I'm trying to do a test run of the logging
module's RotatingFileHandler
as follows:
import logging
from logging.handlers import RotatingFileHandler
# logging.basicConfig(filename="example.log", level=logging.DEBUG)
logger = logging.getLogger('my_logger')
handler = RotatingFileHandler("my_log.log", maxBytes=2000, backupCount=10)
logger.addHandler(handler)
for _ in range(10000):
logger.debug("Hello, world!")
However, with logging.basicConfig
line commented out, the resulting my_log.log
file contains no data:
If I comment in the line with logging.basicConfig(filename="example.log", level=logging.DEBUG)
, I get the expected my_log.log
files with numbered suffixes. However, there is also the example.log
which is a (relatively) large file:
How can I set up the logging so that it only generates the my_log.log
files, and not the large example.log
file?
Python provides 5 logging levels out of the box (in increasing order of severity): DEBUG
, INFO
, WARNING
, ERROR
and CRITICAL
. The default one is WARNING
. The docs says, that
Logging messages which are less severe than lvl will be ignored.
So if you use .debug
with the default settings, you won't see anything in your logs.
The easiest fix would be to use logger.warning
function rather than logger.debug
:
import logging
from logging.handlers import RotatingFileHandler
logger = logging.getLogger('my_logger')
handler = RotatingFileHandler('my_log.log', maxBytes=2000, backupCount=10)
logger.addHandler(handler)
for _ in range(10000):
logger.warning('Hello, world!')
And if you want to change logger level you can use .setLevel
method:
import logging
from logging.handlers import RotatingFileHandler
logger = logging.getLogger('my_logger')
logger.setLevel(logging.DEBUG)
handler = RotatingFileHandler('my_log.log', maxBytes=2000, backupCount=10)
logger.addHandler(handler)
for _ in range(10000):
logger.debug('Hello, world!')