ci-test-and-push-docker.yml

# This workflow builds the config server and creates a multi-arch image for it.
# The image is then pushed to Docker Hub.
#
# The workflow consists of the following jobs:
# 1. build-config-server-jar: Builds the config server and uploads the resulting JAR as an artifact.
# 2. dependency-submission: Generate a dependency graph.
# 2. build-docker-images: Builds a Docker image for multiple platforms with the matrix strategy.
# 3. merge-images: Merges the images for the different platforms into a manifest list and pushes it to Docker Hub.

# To make the build faster, we use a matrix strategy to build the image for multiple platforms in parallel.
# The build of the first job is copied over to the image build jobs, so that the application build is only done once.
# QUEMU is used to emulate the different platforms on the GitHub runner.

# For more information about how to build multi-arch images and advanced settings with Docker Buildx in GitHub actions, see:
# https://docs.docker.com/build/ci/github-actions/multi-platform/

name: Branch Continuous Integration

on:
  push:

env:
  REGISTRY_IMAGE: inspectit/inspectit-gepard-configserver
  GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

jobs:
  build-config-server-jar:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Set up JDK 21
        uses: actions/setup-java@v4
        with:
          java-version: '21'
          distribution: 'temurin'

      # Configure Gradle for optimal use in GiHub Actions, including caching of downloaded dependencies.
      # See: https://github.com/gradle/actions/blob/main/setup-gradle/README.md
      - name: Setup Gradle
        uses: gradle/actions/setup-gradle@417ae3ccd767c252f5661f1ace9f835f9654f2b5 # v3.1.0
        with:
          build-scan-publish: true
          build-scan-terms-of-service-url: 'https://gradle.com/terms-of-service'
          build-scan-terms-of-service-agree: 'yes'

      - name: Build with Gradle
        run: ./gradlew build

      - name: Upload artifact
        uses: actions/upload-artifact@v3
        with:
          name: config-server-artifact
          path: backend/build/libs/backend-0.0.1-SNAPSHOT.jar

  dependency-submission:
    runs-on: ubuntu-latest
    permissions:
      contents: write
    steps:
      - uses: actions/checkout@v4
      - name: Set up JDK 21
        uses: actions/setup-java@v4
        with:
          java-version: '21'
          distribution: 'temurin'

      # Generates and submits a dependency graph, enabling Dependabot Alerts for all project dependencies.
      # See: https://github.com/gradle/actions/blob/main/dependency-submission/README.md
      - name: Generate and submit dependency graph
        uses: gradle/actions/dependency-submission@417ae3ccd767c252f5661f1ace9f835f9654f2b5 # v3.1.0

  build-docker-images:
    runs-on: ubuntu-latest
    needs: build-config-server-jar
    strategy:
      fail-fast: false
      matrix:
        platform:
          - linux/amd64
          - linux/arm64
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Prepare
        run: |
          platform=${{ matrix.platform }}
          echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_ENV          

      - name: Docker meta
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY_IMAGE }}

      - name: Download artifact
        uses: actions/download-artifact@v3
        with:
          name: config-server-artifact
          path: ./  # Download artifact to the root of the Docker build context

      - name: Set up QEMU
        uses: docker/setup-qemu-action@v3

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

      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ vars.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

      - name: Build and push by digest
        id: build
        uses: docker/build-push-action@v6
        with:
          context: .
          file: "./backend/Dockerfile-CR"
          platforms: ${{ matrix.platform }}
          labels: ${{ steps.meta.outputs.labels }}
          outputs: type=image,name=${{ env.REGISTRY_IMAGE }},push-by-digest=true,name-canonical=true,push=true

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

      - name: Upload digest
        uses: actions/upload-artifact@v4
        with:
          name: digests-${{ env.PLATFORM_PAIR }}
          path: /tmp/digests/*
          if-no-files-found: error
          retention-days: 1

  merge-images:
    runs-on: ubuntu-latest
    needs: build-docker-images
    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: Docker meta
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY_IMAGE }}

      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ vars.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_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 ' *)          

      - name: Inspect image
        run: |
          docker buildx imagetools inspect ${{ env.REGISTRY_IMAGE }}:${{ steps.meta.outputs.version }}