[bug#62153] Merging guix pack changes for Docker containers packaging

[Ludovic Courtès]

Hi Oleg,

Apologies for not replying earlier.  I occasionally get reminded of the
fact that building single-layer images is a problem, but only now did I
take the time to look more closely at the latest version of these
patches.

Oleg Pykhalov <go.wigust@gmail.com> skribis:

> I would like to merge 62153.  After 64173 will be merge, merging 62153
> is not possible without conflict resolving with Git.
>
> 64173 introduces ‘%docker-format-options’ variable.  With this variable
> it's possible in 62153 to replace ‘--image-type=docker-layered’ with
> ‘--docker-layers=N’ option, where:
>
>     if ‘N’ is zero, then use current non layered format
>     if ‘N’ is bigger than zero, then use layered format

OK we should do that.  However, the original submitter of #64173
apparently dropped the ball as we were approaching the final version.

Would you like to adopt it and submit/push a version that incorporates
the latest comments?

Alternatively, we could do the opposite: merge the Docker layer patches
first, and then rebase the ‘%docker-format-options’ patch, after which
we could add the ‘--docker-layers’ option.

What’s your preference?

> Number of layers specification is nice to have, because Docker layers
> are limited.  So if user would like to modify a Docker image by adding
> more layers on top, then hacks like squashing layers are not required.
> Also, it will be possible to delete code which builds non layered Docker
> image without deprecating command line options.

Agreed.

Anyway, apart from the stylistic issues I reported, v4 of this patch set
looks great to me.  (For clarity I’d have preferred three patches, one
for (guix docker), one for ‘guix pack’, and one for ‘guix system’; but
it’s really a detail, let’s not block this patch series any longer.)

Thanks,
Ludo’.