pkgwatch/SPEC.md

pkgwatch — declarative package-update watcher/publisher (working name)

Status: design draft, pre-PoC. Captures the design discussion as of 2026-09-11.

Problem

Software not packaged by the distro (Arch/Manjaro here) usually gets installed one of a few ways:

• curl | sh from the vendor's own install script — the classic "trust me, bro." The script and any checksum it embeds share a trust boundary, so it verifies nothing beyond transport corruption.
• Manual download + manual checksum/signature verification, redone by hand every time you want to update. Tedious enough that people stop doing it.
• A distro package (pacman extra, AUR) — trustworthy, but version-lagged behind upstream, and someone else has to maintain the PKGBUILD.

There's no local, low-effort way to say "here's how to fetch and verify package X" once, and have that declaration stay live — checked periodically, re-verified on every new upstream release, and fed into a normal pacman-based workflow without hand-editing a PKGBUILD each time.

Vision

A Rust binary, run as a systemd service (service + timer, periodic not persistent), that:

1. Reads a declarative config of tracked packages — where to check for new versions, how to fetch the artifact, and how to verify it.
2. On each run, checks each tracked package for a new upstream version.
3. If a new version is found, fetches the artifact and runs the verification method declared for that package.
4. If verification succeeds (per the package's trust tier — see below), updates/generates a local PKGBUILD (bump pkgver, refresh sha256sums/signature reference) and rebuilds it into a local pacman repo via makepkg + repo-add.
5. The next pacman -Syu (with the local repo configured) picks up the new version normally — no separate tooling needed on the consuming side.

This is conceptually nvchecker (version checking) + updpkgsums (checksum refresh) + repo-add (local repo publishing), fused into one daemon with a single declarative source of truth, plus an explicit, surfaced trust model that those tools don't provide.

Verification trust tiers

The central design problem: from the install UX, a cryptographically strong verification and a "trust-me-bro" same-domain checksum look identical. The tool's job is to make that difference legible instead of laundering every package into an undifferentiated "verified" bucket.

Tiers, strongest to weakest:

1. Pinned-key signature — GPG/minisign/sigstore-cosign, where the signing key's fingerprint is pinned in our config (not fetched fresh from the vendor each time). Proves authorship, independent of the artifact's own hosting.
2. Build provenance attestation — GitHub/GitLab attestations, SLSA provenance. Ties the artifact to a specific CI run and source commit. Strong, but only as trustworthy as that CI pipeline.
3. Registry-native signing — crates.io, PyPI trusted publishing, npm provenance. Similar strength, scoped to that registry's trust model.
4. Same-origin checksum file — a .sha256/.sha256sum served next to the artifact by the vendor. Proves transport integrity only. If the vendor's server or account is compromised, the attacker controls the artifact and the "verification" in the same move.
5. Checksum embedded in an install script — the classic curl|sh case. The verifier and the thing being verified share a trust boundary.
6. Nothing — bare TLS to a domain, no checksum or signature at all.

Automation posture per tier

This is the load-bearing decision, not just a cosmetic label:

• Tiers 1–3: a passing verification is a real trust signal. Safe to auto-bump, auto-verify, auto-publish unattended.
• Tiers 4–6: a passing "verification" only proves internal consistency of one origin (the checksum and the artifact agree), which tells you nothing about whether that origin was compromised. For these tiers the tool should not treat a pass as "verified, ship it." Instead: treat a version/hash change as a flag-for-human-review event. The value pkgwatch adds at these tiers is diff-and-alert (notice something changed, surface the new hash for a human to look at), not verify-and-trust.

Surfacing trust, not just gating on it

• Every tracked package carries an explicit tier + one-line justification (e.g. "minisign, key pinned 2024-03" vs. "same-domain sha256, no independent signer") in a metadata file alongside the generated PKGBUILD — something repo-add/pacman don't touch, but that a human or pkgwatch audit can read.
• pkgwatch audit (or similar) lists all tracked packages sorted worst-tier-first, so weak links don't hide among strong ones in a repo that otherwise looks uniformly trustworthy.

Config schema (draft)

[package.uv]
source = "github-release"
repo = "astral-sh/uv"
asset_pattern = "uv-x86_64-unknown-linux-gnu.tar.gz"

[package.uv.verification]
tier = 4
method = "same-origin-sha256"
checksum_asset_pattern = "uv-x86_64-unknown-linux-gnu.tar.gz.sha256"

# Tier 1 example:
[package.somepkg]
source = "url-with-version-regex"
url = "https://example.com/downloads/"
version_regex = 'somepkg-(\d+\.\d+\.\d+)\.tar\.gz'

[package.somepkg.verification]
tier = 1
method = "minisign"
pinned_key = "RWQ...base64pubkey..."

Open questions on the schema:

• How much of nvchecker's source-type taxonomy (github, gitlab, pypi, crates.io, regex, htmlparser, ...) to reimplement vs. shell out to nvchecker itself for the version-check step and own only the verification + publish pipeline.
• PKGBUILD generation: full Jinja-style templates per package vs. a small fixed set of PKGBUILD "shapes" (single binary tarball, cargo-install, etc.) parameterized by the config.
• Where the local pacman repo lives and how it's registered in pacman.conf (one-time manual setup step vs. something pkgwatch manages).
• Failure/alerting channel for tier 4–6 change events — log only, or a notification hook (this box already has a wofi/Mako notification setup — see project_wofi_notification_picker in Claude's memory).

Architecture sketch

• Config loader: parses the TOML above into an in-memory package list.
• Checker: per source type, resolves "what's the latest version" — likely reuses nvchecker's logic/sources conceptually, possibly shells out to it initially for the PoC rather than reimplementing every source type in Rust.
• Fetcher: downloads the artifact (and any checksum/signature/ attestation companion) for a resolved version.
• Verifier: tier-specific verification implementations behind a common trait; returns a tier + pass/fail + justification string.
• Publisher: for tiers 1–3 on pass, generates/updates the PKGBUILD, runs makepkg, runs repo-add against the local repo.
• Reviewer queue: for tiers 4–6, records the detected change instead of auto-publishing; a separate pkgwatch review command lets a human approve/reject, which then triggers the publish step.
• Scheduling: systemd .service (oneshot) + .timer running it periodically, matching the pattern already used for other periodic tasks on this box.

Prior art / reference points

• nvchecker — version-check-only, no verification or publish step.
• updpkgsums (pacman-contrib/devtools) — checksum refresh only, manual trigger.
• aurutils — local repo + AUR build automation, but AUR itself carries no stronger verification guarantee than what each PKGBUILD maintainer does.
• repology — cross-distro version tracking, no verification/publish.
• GitHub artifact attestations (gh attestation verify) — tier 2 building block for GitHub-hosted releases.

Status / next steps

• Refine config schema further (see open questions above).
• Decide version-check strategy: shell out to nvchecker vs. own implementation, for the PoC.
• PoC scope: single tier-4 package (e.g. uv, ironically) end-to-end — check, fetch, same-origin-checksum verify, flag-for-review, manual approve, PKGBUILD generation, local repo publish.
• Decide on project home: local-only for now, or push to code.austinschaefer.com (Forgejo) once the spec settles.