`cvmfs_customizations` option is broken

[bedroge]

The buildenv section (see https://github.com/EESSI/eessi-bot-software-layer?tab=readme-ov-file#buildenv-section) has a parameter cvmfs_customizations that should allow you to override CVMFS options. However, this seems completely broken at the moment. There's a function apply_cvmfs_customizations (https://github.com/EESSI/eessi-bot-software-layer/blob/develop/tasks/build.py#L516) that should handle this, but it's not being called anywhere in the code.

I've tried a quick fix by adding the following to this line:

            apply_cvmfs_customizations(build_env_cfg[config.BUILDENV_SETTING_CVMFS_CUSTOMIZATIONS], job_dir)

Now it does at least something, it generated a file default.local in the job dir with the expected contents based on my settings:

cvmfs_customizations = { "/etc/cvmfs/default.local": "EESSI_NVIDIA_OVERRIDE_DEFAULT=/scratch/f118536/shared/nvidia"}

However, it still does not seem to use it in any way. I couldn't figure out in the code how this is supposed to work, I suspect it would have to merge it with the default config file from the repos cfg bundle?

[bedroge]

I was trying to use this to configure the new NVIDIA variant symlink for the bots. As a workaround, I came up with the following approach that can be used in the bot's site_config_script to bind mount an additional config file into the build container:

NVIDIA_OVERRIDE_DIR=/shared/fs/dir/nvidia
EESSI_LOCAL_CVMFS_CONFIG=$(mktemp)
cat > ${EESSI_LOCAL_CVMFS_CONFIG} <<EOF
EESSI_NVIDIA_OVERRIDE_DEFAULT=${NVIDIA_OVERRIDE_DIR}
EOF
export SINGULARITY_BIND=${EESSI_LOCAL_CVMFS_CONFIG}:/etc/cvmfs/config.d/software.eessi.io.local