nix-serve's secretKeyFile was a manual, undocumented-outside-a-comment
`nix-store --generate-binary-cache-key` step per host -- easy to miss on
a fresh nix-cache instance (as lxc-nix-cache testing just found: systemd
fails the unit with EXIT_CREDENTIALS when LoadCredential can't find the
source file, which nginx then reports as a 502 from clients). It also
can't be regenerated per-host safely: modules/nix-cache/client.nix
hardcodes every client's trust in one specific public key, so every
nix-cache instance has to share the exact same keypair.
Sourced from secrets/nix-cache.yaml's new cache-priv-key entry instead,
via the same sops-nix pattern every other secret in this repo already
uses. Verified the added value derives to the exact public key
modules/nix-cache/client.nix already trusts before committing.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01La55Nsss8jZ7ZuzUV9mfot
CLAUDE.md's "Composition pattern" section still described the
pre-refactor layout (hosts/<host>/configuration.nix as a thin imports
list, hardware-configuration wired in from flake.nix) from before the
platform x build-type matrix landed. Rewrite it to match the current
mkTarget/host.nix architecture and the module moves from the prior
commit. Also fixes docs/nix-cache.md, which referenced a
modules/nix/ path that never existed in this repo.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01La55Nsss8jZ7ZuzUV9mfot