Add seprate metrics endpoint for grpc and optionally http server

[Kangyan-Zhou]

Prometheus cannot scrape server metrics with grpc ports

[gemini-code-assist]

Summary of Changes

Hello @Kangyan-Zhou, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the operational flexibility and security posture of the SGLang server and router. It provides a dedicated mechanism for exposing Prometheus metrics, which is essential for monitoring gRPC-based deployments, and introduces robust mutual TLS authentication for secure router-worker interactions. Additionally, it enables standard TLS for the HTTP server, ensuring encrypted communication for all server types.

Highlights

• Separate Metrics Endpoint: Introduced a new --metrics-port argument allowing Prometheus metrics to be served on a dedicated HTTP port, separate from the main server. This is particularly useful for gRPC mode, where HTTP endpoints cannot share the gRPC server's port.
• Mutual TLS (mTLS) for Router-Worker Communication: Added support for mTLS to secure communication between the SGLang router and its workers. New CLI arguments (--client-cert-path, --client-key-path, --ca-cert-path) are available for configuring client certificates, private keys, and CA certificates for worker verification.
• TLS/SSL for HTTP Server: Enabled standard TLS/SSL for the HTTP server, allowing secure connections using --ssl-keyfile, --ssl-certfile, --ssl-ca-certs, and --ssl-keyfile-password.

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[gemini-code-assist]

Code Review

This pull request introduces two significant features: a separate metrics endpoint and mTLS support for both the Python server and the Rust router. The implementation is well-structured, with corresponding changes in documentation, server arguments, and core logic. The new --metrics-port argument allows metrics to be served on a dedicated port, which is particularly useful in gRPC mode. The mTLS support enhances security for server-worker communication. My review includes a couple of suggestions to improve code clarity and maintainability.

[Kangyan-Zhou]

/tag-and-rerun-ci