Add a method to list the current named logging levels

[Edward Spencer]

Sometimes I like to pass the logging level up to the command line params so my user can specific what level of logging they want. However there is no easy method for pulling the named logging level names.

Looking into the code, it would actually be incredibly easy to implement;

in `logging.__init__.py`;

def listLevelNames():
return _nameToLevel.keys()

You could obviously add some other features, like listing only the defaults, sorted by numerical level or alphabetically, etc. But really this basic implementation would be enough to expose the internal variables which shouldn't be accessed because they change (and in fact, between python 2 and 3, they did).

Any thoughts?

Thanks,
Ed Spencer

[Dieter Maurer]

Usually, you use 5 well known log levels: "DEBUG", "INFO", "WARNING",
"ERROR" and "CRITICAL".
No need to provide a special function listing those levels.



--
Dieter

[Barry]

> On 2 Sep 2021, at 23:38, Dieter Maurer <die...@handshake.de> wrote:

I add my own levels, but then I know I did it.

Barry

>
>
>
> --
> Dieter
> --
> https://mail.python.org/mailman/listinfo/python-list
>

[Edward Spencer]

Yes, the names are already well defined. But every software project anyone has that needs to use logging then has to define that list, which is a waste of time since they're already defined inside the logging repo. But no-one can access them unless they use protected variables. If it's a case of not wanting users to be able to modify the defaults, then just define that list of log levels as a tuple. Hiding it is unnecessary.

[Barry]

> On 30 Mar 2022, at 16:11, Edward Spencer <tedpfs...@gmail.com> wrote:

Is logging.getLevelNamesMapping() what you are looking for?

Barry


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[Edward Spencer]

Hi Barry,

What version for python / logging are you seeing that method in? I don't appear to be able to find it.
I vaguely remember seeing something similar to it though, did it return a dict of {<str name>: <int level>} only or did it also include the reverse of int to str?

Thanks,
Ed

[Chris Angelico]

New in 3.11:

https://docs.python.org/3.11/library/logging.html#logging.getLevelNamesMapping

I'd say it's reasonable to use this, and then to backport it to older
versions by monkeypatching it in (by referencing the internal). You
potentially might have issues with other Python implementations, but
I'm pretty sure CPython has logging._nameToLevel with the same
semantics for quite a while.

ChrisA

[Tim Chase]

On 2022-03-30 16:37, Barry wrote:
> Is logging.getLevelNamesMapping() what you are looking for?

Is this in some version newer than the 3.8 that comes stock on my
machine?

$ python3 -q
>>> import logging
>>> logging.getLevelNamesMapping()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: module 'logging' has no attribute 'getLevelNamesMapping'

-tkc

[Mats Wichmann]

On 3/30/22 10:39, Chris Angelico wrote:

> New in 3.11:
>
> https://docs.python.org/3.11/library/logging.html#logging.getLevelNamesMapping
>
> I'd say it's reasonable to use this, and then to backport it to older
> versions by monkeypatching it in (by referencing the internal). You
> potentially might have issues with other Python implementations, but
> I'm pretty sure CPython has logging._nameToLevel with the same
> semantics for quite a while.

since 2013, it looks like.