werkator/AGENTS.md

Werkator — Agent Instructions

This file holds the shared, tool-agnostic instructions for all AI coding agents. Claude Code imports it from CLAUDE.md via @AGENTS.md; Claude-Code-specific instructions belong in CLAUDE.md, everything else here. Detailed guides live as Agent Skills under .claude/skills/ (SKILL.md format); they load on demand — see Skills.

Build and Test Commands

./gradlew build          # compile + ktlintCheck + test
./gradlew ktlintFormat   # auto-format before committing
./gradlew test           # run all tests (can be slow, prefer single test)
./gradlew test --tests "de.hoennig.werkator.ApplicationContextTest"  # example for running a single test class

Run the JAR directly:

java -jar build/libs/werkator.jar --help
java -jar build/libs/werkator.jar init

ktlintFormat must be run before build passes — the formatter is enforced as part of the check lifecycle.

Architecture Overview

Werkator is a lightweight, declarative CI/CD build system: git-centric, one instance per repository, builds native or in Docker, statuses reported to Gitea. It is a dual-mode application: CLI (interactive, status, config) and Server (HTTP, persistent web UI + JSON API). IMPORTANT: Before designing or modifying code in any production package, load the architecture skill — it holds the subsystem details (CLI wiring, server mode, web UI, config system, git access, build execution, watcher, metrics).

Package Structure

All production code lives under de.hoennig.werkator, with sub-packages commands (picocli subcommands), config (YAML config loading and schema), git (git CLI access), gitea (Gitea commit-status API client), build (build execution, results, workspaces), artifacts (filesystem artifact store), watcher (branch polling, auto-builds, startup recovery), metrics (system resource sampling and aggregation), and server (JSON API controllers, Thymeleaf UI, artifact serving, control token, watcher and metrics lifecycles). Tests mirror this structure under src/test/kotlin.

Hard Invariants

• exitProcess is called only from main() — never inside CliRunner.run(); this keeps the Spring context alive during tests.
• Nothing is scheduled during CLI runs or tests: the watcher poll loop and metrics sampling start only via an explicit start() in the server profile.
• Builds run detached in worktrees under .git/werkator/worktrees/<branchKey>; the primary checkout is never used for builds; never assume a single running build.
• When config keys change, three places must stay in sync: the WerkatorConfig data classes, the InitCommand templates, and docs/configuration.md.
• Every config file may declare werkator.version.since/below (the Werkator it is written for, never a format version — no API is involved). since is enforced in both directions, using ConfigVersions.FORMAT_BROKE_IN for "file predates a breaking change"; below only warns. A violation aborts the start for the machine and project config, but fails only that branch's builds for a branch config.
• A branch describes its own CI: its committed .werkator.yml is the branch layer (ConfigLoader.loadWithBranchLayer, used by the watcher per origin branch and by loadForWorktree at build time) and takes precedence over .git/project — including the whole builds section, so a new configuration can be tried out on a branch without affecting other branches. Only the pinned set is stripped from that layer: secrets (git), host/repository sections (server, gitea, executor, watcher), the docker (docker.enabled, docker.network) and bubblewrap (bwrap.enabled, bwrap.rootfs) sandbox policies, and the trust gate (requirePullRequest). A branch must never reach credentials, disable its container or sandbox, change its network, substitute a foreign rootfs, raise global concurrency, or bypass its own pull-request gate; a branch's definitions apply to that branch alone.
• A build definition carries the complete description of its build, split in two: the trigger block (onPush, atTimes, branches, activeWithin) says when and for which branches it runs, everything else what it does. builds.default is the base every other definition inherits its settings — never its trigger — from. The split is structural so that a selector added to TriggerConfig later is non-inheritable by construction; writing a trigger key flat is refused, never ignored, because ignoring it leaves a build that silently stops running. A ! prefix in trigger.branches excludes and always wins.
• The inheritance is applied after all layers are merged: that order is what makes a build a branch invents inherit the host's sandbox policy instead of the data-class default, so the pinning also holds for a build the host has never heard of. Pinned are requirePullRequest, statusContext, docker.enabled, docker.network, bwrap.enabled, and bwrap.rootfs. Docker and bwrap are mutually exclusive per branch — enabling both is rejected at start.
• builds or the legacy branches, never both: branches is read only while the merged config defines no build at all (builds.maxConcurrent is not one), and ignored with a warning as soon as one exists. The section is deprecated and goes away once the repositories have migrated; then ConfigVersions.FORMAT_BROKE_IN gets set and a leftover branches: key must be rejected by name — the version check alone cannot catch a file that declares no version.
• Web UI: server-rendered Thymeleaf plus one hand-written static/werkator.js — no SPA framework, no frontend build pipeline; every fetch has a timeout and an explicit error badge; UiFormats and werkator.js must produce identical display formats.
• Git and Docker access shells out to the CLIs (GitCommandRunner, docker) — no JGit, no Docker SDK.

Testing

Tests use Kotest FunSpec with MockK; SpringExtension is registered globally in io.kotest.provided.ProjectConfig — do not add it per-spec. IMPORTANT: Before writing or changing tests, load the writing-tests skill — it holds the spec structure and the Spring-slice mocking patterns.

File-Formatting

Markdown

Write documentation in English in Markdown files. In Markdown, use a single line per sentence. Keep sentences short.

Documentation

• docs/Werkator-Konzept.md — product concept and target architecture (in German): git-centric CI, builds in Docker, one instance per repository, status reported back to Gitea.
• docs/configuration.md — configuration reference; keep in sync with WerkatorConfig and the init templates.
• docs/bootstrapping.md — how init prepares a repository.
• docs/deployment.md — running Werkator as a systemd user service behind an existing reverse proxy (init --systemd generates the unit).
• docs/werkator-migrationsplan.md — renaming a running installation from GitTally to Werkator: what the name fallback covers and what has to be moved by hand.
• docs/plan/ — the step-by-step rewrite plan; docs/plan/README.md explains how to execute a step, docs/plan/00-legacy-analysis.md summarizes the legacy bash script.
• docs/prs/ — one document per pull request; every PR needs one. IMPORTANT: Before opening or finishing a pull request, load the pr-doc skill and write the PR-doc.

Key Architectural Decisions

All major decisions are in docs/adrs/. Run adr-status (after source .envrc) for a one-line summary of each. Decisions in force:

• Test framework: Kotest + MockK + WireMock + Testcontainers (ADR 0001)
• Gradle: 8.14.5 (ADR 0002)
• Spring Boot: 4.0.6 (ADR 0003)
• Rewrite architecture: JSON-file persistence behind a repository interface, server-rendered UI with JSON polling, no managed nginx — systemd unit behind the host's reverse proxy (ADR 0004)
• Managed nginx/TLS: revises ADR 0004 — an opt-in nginx+certbot container for hosts without a reverse proxy (e.g. Hostsharing), planned as docs/plan/13-nginx-tls.md (ADR 0005)
• Runtime bundle distribution: ./gradlew runtimeBundle builds a jlink-trimmed JRE + jar tarball for hosts without a Java runtime; GraalVM native image and a containerized runtime were rejected (ADR 0006)

Skills

On-demand guides in the cross-tool SKILL.md format; agents with skill support load them automatically by description, all others should read the linked files when the topic comes up:

• architecture — subsystem details: CLI wiring, server mode, web UI, config, git access, build execution, watcher, metrics.
• writing-tests — Kotest/MockK conventions and Spring slice-test mocking patterns.
• pr-doc — how to write the mandatory per-PR documentation in docs/prs/.