ci(maestro): cache nix store, trim CI hot paths #132

2026-09-02T17:48:44+01:00

naps62-yolo commented

2026-09-02 17:48:44 +01:00

The flake job was the pipeline critical path at ~9 minutes, all of it one cold nix build — an empty /nix every run means recompiling the whole release closure under lto = "thin" + codegen-units = 1.

Cache /nix across runs, keyed on the lockfiles the closure derives from, so crane deps-only derivation survives and only maestro own crates rebuild. Saved from pushes only, so a PR cannot write a partial store.
Build only .#webFrontend on PRs — the step that guards pnpmDeps.hash. Release binaries stay on main. Trade-off: a Nix-packaging-specific break surfaces on main, not on the PR.
Swatinem/rust-cache replaces the hand-rolled target/ cache, which accumulated stale artifacts behind a prefix restore-key and cost ~60s per run to move.
Tests run under cargo-nextest, capped at 4 threads in .config/nextest.toml — the tmux-backed tests starve each other at the num-cpus default and trip their 5s deadlines.
actions/setup-node instead of a second apt-get pass via nodesource.

Measured before

job	total	breakdown
flake	557s	nix build 516s
rust	235s	cache 62s, test 69s, feature matrix 41s
web	100s	—

The `flake` job was the pipeline critical path at ~9 minutes, all of it one cold `nix build` — an empty /nix every run means recompiling the whole release closure under `lto = "thin"` + `codegen-units = 1`. - Cache `/nix` across runs, keyed on the lockfiles the closure derives from, so crane deps-only derivation survives and only maestro own crates rebuild. Saved from pushes only, so a PR cannot write a partial store. - Build only `.#webFrontend` on PRs — the step that guards `pnpmDeps.hash`. Release binaries stay on main. Trade-off: a Nix-packaging-specific break surfaces on main, not on the PR. - Swatinem/rust-cache replaces the hand-rolled `target/` cache, which accumulated stale artifacts behind a prefix restore-key and cost ~60s per run to move. - Tests run under cargo-nextest, capped at 4 threads in `.config/nextest.toml` — the tmux-backed tests starve each other at the num-cpus default and trip their 5s deadlines. - actions/setup-node instead of a second apt-get pass via nodesource. <details> <summary>Measured before</summary> | job | total | breakdown | |---|---|---| | flake | 557s | nix build 516s | | rust | 235s | cache 62s, test 69s, feature matrix 41s | | web | 100s | — | </details>

naps62-yolo added 1 commit 2026-09-02 17:48:45 +01:00

ci(maestro): cache nix store, trim CI hot paths

ci / web (pull_request) Successful in 40s

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ci / flake (pull_request) Successful in 3m58s

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ci / rust (pull_request) Successful in 4m36s

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64d5829037

The `flake` job was the pipeline's critical path at ~9 minutes, all of it
one cold `nix build`: with an empty /nix every run, it recompiled the whole
release closure under `lto = "thin"` + `codegen-units = 1`.

- Cache /nix across runs, keyed on the lockfiles the closure derives from,
  so crane's deps-only derivation survives and only maestro's own crates
  rebuild. Saved from pushes only, so a PR cannot write a partial store.
- Build only `.#webFrontend` on PRs — that is the step that guards
  pnpmDeps.hash. The release binaries stay on main.
- Replace the hand-rolled `target/` cache with Swatinem/rust-cache, which
  prunes to the current lockfile instead of accumulating stale artifacts
  behind a prefix restore-key. ~60s per run went into moving that entry.
- Run tests under cargo-nextest, which parallelises across the 20
  integration binaries. Capped at 4 threads in .config/nextest.toml: the
  tmux-backed tests starve each other at the num-cpus default and trip
  their 5s deadlines.
- actions/setup-node instead of a second apt-get pass via nodesource.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

naps62-yolo merged commit f84199d292 into main

2026-09-02 17:53:56 +01:00

naps62-yolo deleted branch ci

2026-09-02 17:53:56 +01:00

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Reference: naps62/maestro#132