Add test workflow for multi-arch build from scratch (#84)

Signed-off-by: divyansh42 <diagrawa@redhat.com>

.github/workflows/multiarch.yml

@@ -7,12 +7,15 @@ on:
     - cron: '0 0 * * *'  # every day at midnight
 
 env:
-  IMAGE_NAME: hello-world-multiarch
+  PROJECT_DIR: spring-petclinic
+  MVN_REPO_DIR: ~/.m2/repository
   IMAGE_TAG: latest
 
 jobs:
-  build-multiarch:
-    name: Build multi-architecture image using Buildah
+  build-multiarch-containerfile:
+    name: Build multi-architecture image using Containerfile
+    env:
+      IMAGE_NAME: hello-world-multiarch
     runs-on: ubuntu-20.04
     strategy:
       fail-fast: false
@@ -80,8 +83,10 @@ jobs:
         run: |
           podman run --rm ${{ steps.build_image_multiarch.outputs.image }}:${{ env.IMAGE_TAG }}
 
-  build-multiplatform:
-    name: Build multi-platform image using Buildah
+  build-multiplatform-containerfile:
+    name: Build multi-platform image using Containerfile
+    env:
+      IMAGE_NAME: hello-world-multiplatform
     runs-on: ubuntu-20.04
     strategy:
       fail-fast: false
@@ -146,3 +151,108 @@ jobs:
       - name: Run image
         run: |
           podman run --rm ${{ steps.build_image_multiplatform.outputs.image }}:${{ env.IMAGE_TAG }}
+
+  build-multiarch-scratch:
+    name: Build multi-architecture image from scratch
+    env:
+      IMAGE_NAME: spring-petclinic-multiarch
+    runs-on: ubuntu-20.04
+    strategy:
+      fail-fast: false
+      matrix:
+        arch: [ amd64, i386, arm64v8 ]
+        install_latest: [ true, false ]
+
+    steps:
+
+      # Checkout buildah action github repository
+      - name: Checkout Buildah action
+        uses: actions/checkout@v2
+        with:
+          path: "buildah-build"
+
+      - name: Install latest buildah
+        if: matrix.install_latest
+        run: |
+          bash buildah-build/.github/install_latest_buildah.sh
+
+      - name: Install qemu dependency
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y qemu-user-static
+
+      # Checkout spring-petclinic github repository
+      - name: Checkout spring-petclinic project
+        uses: actions/checkout@v2
+        with:
+          repository: "spring-projects/spring-petclinic"
+          path: ${{ env.PROJECT_DIR }}
+
+      # If none of these files has changed, we assume that the contents of
+      # .m2/repository can be fetched from the cache.
+      - name: Hash Maven files
+        working-directory: ${{ env.PROJECT_DIR }}
+        run: |
+          echo "MVN_HASH=${{ hashFiles('**/pom.xml', '.mvn/**/*', 'mvnw*') }}" >> $GITHUB_ENV
+
+      # Download the m2 repository from the cache to speed up the build.
+      - name: Check for Maven cache
+        id: check-mvn-cache
+        uses: actions/cache@v2
+        with:
+          path: ${{ env.MVN_REPO_DIR }}
+          key: ${{ env.MVN_HASH }}
+
+      # Setup java.
+      - name: Setup Java
+        uses: actions/setup-java@v1
+        with:
+          java-version: 11
+
+      # Run maven to build the project
+      - name: Maven
+        working-directory: ${{ env.PROJECT_DIR }}
+        run: |
+          mvn package -ntp -B
+
+       # If there was no cache hit above, store the output into the cache now.
+      - name: Save Maven repo into cache
+        if: ${{ steps.check-mvn-cache.outputs.cache-hit }} != 'true'
+        uses: actions/cache@v2
+        with:
+          path: ${{ env.MVN_REPO_DIR }}
+          key: ${{ env.MVN_HASH }}
+
+      - name: Build Image
+        id: build_image_multiarch
+        uses: ./buildah-build/
+        with:
+          image: ${{ env.IMAGE_NAME }}
+          tags: ${{ env.IMAGE_TAG }}
+          base-image: 'registry.access.redhat.com/openjdk/openjdk-11-rhel7'
+          arch: ${{ matrix.arch }}
+          build-args: ARCH=${{ matrix.arch }}
+          # To avoid hardcoding a particular version of the binary.
+          content: |
+            ./spring-petclinic/target/spring-petclinic-*.jar
+          entrypoint: |
+            java
+            -jar
+            spring-petclinic-*.jar
+          port: 8080
+          workdir: "."
+
+      - name: Echo Outputs
+        run: |
+          echo "Image: ${{ steps.build_image_multiarch.outputs.image }}"
+          echo "Tags: ${{ steps.build_image_multiarch.outputs.tags }}"
+          echo "Tagged Image: ${{ steps.build_image_multiarch.outputs.image-with-tag }}"
+
+      - name: Check images created
+        run: buildah images | grep '${{ env.IMAGE_NAME }}'
+
+      - name: Check image metadata
+        run: |
+          set -x
+          buildah inspect ${{ steps.build_image_multiarch.outputs.image }}:${{ env.IMAGE_TAG }} | jq ".OCIv1.architecture"
+          buildah inspect ${{ steps.build_image_multiarch.outputs.image }}:${{ env.IMAGE_TAG }} | jq ".Docker.architecture"