2023-01-30 — Nix team meeting minutes #28

[thufschmitt]

• Unsmudge fetchGit for reproducibility and security by roberth · Pull Request #4635 · NixOS/nix · GitHub
  • On hold for the time being as @edolstra is working on rewriting this whole thing with libgit
• Add fsync-store-paths option by squalus · Pull Request #7126 · NixOS/nix · GitHub
  • Has the same effect as sync-before-registering (but more efficient), so could just replace the current implementation rather than being a separate option
  • The tests mentioned in the PR description are also interesting and could be integrated to the Hydra checks of Nix
  • Assigned to @edolstra
• simplify flake by zimbatm · Pull Request #6538 · NixOS/nix · GitHubsimplify flake by zimbatm · Pull Request #6538 · NixOS/nix · GitHub
  • @zimbatm was willing to finish it, but first wanted to be sure that it would be merged
  • Agreement on it, assigned to @roberth
• TCP support in the Nix daemon by edolstra · Pull Request #5265 · NixOS/nix · GitHub
  • Opened by @edolstra as a way to experiment on some stuff, but @Ericson2314 is pushing towards having it merged and usable for production
  • Very basic, but putting socat on front could give SSL and stuff
  • But no proper user authentication, so might not be that useful
    • Could be extended to support that, or at least support an external authentication mechanism
    • Could be as simple as an extra opcode in the protocol to opt-out of privileged access
  • Could be merged (as-it-is), provided that we have a concrete use-case for it
    • @Ericson2314 will write-up one
• nix-store: implement --query --unsubstitutable by nrdxp · Pull Request #7526 · NixOS/nix · GitHub
  • Least bad short-term solution to the problem of efficiently using Nix in the CI
  • But should also consider the local store rather than just the substituters
  • Adding that to nix-store isn’t great
    • So will close in favour of path-info: implement --query-substitutes by nrdxp · Pull Request #7587 · NixOS/nix · GitHub which is the same thing, but for the new CLI
• path-info: implement --query-substitutes by nrdxp · Pull Request #7587 · NixOS/nix · GitHub
  • Same comments as above
  • Triggered some discussions on the longer-term solution that we’d like to see
    • “layered stores” (similar to overlay filesystems, but for Nix stores)
      • Shouldn’t be too hard to implement, mostly a new store implementation with a lot of boilerplate
  • Assigned to @edolstra
    • Allowing a different build and destination store, like hydra does
      • Similar to --eval-store that we already have

[ryantm]

Who can I talk to to learn more about the layered stores concept?

[thufschmitt]

Good question. I think at least @Ericson2314 and me would have some ideas about it

[pxc]

If he’s willing to just post about it here that’d be cool. I’m also curious. Is the idea that you would use these on read-only media and with network attached storage for stores and stuff like that?

Or is it for deduplication advantages or for other applications?