RTI dockerfile support for multi-architecture builds

.github/workflows/build-rti.yml

@@ -4,16 +4,32 @@ on:
   workflow_call:
 
 jobs:
-  run:
+  native-build:
     strategy:
       matrix:
         platform: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.platform }}
 
     steps:
       - name: Check out reactor-c repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Build the RTI with AUTH=OFF
         run: .github/scripts/build-rti.sh -DAUTH=OFF
       - name: Build the RTI with AUTH=ON
         run: .github/scripts/build-rti.sh -DAUTH=ON
+
+  docker-build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out reactor-c repository
+        uses: actions/checkout@v4
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      - name: Build Docker image
+        uses: docker/build-push-action@v6
+        with:
+          file: ./core/federated/RTI/rti.Dockerfile
+          context: .
+          platforms: linux/amd64, linux/arm64, linux/arm/v7, linux/riscv64
+          push: false
+          tags: lflang/rti:latest

core/federated/RTI/rti.Dockerfile

@@ -1,5 +1,5 @@
-# Docker file for building the image of the rti
-FROM alpine:latest
+ARG BASEIMAGE=alpine:latest 
+FROM ${BASEIMAGE} as builder
 COPY . /lingua-franca
 WORKDIR /lingua-franca/core/federated/RTI
 RUN set -ex && apk add --no-cache gcc musl-dev cmake make && \
@@ -9,5 +9,14 @@ RUN set -ex && apk add --no-cache gcc musl-dev cmake make && \
     make && \
     make install
 
-# Use ENTRYPOINT not CMD so that command-line arguments go through
-ENTRYPOINT ["RTI"]
+WORKDIR /lingua-franca
+
+# application stage
+FROM ${BASEIMAGE} as app
+LABEL maintainer="lf-lang"
+LABEL source="https://github.com/lf-lang/reactor-c/tree/main/core/federated/RTI"
+COPY --from=builder /usr/local/bin/RTI /usr/local/bin/RTI
+
+WORKDIR /lingua-franca
+
+ENTRYPOINT ["/usr/local/bin/RTI"]