Re: -v, --verbosity=LEVEL use the given verbosity LEVEL

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hi,

Simon Tournier <zimon.toutoune@gmail.com> writes:

> Hi,
>
> On Tue, 26 Sep 2023 at 12:19, Maxim Cournoyer <maxim.cournoyer@gmail.com> wrote:
>
>>> Where should the user of the Guix command-line interface be expected
>>> to read about the verbosity LEVEL argument that they can pass to
>>> `--verbosity` and that is also valid?
>
> To answer a question elsewhere in this threads, I think these levels
> come from Nix and daemon side.
>
>> See info '(guix) Invoking guix build':
>>
>> --8<---------------cut here---------------start------------->8---
>> ‘-v LEVEL’
>> ‘--verbosity=LEVEL’
>>      Use the given verbosity LEVEL, an integer.  Choosing 0 means that
>>      no output is produced, 1 is for quiet output; 2 is similar to 1 but
>>      it additionally displays download URLs; 3 shows all the build log
>>      output on standard error.
>> --8<---------------cut here---------------end--------------->8---
>
> Maybe, we could add an option as ’--list-verbosity’ which would display
> that information.
>
> Well, the main issue, IMHO, is that the option ’--verbosity’ is not
> shared across various command-line scripts, but implemented script per
> script, IIRC.

Oh, is it?  That's not great.  I've never used it, but Guix already
soft-depends on guile-lib, and guile-lib provides a logging library.
Perhaps if we used that we would benefit from some standardized and
global way to perform logging across at least the host-side code?  And
that'd help more straightforwardly reason and explain the levels?

I have experience with logging from Python and would like to have a
similar tool available in Guix.  Instead of adding pk all over the place
when debugging enabling the debug level (assuming we've added a few well
placed debug level logging directives in the code) would help trace
execution and pinpoint where things go wrong easily.

-- 
Thanks,
Maxim