Add Nats messenger (#3525)

bukkit-legacy/build.gradle

@@ -34,6 +34,7 @@ shadowJar {
     relocate 'com.mongodb', 'me.lucko.luckperms.lib.mongodb'
     relocate 'org.bson', 'me.lucko.luckperms.lib.bson'
     relocate 'redis.clients.jedis', 'me.lucko.luckperms.lib.jedis'
+    relocate 'io.nats.client', 'me.lucko.luckperms.lib.nats'
     relocate 'com.rabbitmq', 'me.lucko.luckperms.lib.rabbitmq'
     relocate 'org.apache.commons.pool2', 'me.lucko.luckperms.lib.commonspool2'
     relocate 'ninja.leaping.configurate', 'me.lucko.luckperms.lib.configurate'

bukkit/build.gradle

@@ -44,6 +44,7 @@ shadowJar {
     relocate 'com.mongodb', 'me.lucko.luckperms.lib.mongodb'
     relocate 'org.bson', 'me.lucko.luckperms.lib.bson'
     relocate 'redis.clients.jedis', 'me.lucko.luckperms.lib.jedis'
+    relocate 'io.nats.client', 'me.lucko.luckperms.lib.nats'
     relocate 'com.rabbitmq', 'me.lucko.luckperms.lib.rabbitmq'
     relocate 'org.apache.commons.pool2', 'me.lucko.luckperms.lib.commonspool2'
     relocate 'ninja.leaping.configurate', 'me.lucko.luckperms.lib.configurate'

bukkit/src/main/resources/config.yml

@@ -241,6 +241,8 @@ watch-files: true
 #                below.
 #   => rabbitmq  Uses RabbitMQ pub-sub to push changes. Your server connection info must be
 #                configured below.
+#   => nats      Uses Nats pub-sub to push changes. Your server connection info must be
+#                configured below.
 #   => custom    Uses a messaging service provided using the LuckPerms API.
 #   => auto      Attempts to automatically setup a messaging service using redis or sql.
 messaging-service: auto
@@ -266,6 +268,14 @@ redis:
   username: ''
   password: ''
 
+# Settings for Nats.
+# Port 4222 is used by default; set address to "host:port" if differs
+nats:
+  enabled: false
+  address: localhost
+  username: ''
+  password: ''
+
 # Settings for RabbitMQ.
 # Port 5672 is used by default; set address to "host:port" if differs
 rabbitmq:

bungee/build.gradle

@@ -36,6 +36,7 @@ shadowJar {
     relocate 'com.mongodb', 'me.lucko.luckperms.lib.mongodb'
     relocate 'org.bson', 'me.lucko.luckperms.lib.bson'
     relocate 'redis.clients.jedis', 'me.lucko.luckperms.lib.jedis'
+    relocate 'io.nats.client', 'me.lucko.luckperms.lib.nats'
     relocate 'com.rabbitmq', 'me.lucko.luckperms.lib.rabbitmq'
     relocate 'org.apache.commons.pool2', 'me.lucko.luckperms.lib.commonspool2'
     relocate 'ninja.leaping.configurate', 'me.lucko.luckperms.lib.configurate'

bungee/src/main/resources/config.yml

@@ -239,6 +239,8 @@ watch-files: true
 #                    the RedisBungee plugin installed.
 #   => rabbitmq      Uses RabbitMQ pub-sub to push changes. Your server connection info must be
 #                    configured below.
+#   => nats          Uses Nats pub-sub to push changes. Your server connection info must be
+#                    configured below.
 #   => custom        Uses a messaging service provided using the LuckPerms API.
 #   => auto          Attempts to automatically setup a messaging service using redis or sql.
 messaging-service: auto
@@ -264,6 +266,14 @@ redis:
   username: ''
   password: ''
 
+# Settings for Nats.
+# Port 4222 is used by default; set address to "host:port" if differs
+nats:
+  enabled: false
+  address: localhost
+  username: ''
+  password: ''
+
 # Settings for RabbitMQ.
 # Port 5672 is used by default; set address to "host:port" if differs
 rabbitmq:

common/build.gradle

@@ -72,6 +72,7 @@ dependencies {
     }
     api 'com.zaxxer:HikariCP:4.0.3'
     api 'redis.clients:jedis:3.5.2'
+    api 'io.nats:jnats:2.16.4'
     api 'com.rabbitmq:amqp-client:5.12.0'
     api 'org.mongodb:mongodb-driver-legacy:4.5.0'
     api 'org.yaml:snakeyaml:1.28'

common/src/main/java/me/lucko/luckperms/common/config/ConfigKeys.java

@@ -651,6 +651,31 @@ public final class ConfigKeys {
      */
     public static final ConfigKey<Boolean> REDIS_SSL = notReloadable(booleanKey("redis.ssl", false));
 
+    /**
+     * If nats messaging is enabled
+     */
+    public static final ConfigKey<Boolean> NATS_ENABLED = notReloadable(booleanKey("nats.enabled", false));
+
+    /**
+     * The address of the nats server
+     */
+    public static final ConfigKey<String> NATS_ADDRESS = notReloadable(stringKey("nats.address", null));
+
+    /**
+     * The username to connect with, or an empty string if it should use default
+     */
+    public static final ConfigKey<String> NATS_USERNAME = notReloadable(stringKey("nats.username", ""));
+
+    /**
+     * The password in use by the nats server, or an empty string if there is no password
+     */
+    public static final ConfigKey<String> NATS_PASSWORD = notReloadable(stringKey("nats.password", ""));
+
+    /**
+     * If the nats connection should use SSL
+     */
+    public static final ConfigKey<Boolean> NATS_SSL = notReloadable(booleanKey("nats.ssl", false));
+
     /**
      * If rabbitmq messaging is enabled
      */

common/src/main/java/me/lucko/luckperms/common/dependencies/Dependency.java

@@ -245,6 +245,13 @@ public enum Dependency {
             Relocation.of("jedis", "redis{}clients{}jedis"),
             Relocation.of("commonspool2", "org{}apache{}commons{}pool2")
     ),
+    NATS(
+        "io.nats",
+        "jnats",
+        "2.16.4",
+        "/WZgFi9iJToRGIiGoShlwE5aHwstOuNGZyr4UaBRilM=",
+        Relocation.of("nats", "io{}nats{}client")
+    ),
     RABBITMQ(
             "com{}rabbitmq",
             "amqp-client",

common/src/main/java/me/lucko/luckperms/common/dependencies/DependencyManager.java

@@ -128,8 +128,8 @@ public class DependencyManager {
         }
     }
 
-    public void loadStorageDependencies(Set<StorageType> storageTypes, boolean redis, boolean rabbitmq) {
+    public void loadStorageDependencies(Set<StorageType> storageTypes, boolean redis, boolean rabbitmq, boolean nats) {
-        loadDependencies(this.registry.resolveStorageDependencies(storageTypes, redis, rabbitmq));
+        loadDependencies(this.registry.resolveStorageDependencies(storageTypes, redis, rabbitmq, nats));
     }
 
     public void loadDependencies(Set<Dependency> dependencies) {

common/src/main/java/me/lucko/luckperms/common/dependencies/DependencyRegistry.java

@@ -72,7 +72,7 @@ public class DependencyRegistry {
         this.platformType = platformType;
     }
 
-    public Set<Dependency> resolveStorageDependencies(Set<StorageType> storageTypes, boolean redis, boolean rabbitmq) {
+    public Set<Dependency> resolveStorageDependencies(Set<StorageType> storageTypes, boolean redis, boolean rabbitmq, boolean nats) {
         Set<Dependency> dependencies = new LinkedHashSet<>();
         for (StorageType storageType : storageTypes) {
             dependencies.addAll(STORAGE_DEPENDENCIES.get(storageType));
@@ -85,6 +85,10 @@ public class DependencyRegistry {
             dependencies.add(Dependency.SLF4J_SIMPLE);
         }
 
+        if (nats) {
+            dependencies.add(Dependency.NATS);
+        }
+
         if (rabbitmq) {
             dependencies.add(Dependency.RABBITMQ);
         }

common/src/main/java/me/lucko/luckperms/common/messaging/MessagingFactory.java

@@ -27,6 +27,7 @@ package me.lucko.luckperms.common.messaging;
 
 import me.lucko.luckperms.common.config.ConfigKeys;
 import me.lucko.luckperms.common.config.LuckPermsConfiguration;
+import me.lucko.luckperms.common.messaging.nats.NatsMessenger;
 import me.lucko.luckperms.common.messaging.rabbitmq.RabbitMQMessenger;
 import me.lucko.luckperms.common.messaging.redis.RedisMessenger;
 import me.lucko.luckperms.common.messaging.sql.SqlMessenger;
@@ -67,6 +68,8 @@ public class MessagingFactory<P extends LuckPermsPlugin> {
                 messagingType = "redis";
             } else if (this.plugin.getConfiguration().get(ConfigKeys.RABBITMQ_ENABLED)) {
                 messagingType = "rabbitmq";
+            } else if (this.plugin.getConfiguration().get(ConfigKeys.NATS_ENABLED)) {
+                messagingType = "nats";
             } else {
                 for (StorageImplementation implementation : this.plugin.getStorage().getImplementations()) {
                     if (implementation instanceof SqlStorage) {
@@ -84,13 +87,16 @@ public class MessagingFactory<P extends LuckPermsPlugin> {
             return null;
         }
 
-        this.plugin.getLogger().info("Loading messaging service... [" + messagingType.toUpperCase(Locale.ROOT) + "]");
+        if (messagingType.equals("custom")) {
+            this.plugin.getLogger().info("Messaging service is set to custom. No service is initialized at this stage yet.");
+            return null;
+        }
 
+        this.plugin.getLogger().info("Loading messaging service... [" + messagingType.toUpperCase(Locale.ROOT) + "]");
         InternalMessagingService service = getServiceFor(messagingType);
         if (service != null) {
             return service;
         }
-
         this.plugin.getLogger().warn("Messaging service '" + messagingType + "' not recognised.");
         return null;
     }
@@ -106,6 +112,16 @@ public class MessagingFactory<P extends LuckPermsPlugin> {
             } else {
                 this.plugin.getLogger().warn("Messaging Service was set to redis, but redis is not enabled!");
             }
+        } else if (messagingType.equals("nats")) {
+            if (this.plugin.getConfiguration().get(ConfigKeys.NATS_ENABLED)) {
+                try {
+                    return new LuckPermsMessagingService(this.plugin, new NatsMesengerProvider());
+                } catch (Exception e) {
+                    getPlugin().getLogger().severe("Exception occurred whilst enabling Nats messaging service", e);
+                }
+            } else {
+                this.plugin.getLogger().warn("Messaging Service was set to nats, but nats is not enabled!");
+            }
         } else if (messagingType.equals("rabbitmq")) {
             if (this.plugin.getConfiguration().get(ConfigKeys.RABBITMQ_ENABLED)) {
                 try {
@@ -127,6 +143,34 @@ public class MessagingFactory<P extends LuckPermsPlugin> {
         return null;
     }
 
+    private class NatsMesengerProvider implements MessengerProvider {
+
+        @Override
+        public @NonNull String getName() {
+            return "Nats";
+        }
+
+        @Override
+        public @NonNull Messenger obtain(@NonNull IncomingMessageConsumer incomingMessageConsumer) {
+            NatsMessenger natsMessenger = new NatsMessenger(getPlugin(), incomingMessageConsumer);
+
+            LuckPermsConfiguration configuration = getPlugin().getConfiguration();
+            String address = configuration.get(ConfigKeys.NATS_ADDRESS);
+            String username = configuration.get(ConfigKeys.NATS_USERNAME);
+            String password = configuration.get(ConfigKeys.NATS_PASSWORD);
+            if (password.isEmpty()) {
+                password = null;
+            }
+            if (username.isEmpty()) {
+                username = null;
+            }
+            boolean ssl = configuration.get(ConfigKeys.NATS_SSL);
+
+            natsMessenger.init(address, username, password, ssl);
+            return natsMessenger;
+        }
+    }
+
     private class RedisMessengerProvider implements MessengerProvider {
 
         @Override

common/src/main/java/me/lucko/luckperms/common/messaging/nats/NatsMessenger.java

@@ -0,0 +1,128 @@
+/*
+ * This file is part of LuckPerms, licensed under the MIT License.
+ *
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to deal
+ *  in the Software without restriction, including without limitation the rights
+ *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *  copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ *
+ *  The above copyright notice and this permission notice shall be included in all
+ *  copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ *  SOFTWARE.
+ */
+
+package me.lucko.luckperms.common.messaging.nats;
+
+import com.google.common.io.ByteArrayDataInput;
+import com.google.common.io.ByteArrayDataOutput;
+import com.google.common.io.ByteStreams;
+
+import me.lucko.luckperms.common.plugin.LuckPermsPlugin;
+import me.lucko.luckperms.common.util.Throwing;
+
+import net.luckperms.api.messenger.IncomingMessageConsumer;
+import net.luckperms.api.messenger.Messenger;
+import net.luckperms.api.messenger.message.OutgoingMessage;
+
+import org.checkerframework.checker.nullness.qual.NonNull;
+
+import io.nats.client.Connection;
+import io.nats.client.Dispatcher;
+import io.nats.client.Message;
+import io.nats.client.MessageHandler;
+import io.nats.client.Nats;
+import io.nats.client.Options;
+import io.nats.client.Options.Builder;
+
+import java.time.Duration;
+
+/**
+ * An implementation of Messenger for Nats messaging client.
+ */
+public class NatsMessenger implements Messenger {
+
+    private static final String CHANNEL = "luckperms:update";
+
+    private final LuckPermsPlugin plugin;
+    private final IncomingMessageConsumer consumer;
+    private Connection connection;
+    private Dispatcher messageDispatcher;
+
+    public NatsMessenger(LuckPermsPlugin plugin, IncomingMessageConsumer consumer) {
+        this.plugin = plugin;
+        this.consumer = consumer;
+    }
+
+    @Override
+    public void sendOutgoingMessage(@NonNull OutgoingMessage outgoingMessage) {
+        ByteArrayDataOutput output = ByteStreams.newDataOutput();
+        output.writeUTF(outgoingMessage.asEncodedString());
+        this.connection.publish(CHANNEL, output.toByteArray());
+    }
+
+    public void init(String address, String username, String password, boolean ssl) {
+        String[] addressSplit = address.split(":");
+        String host = addressSplit[0];
+        int port = addressSplit.length > 1 ? Integer.parseInt(addressSplit[1]) : Options.DEFAULT_PORT;
+
+        this.connection = createConnection(builder -> {
+            builder.server("nats://" + host + ":" + port)
+                    .reconnectWait(Duration.ofSeconds(5))
+                    .maxReconnects(Integer.MAX_VALUE)
+                    .connectionName("LuckPerms");
+
+            if (username != null && password != null) {
+                builder.userInfo(username, password);
+            }
+
+            if (ssl) {
+                builder.secure();
+            }
+        });
+        this.messageDispatcher = this.connection.createDispatcher(new Handler()).subscribe(CHANNEL);
+    }
+
+    private Connection createConnection(Throwing.Consumer<Builder> config) {
+        try {
+            Builder builder = new Builder();
+            config.accept(builder);
+            return Nats.connect(builder.build());
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    @Override
+    public void close() {
+        try {
+            this.connection.closeDispatcher(this.messageDispatcher);
+            this.connection.close();
+        } catch (InterruptedException e) {
+            this.plugin.getLogger().warn("An error occurred during closing messenger.", e);
+        }
+    }
+
+    private class Handler implements MessageHandler {
+
+        @Override
+        public void onMessage(Message message) {
+            byte[] data = message.getData();
+            ByteArrayDataInput input = ByteStreams.newDataInput(data);
+            String messageAsString = input.readUTF();
+
+            NatsMessenger.this.consumer.consumeIncomingMessageAsString(messageAsString);
+        }
+    }
+}

common/src/main/java/me/lucko/luckperms/common/plugin/AbstractLuckPermsPlugin.java

@@ -162,7 +162,8 @@ public abstract class AbstractLuckPermsPlugin implements LuckPermsPlugin {
         this.dependencyManager.loadStorageDependencies(
                 storageFactory.getRequiredTypes(),
                 getConfiguration().get(ConfigKeys.REDIS_ENABLED),
-                getConfiguration().get(ConfigKeys.RABBITMQ_ENABLED)
+                getConfiguration().get(ConfigKeys.RABBITMQ_ENABLED),
+                getConfiguration().get(ConfigKeys.NATS_ENABLED)
         );
 
         // register listeners

fabric/build.gradle

@@ -66,6 +66,7 @@ shadowJar {
     relocate 'com.mongodb', 'me.lucko.luckperms.lib.mongodb'
     relocate 'org.bson', 'me.lucko.luckperms.lib.bson'
     relocate 'redis.clients.jedis', 'me.lucko.luckperms.lib.jedis'
+    relocate 'io.nats.client', 'me.lucko.luckperms.lib.nats'
     relocate 'com.rabbitmq', 'me.lucko.luckperms.lib.rabbitmq'
     relocate 'org.apache.commons.pool2', 'me.lucko.luckperms.lib.commonspool2'
     relocate 'ninja.leaping.configurate', 'me.lucko.luckperms.lib.configurate'

fabric/src/main/resources/luckperms.conf

@@ -244,6 +244,8 @@ watch-files = true
 #                below.
 #   => rabbitmq  Uses RabbitMQ pub-sub to push changes. Your server connection info must be
 #                configured below.
+#   => nats      Uses Nats pub-sub to push changes. Your server connection info must be
+#                configured below.
 #   => custom    Uses a messaging service provided using the LuckPerms API.
 #   => auto      Attempts to automatically setup a messaging service using redis or sql.
 messaging-service = "auto"
@@ -270,6 +272,15 @@ redis {
   password = ""
 }
 
+# Settings for nats.
+# Port 4222 is used by default; set address to "host:port" if differs
+nats {
+  enabled = false
+  address = "localhost"
+  username = ""
+  password = ""
+}
+
 # Settings for RabbitMQ.
 # Port 5672 is used by default; set address to "host:port" if differs
 rabbitmq {

forge/build.gradle

@@ -65,6 +65,7 @@ shadowJar {
     relocate 'com.mongodb', 'me.lucko.luckperms.lib.mongodb'
     relocate 'org.bson', 'me.lucko.luckperms.lib.bson'
     relocate 'redis.clients.jedis', 'me.lucko.luckperms.lib.jedis'
+    relocate 'io.nats.client', 'me.lucko.luckperms.lib.nats'
     relocate 'com.rabbitmq', 'me.lucko.luckperms.lib.rabbitmq'
     relocate 'org.apache.commons.pool2', 'me.lucko.luckperms.lib.commonspool2'
     relocate 'ninja.leaping.configurate', 'me.lucko.luckperms.lib.configurate'

nukkit/build.gradle

@@ -35,6 +35,7 @@ shadowJar {
     relocate 'com.mongodb', 'me.lucko.luckperms.lib.mongodb'
     relocate 'org.bson', 'me.lucko.luckperms.lib.bson'
     relocate 'redis.clients.jedis', 'me.lucko.luckperms.lib.jedis'
+    relocate 'io.nats.client', 'me.lucko.luckperms.lib.nats'
     relocate 'com.rabbitmq', 'me.lucko.luckperms.lib.rabbitmq'
     relocate 'org.apache.commons.pool2', 'me.lucko.luckperms.lib.commonspool2'
     relocate 'ninja.leaping.configurate', 'me.lucko.luckperms.lib.configurate'

nukkit/src/main/resources/config.yml

@@ -236,6 +236,8 @@ watch-files: true
 #                below.
 #   => rabbitmq  Uses RabbitMQ pub-sub to push changes. Your server connection info must be
 #                configured below.
+#   => nats      Uses Nats pub-sub to push changes. Your server connection info must be
+#                configured below.
 #   => custom    Uses a messaging service provided using the LuckPerms API.
 #   => auto      Attempts to automatically setup a messaging service using redis or sql.
 messaging-service: auto
@@ -261,6 +263,14 @@ redis:
   username: ''
   password: ''
 
+# Settings for Nats.
+# Port 4222 is used by default; set address to "host:port" if differs
+nats:
+  enabled: false
+  address: localhost
+  username: ''
+  password: ''
+
 # Settings for RabbitMQ.
 # Port 5672 is used by default; set address to "host:port" if differs
 rabbitmq:

sponge/build.gradle

@@ -47,6 +47,7 @@ shadowJar {
     relocate 'com.mongodb', 'me.lucko.luckperms.lib.mongodb'
     relocate 'org.bson', 'me.lucko.luckperms.lib.bson'
     relocate 'redis.clients.jedis', 'me.lucko.luckperms.lib.jedis'
+    relocate 'io.nats.client', 'me.lucko.luckperms.lib.nats'
     relocate 'com.rabbitmq', 'me.lucko.luckperms.lib.rabbitmq'
     relocate 'org.apache.commons.pool2', 'me.lucko.luckperms.lib.commonspool2'
     relocate 'ninja.leaping.configurate', 'me.lucko.luckperms.lib.configurate'

sponge/src/main/resources/luckperms.conf

@@ -244,6 +244,8 @@ watch-files = true
 #                below.
 #   => rabbitmq  Uses RabbitMQ pub-sub to push changes. Your server connection info must be
 #                configured below.
+#   => nats      Uses Nats pub-sub to push changes. Your server connection info must be
+#                configured below.
 #   => custom    Uses a messaging service provided using the LuckPerms API.
 #   => auto      Attempts to automatically setup a messaging service using redis or sql.
 messaging-service = "auto"
@@ -270,6 +272,15 @@ redis {
   password = ""
 }
 
+# Settings for nats.
+# Port 4222 is used by default; set address to "host:port" if differs
+nats {
+  enabled = false
+  address = "localhost"
+  username = ""
+  password = ""
+}
+
 # Settings for RabbitMQ.
 # Port 5672 is used by default; set address to "host:port" if differs
 rabbitmq {

standalone/build.gradle

@@ -30,6 +30,7 @@ shadowJar {
     relocate 'com.mongodb', 'me.lucko.luckperms.lib.mongodb'
     relocate 'org.bson', 'me.lucko.luckperms.lib.bson'
     relocate 'redis.clients.jedis', 'me.lucko.luckperms.lib.jedis'
+    relocate 'io.nats.client', 'me.lucko.luckperms.lib.nats'
     relocate 'com.rabbitmq', 'me.lucko.luckperms.lib.rabbitmq'
     relocate 'org.apache.commons.pool2', 'me.lucko.luckperms.lib.commonspool2'
     relocate 'ninja.leaping.configurate', 'me.lucko.luckperms.lib.configurate'

standalone/src/main/resources/config.yml

@@ -226,6 +226,8 @@ watch-files: true
 #                below.
 #   => rabbitmq  Uses RabbitMQ pub-sub to push changes. Your server connection info must be
 #                configured below.
+#   => nats      Uses Nats pub-sub to push changes. Your server connection info must be
+#                configured below.
 #   => custom    Uses a messaging service provided using the LuckPerms API.
 #   => auto      Attempts to automatically setup a messaging service using redis or sql.
 messaging-service: auto
@@ -251,6 +253,14 @@ redis:
   username: ''
   password: ''
 
+# Settings for Nats.
+# Port 4222 is used by default; set address to "host:port" if differs
+nats:
+  enabled: false
+  address: localhost
+  username: ''
+  password: ''
+
 # Settings for RabbitMQ.
 # Port 5672 is used by default; set address to "host:port" if differs
 rabbitmq:

velocity/build.gradle

@@ -41,6 +41,7 @@ shadowJar {
     relocate 'com.mongodb', 'me.lucko.luckperms.lib.mongodb'
     relocate 'org.bson', 'me.lucko.luckperms.lib.bson'
     relocate 'redis.clients.jedis', 'me.lucko.luckperms.lib.jedis'
+    relocate 'io.nats.client', 'me.lucko.luckperms.lib.nats'
     relocate 'com.rabbitmq', 'me.lucko.luckperms.lib.rabbitmq'
     relocate 'org.apache.commons.pool2', 'me.lucko.luckperms.lib.commonspool2'
     relocate 'ninja.leaping.configurate', 'me.lucko.luckperms.lib.configurate'

velocity/src/main/resources/config.yml

@@ -230,6 +230,8 @@ watch-files: true
 #                    configured below.
 #   => rabbitmq      Uses RabbitMQ pub-sub to push changes. Your server connection info must be
 #                    configured below.
+#   => nats          Uses Nats pub-sub to push changes. Your server connection info must be
+#                    configured below.
 #   => custom        Uses a messaging service provided using the LuckPerms API.
 #   => auto          Attempts to automatically setup a messaging service using redis or sql.
 messaging-service: auto
@@ -255,6 +257,14 @@ redis:
   username: ''
   password: ''
 
+# Settings for Nats.
+# Port 4222 is used by default; set address to "host:port" if differs
+nats:
+  enabled: false
+  address: localhost
+  username: ''
+  password: ''
+
 # Settings for RabbitMQ.
 # Port 5672 is used by default; set address to "host:port" if differs
 rabbitmq: