Python 日志记录无法更改根记录器的日志级别

Question

I'm trying to change the log level of the root logger. It appears to change when queried with getEffectiveLevel() but doesn't actually log anything different than it did before the change.

For example:

>>> import logging
>>> root_logger = logging.getLogger()
>>> root_logger.getEffectiveLevel()
30
>>> root_logger.warning('test')
test
>>> root_logger.info('test')
>>> root_logger.setLevel(logging.DEBUG)
>>> root_logger.getEffectiveLevel()
10
>>> root_logger.warning('test')
test
>>> root_logger.info('test')
>>> root_logger.debug('test')

Why is this? Am I missing something else I need to do? It puzzles me that I can set the level and see it with getEffectiveLevel but that it doesn't change the behavior at all.

I am using the built in logging module (version 0.5.1.2) on Python 3.7.3.

Answer 1

You haven't configured any handlers for the logger (or the logging system at all).

This means that, based on the code here , logging defaults to this last-resort logger, which is a stderr logger with the WARNING threshold, and as such, it doesn't handle those debug messages.