build_ghcr.yaml

name: Build Container Images
on:
  workflow_dispatch:
  push:
    paths:
      - "**/Dockerfile"
  schedule:
    - cron: '0 0 */2 * *'
# Avoids Github UI bugs https://github.com/orgs/community/discussions/45969
env:
  BUILDX_NO_DEFAULT_ATTESTATIONS: 1
jobs:
  ghcrbuild:
    strategy:
      fail-fast: false
      matrix:
        ubuntu: [focal, jammy]
        platform: [linux/amd64]

    name: Build container images for GHCR
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3

      - name: Extract metadata for container image
        id: meta
        uses: docker/metadata-action@v4
        with:
          images: ghcr.io/${{ github.repository }}-builder
          tags: |
            type=raw,value=${{ matrix.ubuntu }}

      - name: Extract container name without tag
        id: vars
        run: |
          echo container=$(echo '${{ steps.meta.outputs.tags }}' | awk -F':' '{print $1}') >> $GITHUB_OUTPUT

      - name: Set up QEMU
        uses: docker/setup-qemu-action@v2
        with:
          platforms: arm64
        if: contains(steps.versions.outputs.platform, 'arm64')

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v2
        with:
          platforms: ${{matrix.platform}}

      - name: Login to GHCR
        uses: docker/login-action@v2
        with:
          registry: ghcr.io
          username: ${{ github.repository_owner }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Build and push container image to ghcr
        id: build
        uses: docker/build-push-action@v4
        with:
          build-args: |
            UBUNTU_TAG=${{matrix.ubuntu}}
          file: builder.Dockerfile
          labels: ${{ steps.meta.outputs.labels }}
          outputs: type=image,name=${{ steps.vars.outputs.container }},push-by-digest=true,name-canonical=true,push=true
          platforms: ${{matrix.platform}}
          provenance: false

      - name: Prepare Dockerfile to extract R version with emulator
        run: |
          mkdir -p ${{matrix.ubuntu}}-${{matrix.platform}}
          cat << "EOF" > ${{matrix.ubuntu}}-${{matrix.platform}}-r.Dockerfile
          FROM ${{ steps.vars.outputs.container }}@${{ steps.build.outputs.digest }} as extract
          RUN mkdir /r2utmp && R --version > /r2utmp/rver && cat /etc/os-release > /r2utmp/os-release
          FROM scratch as export
          COPY --from=extract /r2utmp/* /
          EOF

      - name: Build and push container image to ghcr
        uses: docker/build-push-action@v4
        with:
          file: ${{matrix.ubuntu}}-${{matrix.platform}}-r.Dockerfile
          context: .
          push: false
          load: false
          provenance: false
          outputs: type=tar,dest=${{matrix.ubuntu}}-${{matrix.platform}}/r.tar
          tags: ${{ steps.meta.outputs.tags }}-r
          platforms: ${{ matrix.platform }}

      - name: Extract rversion
        id: versions
        run: |
          cd ${{matrix.ubuntu}}-${{matrix.platform}}
          tar -xvf r.tar
          echo rver=$(cat rver | awk 'NR==1{print $3}') >> $GITHUB_OUTPUT
          echo osver=$(awk -F= '/VERSION_ID/ {gsub("\"", "", $2); print $2}' os-release) >> $GITHUB_OUTPUT

      - name: Export digest by ubuntu and r versions
        run: |
          digest="${{ steps.build.outputs.digest }}"
          mkdir -p /tmp/digests/${{matrix.ubuntu}}
          touch "/tmp/digests/${{matrix.ubuntu}}/${digest#sha256:}"
          mkdir -p /tmp/digests/${{matrix.ubuntu}}-r-${{steps.versions.outputs.rver}}
          touch "/tmp/digests/${{matrix.ubuntu}}-r-${{steps.versions.outputs.rver}}/${digest#sha256:}"
          mkdir -p /tmp/digests/${{steps.versions.outputs.osver}}
          touch "/tmp/digests/${{steps.versions.outputs.osver}}/${digest#sha256:}"
          mkdir -p /tmp/digests/${{steps.versions.outputs.osver}}-r-${{steps.versions.outputs.rver}}
          touch "/tmp/digests/${{steps.versions.outputs.osver}}-r-${{steps.versions.outputs.rver}}/${digest#sha256:}"

      - name: Upload digests
        uses: actions/upload-artifact@v3
        with:
          name: r2udigests-${{ github.run_id }}
          path: /tmp/digests/**
          if-no-files-found: error
          retention-days: 1

  merge:
    runs-on: ubuntu-latest
    needs:
      - ghcrbuild
    if: always()
    strategy:
      fail-fast: false
      matrix:
        ubuntu: [focal, jammy]
    steps:
      - name: Download digests
        uses: actions/download-artifact@v3
        with:
          name: r2udigests-${{ github.run_id }}
          path: /tmp/digests

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v2
        with:
          platforms: ${{matrix.platform}}

      - name: Login to GHCR
        uses: docker/login-action@v2
        with:
          registry: ghcr.io
          username: ${{ github.repository_owner }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata for container image
        id: meta
        uses: docker/metadata-action@v4
        with:
          images: ghcr.io/${{ github.repository }}-builder
          tags: |
            type=raw,value=${{ matrix.ubuntu }}

      - name: Extract container name without tag
        id: vars
        run: |
          echo container=$(echo '${{ steps.meta.outputs.tags }}' | awk -F':' '{print $1}') >> $GITHUB_OUTPUT

      - name: Create manifest list and push
        run: |
          cd /tmp/digests
          ls --hide=digestdirs > digestdirs
          cat digestdirs | xargs -i bash -c 'docker buildx imagetools create -t ${{steps.vars.outputs.container}}:{} $(for f in {}/*; do basename "$f"; done | xargs printf "${{steps.vars.outputs.container}}@sha256:%s ")'