Build and push multi-arch image on GitHub Actions

.dockerignore

@@ -1,3 +1,4 @@
 example
 .travis.yml
 .git
+.github

.github/workflows/docker.yml

@@ -0,0 +1,51 @@
+name: Docker Image Build
+
+on:
+  push:
+    branches:
+      - "**"
+    tags:
+      - "v*.*.*"
+  pull_request:
+    branches:
+      - "**"
+
+jobs:
+  docker:
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+
+      - name: Generate Docker tags and labels
+        if: startsWith(github.ref, 'refs/tags/v')
+        id: meta
+        uses: docker/metadata-action@v3
+        with:
+          images: thomseddon/traefik-forward-auth
+          # generate semver tags and 'latest' tag
+          tags: |
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+
+      - name: Login to Docker Hub
+        if: startsWith(github.ref, 'refs/tags/v')
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKER_HUB_USERNAME }}
+          password: ${{ secrets.DOCKER_HUB_TOKEN }}
+
+      - name: Build (and push)
+        uses: docker/build-push-action@v2
+        with:
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          platforms: linux/amd64,linux/386,linux/arm64/v8,linux/arm/v7,linux/arm/v6,linux/ppc64le,linux/s390x
+          push: ${{ startsWith(github.ref, 'refs/tags/v') }}

Dockerfile

@@ -9,7 +9,7 @@ RUN apk add --no-cache git
 
 # Copy & build
 ADD . /go/src/github.com/thomseddon/traefik-forward-auth/
-RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 GO111MODULE=on go build -a -installsuffix nocgo -o /traefik-forward-auth github.com/thomseddon/traefik-forward-auth/cmd
+RUN CGO_ENABLED=0 GOOS=linux GO111MODULE=on go build -a -installsuffix nocgo -o /traefik-forward-auth github.com/thomseddon/traefik-forward-auth/cmd
 
 # Copy into scratch container
 FROM scratch