How to list all existing loggers using python.logging module

Question

Is there a way in Python to get a list of all defined loggers?

I mean, does something exist such as logging.getAllLoggers() which would return a list of Logger objects?

I searched the python.logging documentation but couldn't find such a method.

Lindbergh

similar: https://mcmap.net/q/130489/-how-to-print-current-logging-configuration-used-by-the-python-logging-module – Brashear

since python 3.12 there is logging.getLogger().getChildren() – Ours

Answer 1

Loggers are held in a hierarchy by a logging.Manager instance. You can interrogate the manager on the root logger for the loggers it knows about.

import logging

loggers = [logging.getLogger(name) for name in logging.root.manager.loggerDict]

Calling getLogger(name) ensures that any placeholder loggers held by loggerDict are fully initialized when they are added to the list.

Thickleaf

In fact, getting the dict of Logger per name is better than simply a list of Logger alone, so logging.root.manager.loggerDict was exactly what I was searching for, thank you! – Lindbergh

A small note here is that root logger is not returned by this snippet. – Aurignacian

Anyone has an explanation about why PyCharm's linting warns about this snippet: Unresolved attribute reference 'manager' for class 'RootLogger'? I know it can be easily disabled, but still... – Faveolate

Note you can access the manager from any logger, i.e. my_logger.manager is logging.root.manager. From the source: "There is [under normal circumstances] just one Manager instance ..." – Brashear

Answer 2

If you want to include RootLogger in the list as well, do something similar to:

import logging
loggers = [logging.getLogger()]  # get the root logger
loggers = loggers + [logging.getLogger(name) for name in logging.root.manager.loggerDict]

tested on Python 3.7.4

Ramachandra

This was what solved it for me: the missing root logger was the source of all the problems I had. – Radom

Answer 3

If you are trying to examine the hierarchy of logging objects, I'd recommend using logging_tree.printout():

import logging_tree

logging_tree.printout()

Or, if you want to have the logging tree accessible to your code:

logging_tree.tree()

See https://pypi.org/project/logging_tree/ for more info.

Kinfolk

I would have preferred to do it without depending on a third party library, but thank you for the link :) – Lindbergh