[bug#43920,SHEPHERD] shepherd: Move log file to XDG_CACHE_DIR.

* modules/shepherd/support.scm (%user-log-dir): New variable.
(user-default-log-file): Use it.
* doc/shepherd.texi: (Invoking shepherd): Adjust listed default log
file.
* tests/basic.sh: Adjust for separate log directory.
---
 doc/shepherd.texi            |  2 +-
 modules/shepherd/support.scm | 10 ++++++++--
 tests/basic.sh               |  4 ++++
 3 files changed, 13 insertions(+), 3 deletions(-)

Hi,

Efraim Flashner <efraim@flashner.co.il> skribis:

> * modules/shepherd/support.scm (%user-log-dir): New variable.
> (user-default-log-file): Use it.
> * doc/shepherd.texi: (Invoking shepherd): Adjust listed default log
> file.
> * tests/basic.sh: Adjust for separate log directory.

[...]

>  For unprivileged users, the default log file is
> -@file{$XDG_CONFIG_HOME/shepherd/shepherd.log}.
> +@file{$XDG_CACHE_DIR/shepherd/shepherd.log}.

The previous location wasn’t perfect, but the proposed one isn’t great
either: one can generally assume “rm -rf ~/.cache” won’t lose anything
that cannot be reconstructed, and the log is something that cannot be
reconstructed.

Do the XDG spec have something else that might be more appropriate?

Thanks,
Ludo’.

> The previous location wasn’t perfect, but the proposed one isn’t
> great
> either: one can generally assume “rm -rf ~/.cache” won’t lose
> anything
> that cannot be reconstructed, and the log is something that cannot be
> reconstructed.
That is actually not part of the XDG specification – it merely states,
that non-essential files be put there.  Whether or not one considers
the shepherd log essential is debatable.

You could alternatively put it under $XDG_DATA_HOME.  Some projects
like Xorg seem to do that.  Of course, there always remains the option
of having yet another environment variable or command line parameter
for the placement of the log file.

Regards, Leo

Hi,

Leo Prikler <leo.prikler@student.tugraz.at> skribis:

>> The previous location wasn’t perfect, but the proposed one isn’t
>> great
>> either: one can generally assume “rm -rf ~/.cache” won’t lose
>> anything
>> that cannot be reconstructed, and the log is something that cannot be
>> reconstructed.
> That is actually not part of the XDG specification – it merely states,
> that non-essential files be put there.  Whether or not one considers
> the shepherd log essential is debatable.

Right, that’s my interpretation of what “cache” means.

> You could alternatively put it under $XDG_DATA_HOME.  Some projects
> like Xorg seem to do that.  Of course, there always remains the option
> of having yet another environment variable or command line parameter
> for the placement of the log file.

Yup, XDG_DATA_HOME would work for me; it seems to be rather in line with
what the XDG states and what Xorg does, as you note.

  https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html

WDYT, Efraim & Janneke?

Ludo’.

On October 24, 2020 4:15:33 PM UTC, "Ludovic Courtès" <ludo@gnu.org> wrote:
>Hi,
>
>Leo Prikler <leo.prikler@student.tugraz.at> skribis:
>
>>> The previous location wasn’t perfect, but the proposed one isn’t
>>> great
>>> either: one can generally assume “rm -rf ~/.cache” won’t lose
>>> anything
>>> that cannot be reconstructed, and the log is something that cannot be
>>> reconstructed.
>> That is actually not part of the XDG specification – it merely states,
>> that non-essential files be put there.  Whether or not one considers
>> the shepherd log essential is debatable.
>
>Right, that’s my interpretation of what “cache” means.
>

I felt like it belongs in cache much more than in a config dir.

>> You could alternatively put it under $XDG_DATA_HOME.  Some projects
>> like Xorg seem to do that.  Of course, there always remains the option
>> of having yet another environment variable or command line parameter
>> for the placement of the log file.
>
>Yup, XDG_DATA_HOME would work for me; it seems to be rather in line with
>what the XDG states and what Xorg does, as you note.
>
>  https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
>
>WDYT, Efraim & Janneke?

I don't think it's really data, it's not like it belongs in something/share. As another data point keybase writes its (verbose) logs in .cache/keybase.

>
>Ludo’.

Ludovic Courtès writes:

Hello,

> Leo Prikler <leo.prikler@student.tugraz.at> skribis:
>
>>> The previous location wasn’t perfect, but the proposed one isn’t
>>> great
>>> either: one can generally assume “rm -rf ~/.cache” won’t lose
>>> anything
>>> that cannot be reconstructed, and the log is something that cannot be
>>> reconstructed.
>> That is actually not part of the XDG specification – it merely states,
>> that non-essential files be put there.  Whether or not one considers
>> the shepherd log essential is debatable.
>
> Right, that’s my interpretation of what “cache” means.

Yes, essential is pretty vague; a cache is something that can be
re-generated.

>> You could alternatively put it under $XDG_DATA_HOME.  Some projects
>> like Xorg seem to do that.  Of course, there always remains the option
>> of having yet another environment variable or command line parameter
>> for the placement of the log file.
>
> Yup, XDG_DATA_HOME would work for me; it seems to be rather in line with
> what the XDG states and what Xorg does, as you note.
>
>   https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
>
> WDYT, Efraim & Janneke?

Data sounds a bit strong (I would consider a database to be data), and
cache is too loose.  Otoh, losing a log can be crucial; so I'd go for
XDG_DATA_HOME.

Janneke

Hi,

Efraim Flashner <efraim@flashner.co.il> skribis:

> On October 24, 2020 4:15:33 PM UTC, "Ludovic Courtès" <ludo@gnu.org> wrote:

[...]

>>>> The previous location wasn’t perfect, but the proposed one isn’t
>>>> great
>>>> either: one can generally assume “rm -rf ~/.cache” won’t lose
>>>> anything
>>>> that cannot be reconstructed, and the log is something that cannot be
>>>> reconstructed.

[...]

> I don't think it's really data, it's not like it belongs in something/share. As another data point keybase writes its (verbose) logs in .cache/keybase.

To me the question whether it’s OK to lose the log.  In a way, storing
the log in ~/.cache akin to storing it in /tmp.

If we agree on that, then we have the choice between ~/.local/share
aka. XDG_DATA_HOME (like Xorg does), or maybe using ~/.local/var/log or
something similar that goes beyond XDG?

Thoughts?

Naming directories is hard.  :-)

Ludo’.

Hi,

Ludovic Courtès <ludo@gnu.org> skribis:

> Efraim Flashner <efraim@flashner.co.il> skribis:
>
>> On October 24, 2020 4:15:33 PM UTC, "Ludovic Courtès" <ludo@gnu.org> wrote:
>
> [...]
>
>>>>> The previous location wasn’t perfect, but the proposed one isn’t
>>>>> great
>>>>> either: one can generally assume “rm -rf ~/.cache” won’t lose
>>>>> anything
>>>>> that cannot be reconstructed, and the log is something that cannot be
>>>>> reconstructed.
>
> [...]
>
>> I don't think it's really data, it's not like it belongs in something/share. As another data point keybase writes its (verbose) logs in .cache/keybase.
>
> To me the question whether it’s OK to lose the log.  In a way, storing
> the log in ~/.cache akin to storing it in /tmp.
>
> If we agree on that, then we have the choice between ~/.local/share
> aka. XDG_DATA_HOME (like Xorg does), or maybe using ~/.local/var/log or
> something similar that goes beyond XDG?

I pushed a variant of your patch that uses XDG_DATA_HOME instead:

  https://git.savannah.gnu.org/cgit/shepherd.git/commit/?id=c6382a6898f2851d78b675f209787c5ff9ad4320

There’s a now ‘%user-log-dir’ so it’ll be easier to adjust going
forward if we change our mind.

Thanks,
Ludo’.