How can I set the logging levels in Python?

General Discussions
1

How can I set the logging levels in Python?

I’m trying to use the standard library to debug my code. This works fine:

import logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)
logger.info('message')

However, I can’t get the logger to work for the lower levels:

logging.basicConfig(level=logging.DEBUG)
logger = logging.getLogger(__name__)
logger.info('message')

logging.basicConfig(level=logging.DEBUG)
logger = logging.getLogger(__name__)
logger.debug('message')

I don’t get any response for either of these. How can I resolve this using the Python logging set level?

2

The issue may stem from calling logging.basicConfig() after creating the logger. Ensure that you configure the logging level before obtaining the logger: import logging

# Set logging level before creating the logger
logging.basicConfig(level=logging.DEBUG)
logger = logging.getLogger(__name__)

# This will show because the level is set to DEBUG
logger.debug('This is a debug message')

# Info level will also show
logger.info('This is an info message')
3

If you need more control over logging output, you can add custom logging handlers, such as StreamHandler:

import logging

logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)  # Set the logger's level to DEBUG

# Set a stream handler to output to the console
console_handler = logging.StreamHandler()
console_handler.setLevel(logging.DEBUG)

# Add the handler to the logger
logger.addHandler(console_handler)

# Log messages
logger.debug('This is a debug message')
logger.info('This is an info message')
4

logging.basicConfig() should only be called once, as it has no effect if called multiple times. You can check the current configuration before setting it:

import logging

# Ensure that basicConfig is not called multiple times
logging.basicConfig(level=logging.DEBUG)
logger = logging.getLogger(__name__)

# Log messages
logger.debug('Debug message should appear')
logger.info('Info message should appear')