'level': 'DEBUG',
        'handlers': ['app_file', 'errors_file', 'console'],
    },
}

logging.config.dictConfig(CONFIG)
logger = logging.getLogger('billing')

logger.info('invoice generated', extra={'invoice_id': 'inv-88'})
logger.warning('payment retry scheduled')
logger.error('gateway rejected settlement', exc_info=RuntimeError('timeout'))
logger.debug('this line only reaches root handlers')

Related Examples