Should Gradient Cache enforce blake3-hashes

[DerDennisOP]

blake3-hashes are great! Especially because it allows to hash objects with multiple cores. Since Gradient uses their workers to hash and compress their builds, it would speedup build time by quite some amount. Nix has an experimental feature called "blake3-hashes", but when we hash for this specific feature, every cache substituter would also need to also enable this experimental feature.

TLDR': If the cache only supports blake3-hashes, every machine that substitutes from it needs to also have this experimental feature enabled.

Why is blak3-hashes a experimental feature? NixOS/nix#12379 (comment)

[krauterbaquette]

Would it be possible to enable blake3-hashes in gradient via a feature flag or does this create to much maintenance burden?

[DerDennisOP]

This is the reason why this question is so explicit. We want to keep maintenance low. If we would make blake3-hashes available per feature flag, it would not be configurable per cache, but rather per Gradient Instance. Gradient Proto would need modifications to tell the worker which hash-type he now has to generate. Generally speaking, not impossible, but much easier without the burden. We are able to find bugs quicker, if all Gradient Instances use the same hashing algorithm. I personally also see it as a opportunity to move forward from the old "sha256" to the new "blake3" for the Nixos Community. We already are only supporting building nix flakes, but blake3-hashes are way less commonly used.