feat: publish container images to GHCR

.github/workflows/docker-image.yml

@@ -0,0 +1,173 @@
+# Inspired by https://github.com/sredevopsorg/multi-arch-docker-github-workflow
+name: Docker Image CI
+
+on:
+  push:
+    tags:
+      - "v[0-9]+.[0-9]+.[0-9]+"
+  workflow_dispatch:
+    inputs:
+      upstream_tag:
+        description: "Upstream tag of nextcloud/notify_push to build"
+        required: false
+
+jobs:
+  build:
+    runs-on: ${{ matrix.runner }}
+
+    permissions:
+      contents: read
+      packages: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - platform: linux/amd64
+            runner: ubuntu-latest
+          - platform: linux/arm64
+            runner: ubuntu-24.04-arm
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v6
+        with:
+          repository: ${{ inputs.upstream_tag && 'nextcloud/notify_push' || github.repository }}
+          ref: ${{ inputs.upstream_tag || github.ref_name }}
+
+      - name: Log in to GitHub Packages
+        uses: docker/login-action@v4
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v4
+
+      - name: Lower case docker image name
+        id: image
+        uses: ASzc/change-string-case-action@v8
+        with:
+          string: ${{ github.repository }}
+
+      - name: Sanitize upstream tag
+        if: inputs.upstream_tag != ''
+        id: tag
+        run: echo "value=${INPUT_TAG#v}" >> $GITHUB_OUTPUT
+        env:
+          INPUT_TAG: ${{ inputs.upstream_tag }}
+
+      - name: Extract metadata
+        id: meta
+        uses: docker/metadata-action@v6
+        with:
+          images: ghcr.io/${{ github.repository }}
+          tags: |
+            type=ref,event=tag
+            type=raw,value=latest
+            type=raw,value=${{ steps.tag.outputs.value }},enable=${{ inputs.upstream_tag != '' }}
+
+      - name: Build and push by digest
+        id: build
+        uses: docker/build-push-action@v7
+        with:
+          context: .
+          platforms: ${{ matrix.platform }}
+          labels: ${{ steps.meta.outputs.labels }}
+          outputs: type=image,name=ghcr.io/${{ steps.image.outputs.lowercase }},push-by-digest=true,name-canonical=true,push=true
+          cache-from: type=gha,scope=${{ matrix.platform }}
+          cache-to: type=gha,mode=max,scope=${{ matrix.platform }}
+
+      - name: Export digest
+        run: |
+          mkdir -p /tmp/digests
+          touch "/tmp/digests/${DIGEST#sha256:}"
+        env:
+          DIGEST: ${{ steps.build.outputs.digest }}
+
+      - name: Upload digest
+        uses: actions/upload-artifact@v7
+        with:
+          name: digests-${{ matrix.platform == 'linux/amd64' && 'amd64' || 'arm64' }}
+          path: /tmp/digests/*
+          if-no-files-found: error
+          retention-days: 1
+
+  merge:
+    runs-on: ubuntu-latest
+    needs: build
+
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Download digests
+        uses: actions/download-artifact@v8
+        with:
+          path: /tmp/digests
+          pattern: digests-*
+          merge-multiple: true
+
+      - name: Log in to GitHub Packages
+        uses: docker/login-action@v4
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v4
+
+      - name: Lower case docker image name
+        id: image
+        uses: ASzc/change-string-case-action@v8
+        with:
+          string: ${{ github.repository }}
+
+      - name: Sanitize upstream tag
+        if: inputs.upstream_tag != ''
+        id: tag
+        run: echo "value=${INPUT_TAG#v}" >> $GITHUB_OUTPUT
+        env:
+          INPUT_TAG: ${{ inputs.upstream_tag }}
+
+      - name: Extract metadata
+        id: meta
+        uses: docker/metadata-action@v6
+        with:
+          images: ghcr.io/${{ github.repository }}
+          tags: |
+            type=ref,event=tag
+            type=raw,value=latest
+            type=raw,value=${{ steps.tag.outputs.value }},enable=${{ inputs.upstream_tag != '' }}
+
+      - name: Get timestamp
+        id: timestamp
+        run: echo "timestamp=$(date -u +"%Y-%m-%dT%H:%M:%SZ")" >> $GITHUB_OUTPUT
+
+      - name: Create and push manifest
+        id: manifest
+        working-directory: /tmp/digests
+        continue-on-error: true
+        run: |
+          docker buildx imagetools create \
+            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
+            --annotation='index:org.opencontainers.image.description=${{ github.event.repository.description }}' \
+            --annotation='index:org.opencontainers.image.created=${{ steps.timestamp.outputs.timestamp }}' \
+            --annotation='index:org.opencontainers.image.url=${{ github.event.repository.url }}' \
+            --annotation='index:org.opencontainers.image.source=${{ github.event.repository.url }}' \
+            $(printf 'ghcr.io/${{ steps.image.outputs.lowercase }}@sha256:%s ' *)
+
+      - name: Create and push manifest (without annotations)
+        if: steps.manifest.outcome == 'failure'
+        working-directory: /tmp/digests
+        run: |
+          docker buildx imagetools create \
+            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
+            $(printf 'ghcr.io/${{ steps.image.outputs.lowercase }}@sha256:%s ' *)
+
+      - name: Inspect manifest
+        run: |
+          docker buildx imagetools inspect 'ghcr.io/${{ steps.image.outputs.lowercase }}:${{ steps.meta.outputs.version }}'