Thanks for the suggestion @kamadorueda. That sounds great.
Motivation / pain points
We were just hoping to save having to download/upload derivations regularly per job, instead of having it mounted and immediately accessible.
So I realise now there’s a few problems with this:
- the docker image we’ve used so far (nixos/nix) itself already has a /nix/store. We could potentially look at using layerfs to layer this with a bind mounted /nix/store from the host/network. Perhaps.
- The docker container (nixos/nix) would maintain its own store db. Persisting this doesn’t sound trivial (with simultaneous read/writes across jobs)
Bootstrap Container Store?
Perhaps the above could be worked around by creating a docker image that has static nix tools in an alternate location, allowing /nix/store to merely contain fetched/built derivations. But again, the question of a persisted and shared/served nix store with db remains. See @zimbatm’s suggestion on this here.
S3 Store Pro/Cons?
So another thing we’ve considered looking at using is a read/write S3 store. I presume/hope this configuration would involve simultaneous read/write options, but again would involve pushing/pulling as required instead of something that’s immediately available at a mount point.
So longer term I’d want to move to more sophisticated tools like makes as you suggest @kamadorueda.
I’m looking for a quick win. The primary caveat atm is downloading artifacts for each job from cache.nixos.org. That’s pretty quick to be fair, but obviously if we can save the time that’ll save us time.
Something like storing/restoring app paths just for our project / branch?
Of course, downloading from cache.nixos.org isn’t the biggest painpoint atm. Just an obvious point of optimisation.