ResInsight/.github/workflows/build-rhel8-image.yml

name: Build RHEL8 CI Image

# Builds the Docker image used by the RHEL8 unit test workflow. The image bakes
# in the toolchain (gcc-toolset-14, libstdc++exp, Qt) and a prebuilt vcpkg
# binary cache so CI runs do not have to reprovision them every time.

on:
  schedule:
    # Nightly at 00:00 UTC, before the RHEL8 unit tests run at 02:00 UTC.
    - cron: "0 0 * * *"
  push:
    paths:
      - ".github/docker/Dockerfile.rhel8"
      - ".github/workflows/build-rhel8-image.yml"
      - ".dockerignore"
      - "vcpkg.json"
      - "vcpkg-configuration-rhel8.json"
      - ".gitmodules"
  workflow_dispatch:
    inputs:
      force_rebuild:
        description: "Rebuild and overwrite today's image even if it already exists in GHCR"
        type: boolean
        default: false

concurrency:
  group: build-rhel8-image
  cancel-in-progress: false

jobs:
  build-image:
    runs-on: ubuntu-latest
    # Cold first build runs the full ResInsight compile in the build-warmup
    # stage (~1.5-2 h). Incremental nightly rebuilds reuse the BuildKit cache
    # mount and finish much faster.
    timeout-minutes: 180
    permissions:
      contents: read
      packages: write
    steps:
      - name: Checkout
        uses: actions/checkout@v7
        with:
          submodules: recursive

      - name: Compute image name and tag
        id: meta
        run: |
          image="ghcr.io/${GITHUB_REPOSITORY,,}/ci-rhel8"
          date="$(date -u +%Y-%m-%d)"
          repo_name_lc="${GITHUB_REPOSITORY##*/}"
          repo_name_lc="${repo_name_lc,,}"
          web_url="${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}/pkgs/container/${repo_name_lc}%2Fci-rhel8"
          {
            echo "image=$image"
            echo "date=$date"
            echo "web_url=$web_url"
          } >> "$GITHUB_OUTPUT"
          echo "Image refs : $image:latest"
          echo "             $image:$date"
          echo "GHCR page  : $web_url"

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v4

      - name: Log in to GitHub Container Registry
        uses: docker/login-action@v4
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      # The image build is expensive (cold ~1.5-2 h). If an image tagged with
      # today's UTC date is already in GHCR, treat the build as already done
      # for this day and skip. To force a same-day rebuild, dispatch the
      # workflow with force_rebuild=true (or delete the dated tag from GHCR
      # and rerun).
      - name: Check if today's image already exists in GHCR
        id: check
        run: |
          if [[ "${{ github.event_name }}" == "workflow_dispatch" && "${{ inputs.force_rebuild }}" == "true" ]]; then
            echo "force_rebuild=true -- skipping existence check."
            echo "exists=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi
          target="${{ steps.meta.outputs.image }}:${{ steps.meta.outputs.date }}"
          if docker buildx imagetools inspect "$target" >/dev/null 2>&1; then
            echo "Image $target already exists -- skipping build."
            echo "See: ${{ steps.meta.outputs.web_url }}"
            echo "exists=true" >> "$GITHUB_OUTPUT"
          else
            echo "Image $target not found -- proceeding with build."
            echo "exists=false" >> "$GITHUB_OUTPUT"
          fi

      - name: Build and push image
        if: steps.check.outputs.exists != 'true'
        uses: docker/build-push-action@v7
        with:
          context: .
          file: .github/docker/Dockerfile.rhel8
          push: true
          tags: |
            ${{ steps.meta.outputs.image }}:latest
            ${{ steps.meta.outputs.image }}:${{ steps.meta.outputs.date }}
          # Layer cache lives in GHCR instead of the GitHub Actions cache: the
          # Actions cache has a 10 GB per-repo limit shared with all other
          # workflows, so the multi-GB mode=max export was evicted immediately
          # (0% hit rate) and the export itself started failing with
          # "not_found" once the repo hit the cap.
          cache-from: type=registry,ref=${{ steps.meta.outputs.image }}:buildcache
          cache-to: type=registry,ref=${{ steps.meta.outputs.image }}:buildcache,mode=max,image-manifest=true