Introduce multi-arch builds with Docker buildx

.github/workflows/build.yaml

@@ -8,19 +8,26 @@ on:
 
 env:
   IMAGE_NAME: trafex/php-nginx
+  IMAGE_TAG: ${{ github.sha }}
 
 jobs:
-  deploy:
+  build:
     runs-on: ubuntu-latest
 
     steps:
       - name: Checkout
         uses: actions/checkout@v2
 
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v1
+
       - name: Build image
         run: |-
-          docker build -t $IMAGE_NAME .
-          docker tag $IMAGE_NAME:latest $IMAGE_NAME:${{ github.sha }}
+          docker build -t $IMAGE_NAME:$IMAGE_TAG .
 
       - name: Smoke test image
         run: |-
@@ -47,17 +54,26 @@ jobs:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
-      - name: Push latest image
+      - name: Build multi-arch image and push latest tag
         if: github.ref == 'refs/heads/master' && github.event_name == 'push'
         run: |-
-          docker push $IMAGE_NAME:latest
+          docker buildx build \
+            --cache-from=$IMAGE_NAME:latest
+            --push \
+            -t $IMAGE_NAME:latest \
+            --platform linux/amd64,linux/arm64,linux/arm/v7,linux/arm/v6 \
+            .
 
       - name: Set tag in environment
         if: contains(github.ref, 'refs/tags/')
         run: echo "RELEASE_VERSION=${GITHUB_REF#refs/*/}" >> $GITHUB_ENV
 
-      - name: Push tagged image
+      - name: Build multi-arch image and push release tag
         if: contains(github.ref, 'refs/tags/')
         run: |-
-          docker tag $IMAGE_NAME:${{ github.sha }} $IMAGE_NAME:$RELEASE_VERSION
-          docker push $IMAGE_NAME:$RELEASE_VERSION
+          docker buildx build \
+            --cache-from=$IMAGE_NAME:latest
+            --push \
+            -t $IMAGE_NAME:$RELEASE_VERSION \
+            --platform linux/amd64,linux/arm64,linux/arm/v7,linux/arm/v6 \
+            .

docker-compose.test.yml

@@ -1,6 +1,7 @@
 version: '3.5'
 services:
   app:
+    image: ${IMAGE_NAME}:${IMAGE_TAG}
     build: .
   sut:
     image: alpine:3.13