docker.yml

name: docker

# Build the ced-cli container image and publish it to GitHub Container Registry
# (ghcr.io/<owner>/ced.cpp-cli) as a multi-arch image (linux/amd64 + linux/arm64).
#
# Every arch is built natively on its own runner (no QEMU): amd64 on
# ubuntu-24.04, arm64 on ubuntu-24.04-arm. The per-arch images are pushed by
# digest, then a merge job assembles one multi-arch manifest.
#
# pull_request builds only (a fast Dockerfile gate, nothing pushed). Pushes to
# the default branch and tags build and push.

on:
  push:
    branches: [main]
    tags: ['v*']
  pull_request:
  workflow_dispatch:

env:
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}-cli

jobs:
  build:
    runs-on: ${{ matrix.runner }}
    permissions:
      contents: read
      packages: write
    strategy:
      fail-fast: false
      matrix:
        include:
          - arch: amd64
            runner: ubuntu-24.04
          - arch: arm64
            runner: ubuntu-24.04-arm
    steps:
      - name: Checkout (with submodules)
        uses: actions/checkout@v4
        with:
          submodules: recursive

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

      - name: Log in to ghcr.io
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Build and push by digest (${{ matrix.arch }})
        id: build
        uses: docker/build-push-action@v6
        with:
          context: .
          file: ./Dockerfile
          platforms: linux/${{ matrix.arch }}
          outputs: ${{ github.event_name != 'pull_request' && format('type=image,name={0}/{1},push-by-digest=true,name-canonical=true,push=true', env.REGISTRY, env.IMAGE_NAME) || 'type=cacheonly' }}
          cache-from: type=gha,scope=cpu-${{ matrix.arch }}
          cache-to: type=gha,mode=max,scope=cpu-${{ matrix.arch }}

      - name: Export digest
        if: github.event_name != 'pull_request'
        run: |
          mkdir -p /tmp/digests
          digest="${{ steps.build.outputs.digest }}"
          touch "/tmp/digests/${digest#sha256:}"

      - name: Upload digest
        if: github.event_name != 'pull_request'
        uses: actions/upload-artifact@v4
        with:
          name: digests-${{ matrix.arch }}
          path: /tmp/digests/*
          if-no-files-found: error
          retention-days: 1

  merge:
    if: github.event_name != 'pull_request'
    needs: build
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
    steps:
      - name: Download digests
        uses: actions/download-artifact@v4
        with:
          path: /tmp/digests
          pattern: digests-*
          merge-multiple: true

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

      - name: Log in to ghcr.io
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Compute image tags
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: |
            type=raw,value=latest,enable={{is_default_branch}}
            type=ref,event=tag
            type=sha

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

      - name: Inspect manifest
        run: |
          docker buildx imagetools inspect \
            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest