docker-constructive.yaml

name: Constructive Docker

on:
  push:
    branches:
      - main
      - v1
      - release/*
  pull_request:
    branches:
      - main
      - v1
    types: [opened, reopened, synchronize, ready_for_review]
  workflow_dispatch: {}

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

jobs:
  build-push-constructive:
    if: github.event_name != 'pull_request'
    strategy:
      fail-fast: false
      matrix:
        include:
          - platform: linux/amd64
            arch: amd64
            runner: ubuntu-latest      # x86_64
          - platform: linux/arm64
            arch: arm64
            runner: ubuntu-24.04-arm   # native arm
    runs-on: ${{ matrix.runner }}

    permissions:
      contents: read
      packages: write

    env:
      REPO: ghcr.io/${{ github.repository_owner }}
      IMAGE_NAME: constructive

    steps:
      - name: Checkout
        uses: actions/checkout@v4

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

      - name: Login to GHCR
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REPO }}/${{ env.IMAGE_NAME }}
          tags: |
            type=ref,event=branch
            type=ref,event=pr
            type=semver,pattern={{version}}
            type=semver,pattern={{major}}.{{minor}}
            type=sha,format=short,prefix=
            type=raw,value=latest,enable={{is_default_branch}}

      # For pull_request events (if they are re-enabled),
      # do a quick amd64-only build without pushing.
      - name: Build (no push, PR only)
        if: github.event_name == 'pull_request' && matrix.platform == 'linux/amd64'
        uses: docker/build-push-action@v5
        with:
          context: .
          file: ./Dockerfile
          platforms: linux/amd64
          push: false
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max

      # For non-PR events, build one architecture per runner
      # and push images by digest. These digests are later
      # assembled into a multi-arch manifest.
      - name: Build & push by digest
        if: github.event_name != 'pull_request'
        id: build
        uses: docker/build-push-action@v6
        with:
          context: .
          file: ./Dockerfile
          platforms: ${{ matrix.platform }}
          labels: ${{ steps.meta.outputs.labels }}
          outputs: type=image,name=${{ env.REPO }}/${{ env.IMAGE_NAME }},push-by-digest=true,push=true
          cache-from: type=gha
          cache-to: type=gha,mode=max

      - name: Export digest
        if: github.event_name != 'pull_request'
        run: |
          mkdir -p "${{ runner.temp }}/digests"
          digest="${{ steps.build.outputs.digest }}"
          touch "${{ runner.temp }}/digests/${digest#sha256:}"

      - name: Upload digest
        if: github.event_name != 'pull_request'
        uses: actions/upload-artifact@v4
        with:
          # Artifact names cannot contain slashes, so we use matrix.arch
          name: digests-${{ matrix.arch }}
          path: ${{ runner.temp }}/digests/*

  # Assemble per-architecture images into a single
  # multi-arch manifest for each tag.
  publish-constructive-manifest:
    if: github.event_name != 'pull_request'
    runs-on: ubuntu-latest
    needs: build-push-constructive

    permissions:
      contents: read
      packages: write

    env:
      REPO: ghcr.io/${{ github.repository_owner }}
      IMAGE_NAME: constructive

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

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

      - name: Download digests
        uses: actions/download-artifact@v4
        with:
          pattern: digests-*
          path: ${{ runner.temp }}/digests
          merge-multiple: true

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REPO }}/${{ env.IMAGE_NAME }}
          tags: |
            type=ref,event=branch
            type=ref,event=pr
            type=semver,pattern={{version}}
            type=semver,pattern={{major}}.{{minor}}
            type=sha,format=short,prefix=
            type=raw,value=latest,enable={{is_default_branch}}

      - name: Create and push multi-arch manifests
        run: |
          set -euo pipefail

          image="${{ env.REPO }}/${{ env.IMAGE_NAME }}"
          digest_dir="${{ runner.temp }}/digests"

          if [ ! -d "$digest_dir" ]; then
            echo "No digests directory found at $digest_dir"
            exit 1
          fi

          digests=""
          for digest_file in "$digest_dir"/*; do
            digest="$(basename "$digest_file")"
            digests="$digests $image@sha256:$digest"
          done

          if [ -z "$digests" ]; then
            echo "No digests found to create manifest"
            exit 1
          fi

          echo "Creating manifests for tags:"
          echo "${{ steps.meta.outputs.tags }}"

          # metadata-action outputs tags as a newline-separated list
          echo "${{ steps.meta.outputs.tags }}" | while read -r tag; do
            [ -z "$tag" ] && continue
            echo "Creating multi-arch manifest for $tag"
            docker buildx imagetools create -t "$tag" $digests
          done