build.yml

name: Build Docker Image

on:
  pull_request:
    branches:
      - trunk
  merge_group:
  workflow_dispatch:

permissions:
  contents: read

jobs:
  prepare:
    name: Prepare list of images to build
    runs-on: ubuntu-latest
    outputs:
      images: ${{ steps.set-matrix.outputs.images }}
    steps:
      - name: Check out the repo
        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683

      - name: Set matrix
        id: set-matrix
        run: echo images="$(jq '."x-build"' images/src/*/.devcontainer.json | jq --slurp -c .)" >> "${GITHUB_OUTPUT}"

  build:
    needs: prepare
    strategy:
      fail-fast: false
      matrix:
        image: ${{ fromJson(needs.prepare.outputs.images) }}
    name: Build image ${{ matrix.image.name }}
    runs-on: ubuntu-latest
    steps:
      - name: Check out the repo
        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
        with:
          fetch-depth: 0

      - name: Check changed files
        id: changes
        run: |
          base="${{ github.event.pull_request.base.sha }}"
          head="${{ github.event.pull_request.head.sha }}"
          image="images/src/${{ matrix.image.image-name }}"
          changes="$(git diff --name-only "${base}" "${head}" -- "${image}" | grep -Fv "${image}/README.md" || true)"
          if [ -n "${changes}" ]; then
            echo needs_build=true >> "${GITHUB_OUTPUT}"
          else
            echo needs_build=false >> "${GITHUB_OUTPUT}"
          fi

      - name: Set up QEMU
        uses: docker/setup-qemu-action@49b3bc8e6bdd4a60e6116a5414239cba5943d3cf # v3.2.0
        if: steps.changes.outputs.needs_build == 'true'

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@6524bf65af31da8d45b59e8c27de4bd072b392f5 # v3.8.0
        if: steps.changes.outputs.needs_build == 'true'

      - name: Install @devcontainers/cli
        run: npm install -g @devcontainers/cli
        if: steps.changes.outputs.needs_build == 'true'

      - name: Expose GitHub Runtime
        uses: Automattic/vip-actions/expose-github-runtime@e1faabf165941008de4c0c1381df153e49d8ad2c # v0.6.0
        if: steps.changes.outputs.needs_build == 'true'

      - name: Build image
        run: |
          devcontainer build \
            --workspace-folder "images/src/${{ matrix.image.image-name }}" \
            --platform linux/amd64,linux/arm64 \
            --output type=image \
            --cache-from type=gha \
            --cache-to type=gha,mode=max
        if: steps.changes.outputs.needs_build == 'true'