RedisBridge is a complete rewrite of my previous plugin JBridge, developed for Nukkit and WaterdogPE. It provides automatic server registration, player management, and seamless communication between backend servers and the proxy.

⚙️ Available Commands

RedisBridge includes ready-to-use commands for your WaterdogPE proxy or Nukkit backend servers:

• /lobby Teleports the player to an available lobby instance using the LOWEST_PLAYERS strategy to avoid overloading a single lobby while keeping activity balanced.

• /transfer <server> Transfers the player to a specific instance if available. Useful for networks with multiple game modes.

• /whereami Displays information to the player showing which instance and proxy they are currently in.

📡 Instance Management Usage

RedisBridge includes a distributed instance discovery and selection system for minigame servers, lobbies, or backend servers using Redis and a low-latency distributed cache.

Each server instance sends automatic heartbeats via InstanceHeartbeatMessage containing:

• id (unique identifier)

• group (e.g., lobby, solo_skywars, duels)

• players (current online players)

• maxPlayers (maximum capacity)

• host and port

This allows other servers and the proxy to know in real time which instances are available, their capacity, and their status.

The InstanceManager:

• Uses a local cache with a 10-second expiration to keep instance state updated efficiently.

• Allows you to:

  • Retrieve instances by ID (getInstanceById)

  • Retrieve all instances in a group (getGroupInstances)

  • Get total player counts or per group (getTotalPlayerCount, getGroupPlayerCount)

  • Get total maximum player capacity or per group (getTotalMaxPlayers, getGroupMaxPlayers)

Provides automatic available instance selection using different strategies:

• RANDOM: Selects a random instance in the group.

• LOWEST_PLAYERS: Selects the instance with the fewest players.

• MOST_PLAYERS_AVAILABLE: Selects the instance with the most players while still having available slots.

Example:

InstanceInfo instance = InstanceManager.getInstance().selectAvailableInstance("lobby", InstanceManager.SelectionStrategy.LOWEST_PLAYERS);

if (instance != null) {
    // Connect player to this instance
}

This system enables your network to distribute players dynamically without relying on a heavy centralized matchmaking server.

🚀 Communication Usage

RedisBridge simplifies inter-server communication over Redis, enabling you to publish and subscribe to messages seamlessly between your proxy and backend servers.

How it works?

• Uses Redis Pub/Sub on a single channel (redis-bridge-channel) for all message transmission.

• Messages are serialized in JSON and identified using their type field.

• Each message type can have:

  • A registered class (MessageRegistry) for deserialization.

  • An optional handler (MessageHandlerRegistry) for automatic processing when received.

• Includes default messages for instance heartbeat and shutdown announcements to enable automatic instance tracking.

Publishing Messages

To send a message to all connected instances:

YourCustomMessage message = new YourCustomMessage();
// fill your message data here

redisBridge.publish(message, "sender-id");

Handling Incoming Messages

• Register your message type:

  MessageRegistry.register("your-message-type", YourCustomMessage.class);

• Register your message handler:

  MessageHandlerRegistry.register("your-message-type", new MessageHandler<YourCustomMessage>() {
      @Override
      public void handle(YourCustomMessage message) {
          // handle your message here
      }
  });

License

RedisBridge is licensed under the MIT License. Feel free to use, modify, and distribute it in your projects.