build.yml

name: Build and push Docker image

on:
  push:
    branches:
      - '*'

jobs:
  prepare:
    name: Determine base tag and full tag
    runs-on: ubuntu-24.04
    outputs:
      base_tag: ${{ steps.tags.outputs.base_tag }}
      full_tag: ${{ steps.tags.outputs.full_tag }}

    steps:
      - name: Determine base tag and full tag
        id: tags
        run: |
          if [ "${GITHUB_REF_NAME#*-}" = "${GITHUB_REF_NAME}" ]; then
              base=${GITHUB_REF_NAME}
              full=$base
              echo "base_tag=$base" >> "$GITHUB_OUTPUT"
              echo "full_tag=$full" >> "$GITHUB_OUTPUT"
          else
              main=${GITHUB_REF_NAME%-*}
              base=${GITHUB_REF_NAME##*-}
              full=$main-$base
              if [ "${base#*u}" ]; then
                  base=${base%%u*}
              fi
              echo "base_tag=$base" >> "$GITHUB_OUTPUT"
              echo "full_tag=$full" >> "$GITHUB_OUTPUT"
          fi

  build-base:
    name: Build base image (${{ matrix.platform }})
    runs-on: ${{ matrix.runner }}
    needs: prepare
    strategy:
      fail-fast: false
      matrix:
        include:
          - platform: linux/amd64
            runner: ubuntu-24.04
          - platform: linux/arm64
            runner: ubuntu-24.04-arm

    steps:
      - uses: actions/checkout@v4

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

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

      # Build and push platform-specific digest (no manifest tag yet)
      - name: Build and push by digest
        id: build
        uses: docker/build-push-action@v6
        with:
          context: .
          file: Dockerfile
          platforms: ${{ matrix.platform }}
          push: true
          build-args: |
            BASE_TAG=${{ needs.prepare.outputs.base_tag }}
          outputs: type=image,name=apluslms/grade-python,push-by-digest=true,name-canonical=true

      # Save the digest so the merge job can find it
      - name: Export digest
        run: |
          mkdir -p /tmp/digests
          digest="${{ steps.build.outputs.digest }}"
          touch "/tmp/digests/${digest#sha256:}"

      - name: Upload digest artifact
        uses: actions/upload-artifact@v4
        with:
          name: digest-base-${{ matrix.platform == 'linux/amd64' && 'amd64' || 'arm64' }}
          path: /tmp/digests/*
          retention-days: 1

  merge-base:
    name: Merge base manifests
    runs-on: ubuntu-24.04
    needs: build-base

    steps:
      - name: Download digests
        uses: actions/download-artifact@v4
        with:
          path: /tmp/digests
          pattern: digest-base-*
          merge-multiple: true

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

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

      - name: Determine tags
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: apluslms/grade-python
          flavor: |
            latest=false
          tags: |
            type=raw,enable=${{ github.ref == 'refs/heads/master' }},value=latest
            type=ref,enable=${{ github.ref != 'refs/heads/master' }},event=branch

      - name: Create and push multi-arch manifest
        working-directory: /tmp/digests
        run: |
          docker buildx imagetools create \
            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
            $(printf 'apluslms/grade-python@sha256:%s ' *)

  build-math:
    name: Build math image (${{ matrix.platform }})
    runs-on: ${{ matrix.runner }}
    needs:
      - prepare
      - merge-base
    strategy:
      fail-fast: false
      matrix:
        include:
          - platform: linux/amd64
            runner: ubuntu-24.04
          - platform: linux/arm64
            runner: ubuntu-24.04-arm

    steps:
      - uses: actions/checkout@v4

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

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

      # Build and push platform-specific digest (no manifest tag yet)
      - name: Build and push by digest
        id: build
        uses: docker/build-push-action@v6
        with:
          context: .
          file: Dockerfile.math
          platforms: ${{ matrix.platform }}
          push: true
          build-args: |
            FULL_TAG=${{ needs.prepare.outputs.full_tag }}
          outputs: type=image,name=apluslms/grade-python,push-by-digest=true,name-canonical=true

      # Save the digest so the merge job can find it
      - name: Export digest
        run: |
          mkdir -p /tmp/digests
          digest="${{ steps.build.outputs.digest }}"
          touch "/tmp/digests/${digest#sha256:}"

      - name: Upload digest artifact
        uses: actions/upload-artifact@v4
        with:
          name: digest-math-${{ matrix.platform == 'linux/amd64' && 'amd64' || 'arm64' }}
          path: /tmp/digests/*
          retention-days: 1

  merge-math:
    name: Merge math manifests
    runs-on: ubuntu-24.04
    needs:
      - prepare
      - build-math

    steps:
      - name: Download digests
        uses: actions/download-artifact@v4
        with:
          path: /tmp/digests
          pattern: digest-math-*
          merge-multiple: true

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

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

      - name: Determine tags
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: apluslms/grade-python
          flavor: |
            latest=false
          tags: |
            type=raw,enable=${{ github.ref == 'refs/heads/master' }},value=math-latest
            type=raw,enable=${{ github.ref != 'refs/heads/master' }},value=math-${{ needs.prepare.outputs.full_tag }}

      - name: Create and push multi-arch manifest
        working-directory: /tmp/digests
        run: |
          docker buildx imagetools create \
            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
            $(printf 'apluslms/grade-python@sha256:%s ' *)