add Dockerfile and release workflow for Docker GHCR

.github/workflows/release-docker.yaml

@@ -0,0 +1,49 @@
+name: Docker Release
+
+on:
+  release:
+    types:
+      - published
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/${{ github.repository }}
+          tags: |
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+            type=raw,value=latest,enable={{is_default_branch}}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64,linux/arm/v7
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max

Dockerfile

@@ -0,0 +1,66 @@
+# Build stage
+FROM --platform=$BUILDPLATFORM debian:bullseye-slim AS builder
+
+ARG TARGETPLATFORM
+ARG BUILDPLATFORM
+
+# Install build dependencies
+RUN set -ex; \
+  apt-get update; \
+  apt-get install -y \
+  autoconf \
+  automake \
+  pkg-config; \
+  case "$TARGETPLATFORM" in \
+  "$BUILDPLATFORM") apt-get install -y build-essential ;; \
+  "linux/arm64") \
+  dpkg --add-architecture arm64 && \
+  apt-get install -y \
+  crossbuild-essential-arm64 \
+  gcc-aarch64-linux-gnu ;; \
+  "linux/arm/v7") \
+  dpkg --add-architecture armhf && \
+  apt-get install -y \
+  crossbuild-essential-armhf \
+  gcc-arm-linux-gnueabihf ;; \
+  "linux/amd64") \
+  dpkg --add-architecture amd64 && \
+  apt-get install -y \
+  crossbuild-essential-amd64 \
+  gcc-x86-64-linux-gnu ;; \
+  *) echo "Unsupported platform combination: $BUILDPLATFORM -> $TARGETPLATFORM" && exit 1 ;; \
+  esac && \
+  rm -rf /var/lib/apt/lists/*
+
+# Copy source code
+WORKDIR /workdir
+COPY . .
+
+RUN case "$TARGETPLATFORM" in \
+  "$BUILDPLATFORM") ARCH_FLAGS="" ;; \
+  "linux/amd64")  ARCH_FLAGS="--host=x86_64-linux-gnu" ;; \
+  "linux/arm64")  ARCH_FLAGS="--host=aarch64-linux-gnu" ;; \
+  "linux/arm/v7") ARCH_FLAGS="--host=arm-linux-gnueabihf" ;; \
+  esac && \
+  echo "Building with ARCH_FLAGS=$ARCH_FLAGS" && \
+  autoreconf -fi && \
+  ./configure ${ARCH_FLAGS} && \
+  make
+
+# Runtime stage
+FROM debian:bullseye-slim
+
+# Install runtime dependencies
+RUN apt-get update && apt-get install -y \
+  libgcc1 \
+  && rm -rf /var/lib/apt/lists/*
+
+# Copy the built binary and config
+COPY --from=builder /workdir/src/rtp2httpd /usr/local/bin/
+COPY --from=builder /workdir/rtp2httpd.conf /usr/local/etc/
+
+# Expose the default port
+EXPOSE 8080
+
+# Run the application
+ENTRYPOINT ["/usr/local/bin/rtp2httpd"]