fancy-dns/.github/workflows/ci.yml

name: ci

on:
  push:
    branches: [main]
  pull_request:
  # A push to a fork's branch is the common case for a PR-based workflow, so
  # run on any branch that has a PR rather than only on main.
  workflow_dispatch:

permissions:
  contents: read

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

env:
  # Must track the `go` directive in go.mod; an older runner fails every
  # build with "go.mod requires go >= ...". The fmt check only has real teeth
  # when the toolchain is new enough (gofmt is part of the Go toolchain in 1.27).
  GO_VERSION: "1.27"
  NODE_VERSION: "22"

jobs:
  go:
    name: Go build, vet and test
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - uses: actions/setup-go@v5
        with:
          go-version: ${{ env.GO_VERSION }}
          cache: true

      # The placeholder keeps //go:embed valid when the console has not been
      # built in this job, so the Go checks do not depend on the web toolchain.
      - name: Ensure the embed directory exists
        run: mkdir -p internal/web/dist && touch internal/web/dist/.gitkeep

      - name: gofmt
        run: |
          unformatted=$(gofmt -l .)
          if [ -n "$unformatted" ]; then
            echo "gofmt needed on:"; echo "$unformatted"; exit 1
          fi

      - name: go vet
        run: go vet ./...

      # The race detector is not optional here: the whole design leans on
      # atomic holders and swap hooks, and a regression there is silent at
      # runtime and only shows up as a data race under load.
      - name: go test -race
        run: go test -race -count=1 ./...

      - name: go test -short (no race, coverage)
        run: go test -short -count=1 -coverprofile=coverage.out ./...

      - name: Coverage summary
        run: go tool cover -func=coverage.out | tail -20

      - name: Build without the console
        run: CGO_ENABLED=0 go build -trimpath -o /tmp/fancy-dns ./cmd/fancy-dns

  web:
    name: Console typecheck and build
    runs-on: ubuntu-latest
    defaults:
      run:
        working-directory: web
    steps:
      - uses: actions/checkout@v4

      - uses: actions/setup-node@v4
        with:
          node-version: ${{ env.NODE_VERSION }}
          cache: npm
          cache-dependency-path: web/package-lock.json

      - name: Install
        run: npm ci --no-audit --no-fund

      - name: Typecheck
        run: npx tsc -b --noEmit

      - name: Build
        run: npm run build

      - name: Assert the console landed where the Go embed looks
        run: test -f ../internal/web/dist/index.html

  binary:
    name: Binary with the console embedded
    runs-on: ubuntu-latest
    needs: [go, web]
    steps:
      - uses: actions/checkout@v4

      - uses: actions/setup-go@v5
        with:
          go-version: ${{ env.GO_VERSION }}
          cache: true

      - uses: actions/setup-node@v4
        with:
          node-version: ${{ env.NODE_VERSION }}
          cache: npm
          cache-dependency-path: web/package-lock.json

      - name: Install console dependencies
        working-directory: web
        run: npm ci --no-audit --no-fund

      - name: Build the console
        working-directory: web
        run: npm run build

      - name: Build the binary
        run: |
          CGO_ENABLED=0 go build -trimpath \
            -ldflags "-s -w -X git.k8s-git-k6n.net/mats/fancy-dns/internal/app.Version=${{ github.sha }}" \
            -o fancy-dns ./cmd/fancy-dns

      # A binary that starts, binds, and validates a config end to end: this
      # catches a broken embed or a bad default that unit tests never exercise.
      - name: Smoke test the real binary
        run: |
          set -euo pipefail
          mkdir -p /tmp/smoke
          # Unprivileged ports, and trust_loopback off: the example config trusts
          # loopback, which would make the 401 assertion below pass for the
          # wrong reason (the request would be authorised as a local caller).
          sed \
            -e 's#127.0.0.1:8080#127.0.0.1:18080#' \
            -e 's#0.0.0.0:53#127.0.0.1:15353#g' \
            -e 's#\[::\]:53#[::1]:15353#g' \
            -e 's#trust_loopback: true#trust_loopback: false#' \
            deploy/config.example.yaml > /tmp/smoke/config.yaml

          ./fancy-dns -config /tmp/smoke/config.yaml -check

          ./fancy-dns -config /tmp/smoke/config.yaml &
          pid=$!
          trap 'kill $pid 2>/dev/null || true' EXIT
          for i in $(seq 1 40); do
            curl -fsS http://127.0.0.1:18080/api/healthz >/dev/null 2>&1 && break
            sleep 0.5
          done

          echo "--- health"
          curl -fsS http://127.0.0.1:18080/api/healthz | tee /dev/stderr | grep -q '"status"'

          echo "--- console is embedded"
          curl -fsS http://127.0.0.1:18080/ | grep -qi '<!doctype html'

          echo "--- unauthenticated admin API is refused"
          code=$(curl -s -o /dev/null -w '%{http_code}' http://127.0.0.1:18080/api/whoami)
          test "$code" = "401" || { echo "expected 401, got $code"; exit 1; }

          echo "--- authenticated admin API works"
          curl -fsS -H "X-API-Key: CHANGE-ME-long-random-string" \
            http://127.0.0.1:18080/api/whoami | grep -q '"can_write":true'

          echo "smoke test passed"

      - name: Upload the binary
        uses: actions/upload-artifact@v4
        with:
          name: fancy-dns-linux-amd64
          path: fancy-dns
          retention-days: 14

  image:
    name: Container image
    runs-on: ubuntu-latest
    needs: [binary]
    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
    permissions:
      contents: read
      packages: write
    steps:
      - uses: actions/checkout@v4

      - uses: docker/setup-buildx-action@v3

      - name: Log in to the registry
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Build and push
        uses: docker/build-push-action@v6
        with:
          context: .
          push: true
          tags: |
            ghcr.io/${{ github.repository }}:latest
            ghcr.io/${{ github.repository }}:${{ github.sha }}
          build-args: |
            VERSION=${{ github.sha }}
          cache-from: type=gha
          cache-to: type=gha,mode=max