BLO-4373 Allow to set target architecture

Author: kaitimmer

README.md

@@ -1,11 +1,13 @@
 # 🚀 GitHub Action for GitOps
 
-This GitHub Action can be used for our GitOps workflow. The GitHub Action will build and push the Docker image for your service and deploys
+This GitHub Action can be used for our GitOps workflow. The GitHub Action will build and push the Docker image for your
+service and deploys
 the new version at your Kubernetes clusters.
 
 ## Requirement
 
-When you want to use this GitHub Action your GitHub repository should have a `dev` and `master` / `main` branch and it should use tags for
+When you want to use this GitHub Action your GitHub repository should have a `dev` and `master` / `main` branch and it
+should use tags for
 releases.
 
 - For the `dev` branch we will change the files specified under `gitops-dev`.
@@ -119,6 +121,7 @@ jobs:
 | `docker-build-secrets`      | List of secrets to expose to the build (e.g., key=string, GIT_AUTH_TOKEN=mytoken)                                              |                                                      |
 | `docker-build-secret-files` | List of secret files to expose to the build (e.g., key=filename, MY_SECRET=./secret.txt)                                       |                                                      |
 | `docker-build-target`       | Sets the target stage to build like: "runtime"                                                                                 |                                                      |
+| `docker-build-platforms`       | Sets the target platforms for build                                                                                 | linux/amd64 |
 | `docker-build-provenance`   | Generate [provenance](https://docs.docker.com/build/attestations/slsa-provenance/) attestation for the build                   | `false`                                              |
 | `docker-disable-retagging`  | Disables retagging of existing images and run a new build instead                                                              | `false`                                              |
 | `gitops-organization`       | GitHub Organization for GitOps                                                                                                 | `Staffbase`                                          |
@@ -140,7 +143,8 @@ jobs:
 
 ## Contributing
 
-Please read [CONTRIBUTING.md](CONTRIBUTING.md) for details on our code of conduct, and the process for submitting pull requests to us.
+Please read [CONTRIBUTING.md](CONTRIBUTING.md) for details on our code of conduct, and the process for submitting pull
+requests to us.
 
 ## License
 
@@ -161,4 +165,5 @@ This project is licensed under the Apache-2.0 License - see the [LICENSE.md](LIC
 
 ## Releasing new versions
 
-Go to the release overview page and publish the draft release with a new version number. Make sure to update the floating version commit.
+Go to the release overview page and publish the draft release with a new version number. Make sure to update the
+floating version commit.

action.yml

@@ -39,6 +39,10 @@ inputs:
   docker-build-target:
     description: "Sets the target stage to build"
     required: false
+  docker-build-platforms:
+    description: "Sets the target platforms for build"
+    required: false
+    default: 'linux/amd64'
   docker-build-provenance:
     description: "Generate provenance attestation for the build"
     required: false
@@ -151,6 +155,34 @@ runs:
         echo "tag=$TAG" >> $GITHUB_OUTPUT
         echo "tag_list=$TAG_LIST" >> $GITHUB_OUTPUT
 
+    - name: Verify Architecture Match
+      shell: bash
+      if: steps.preparation.outputs.build == 'true'
+      run: |
+        RUNNER_ARCH="${{ runner.arch }}" # X64 (AMD64) or ARM64
+        TARGET_PLATFORMS="${{ inputs.docker-build-platforms }}"
+        
+        echo "Runner CPU Architecture: $RUNNER_ARCH"
+        echo "Requested Build Platforms: $TARGET_PLATFORMS"
+
+        # Check for AMD64 mismatch (Runner is X64, but user requests ONLY arm64, OR user requests multi-arch which requires emulation)
+        if [[ "$RUNNER_ARCH" == "X64" ]]; then
+          if [[ "$TARGET_PLATFORMS" == *"linux/arm64"* ]]; then
+            echo "::error::Runner is X64 (Intel/AMD) but build includes 'linux/arm64'. This requires emulation. Aborting strictly."
+            exit 1
+          fi
+        fi
+
+        # Check for ARM64 mismatch
+        if [[ "$RUNNER_ARCH" == "ARM64" ]]; then
+          if [[ "$TARGET_PLATFORMS" == *"linux/amd64"* ]]; then
+            echo "::error::Runner is ARM64 (Apple Silicon/Graviton) but build includes 'linux/amd64'. This requires emulation. Aborting strictly."
+            exit 1
+          fi
+        fi
+        
+        echo "Architecture match verified for native build ✅"
+
     - name: Set up Docker Buildx
       if: inputs.docker-username != '' && inputs.docker-password != ''
       uses: docker/setup-buildx-action@v3
@@ -177,7 +209,7 @@ runs:
         tags: ${{ steps.preparation.outputs.tag_list }}
         secrets: ${{ inputs.docker-build-secrets }}
         secret-files: ${{ inputs.docker-build-secret-files }}
-        platforms: linux/amd64
+        platforms: ${{ inputs.docker-build-platforms }}
         cache-from: type=gha
         cache-to: type=gha,mode=max
         provenance: ${{ inputs.docker-build-provenance }}