build.yaml

name: build-custom-silverblue
on:
  pull_request:
  merge_group:
  schedule:
    - cron: '5 3 * * *'  # 3am-ish UTC everyday (timed against official fedora container pushes)
  workflow_dispatch:

jobs:
  build-custom-silverblue:
    name: Build, sign, then push
    runs-on: ubuntu-24.04
    permissions:
      contents: read
      packages: write
      id-token: write

    steps:
      - name: Checkout
        uses: actions/checkout@v4
      
      - name: Install cosign
        if: ${{ github.event_name != 'pull_request' }}
        uses: sigstore/cosign-installer@v3.6.0
        with:
          cosign-release: 'v2.4.0'

      - name: Build image
        id: build
        uses: redhat-actions/buildah-build@v2
        with:
          containerfiles: |
            ./Containerfile
          image: custom-silverblue
          tags: |
            ${{ github.sha }}
            40
      
      - name: Log in to GitHub Container Registry
        uses: redhat-actions/podman-login@v1
        if: ${{ github.event_name != 'pull_request' }}
        with:
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}
          registry: ghcr.io/${{ github.repository_owner }}

      - name: Push to GitHub Container Registry
        uses: redhat-actions/push-to-registry@v2
        id: push
        if: ${{ github.event_name != 'pull_request' }}
        with:
          image: ${{ steps.build.outputs.image }}
          tags: ${{ steps.build.outputs.tags }}
          registry: ghcr.io/${{ github.repository_owner }}

      - name: Sign the published OCI image
        if: ${{ github.event_name != 'pull_request' }}
        env:
          digest: ${{ steps.push.outputs.digest }}
          fully_qualified_image_names_json: ${{ steps.push.outputs.registry-paths }} 
        run: >
          echo "${fully_qualified_image_names_json}" 
          | jq -r '.[]' 
          | xargs -I {} cosign sign --yes "{}@${digest}"

      - name: Echo outputs for auditing
        if: github.event_name != 'pull_request'
        run: |
          echo "${{ toJSON(steps.push.outputs) }}"