Re: Multi repo support

[Henning Schild <henning.schild@siemens.com>]

Am Thu, 1 Feb 2018 16:16:58 +0100
schrieb "[ext] Henning Schild" <henning.schild@siemens.com>:

> Am Thu, 1 Feb 2018 15:54:26 +0100
> schrieb "[ext] Claudius Heine" <claudius.heine.ext@siemens.com>:
> 
> > Hi,
> > 
> > I would like to start the discussion about how to best implement
> > muti repository support in isar.
> > 
> > Does someone already has some ideas or even something in the
> > pipeline for this?
> > 
> > If not then I do have an idea that was outlined together with Jan:
> > 
> > Adding and configuring apt repositories should be done via config
> > files. It should be possible to define own multiconfigs while
> > including multiconfigs from other layers. These configs then append
> > filepaths to a global variable.
> > 
> > Every file that is added this way contains 'sources.list'
> > compatible repository definitions. So one repo each line.
> >
> > For every line in those files a repository entry for multistrap.conf
> > is created. Here we might need some more complex code to convert
> > such a apt repo tripel to the right format multistrap expects. But
> > by using the 'sources.lists' format we would be independent of
> > multistrap and become more future proof.

We will also need a way to tell apt the priorities of these repos.
Multistrap just adds them and apt-get installs packages according to
its default behavior.
That means that a package with the same name and version will get
picked from a "random" repo. Overlays will need to make sure to always
have a greater version or we will need apt configuration.
https://wiki.debian.org/AptPreferences
The big question here is how/whether multistrap will handle apt
preference.

Alex already ran into that when he wanted to modify "hello". Renaming
packages - like Alex suggested - is not the way to go. Because the ones
we do overlay could be deps of packages we do not overlay.

Henning

> > Comments are welcome.  
> 
> Sounds good to me, cant wait to review the first patches ;).
> 
> Henning
>  
> > Cheers,
> > Claudius
> >   
>