golem

golem is a lightweight Minecraft server proxy with autostart/stop written in Go.

Usage

Usage of golem:
  -debug
        Log all traffic
  -playersMax int
        Maximum number of players (to display in status message) (default 20)
  -proxyAddr string
        Proxy server address (default ":25565")
  -serverAddr string
        Minecraft server address (default ":25566")
  -serverDirectory string
        Minecraft server working directory
  -serverStart string
        Minecraft start command. Empty disables autostart/stop
  -stopTimeout int
        Wait period to stop server after last disconnect (seconds) (default 60)
  -versionName string
        Minecraft version name (default "1.17.1")
  -versionProtocol int
        Minecraft protocol version (default 756)

Appendix

Codebase

• protocol provides a wrapper of net.Conn that implements the Minecraft protocol.
• proxy provides a Proxy which intercepts and forwards packets in the Minecraft protocol and orchestrates server management.
• server defines an interface Server for a server manager (start, stop, execute commands) and implements a basic manager which does no managing.
  • server/process implements a server manager by supervising a child process.
  • Future server managers can be implemented such as for a remote process or a Docker container.

Distribution on NixOS

The following configuration declaratively enables/disables running Minecraft behind a proxy with the proxy.enable flag. In this example, ./golem is a local package built by buildGoModule, where the source points to either this repository via fetchFromGithub or a tarball made by make archive.

let
  server-port = 25565; # port to expose (external) minecraft server

  proxy = {
    enable = true;
    package = pkgs.callPackage ./golem { };
    server-port = 25566; # port to run (internal) minecraft server
  };
in
{
  services.minecraft-server = {
    enable = true;
    eula = true;
    declarative = true;
    serverProperties = {
      server-port = (if proxy.enable then proxy.server-port else server-port);
      # ...
    };
  };

  systemd.services.minecraft-server = {
    serviceConfig.ExecStart = lib.mkIf proxy.enable (lib.mkForce
      ''${proxy.package}/bin/golem \
        -proxyAddr :${toString server-port} \
        -serverAddr :${toString proxy.server-port} \
        -serverDirectory ${config.services.minecraft-server.dataDir} \
        -serverStart "${config.services.minecraft-server.package}/bin/minecraft-server ${config.services.minecraft-server.jvmOpts}"
      '');
  };
}