build-push.yml

name: Build and Push Images

on:
  push:
    branches: [main]
    tags: ['v*']
    paths:
      - 'base/**'
      - 'dev/**'
      - '.github/workflows/build-push.yml'
  pull_request:
    branches: [main]
    paths:
      - 'base/**'
      - 'dev/**'
  schedule:
    # Weekly rebuild to pick up security patches
    - cron: '0 6 * * 1'
  workflow_dispatch:
    inputs:
      force_base_build:
        description: 'Force rebuild of base image'
        required: false
        default: 'false'
        type: boolean

env:
  DOCKER_HUB_BASE: ${{ secrets.DOCKERHUB_USERNAME }}/ocaml-devcontainer-base
  DOCKER_HUB_DEV: ${{ secrets.DOCKERHUB_USERNAME }}/ocaml-devcontainer
  GHCR_BASE: ghcr.io/${{ github.repository_owner }}/ocaml-devcontainer-base
  GHCR_DEV: ghcr.io/${{ github.repository_owner }}/ocaml-devcontainer

jobs:
  # ============================================================================
  # Check what changed to determine if base needs rebuilding
  # ============================================================================
  changes:
    runs-on: ubuntu-latest
    outputs:
      base: ${{ steps.filter.outputs.base }}
      dev: ${{ steps.filter.outputs.dev }}
    steps:
      - uses: actions/checkout@v6

      - uses: dorny/paths-filter@v3
        id: filter
        with:
          filters: |
            base:
              - 'base/**'
            dev:
              - 'dev/**'

  # ============================================================================
  # Fan-out: Build Base Images (parallel per architecture)
  # ============================================================================
  build-base-amd64:
    needs: changes
    if: |
      needs.changes.outputs.base == 'true' ||
      github.event.inputs.force_base_build == 'true' ||
      startsWith(github.ref, 'refs/tags/') ||
      github.event_name == 'schedule'
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

    steps:
      - name: Checkout
        uses: actions/checkout@v6

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

      - name: Login to Docker Hub
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

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

      - name: Build and push base image (amd64)
        uses: docker/build-push-action@v7
        with:
          context: ./base
          file: ./base/Dockerfile
          platforms: linux/amd64
          push: ${{ github.event_name != 'pull_request' }}
          tags: |
            ${{ env.GHCR_BASE }}:latest-amd64
            ${{ env.DOCKER_HUB_BASE }}:latest-amd64
          labels: |
            org.opencontainers.image.source=https://github.com/${{ github.repository }}
            org.opencontainers.image.revision=${{ github.sha }}
          cache-from: type=gha,scope=base-amd64
          cache-to: type=gha,mode=max,scope=base-amd64

  build-base-arm64:
    needs: changes
    if: |
      needs.changes.outputs.base == 'true' ||
      github.event.inputs.force_base_build == 'true' ||
      startsWith(github.ref, 'refs/tags/') ||
      github.event_name == 'schedule'
    runs-on: ubuntu-24.04-arm
    permissions:
      contents: read
      packages: write

    steps:
      - name: Checkout
        uses: actions/checkout@v6

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

      - name: Login to Docker Hub
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

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

      - name: Build and push base image (arm64)
        uses: docker/build-push-action@v7
        with:
          context: ./base
          file: ./base/Dockerfile
          platforms: linux/arm64
          push: ${{ github.event_name != 'pull_request' }}
          tags: |
            ${{ env.GHCR_BASE }}:latest-arm64
            ${{ env.DOCKER_HUB_BASE }}:latest-arm64
          labels: |
            org.opencontainers.image.source=https://github.com/${{ github.repository }}
            org.opencontainers.image.revision=${{ github.sha }}
          cache-from: type=gha,scope=base-arm64
          cache-to: type=gha,mode=max,scope=base-arm64

  # ============================================================================
  # Fan-out: Build Dev Images (fast-lane: each arch depends only on its base)
  # ============================================================================
  build-dev-amd64:
    needs: [changes, build-base-amd64]
    if: |
      always() &&
      (needs.build-base-amd64.result == 'success' ||
       needs.build-base-amd64.result == 'skipped') &&
      (needs.changes.outputs.dev == 'true' ||
       needs.changes.outputs.base == 'true' ||
       startsWith(github.ref, 'refs/tags/') ||
       github.event_name == 'workflow_dispatch' ||
       github.event_name == 'schedule')
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

    steps:
      - name: Checkout
        uses: actions/checkout@v6

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

      - name: Login to Docker Hub
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

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

      - name: Build and push dev image (amd64)
        uses: docker/build-push-action@v7
        with:
          context: ./dev
          file: ./dev/Dockerfile
          platforms: linux/amd64
          push: ${{ github.event_name != 'pull_request' }}
          tags: |
            ${{ env.GHCR_DEV }}:latest-amd64
            ${{ env.DOCKER_HUB_DEV }}:latest-amd64
          labels: |
            org.opencontainers.image.source=https://github.com/${{ github.repository }}
            org.opencontainers.image.revision=${{ github.sha }}
          build-args: |
            BASE_IMAGE=${{ env.GHCR_BASE }}:latest-amd64
          cache-from: type=gha,scope=dev-amd64
          cache-to: type=gha,mode=max,scope=dev-amd64

  build-dev-arm64:
    needs: [changes, build-base-arm64]
    if: |
      always() &&
      (needs.build-base-arm64.result == 'success' ||
       needs.build-base-arm64.result == 'skipped') &&
      (needs.changes.outputs.dev == 'true' ||
       needs.changes.outputs.base == 'true' ||
       startsWith(github.ref, 'refs/tags/') ||
       github.event_name == 'workflow_dispatch' ||
       github.event_name == 'schedule')
    runs-on: ubuntu-24.04-arm
    permissions:
      contents: read
      packages: write

    steps:
      - name: Checkout
        uses: actions/checkout@v6

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

      - name: Login to Docker Hub
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

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

      - name: Build and push dev image (arm64)
        uses: docker/build-push-action@v7
        with:
          context: ./dev
          file: ./dev/Dockerfile
          platforms: linux/arm64
          push: ${{ github.event_name != 'pull_request' }}
          tags: |
            ${{ env.GHCR_DEV }}:latest-arm64
            ${{ env.DOCKER_HUB_DEV }}:latest-arm64
          labels: |
            org.opencontainers.image.source=https://github.com/${{ github.repository }}
            org.opencontainers.image.revision=${{ github.sha }}
          build-args: |
            BASE_IMAGE=${{ env.GHCR_BASE }}:latest-arm64
          cache-from: type=gha,scope=dev-arm64
          cache-to: type=gha,mode=max,scope=dev-arm64

  # ============================================================================
  # Fan-in: Merge Base Image Tags into Multi-Arch Manifest
  # ============================================================================
  merge-base:
    needs: [build-base-amd64, build-base-arm64]
    if: |
      always() &&
      needs.build-base-amd64.result == 'success' &&
      needs.build-base-arm64.result == 'success' &&
      github.event_name != 'pull_request'
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

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

      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

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

      - name: Create and push multi-arch manifest (GHCR)
        run: |
          docker buildx imagetools create -t ${{ env.GHCR_BASE }}:latest \
            ${{ env.GHCR_BASE }}:latest-amd64 \
            ${{ env.GHCR_BASE }}:latest-arm64

          # Add version tag if this is a release
          if [[ "${{ github.ref }}" == refs/tags/v* ]]; then
            VERSION=${GITHUB_REF#refs/tags/}
            docker buildx imagetools create -t ${{ env.GHCR_BASE }}:${VERSION} \
              ${{ env.GHCR_BASE }}:latest-amd64 \
              ${{ env.GHCR_BASE }}:latest-arm64
          fi

      - name: Create and push multi-arch manifest (Docker Hub)
        run: |
          docker buildx imagetools create -t ${{ env.DOCKER_HUB_BASE }}:latest \
            ${{ env.DOCKER_HUB_BASE }}:latest-amd64 \
            ${{ env.DOCKER_HUB_BASE }}:latest-arm64

          # Add version tag if this is a release
          if [[ "${{ github.ref }}" == refs/tags/v* ]]; then
            VERSION=${GITHUB_REF#refs/tags/}
            docker buildx imagetools create -t ${{ env.DOCKER_HUB_BASE }}:${VERSION} \
              ${{ env.DOCKER_HUB_BASE }}:latest-amd64 \
              ${{ env.DOCKER_HUB_BASE }}:latest-arm64
          fi

      - name: Verify multi-arch manifest
        run: |
          echo "=== GHCR Base Image ==="
          docker buildx imagetools inspect ${{ env.GHCR_BASE }}:latest
          echo ""
          echo "=== Docker Hub Base Image ==="
          docker buildx imagetools inspect ${{ env.DOCKER_HUB_BASE }}:latest

  # ============================================================================
  # Fan-in: Merge Dev Image Tags into Multi-Arch Manifest
  # ============================================================================
  merge-dev:
    needs: [build-dev-amd64, build-dev-arm64]
    if: |
      always() &&
      needs.build-dev-amd64.result == 'success' &&
      needs.build-dev-arm64.result == 'success' &&
      github.event_name != 'pull_request'
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

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

      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

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

      - name: Create and push multi-arch manifest (GHCR)
        run: |
          docker buildx imagetools create -t ${{ env.GHCR_DEV }}:latest \
            ${{ env.GHCR_DEV }}:latest-amd64 \
            ${{ env.GHCR_DEV }}:latest-arm64

          # Add version tag if this is a release
          if [[ "${{ github.ref }}" == refs/tags/v* ]]; then
            VERSION=${GITHUB_REF#refs/tags/}
            docker buildx imagetools create -t ${{ env.GHCR_DEV }}:${VERSION} \
              ${{ env.GHCR_DEV }}:latest-amd64 \
              ${{ env.GHCR_DEV }}:latest-arm64
          fi

      - name: Create and push multi-arch manifest (Docker Hub)
        run: |
          docker buildx imagetools create -t ${{ env.DOCKER_HUB_DEV }}:latest \
            ${{ env.DOCKER_HUB_DEV }}:latest-amd64 \
            ${{ env.DOCKER_HUB_DEV }}:latest-arm64

          # Add version tag if this is a release
          if [[ "${{ github.ref }}" == refs/tags/v* ]]; then
            VERSION=${GITHUB_REF#refs/tags/}
            docker buildx imagetools create -t ${{ env.DOCKER_HUB_DEV }}:${VERSION} \
              ${{ env.DOCKER_HUB_DEV }}:latest-amd64 \
              ${{ env.DOCKER_HUB_DEV }}:latest-arm64
          fi

      - name: Verify multi-arch manifest
        run: |
          echo "=== GHCR Dev Image ==="
          docker buildx imagetools inspect ${{ env.GHCR_DEV }}:latest
          echo ""
          echo "=== Docker Hub Dev Image ==="
          docker buildx imagetools inspect ${{ env.DOCKER_HUB_DEV }}:latest