How to add a custom loglevel to Python's logging facility

Question

I\'d like to have loglevel TRACE (5) for my application, as I don\'t think that debug() is sufficient. Additionally log(5, msg) isn\'t what I want.

Answer 1

This worked for me:

import logging
logging.basicConfig(
    format='  %(levelname)-8.8s %(funcName)s: %(message)s',
)
logging.NOTE = 32  # positive yet important
logging.addLevelName(logging.NOTE, 'NOTE')      # new level
logging.addLevelName(logging.CRITICAL, 'FATAL') # rename existing

log = logging.getLogger(__name__)
log.note = lambda msg, *args: log._log(logging.NOTE, msg, args)
log.note('school\'s out for summer! %s', 'dude')
log.fatal('file not found.')

The lambda/funcName issue is fixed with logger._log as @marqueed pointed out. I think using lambda looks a bit cleaner, but the drawback is that it can't take keyword arguments. I've never used that myself, so no biggie.

  NOTE     setup: school's out for summer! dude
  FATAL    setup: file not found.