Re: [PATCH v2 0/4] Fix ccache issues

["Moessbauer, Felix" <felix.moessbauer@siemens.com>]

On Sun, 2023-04-02 at 20:44 +0200, Baurzhan Ismagulov wrote:
> On 2023-03-29 12:43, Moessbauer, Felix wrote:
> > > You might have /ccache/a/ created earlier by 'root', and not it
> > > can't
> > > create a 
> > > subdir as sbuild user.
> > 
> > Hi, this could very well be the case. However, when running in a CI
> > on
> > a project with multiple branches (e.g. during feature integration),
> > this situation cannot be avoided. The cache is shared across all
> > builds
> > of a single project, but these builds might use different ISAR
> > versions.
> > 
> > This technically means, we need to update all branches of the
> > project
> > in a lockstep to be able to re-enable the ccache.
> > 
> > It would be good if we could find a way to avoid this situation.
> 
> What about sudo addgroup ccache; sudo adduser build ccache; sudo
> chgrp -R
> ccache /ccache; sudo chmod -R g+w /ccache; find /ccache -type d |sudo
> xargs
> chmod g+s? Maybe also sudo adduser root ccache.

This would solve the permission issues at the cost of always touching a
lot of files. Especially in case the cache is on a NFS, this could be
problematic. All that boils down to the following root causes:

- shared caches across ISAR versions in the same CI
- inconsistent users creating / accessing the cache in ISAR (e.g.
sbuilder as builder, devshell as root)

Also some custom tasks might accidentally use the ccache and break the
build for the following (possibly unrelated) tasks. I don't know which
solution is best. Ideas are highly appreciated.

Felix

> 
> With kind regards,
> Baurzhan
>