ProxySync

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A WaterdogPE plugin that synchronizes player counts and transfers players across multiple proxy instances.

Features

• Aggregated Player Count - Combines player counts from multiple WaterdogPE proxies and displays the total in MOTD/Query responses
• Player Transfer on Shutdown - Automatically transfers connected players to other online proxies when the current proxy shuts down, using round-robin distribution
• Maintenance Mode - Redirects new players to other online proxies while allowing current players to finish; optionally auto-shuts down the proxy when empty
• Remote Proxy Monitoring - Periodically queries remote proxies via the Minecraft Bedrock UDP MOTD protocol to track their status and player counts
• Public Address Translation - Supports replacing localhost addresses with a public IP for player transfer packets in NAT environments

Requirements

• Java 17+
• WaterdogPE 2.0.4-SNAPSHOT or compatible

Build

mvn clean package

The compiled JAR will be at target/ProxySync-1.0.0-SNAPSHOT.jar.

Installation

1. Build the plugin or download the JAR
2. Place the JAR in the plugins/ directory of your WaterdogPE proxy
3. Start the proxy to generate the default configuration
4. Edit plugins/ProxySync/config.yml to configure remote proxy addresses
5. Restart the proxy

Configuration

plugins/ProxySync/config.yml:

# Remote WDPE proxy addresses (IP:port)
remote-proxies:
  - "192.168.1.10:19132"
  - "192.168.1.11:19132"

# Query interval (seconds)
query-interval: 30

# Aggregate online player count (true=sum of all proxies, false=local only)
aggregate-player-count: false

# Aggregate max player count (true=sum of all proxies, false=local config only)
aggregate-max-players: false

# Transfer players to other online proxies on shutdown
transfer-on-shutdown: true

# Public IP for client transfer (replaces 127.0.0.1 in transfer packets)
# Leave empty to use the address as-is
public-address: ""

# Maintenance mode kick message (shown when no remote proxy is available)
maintenance-message: "Server is under maintenance, please try again later."

# Delay before transferring player in maintenance mode (ticks, 20 ticks = 1 second)
maintenance-transfer-delay: 100

# Title text shown to player before transfer
maintenance-title: "§cServer Maintenance"

# Subtitle text shown to player before transfer
maintenance-subtitle: "§eTransferring to another server..."

Option	Type	Default	Description
remote-proxies	List	-	List of remote WaterdogPE proxy addresses in IP:port format
query-interval	Integer	30	Interval in seconds between remote proxy queries
aggregate-player-count	Boolean	false	Add remote player counts to MOTD/Query responses
aggregate-max-players	Boolean	false	Add remote max player slots to MOTD/Query responses
transfer-on-shutdown	Boolean	true	Transfer players to online remote proxies on shutdown
public-address	String	""	Public IP to replace localhost in transfer packets
maintenance-message	String	"Server is under maintenance, please try again later."	Message shown when a player is rejected during maintenance (no remote proxy available)
maintenance-transfer-delay	Integer	100	Delay in ticks before transferring a player in maintenance mode (20 ticks = 1 second)
maintenance-title	String	"§cServer Maintenance"	Title text shown to the player before transfer
maintenance-subtitle	String	"§eTransferring to another server..."	Subtitle text shown to the player before transfer

Commands

Command	Permission	Description
/ps mt on	proxysync.maintenance	Enable maintenance mode (new players are transferred to other proxies)
/ps mt on shutdown	proxysync.maintenance	Enable maintenance mode and auto-shutdown when no players remain
/ps mt off	proxysync.maintenance	Disable maintenance mode
/ps mt status	proxysync.maintenance	Show current maintenance and shutdown status

How It Works

1. On startup, the plugin parses configured remote proxy addresses (automatically skipping the local proxy's own address)
2. A scheduled task periodically sends UDP MOTD query packets to each remote proxy and caches the results (online count + max count)
3. When aggregate-player-count or aggregate-max-players is enabled, the plugin intercepts ProxyPingEvent and ProxyQueryEvent to add remote counts to the response
4. On proxy shutdown (if transfer-on-shutdown is enabled), connected players are distributed to online remote proxies via TransferPacket using round-robin
5. Maintenance mode shows a Title notification to new players, then redirects them to other online proxies via TransferPacket after a configurable delay; if no remote proxy is available, the login is rejected with a configurable message
6. When shutdown is specified with maintenance mode, the proxy automatically shuts down once all players have left