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I'm trying to create a logger that prints "debug" messages. I've defined handlers with the correct level set. Still it only prints warning levels and above.

This is my code:

import logging

# Create a custom logger
logger = logging.getLogger(__name__)

# Create handlers
c_handler = logging.StreamHandler()
f_handler = logging.FileHandler('file.log')
c_handler.setLevel(logging.DEBUG)
f_handler.setLevel(logging.DEBUG)

# Create formatters and add it to handlers
c_format = logging.Formatter('%(name)s - %(levelname)s - %(message)s')
f_format = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
c_handler.setFormatter(c_format)
f_handler.setFormatter(f_format)

# Add handlers to the logger
logger.addHandler(c_handler)
logger.addHandler(f_handler)

logger.warning('This is a warning')
logger.error('This is an error')
logger.info('This is an info')
logger.debug('This is a debug')

While this is the console output I get:

__main__ - WARNING - This is a warning
__main__ - ERROR - This is an error

Process finished with exit code 0

I've found similar posts about this problem, but in that case the handlers were not set. My handlers are set.

What's wrong here?

PS: Code is a slightly altered version of this page, section "using handlers".

ThaNoob
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    Your handlers are `DEBUG`-level, but the _logger_ is not (it's [level 0](https://docs.python.org/3/library/logging.html#logging-levels) by default, `NOTSET`). – jonrsharpe May 22 '22 at 12:10

1 Answers1

2

You are forgetting to set the logger level

import logging

# Create a custom logger
logger = logging.getLogger(__name__)

# Create handlers
c_handler = logging.StreamHandler()
f_handler = logging.FileHandler('file.log')

# handler level is different from logger level
c_handler.setLevel(logging.DEBUG)
f_handler.setLevel(logging.DEBUG)

# this will do the trick
logger.setLevel(logging.DEBUG)

# Create formatters and add it to handlers
c_format = logging.Formatter('%(name)s - %(levelname)s - %(message)s')
f_format = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
c_handler.setFormatter(c_format)
f_handler.setFormatter(f_format)

# Add handlers to the logger
logger.addHandler(c_handler)
logger.addHandler(f_handler)

logger.warning('This is a warning')
logger.error('This is an error')
logger.info('This is an info')
logger.debug('This is a debug')

You can find more info here

Gianfranco Reppucci
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