added docker workflow

.github/workflows/docker.yaml

@@ -0,0 +1,46 @@
+name: Docker
+
+on:
+  push:
+    tags:
+      - 'v*'
+    branches:
+      - 'master'
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  build-and-push-image:
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Log in to the Container registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          build-args: "VERSION=${GITHUB_REF##*/}"

Dockerfile

@@ -0,0 +1,29 @@
+# Step 1: Use the official Golang image as the build environment.
+# This image includes all the tools needed to compile Go applications.
+FROM golang:1.21 as builder
+
+# Version will be passed as a part of the build.
+ARG VERSION=dev
+
+# Set the Current Working Directory inside the container.
+WORKDIR /app
+
+# Copy the local package files to the container's workspace.
+COPY . .
+
+# Build the Go app for a Linux system. The -o flag specifies the output binary
+# name.
+RUN VERSION=${VERSION} make build
+
+# Step 2: Use a Docker multi-stage build to create a lean production image.
+# Start from a scratch (empty) image to keep the image size small.
+FROM scratch
+
+# Copy the binary from the builder stage to the production image.
+COPY --from=builder /app/udptlspipe /
+
+# Exact protocol depends on operation mode: tcp for server and udp for client.
+EXPOSE 8443/tcp
+EXPOSE 8443/udp
+
+ENTRYPOINT ["/udptlspipe", "-h"]

Makefile

@@ -17,7 +17,7 @@ endif
 default: build
 
 build: clean
-	go build -ldflags "-X $(VERSIONPKG).version=$(VERSION)"
+	CGO_ENABLED=0 go build -ldflags "-X $(VERSIONPKG).version=$(VERSION)" -o $(NAME)
 
 release: check-env-release
 	mkdir -p $(BUILDDIR)