Use self-hosted runner for ARM builds (#477)

.github/workflows/pr.yml

@@ -3,23 +3,32 @@ name: PR Workflow
 on: pull_request_target
 
 jobs:
-  release:
+  release-snapshot:
     name: Release snapshot
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        runner-platform:
+          - ubuntu-latest
+          - self-hosted
+        include:
+          - runner-platform: ubuntu-latest
+            build-arch: linux/amd64
+            tagged-platform: amd64
+          - runner-platform: self-hosted
+            build-arch: linux/arm64
+            tagged-platform: arm64
+    runs-on: ${{ matrix.runner-platform }}
     steps:
       - name: Set up Buildx
         uses: docker/setup-buildx-action@v1
 
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v1
-
       - name: Cache Docker layers
         uses: actions/cache@v2
         with:
           path: /tmp/.buildx-cache
-          key: ${{ runner.os }}-buildx-prs-${{ github.sha }}
+          key: ${{ runner.os }}-buildx-prs-${{ matrix.build-arch }}-${{ github.sha }}
           restore-keys: |
-            ${{ runner.os }}-buildx-prs-
+            ${{ runner.os }}-buildx-prs-${{ matrix.build-arch }}
 
       - name: Login to DockerHub
         uses: docker/login-action@v1
@@ -32,17 +41,37 @@ jobs:
         uses: docker/build-push-action@v2
         with:
           push: true
-          tags: codetheweb/muse:${{ github.event.pull_request.head.sha }}
+          tags: codetheweb/muse:${{ github.event.pull_request.head.sha }}-${{ matrix.tagged-platform }}
           cache-from: type=local,src=/tmp/.buildx-cache
           cache-to: type=local,dest=/tmp/.buildx-cache,mode=max
+          platforms: ${{ matrix.build-arch }}
+
+  combine-and-comment:
+    name: Combine platform tags and leave comment
+    runs-on: ubuntu-latest
+    needs: release-snapshot
+    steps:
+      - name: Set up Buildx
+        uses: docker/setup-buildx-action@v1
+
+      - name: Login to DockerHub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Combine tags
+        run: docker buildx imagetools create -t 'codetheweb/muse:pr-${{ github.event.number }}' -t 'codetheweb/muse:${{ github.event.pull_request.head.sha }}' 'codetheweb/muse:${{ github.event.pull_request.head.sha }}-arm64' 'codetheweb/muse:${{ github.event.pull_request.head.sha }}-amd64'
 
       - name: Create comment
         uses: marocchino/sticky-pull-request-comment@v2
         with:
           header: "pr-release"
           message: |
-            #### :package: A new release has been made for this pull request
+            #### :package: A new release has been made for this pull request.
 
-            To play around with this PR, pull `codetheweb/muse:${{ github.event.pull_request.head.sha }}`.
+            To play around with this PR, pull `codetheweb/muse:pr-${{ github.event.number }}` or `codetheweb/muse:${{ github.event.pull_request.head.sha }}`.
+
+            Images are available for x86_64 and ARM64.
 
             > Latest commit: ${{ github.event.pull_request.head.sha }}