Add Docker buildx build workflow

.dockerignore

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

.github/workflows/build.yml

@@ -0,0 +1,78 @@
+name: build
+
+on:
+  push:
+    branches: [ master ]
+    tags: '*'
+    paths:
+    - '.github/workflows/build.yml'
+    - 'Dockerfile'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Prepare
+      id: prepare
+      run: |
+        if [[ $GITHUB_REF == refs/tags/* ]]; then
+          TAG=${GITHUB_REF#refs/tags/}
+          echo ::set-output name=tag_name::${TAG}
+          echo ::set-output name=version::${TAG%-*}
+        else
+          echo ::set-output name=version::latest
+        fi
+        echo ::set-output name=build_date::$(date -u +'%Y-%m-%dT%H:%M:%SZ')
+        echo ::set-output name=docker_platforms::linux/386,linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64,linux/ppc64le,linux/s390x
+        echo ::set-output name=docker_username::thomseddon
+        echo ::set-output name=docker_image::thomseddon/traefik-forward-auth
+
+    - name: Set up Docker Buildx
+      uses: crazy-max/ghaction-docker-buildx@v1
+      with:
+        version: latest
+
+    - name: Checkout
+      uses: actions/checkout@v2
+
+    - name: Docker Buildx (no push)
+      run: |
+        docker buildx build --no-cache \
+          --platform ${{ steps.prepare.outputs.docker_platforms }} \
+          --output "type=image,push=false" \
+          --build-arg "BUILD_DATE=${{ steps.prepare.outputs.build_date }}" \
+          --build-arg "VCS_REF=${GITHUB_SHA::8}" \
+          --build-arg "VERSION=${{ steps.prepare.outputs.version }}" \
+          --tag "${{ steps.prepare.outputs.docker_image }}:${{ steps.prepare.outputs.version }}" \
+          --file Dockerfile .
+
+    - name: Docker Login
+      if: success()
+      env:
+        DOCKER_PASSWORD: ${{ secrets.DOCKER_PASSWORD }}
+      run: |
+        echo "${DOCKER_PASSWORD}" | docker login --username "${{ steps.prepare.outputs.docker_username }}" --password-stdin
+
+    - name: Docker Buildx (push)
+      if: success()
+      run: |
+        docker buildx build \
+          --platform ${{ steps.prepare.outputs.docker_platforms }} \
+          --output "type=image,push=true" \
+          --build-arg "BUILD_DATE=${{ steps.prepare.outputs.build_date }}" \
+          --build-arg "VCS_REF=${GITHUB_SHA::8}" \
+          --build-arg "VERSION=${{ steps.prepare.outputs.version }}" \
+          --tag "${{ steps.prepare.outputs.docker_image }}:${{ steps.prepare.outputs.version }}" \
+          --tag "${{ steps.prepare.outputs.docker_image }}:latest" \
+          --file Dockerfile .
+
+    - name: Docker Check Manifest
+      if: always()
+      run: |
+        docker run --rm mplatform/mquery ${{ steps.prepare.outputs.docker_image }}:${{ steps.prepare.outputs.version }}
+
+    - name: Clear
+      if: always()
+      run: |
+        rm -f ${HOME}/.docker/config.json

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