Make particle-os buildable in OBS

[bluca]

This is for a new branch, as a temporary solution until there is post-processing in place.

With this we can build fully signed UKIs on OBS

[behrmann]

needs a rebase to get rid of the commits already on main

[ddstreet]

I don't think this (directly including mkosi-obs from project config) should go into any of the config files in the project, since it should only apply when actually building in OBS; I think it would be better to instead add --include mkosi-obs to the params that the OBS service uses when calling mkosi.

After that, there is still an issue of the mkosi-obs config getting applied before all the actual project config, and thus getting overridden; instead, the mkosi-obs config needs to override all the project config. I can think of 2 potential ways to do it; 1) any config added using the cmdline --include should be placed into the cli namespace, so it will override the standard project config; and/or 2) add a Priority= config that can be added into the mkosi-obs/mkosi.conf to place its priority above the rest of the project config.

Adding priorities would, I think, be more flexible and actually simplify the mkosi/config.py code (to remove the special handling of cli vs config configuration) but is a larger change than just increasing an --include config up to the cli level.

@DaanDeMeyer @bluca any thoughts?

[bluca]

I don't think this (directly including mkosi-obs from project config) should go into any of the config files in the project, since it should only apply when actually building in OBS; I think it would be better to instead add --include mkosi-obs to the params that the OBS service uses when calling mkosi.

There are a few problems - first of all, those configs are only available very recently, so building images with an existing version of mkosi would suddenly break if it's hardcoded. Older distros need to continue working.

Secondly, this implies a lot of policy and a lot of decisions, that would become impossible to override anymore, and I think that would end up removing way too much flexibility overall

[ddstreet]

I don't think this (directly including mkosi-obs from project config) should go into any of the config files in the project, since it should only apply when actually building in OBS; I think it would be better to instead add --include mkosi-obs to the params that the OBS service uses when calling mkosi.

There are a few problems - first of all, those configs are only available very recently, so building images with an existing version of mkosi would suddenly break if it's hardcoded. Older distros need to continue working.

Secondly, this implies a lot of policy and a lot of decisions, that would become impossible to override anymore, and I think that would end up removing way too much flexibility overall

I'm not following what would be impossible to override, but in any case, do you have an alternate proposal? Obviously actually adding the Include=mkosi-obs directly into the particleos mkosi.conf file isn't correct.

[bluca]

There are various settings that are needed specifically for particleos, but that not necessarily apply to all mkosi builds done on OBS, so we can't hardcode things for everyone, it needs to come from each build. eg: one might not want to use zstd.

I think we are fine just using a fork as we are doing now. Things change very very rarely anyway, so at most there's a copy/paste of a package name or two that has to be done every couple of months, not a big deal. This is just a collection of configurations, all the logic is elsewhere.

@DaanDeMeyer said he wanted to have some mechanism to generate a branch/tag via GHA on merge that would have the expected configuration setup, but I don't think there's any progress on that front.

[bluca]

as agreed with Daan this content will just be pushed on the obs branch so that it can be used