🤖 feat: add Docker image for mux server (#849)

Adds Dockerfile and docker-compose.yml for running mux server in
containers.

## Usage

```bash
# Build
docker build -t mux-server .

# Run
docker run -p 3000:3000 -v ~/.mux:/root/.mux mux-server

# Or with docker-compose
docker compose up -d
```

## Details

- Multi-stage build with slim runtime image (~2GB)
- Health check at `/health`
- Volume mount for `~/.mux` persistence
- Excludes test files during build to avoid rootDir issues
- CI smoke test runs in merge queue (validates health + version
endpoints)

_Generated with `mux`_

Author: ibetitsmike

.dockerignore

@@ -0,0 +1,52 @@
+# Dependencies (will be installed fresh)
+node_modules/
+
+# Build outputs
+dist/
+build/
+*.tsbuildinfo
+
+# Git
+.git/
+.gitignore
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# Test artifacts
+coverage/
+.nyc_output/
+
+# Development files
+*.log
+*.local
+.env
+.env.*
+!.env.example
+
+# Documentation build
+docs/book/
+
+# Mobile app (not needed for server)
+mobile/
+
+# Electron-specific (not needed for server)
+*.dmg
+*.exe
+*.AppImage
+*.snap
+*.deb
+*.rpm
+
+# Storybook
+storybook-static/
+
+# Misc
+.DS_Store
+Thumbs.db
+*.md
+!README.md
+LICENSE

.github/workflows/ci.yml

@@ -171,6 +171,73 @@ jobs:
         env:
           ELECTRON_DISABLE_SANDBOX: 1
 
+  docker-smoke-test:
+    name: Docker Smoke Test
+    runs-on: ${{ github.repository_owner == 'coder' && 'depot-ubuntu-22.04-16' || 'ubuntu-latest' }}
+    # Only run in merge queue (Docker builds are slow)
+    if: github.event_name == 'merge_group'
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0 # Required for git describe to find tags
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Build Docker image
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          load: true
+          tags: mux-server:test
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+
+      - name: Start container
+        run: |
+          docker run -d --name mux-test -p 3000:3000 mux-server:test
+          # Wait for server to be ready
+          for i in {1..30}; do
+            if curl -sf http://localhost:3000/health; then
+              echo "Server is ready"
+              break
+            fi
+            echo "Waiting for server... ($i/30)"
+            sleep 1
+          done
+
+      - name: Health check
+        run: |
+          response=$(curl -sf http://localhost:3000/health)
+          echo "Health response: $response"
+          if ! echo "$response" | grep -q '"status":"ok"'; then
+            echo "Health check failed"
+            exit 1
+          fi
+
+      - name: Version check
+        run: |
+          response=$(curl -sf http://localhost:3000/version)
+          echo "Version response: $response"
+          # Verify response contains expected fields
+          if ! echo "$response" | grep -q '"mode":"server"'; then
+            echo "Version check failed: missing mode=server"
+            exit 1
+          fi
+          if ! echo "$response" | grep -q '"version"'; then
+            echo "Version check failed: missing version field"
+            exit 1
+          fi
+
+      - name: Show container logs on failure
+        if: failure()
+        run: docker logs mux-test
+
+      - name: Cleanup
+        if: always()
+        run: docker rm -f mux-test || true
+
   check-codex-comments:
     name: Check Codex Comments
     runs-on: ${{ github.repository_owner == 'coder' && 'depot-ubuntu-22.04-16' || 'ubuntu-latest' }}

Dockerfile

@@ -0,0 +1,103 @@
+# mux server Docker image
+# Multi-stage build for minimal runtime image size
+#
+# Build:   docker build -t mux-server .
+# Run:     docker run -p 3000:3000 -v ~/.mux:/root/.mux mux-server
+#
+# See docker-compose.yml for easier orchestration
+
+# ==============================================================================
+# Stage 1: Build
+# ==============================================================================
+FROM node:22-slim AS builder
+
+WORKDIR /app
+
+# Install bun (used for package management and build tooling)
+RUN npm install -g bun@1.2
+
+# Install git (needed for version generation)
+RUN apt-get update && apt-get install -y git && rm -rf /var/lib/apt/lists/*
+
+# Copy package files first for better layer caching
+COPY package.json bun.lock bunfig.toml ./
+
+# Copy postinstall script (needed by bun install)
+COPY scripts/postinstall.sh scripts/
+
+# Install build tools needed for native modules
+RUN apt-get update && apt-get install -y python3 make g++ && rm -rf /var/lib/apt/lists/*
+
+# Install dependencies (postinstall detects server mode and skips Electron rebuild)
+# Note: node-pty is in optionalDependencies and will be built for Node.js
+RUN bun install --frozen-lockfile
+
+# Copy source files needed for build
+COPY src/ src/
+COPY tsconfig.json tsconfig.main.json ./
+COPY scripts/generate-version.sh scripts/
+COPY index.html terminal.html vite.config.ts ./
+COPY public/ public/
+COPY static/ static/
+
+# Remove test files (they import from tests/ which is outside rootDir)
+RUN find src -name '*.test.ts' -delete
+
+# Initialize git for version script (uses placeholder if not a real repo)
+RUN git init && \
+    git config user.email "docker@build" && \
+    git config user.name "Docker Build" && \
+    git add -A && \
+    git commit -m "docker build" --allow-empty || true
+
+# Generate version info
+RUN ./scripts/generate-version.sh
+
+# Build main process (server + backend)
+RUN NODE_ENV=production bun x tsc -p tsconfig.main.json && \
+    NODE_ENV=production bun x tsc-alias -p tsconfig.main.json
+
+# Build renderer (frontend)
+RUN bun x vite build
+
+# Copy static assets
+RUN mkdir -p dist/static && cp -r static/* dist/static/ 2>/dev/null || true
+
+# ==============================================================================
+# Stage 2: Runtime
+# ==============================================================================
+FROM node:22-slim
+
+WORKDIR /app
+
+# Install runtime dependencies
+# - git: required for workspace operations (clone, worktree, etc.)
+# - openssh-client: required for SSH runtime support
+RUN apt-get update && \
+    apt-get install -y git openssh-client && \
+    rm -rf /var/lib/apt/lists/*
+
+# Copy built artifacts from builder
+COPY --from=builder /app/dist ./dist
+COPY --from=builder /app/node_modules ./node_modules
+COPY --from=builder /app/package.json ./
+
+# Create mux data directory
+RUN mkdir -p /root/.mux
+
+# Default environment variables
+ENV NODE_ENV=production
+ENV MUX_HOME=/root/.mux
+
+# Expose server port
+EXPOSE 3000
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+    CMD node -e "fetch('http://localhost:3000/health').then(r => r.ok ? process.exit(0) : process.exit(1)).catch(() => process.exit(1))"
+
+# Run mux server
+# --host 0.0.0.0: bind to all interfaces (required for Docker networking)
+# --port 3000: default port (can be remapped via docker run -p)
+ENTRYPOINT ["node", "dist/cli/index.js", "server"]
+CMD ["--host", "0.0.0.0", "--port", "3000"]

docker-compose.yml

@@ -0,0 +1,22 @@
+# mux server docker-compose configuration
+#
+# Quick start:
+#   docker compose up -d
+#
+# Add a project:
+#   docker compose run --rm mux-server --add-project /projects/my-repo
+
+services:
+  mux-server:
+    build: .
+    container_name: mux-server
+    ports:
+      - "3000:3000"
+    volumes:
+      - mux-data:/root/.mux
+      # Mount project directories as needed:
+      # - ~/projects:/projects:rw
+    restart: unless-stopped
+
+volumes:
+  mux-data: