logtest.py

#!/usr/bin/python3

import logging
from logging.handlers import RotatingFileHandler

logger = logging.getLogger( 'logger_test' )
handler = RotatingFileHandler( 'test.log', maxBytes=100, backupCount=3 )
logger.addHandler( handler )

for i in range(100):
    logger.warning( f'({i}) Hello, world!' )