An experimental server implementation of Mu Online, consisting of multiple microservices communicating over gRPC orchestrated via Docker. The client protocol has been reverse-engineered using IDA Pro and Wireshark. The database layer is implemented using NHibernate and houses a 2nd level cache for all configuration objects.

The server consists of multiple services, each being dedicated to a single task. The services are containerized and can be orchestrated via Docker Compose.

• ConnectServer

  The ConnectServer is directly exposed to the internet, and communicates directly to the client via its binary protocol (TCP), whilst gRPC is used to communicate with the internal microservices. It supplies the client with a list of available game servers upon authentication. It may also require the client to be updated, in case it's outdated.

• LoginServer

  The LoginServer's sole responsibility is to authenticate users and maintain their sessions. Other services may query it, to determine whether a user session is valid. It also throttles login attempts using exponential back off.

• GameServer

  The GameServer represents a single instance of an isolated world. It registers itself at the ConnectServer (gRPC) to flag itself as eligible to receive new clients. Clients can communicate either directly, or via a reverse-proxy, with the GameServer using the client's binary protocol (TCP).

• ChatServer

  The client has built-in support for chatting in between different game servers, but the service itself must be implemented.

• Monitoring

  Integrating Sentry to allow real-time performance monitoring and error tracking.

  Integrating OpenTracing to allow requests to be tracked across different microservices.