Switch to building from source for multi-platform images (#1)

...so we can support platforms that official releases don't exist for (namely Linux on ARM64). Just building x86_64 and ARM64 for now, so I can work on my M1 mac.

.github/workflows/build.yml

@@ -0,0 +1,78 @@
+name: Build
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Prepare
+        id: prep
+        env:
+          HUB_IMAGE: jakejarvis/hugo-extended
+          GHCR_IMAGE: ghcr.io/jakejarvis/hugo-extended
+        run: |
+          TAGS="${HUB_IMAGE}:latest,${GHCR_IMAGE}:latest"
+
+          # If triggered by a new tag, add a version tag to the image
+          if [[ $GITHUB_REF == refs/tags/* ]]; then
+            VERSION=${GITHUB_REF#refs/tags/v}
+            TAGS="$TAGS,${HUB_IMAGE}:${VERSION},${GHCR_IMAGE}:${VERSION}"
+          fi
+
+          # Set output parameters
+          echo ::set-output name=tags::${TAGS}
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@master
+        with:
+          platforms: all
+
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@master
+
+      - name: Cache Docker layers
+        uses: actions/cache@v2
+        with:
+          path: /tmp/.buildx-cache
+          key: ${{ runner.os }}-buildx-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-buildx-
+
+      - name: Login to DockerHub
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v1
+        with:
+          username: jakejarvis
+          password: ${{ secrets.DOCKER_HUB_TOKEN }}
+
+      - name: Login to GitHub Container Registry
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GHCR_PAT }}
+
+      - name: Build and push
+        id: build
+        uses: docker/build-push-action@v2
+        with:
+          builder: ${{ steps.buildx.outputs.name }}
+          context: ./
+          file: ./Dockerfile
+          platforms: linux/amd64,linux/arm64
+          push: true
+          tags: ${{ steps.prep.outputs.tags }}
+          cache-from: type=local,src=/tmp/.buildx-cache
+          cache-to: type=local,dest=/tmp/.buildx-cache
+
+      - name: Image digest
+        run: echo ${{ steps.build.outputs.digest }}

.github/workflows/publish.yml

@@ -1,52 +0,0 @@
-name: Publish to GitHub Container Registry
-
-on:
-  push:
-    # Publish `v*` tags as releases.
-    tags:
-    - v*
-  pull_request:
-
-env:
-  IMAGE_NAME: hugo-extended
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v2
-    - name: Build image
-      run: docker build . --file Dockerfile
-
-  # Push image to GitHub Container Registry
-  push:
-    runs-on: ubuntu-latest
-    if: github.event_name == 'push'
-    needs: build
-    steps:
-    - uses: actions/checkout@v2
-    - name: Build image
-      run: docker build . --file Dockerfile --tag $IMAGE_NAME
-    - name: Login to GitHub Container Registry
-      run: echo "${{ secrets.GHCR_PAT }}" | docker login ghcr.io -u ${{ github.actor }} --password-stdin
-    - name: Push image to GitHub
-      run: |
-        IMAGE_ID=ghcr.io/${{ github.repository_owner }}/$IMAGE_NAME
-
-        # Change all uppercase to lowercase
-        IMAGE_ID=$(echo $IMAGE_ID | tr '[A-Z]' '[a-z]')
-
-        # Strip git ref prefix from version
-        VERSION=$(echo "${{ github.ref }}" | sed -e 's,.*/\(.*\),\1,')
-
-        # Strip "v" prefix from tag name
-        [[ "${{ github.ref }}" == "refs/tags/"* ]] && VERSION=$(echo $VERSION | sed -e 's/^v//')
-
-        echo IMAGE_ID=$IMAGE_ID
-        echo VERSION=$VERSION
-
-        # Push image with both version tag and `latest` tag
-        docker tag $IMAGE_NAME $IMAGE_ID:$VERSION
-        docker tag $IMAGE_NAME $IMAGE_ID:latest
-        docker push $IMAGE_ID:$VERSION
-        docker push $IMAGE_ID:latest