Re: [PATCH 06/10] tests/avocado/kvm_xen_guest.py: cope with asset RW requirements

[Cleber Rosa <crosa@redhat.com>]

On Thu, Aug 1, 2024 at 8:57 AM Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
> > I agree those files should not be modified, but I wonder if you
> > thought about any solution to this? Given that the same user writes
> > (downloads) those files, do you think setting file permissions between
> > the download and the use of the files should be done?
>
> We want to share a cachedir on development hosts with multiple
> developers. OK to alter a downloaded file before adding it to
> the cache; but then once a file is added/hashed it shouldn't be
> modified IMO.
>

I was asking more in terms of what to do before/after the test.  When
it comes to this type of setup, Avocado's cache was designed to
support this use case.  You can provide multiple cache dirs in the
configuration, and some (the first ones, ideally) can be RO (life NFS
mounts).

But this is hardly something that can be configured without proper
user input, so this is not present in the generic "make
check-avocado".

> So far this directory is group=RW but we like the ability to track
> a read-only directory (like owned by a particular user) and adding
> missing assets to current user cachedir, to avoid duplication of
> files and waste of network transfer.
>

That can be done in avocado.conf, something like:

[datadir.paths]
cache_dirs = ['/path/that/is/ro/because/owned/by/someone/else',
'/home/cleber/avocado/data/cache']

The asset library will take care of trying to find assets in the RO
directories, while writing to the RW ones.

Hope this helps,
- Cleber.