ghcr-image-main-fork.yml

name: ghcr-image-main

on:
  push:
    branches:
      - main
  workflow_dispatch:

env:
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}
  IMAGE_TAG: nightly

jobs:
  meta:
    runs-on: ubuntu-latest
    timeout-minutes: 5

    outputs:
      tags: ${{ steps.meta.outputs.tags }}
      labels: ${{ steps.meta.outputs.labels }}
      annotations: ${{ steps.meta.outputs.annotations }}
      json: ${{ steps.meta.outputs.json }}
      image-name: ${{ steps.custom-meta.outputs.image-name }}

    steps:
      - name: Checkout current fork HEAD
        uses: actions/checkout@v4.1.5
        with:
          fetch-depth: 0
          show-progress: false

      - name: Set up upstream git remote
        run: |
          upstream="$(gh repo view "${{ github.repository }}" --json parent --jq '.parent.owner.login + "/" + .parent.name')"
          echo "upstream=$upstream"
          git remote add upstream "https://github.com/$upstream.git"
          git fetch upstream "${{ github.event.repository.default_branch }}"
        env:
          GH_TOKEN: ${{ github.token }}

      - name: Determine number of commits on top of upstream
        id: check-extra-commits
        run: |
          commit_count="$(git rev-list --count "upstream/${{ github.event.repository.default_branch }}..$GITHUB_REF_NAME")"
          echo "commit-count=$commit_count" | tee -a "$GITHUB_OUTPUT"

      - name: Discard our commits
        run: |
          git reset --hard "HEAD~${{ steps.check-extra-commits.outputs.commit-count }}"

      - name: Docker meta
        id: meta
        uses: docker/metadata-action@8e5442c4ef9f78752691e2d8f8d19755c6f78e81 # v5.5.1
        with:
          context: git
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: |
            type=raw,value=${{ env.IMAGE_TAG }}
            type=sha,format=long,priority=899
            type=sha,format=short

      - name: Extract image name
        id: custom-meta
        run: |
          echo "image-name=${DOCKER_TAG%%:*}" | tee -a $GITHUB_OUTPUT
        env:
          DOCKER_TAG: ${{ fromJSON(steps.meta.outputs.json).tags[0] }}

  build:
    runs-on: ubuntu-latest
    timeout-minutes: 15

    needs:
      - meta

    strategy:
      fail-fast: false
      matrix:
        platform:
          - linux/amd64
          - linux/arm64

    env:
      REGISTRY_IMAGE: ${{ needs.meta.outputs.image-name }}

    steps:
      - name: Prepare
        id: meta
        run: |
          platform=${{ matrix.platform }}
          echo "platform-pair=${platform//\//-}" | tee -a "$GITHUB_OUTPUT"

      - name: Set up QEMU
        uses: docker/setup-qemu-action@68827325e0b33c7199eb31dd4e31fbe9023e06e3 # v3.0.0
        with:
          platforms: arm64
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@d70bba72b1f3fd22344832f00baa16ece964efeb # v3.3.0

      - name: Log in to GHCR
        uses: docker/login-action@343f7c4344506bcbf9b4de18042ae17996df046d # v3.1.0
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.repository_owner }}
          password: ${{ secrets.GITHUB_TOKEN }}

      # We can't build directly from git, as that will prevent .git from being available during the build process.
      # lemmy-ui's Dockerfile requires the .git folder to set the version.
      - name: Checkout git repository
        uses: actions/checkout@v4.1.5
        with:
          fetch-depth: 0
          show-progress: false
          submodules: recursive

      - name: Build Docker image
        id: build
        uses: docker/build-push-action@4a13e500e55cf31b7a5d59a38ab2040ab0f42f56 # v5.3.0
        with:
          context: .
          platforms: ${{ matrix.platform }}
          labels: ${{ needs.meta.outputs.labels }}
          annotations: ${{ needs.meta.outputs.annotations }}
          outputs: type=image,name=${{ env.REGISTRY_IMAGE }},push-by-digest=true,name-canonical=true,push=true
          cache-from: type=gha
          cache-to: type=gha,mode=max
        env:
          SOURCE_DATE_EPOCH: 0

      - name: Export image digest
        run: |
          mkdir -p /tmp/digests
          digest="${{ steps.build.outputs.digest }}"
          touch "/tmp/digests/${digest#sha256:}"

      - name: Upload digest
        uses: actions/upload-artifact@v4.3.3
        with:
          name: digests-${{ steps.meta.outputs.platform-pair }}
          path: /tmp/digests/*
          if-no-files-found: error
          retention-days: 1

  merge:
    runs-on: ubuntu-latest
    timeout-minutes: 5

    needs:
      - meta
      - build

    permissions:
      contents: read
      packages: write

    env:
      REGISTRY_IMAGE: ${{ needs.meta.outputs.image-name }}

    steps:
      - name: Download digests
        uses: actions/download-artifact@v4.1.7
        with:
          path: /tmp/digests
          pattern: digests-*
          merge-multiple: true

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@d70bba72b1f3fd22344832f00baa16ece964efeb # v3.3.0

      - name: Log in to GHCR
        uses: docker/login-action@343f7c4344506bcbf9b4de18042ae17996df046d # v3.1.0
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.repository_owner }}
          password: ${{ secrets.GITHUB_TOKEN }}

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

      - name: Inspect image
        run: |
          docker buildx imagetools inspect ${{ env.REGISTRY_IMAGE }}:${{ env.IMAGE_TAG }}