name: Build and Push

on:
  push:
    branches: [main]
  workflow_dispatch:
    inputs:
      service:
        description: "Service to build (all, backend, consumer, worker, forms, updater, tracking, realtime)"
        required: false
        default: "all"

env:
  REGISTRY: ghcr.io
  IMAGE_PREFIX: ghcr.io/${{ github.repository_owner }}/warmbly

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

jobs:
  changes:
    name: Detect Changes
    runs-on: ubuntu-latest
    outputs:
      # JSON consumed as matrix inputs. `go` is a list of service names that
      # cross-compile both arches on one runner. `native` is a list of
      # {service, suffix, args} objects that cannot cross-compile, so each arch
      # builds on a native runner and the digests are merged into one manifest:
      # Rust and Elixir have no cross-compiler, and the Kafka variants of the Go
      # services link librdkafka through cgo, which needs a native toolchain.
      go: ${{ steps.matrix.outputs.go }}
      native: ${{ steps.matrix.outputs.native }}
    steps:
      - uses: actions/checkout@v4
      - uses: dorny/paths-filter@v3
        if: github.event_name == 'push'
        id: filter
        with:
          filters: |
            backend:
              - 'go.mod'
              - 'go.sum'
              - 'internal/**'
              - 'cmd/backend/**'
              - 'deploy/docker/backend.Dockerfile'
            consumer:
              - 'go.mod'
              - 'go.sum'
              - 'internal/**'
              - 'cmd/consumer/**'
              - 'deploy/docker/consumer.Dockerfile'
            worker:
              - 'go.mod'
              - 'go.sum'
              - 'internal/**'
              - 'cmd/worker/**'
              - 'deploy/docker/worker.Dockerfile'
            forms:
              - 'go.mod'
              - 'go.sum'
              - 'internal/**'
              - 'cmd/forms/**'
              - 'forms/**'
              - 'deploy/docker/forms.Dockerfile'
            updater:
              - 'go.mod'
              - 'go.sum'
              # internal/** and not internal/updater/**: the binary links
              # internal/version and whatever else it grows, and an image that
              # silently skips a rebuild is worse than one rebuilt too often.
              - 'internal/**'
              - 'cmd/updater/**'
              - 'deploy/docker/updater.Dockerfile'
            tracking:
              - 'tracking/**'
            realtime:
              - 'realtime/**'
              - 'deploy/docker/realtime.Dockerfile'
      - name: Assemble build matrices
        id: matrix
        env:
          EVENT: ${{ github.event_name }}
          SELECTED: ${{ github.event.inputs.service }}
          BACKEND: ${{ steps.filter.outputs.backend }}
          CONSUMER: ${{ steps.filter.outputs.consumer }}
          WORKER: ${{ steps.filter.outputs.worker }}
          FORMS: ${{ steps.filter.outputs.forms }}
          UPDATER: ${{ steps.filter.outputs.updater }}
          TRACKING: ${{ steps.filter.outputs.tracking }}
          REALTIME: ${{ steps.filter.outputs.realtime }}
          BUILT_AT: ${{ github.event.head_commit.timestamp }}
        run: |
          go=""
          native=""
          # A service that talks to the event bus gets a second, Kafka-linked
          # image published as :<tag>-kafka. backend, consumer, worker and
          # tracking are the four that do; forms and updater never touch it, and
          # realtime is fed by the others rather than reading the bus itself.
          add() {
            case "$1" in
              backend|consumer|worker)
                go="$go\"$1\","
                native="$native{\"service\":\"$1\",\"suffix\":\"-kafka\",\"args\":\"GO_TAGS=kafka\\nBUILT_AT=$BUILT_AT\"},"
                ;;
              forms|updater)
                go="$go\"$1\","
                ;;
              tracking)
                native="$native{\"service\":\"tracking\",\"suffix\":\"\",\"args\":\"\"},"
                native="$native{\"service\":\"tracking\",\"suffix\":\"-kafka\",\"args\":\"CARGO_FEATURES=kafka\"},"
                ;;
              realtime)
                native="$native{\"service\":\"realtime\",\"suffix\":\"\",\"args\":\"\"},"
                ;;
            esac
          }
          if [ "$EVENT" = "workflow_dispatch" ]; then
            sel="${SELECTED:-all}"
            for s in backend consumer worker forms updater tracking realtime; do
              if [ "$sel" = "all" ] || [ "$sel" = "$s" ]; then add "$s"; fi
            done
          else
            [ "$BACKEND" = "true" ] && add backend
            [ "$CONSUMER" = "true" ] && add consumer
            [ "$WORKER" = "true" ] && add worker
            [ "$FORMS" = "true" ] && add forms
            [ "$UPDATER" = "true" ] && add updater
            [ "$TRACKING" = "true" ] && add tracking
            [ "$REALTIME" = "true" ] && add realtime
            true
          fi
          # printf, not echo: the Go Kafka args carry a literal \n separating two
          # build-args, and echo expands backslash escapes in some shells, which
          # would split the value across two lines and break both the JSON and
          # the single-line $GITHUB_OUTPUT format.
          printf 'go=[%s]\n' "${go%,}" >> "$GITHUB_OUTPUT"
          printf 'native=[%s]\n' "${native%,}" >> "$GITHUB_OUTPUT"

  # Go services: the Dockerfiles build on $BUILDPLATFORM and cross-compile to
  # each target arch, so one amd64 runner produces both platforms without QEMU.
  build-go:
    name: Build ${{ matrix.service }}
    needs: changes
    if: needs.changes.outputs.go != '[]'
    strategy:
      fail-fast: false
      matrix:
        service: ${{ fromJSON(needs.changes.outputs.go) }}
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
    steps:
      - uses: actions/checkout@v4

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

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

      - name: Build and push
        uses: docker/build-push-action@v6
        with:
          context: .
          file: deploy/docker/${{ matrix.service }}.Dockerfile
          push: true
          build-args: |
            VERSION=dev-${{ github.sha }}
            COMMIT=${{ github.sha }}
            BUILT_AT=${{ github.event.head_commit.timestamp }}
          tags: |
            ${{ env.IMAGE_PREFIX }}/${{ matrix.service }}:${{ github.sha }}
            ${{ env.IMAGE_PREFIX }}/${{ matrix.service }}:dev
          platforms: linux/amd64,linux/arm64
          cache-from: type=gha,scope=${{ matrix.service }}
          cache-to: type=gha,mode=max,scope=${{ matrix.service }}

  # Everything that cannot cross-compile: Rust (tracking), Elixir (realtime),
  # and the Kafka variants of the Go services, which link librdkafka through
  # cgo. An emulated arm64 build under QEMU runs for an hour or more, so build
  # each arch on a native runner and merge the digests into one manifest (the
  # Docker-documented multi-runner pattern).
  build-native:
    name: Build ${{ matrix.target.service }}${{ matrix.target.suffix }} (${{ matrix.platform }})
    needs: changes
    if: needs.changes.outputs.native != '[]'
    strategy:
      fail-fast: false
      matrix:
        target: ${{ fromJSON(needs.changes.outputs.native) }}
        platform: [linux/amd64, linux/arm64]
    runs-on: ${{ matrix.platform == 'linux/arm64' && 'ubuntu-24.04-arm' || 'ubuntu-latest' }}
    permissions:
      contents: read
      packages: write
    steps:
      - uses: actions/checkout@v4

      # `key` is the per-variant identifier: the image name plus the tag suffix,
      # so a Kafka build never shares a cache scope or a digest artifact with
      # the plain build of the same service.
      - name: Prepare identifiers
        id: prep
        run: |
          echo "pair=${PLATFORM//\//-}" >> "$GITHUB_OUTPUT"
          echo "key=${SERVICE}${SUFFIX}" >> "$GITHUB_OUTPUT"
        env:
          PLATFORM: ${{ matrix.platform }}
          SERVICE: ${{ matrix.target.service }}
          SUFFIX: ${{ matrix.target.suffix }}

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

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

      - name: Build and push by digest
        id: build
        uses: docker/build-push-action@v6
        with:
          context: ${{ matrix.target.service == 'tracking' && './tracking' || '.' }}
          file: ${{ matrix.target.service == 'tracking' && './tracking/Dockerfile' || format('deploy/docker/{0}.Dockerfile', matrix.target.service) }}
          platforms: ${{ matrix.platform }}
          build-args: |
            VERSION=dev-${{ github.sha }}
            COMMIT=${{ github.sha }}
            ${{ matrix.target.args }}
          cache-from: type=gha,scope=${{ steps.prep.outputs.key }}-${{ steps.prep.outputs.pair }}
          cache-to: type=gha,mode=max,scope=${{ steps.prep.outputs.key }}-${{ steps.prep.outputs.pair }}
          outputs: type=image,name=${{ env.IMAGE_PREFIX }}/${{ matrix.target.service }},push-by-digest=true,name-canonical=true,push=true

      - name: Export digest
        run: |
          mkdir -p /tmp/digests
          digest="${{ steps.build.outputs.digest }}"
          touch "/tmp/digests/${digest#sha256:}"

      - name: Upload digest
        uses: actions/upload-artifact@v4
        with:
          name: digests-${{ steps.prep.outputs.key }}-${{ steps.prep.outputs.pair }}
          path: /tmp/digests/*
          if-no-files-found: error
          retention-days: 1

  merge-native:
    name: Merge ${{ matrix.target.service }}${{ matrix.target.suffix }} manifest
    needs: [changes, build-native]
    if: needs.changes.outputs.native != '[]'
    strategy:
      fail-fast: false
      matrix:
        target: ${{ fromJSON(needs.changes.outputs.native) }}
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
    steps:
      - name: Download digests
        uses: actions/download-artifact@v4
        with:
          path: /tmp/digests
          pattern: digests-${{ matrix.target.service }}${{ matrix.target.suffix }}-linux-*
          merge-multiple: true

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

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Create manifest list and push
        working-directory: /tmp/digests
        run: |
          docker buildx imagetools create \
            -t ${{ env.IMAGE_PREFIX }}/${{ matrix.target.service }}:${{ github.sha }}${{ matrix.target.suffix }} \
            -t ${{ env.IMAGE_PREFIX }}/${{ matrix.target.service }}:dev${{ matrix.target.suffix }} \
            $(printf '${{ env.IMAGE_PREFIX }}/${{ matrix.target.service }}@sha256:%s ' *)

  # A package on GHCR is created private and does not inherit the repository's
  # visibility, and no API can change that: an owner has to flip it by hand.
  # So a new service image is born unpullable, and the first sign of it would
  # otherwise be a stranger's failed install (#371).
  #
  # This is the early warning: main is where a new image first appears, and
  # finding out here costs nothing, while finding out at tag time blocks a
  # release. It only warns, because the fix is not in this repo and nobody can
  # land a PR that makes main green again.
  verify-public:
    name: Warn if images are not publicly pullable
    needs: [build-go, merge-native]
    if: always() && github.event_name == 'push'
    runs-on: ubuntu-latest
    permissions:
      contents: read
    steps:
      - uses: actions/checkout@v4
      # Only what this workflow publishes. web, admin and cli are built at
      # tag time and have no :dev tag, so checking them here would warn about
      # something no push to main can fix.
      - name: Pull-test every image anonymously
        run: |
          ./scripts/check-images-public.sh --prefix "$IMAGE_PREFIX" --tag dev --warn \
            backend consumer worker forms updater tracking realtime