Add new GitHub action workflow on-tag to build and push to DockerHub

.github/workflows/on-tag.yml

@@ -0,0 +1,73 @@
+name: Docker build on tag
+env:
+  DOCKER_CLI_EXPERIMENTAL: enabled
+  TAG_FMT: '^refs/tags/(((.?[0-9]+){3,4}))$'
+
+on:
+  push:
+    tags:
+      - v[0-9]+.[0-9]+.[0-9]+
+      - v[0-9]+.[0-9]+.[0-9]+-*
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        service:
+          - frontend
+          - backend
+          - mysql
+    runs-on: ubuntu-18.04
+    name: Build and push manager image
+    steps:
+      - name: Set env variables
+        run: echo "TAG=${GITHUB_REF/refs\/tags\//}" >> $GITHUB_ENV
+
+      - name: Show set environment variables
+        run: |
+          printf "      TAG: %s\n"  "$TAG"
+
+      - name: Login to Docker for building
+        run: echo "${{ secrets.DOCKER_PASSWORD }}" | docker login -u "${{ secrets.DOCKER_USERNAME }}" --password-stdin
+
+      - name: Checkout project
+        uses: actions/checkout@v2
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+        id: qemu
+
+      - name: Setup Docker buildx action
+        uses: docker/setup-buildx-action@v1
+        id: buildx
+
+      - name: Available platforms
+        run: echo ${{ steps.buildx.outputs.platforms }}
+
+      - name: Cache Docker layers
+        uses: actions/cache@v2
+        id: cache
+        with:
+        path: /tmp/.buildx-cache
+        key: ${{ runner.os }}-buildx-${{ github.sha }}
+        restore-keys: |
+          ${{ runner.os }}-buildx-
+
+      - name: Run Docker buildx for ${{ matrix.service }} against tag
+        run: |
+          docker buildx build \
+          --cache-from "type=local,src=/tmp/.buildx-cache" \
+          --cache-to "type=local,dest=/tmp/.buildx-cache" \
+          --platform linux/amd64,linux/arm64,linux/arm/v7 \
+          --tag ${{ secrets.DOCKER_HUB_USER }}/mempool-frontend:$TAG \
+          --output "type=registry" ./${{ matrix.service }}/
+
+      - name: Run Docker buildx for ${{ matrix.service }} against latest
+        run: |
+          docker buildx build \
+          --cache-from "type=local,src=/tmp/.buildx-cache" \
+          --cache-to "type=local,dest=/tmp/.buildx-cache" \
+          --platform linux/amd64,linux/arm64,linux/arm/v7 \
+          --tag ${{ secrets.DOCKER_HUB_USER }}/mempool-frontend:latest \
+          --output "type=registry" ./${{ matrix.service }}/
+