Updating github docker build action to build for multiple platform

Author: mrjosh

.github/workflows/docker-publish.yml

@@ -7,32 +7,42 @@ on:
       - v*
 jobs:
   push_to_registries:
-    name: Push Docker image to Dockerhub and Github
+    name: Push Docker image to Dockerhub
     runs-on: ubuntu-latest
+    env:
+      DOCKER_REGISTRY: docker.io
+      DOCKER_IMAGE: castyapp/dashboard
+      DOCKER_USERNAME: ${{ secrets.DOCKERHUB_USERNAME }}
+      DOCKER_TOKEN: ${{ secrets.DOCKERHUB_TOKEN }}
+      DOCKER_TARGET_PLATFORM: linux/amd64,linux/arm64,linux/arm/v7
     steps:
       - name: Check out the repo
         uses: actions/checkout@v2
-      - uses: docker/setup-buildx-action@v1
-
-      - name: Login to DockerHub
-        uses: docker/login-action@v1 
+            
+      - name: Set up Docker Buildx
+        uses: crazy-max/ghaction-docker-buildx@v2
         with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_TOKEN }}
-          logout: true
+          version: latest
 
-      - name: Build and Push to Docker Hub
-        uses: docker/build-push-action@v2
-        with:
-          context: .
-          file: ./Dockerfile
-          tags: castylab/dashboard:latest
-          push: true
+      - name: Prepare
+        if: success()
+        id: prepare
+        run: |
+          echo ::set-output name=docker_platform::${DOCKER_TARGET_PLATFORM}
+          echo ::set-output name=docker_image::${DOCKER_REGISTRY}/${DOCKER_IMAGE}
+          echo ::set-output name=release_version::${GITHUB_REF#refs/*/}
 
-      - name: Build alpine and Push to Docker Hub
-        uses: docker/build-push-action@v2
-        with:
-          context: .
-          file: ./Dockerfile
-          tags: castylab/dashboard:alpine
-          push: true
+      - name: Login to DockerHub
+        if: success()
+        run: |
+          echo "${DOCKER_TOKEN}" | docker login ${DOCKER_REGISTRY} --username "${DOCKER_USERNAME}" --password-stdin
+
+      - name: Run Buildx (push image)
+        if: success()
+        run: |
+          docker buildx build \
+          --platform ${{ steps.prepare.outputs.docker_platform }} \
+          --tag ${{ steps.prepare.outputs.docker_image }}:latest \
+          --tag ${{ steps.prepare.outputs.docker_image }}:${{ steps.prepare.outputs.release_version }} \
+          --file ./Dockerfile \
+          --output type=image,push=true .