I'm trying to do some basic logging. I'm doing the following:
log = logging.getLogger('test')
log.error('test') # 'test' gets logged
log.info('test') # Nothing gets logged, as expected
log.setLevel(logging.INFO) # Now info should be logged, right?
log.info('test') # No output
log.setLevel(logging.INFO) # Getting desperate
log.info('test') # Still nothing
What aspect of the logging module am I missing?
You have forgot to add handlers i.e. logging.basicConfig(), can you check if following code works for you.
import logging
logging.basicConfig()
log = logging.getLogger('test')
log.setLevel(logging.INFO)
log.error('test')
log.info('test')
You need to configure logging before you use it like below. You can configure it beautifully in python.
logging.basicConfig(format='%(asctime)s %(name)25s %(lineno)4d %(levelname)8s: %(message)s', level=40)
above statement will print timestamp, name of the file, line number, level type, message
level of logging also can be set during basic Config itself (40 = ERROR)
It is not necessary to call basicConfig.
However, the issue is about handlers (as pointed out by @Mahesh Karia).
You see, if you don't define some handlers you are dependent on whatever is already "in place" for you and that raises lots of confusion.
Check this:
You create your "test" logger
>>> log = logging.getLogger('test')
which prints WARNING messages but does not print INFO messages even after setting the level to INFO:
>>> log.warning('hi')
hi
>>> log.setLevel(logging.INFO)
>>> log.info('hi')
>>>
(personally, I think this is very wrong behaviour)
It can be "solved" by manipulating "handlers".
Your "test" logger has none
>>> log.handlers
[]
nor does it parent, the "root logger"
>>> log.parent
<RootLogger root (WARNING)>
>>> log.parent.handlers
[]
however, one can add a handler easy enough (to the root logger)
>>> log.parent.addHandler(logging.StreamHandler())
and now your "test" logger "works":
>>> log.info('hi')
hi
PS. Was using Python 3.8.2 prompt after importing logging module.