werkator/docs/plan/22-multi-repo.md

Step 22: One Werkator Instance, Many Repositories

Prerequisites: none in code; step 21's Werkdock work is independent. Read README.md first. This step is a roadmap in sessions (A–E), like step 21; each session is sized for one focused Claude Code session.

The Problem

"One instance per repository" is a founding tenet (docs/Werkator-Konzept.md, AGENTS.md) — and on a Managed Webspace it does not scale even to two repositories. Building Werkbaum next to Werkator on mih34 today means: a second pac user or a second service, a second assigned port, a second tunnel or domain, a second UI, a second metrics page. Every repository added multiplies operations, while the instance-level resources (port, UI, watcher schedule, executor slots, metrics) could be shared. The goal: one Werkator instance serves a set of repositories — one service, one port, one UI — while each repository keeps its own configuration, secrets, history, and artifacts.

The Guiding Idea: the Repository Stays Self-Contained

Everything repository-specific already lives inside the repository: the machine config with secrets in .git/werkator/, build results, auto-build slots, worktrees, buildenvs — and the artifact store is already keyed per repo path. The multi-repo instance therefore does not absorb repository state; it becomes an aggregator over self-contained repositories. Consequences:

• Adding or removing a repository is editing a registry entry, never a data migration.
• A repository can move between instances (or back to its own) without losing anything.
• Single-repo mode stays the degenerate case: a registry of one, implicitly the current working directory — existing installations keep working without any config change.

Key Ownership Splits

Today all config comes from the repo's own layers; multi-repo splits ownership:

• Instance-level (new instance config, not per repo): server.* (port, bind address, public base URL, nginx), the control token (one UI, one token), executor.maxConcurrent as the global cap, watcher interval, metrics.
• Repo-level (unchanged, from the repo's config layers): gitea.* (each repo has its own owner/repo/token/statusContext), git.* credentials, builds/branch layer, retention, per-repo watcher options (e.g. pullRequestGate), sandbox policy and its pinning.
• Both: a per-repo concurrency cap below the global one may come later; not in the first cut.

The pinning model is untouched: pinned keys still come from each repo's machine config, and the branch layer still cannot reach them.

The Sessions

A — Decision and schema (ADR 0009)

• Write ADR 0009: revise the one-instance-per-repository tenet to one-instance-per-set; record the aggregator idea and the key ownership split above. Considered alternative to record: a federation dashboard proxying several single-repo instances — less invasive, but it keeps N services/ports and solves only the UI, not the operations burden.
• Define the instance registry: an instance config file (e.g. ~/.config/werkator/<instance>.yml or a file in an instance directory) listing repository paths, plus the instance-level keys. werkator server without a registry serves the current directory exactly as today.
• Define repo identity for display and routes: a short unique name per registry entry (default: directory basename), used as the route segment (/repos/<name>/…) and UI grouping key.
• Update docs/Werkator-Konzept.md and AGENTS.md wording ("one instance per repository set").

B — RepoContext refactor, behavior unchanged

• Introduce a RepoContext (working dir, config loading, git access, result repository, artifact store key, watcher state) and thread it through executor, watcher, and server code paths that today implicitly use the single workingDir.
• The executor becomes instance-global with repo-scoped pools: serialization per (repo, branch), the global maxConcurrent across repos; BuildResult needs no schema change — results stay in each repo's own JSON file, the repo dimension exists only in memory and in routes.
• Single-repo behavior, routes, and UI stay byte-identical; the full test suite is the acceptance gate.

C — The registry and N repositories

• Load the registry, build one RepoContext per entry; fail the start loudly on duplicate names or unreadable repos (config-version violations abort only that repo's registration, like branch-config violations fail only that branch).
• Watcher multiplexing: one poll cycle iterates the contexts (fetch, enqueue, prune per repo) with per-repo error isolation — one unreachable origin must not starve the others; WatcherState gains the repo dimension for the health banner.
• Startup recovery per repo; auto-build slots stay in each repo's .git/werkator/.
• CLI commands gain an optional repo selector and default to the current working directory, so werkator status inside a repo behaves as today.

D — Server, API, and UI scoping

• Routes gain the repo segment (/api/repos/<name>/builds/…, /repos/<name>/builds/<key>); with exactly one registered repo the today-routes keep working (redirect or alias) so bookmarks and posted Gitea links survive.
• Latest/branches/history views group by repo or gain a repo column; one instance-wide metrics page; one control token.
• Gitea status links use the repo-scoped URLs.

E — Rollout on mih34: Werkbaum joins

• Registry with the Werkator and Werkbaum repositories under the existing user, one service, one port, the existing tunnel.
• Write Werkbaum's .werkator.yml: Gradle backend build and npm frontend build in the shared trimmed image (Node is already in it).
• Record the deployment; retire the second-instance/second-user idea from the notes.

Open Questions

• Fairness across repos when the global concurrency cap is contended (round-robin per repo vs. FIFO) — decide in session C with the real queue behavior at hand.
• Whether buildenv rootfs trees should be shared across repos (today each repo unpacks its own under .git/werkator/buildenv/) — the natural answer is Werkdock's image store (step 21 session C), not instance-level state; until then duplicate unpacked rootfs trees are the accepted cost.
• Whether artifactKey needs a repo prefix or stays globally unique by construction (random suffix) — decide in session B when the routes are designed.

Acceptance Criteria

• Session A: ADR 0009 merged; registry and key-ownership documented in docs/configuration.md.
• Session B: full suite green with RepoContext threaded through; no route or behavior change observable.
• Session C: an instance with two registered repos builds pushes in both, with per-repo error isolation proven by a test (one broken origin, the other keeps building).
• Session D: both repos browsable in one UI; single-repo installations keep their existing URLs.
• Session E: mih34 builds Werkator and Werkbaum from one service; docs/deployment.md describes the registry setup.