Sunshine

Sunshine is a lightweight, self‑hosted game streaming server that implements the P2P streaming protocol used by NVIDIA’s GameStream. It exposes a single TCP/UDP port and negotiates with Moonlight clients (Android, iOS, Windows, macOS, Linux, Xbox, etc.) to deliver a low‑latency, full‑resolution video feed of the host machine’s desktop. From a developer standpoint, Sunshine is essentially an edge device that bridges raw GPU frames to a WebRTC‑style transport, while also providing an HTTP/JSON API for discovery and configuration.

Technical Stack

• Language & Runtime: The core is written in Rust, chosen for its zero‑cost abstractions, safety guarantees, and native support for asynchronous I/O via the tokio runtime.
• Encoding & GPU Access: Hardware encoding is delegated to platform‑specific backends:
  • Windows: DirectX Video Acceleration (DXVA) via the dxva2 crate.
  • Linux: VA‑API (AMD/Intel) or NVENC through the nvenc crate.
  • macOS: VideoToolbox (Apple’s hardware encoder).
• Networking: Implements the GameStream protocol over UDP, with optional TCP fallback for control channels. Uses tokio::net for non‑blocking sockets and serde_json for the JSON control API.
• Web UI: A minimal single‑page app served by warp (Rust web framework). The UI communicates with the backend over a local WebSocket for real‑time status updates.
• Database: No persistent database; configuration is stored in a simple toml file and runtime state is kept in memory.

Core Capabilities

Deployment & Infrastructure

• Self‑Hosting: Sunshine runs as a single binary with no external dependencies beyond the GPU driver stack. It can be launched on bare‑metal PCs, Raspberry Pi 4 (with NVENC support), or any Docker host.
• Containerization: Official Docker images are available on Docker Hub, GHCR, and Flathub. The container exposes ports 47984 (UDP) and 47998/48010 (TCP) and mounts a volume for the config file.
• Scalability: Each Sunshine instance handles one client at a time due to the nature of GameStream. For multi‑player setups, developers can orchestrate multiple Sunshine instances behind a load balancer and use a custom session manager to route clients.
• Resource Utilization: Because encoding runs on the GPU, CPU usage is minimal. Memory footprint stays below 50 MiB for a typical game stream.

Integration & Extensibility

• Plugin Hooks: Sunshine exposes a simple plugin API via dynamic library loading (.so/.dll). Plugins can intercept input events or modify encoder settings at runtime.
• Webhooks: The HTTP API supports POST callbacks on pairing events, enabling integration with home‑automation systems (e.g., trigger a smart light when a stream starts).
• Custom UI: The front‑end is written in vanilla JS and can be forked; developers may replace it with a React or Vue wrapper if they need richer analytics dashboards.
• SDK: The Rust crate sunshine-client (not yet published) provides a thin wrapper around the GameStream protocol, useful for building custom clients or bots.

Developer Experience

• Documentation: The GitHub repo contains a comprehensive README, API reference (JSON schemas), and example configuration snippets. The codebase follows Rust idioms, making it approachable for developers familiar with async patterns.
• Community: An active Discord channel and issue tracker allow rapid feedback. The project is open‑source under the MIT license, facilitating commercial use without licensing fees.
• Testing: Unit tests cover protocol parsing and configuration logic; integration tests use a headless Moonlight client to validate end‑to‑end streaming.

Use Cases

1. Home Cloud Gaming – Run Sunshine on a high‑end PC to stream games to phones or smart TVs without paying for commercial services.
2. Embedded Gaming Appliances – Deploy Sunshine on a Raspberry Pi 4 with an NVIDIA Jetson GPU to create low‑cost streaming boxes for retro gaming.
3. Enterprise Training – Use Sunshine in a lab to provide instructors with remote, low‑latency access to simulation software on powerful workstations.
4. IoT Edge Gaming – Combine Sunshine with a custom IoT controller to create “living room” kiosks that stream games on demand.

Advantages

• Zero Cost & Full Control – No subscription fees; all data stays on local hardware.
• Low Latency & High Fidelity – Hardware‑accelerated encoding and UDP transport deliver <30 ms latency on modern networks.