Add support clusterlinks command (#2986)

* Add support clusterlinks command

* Add test RedisCommandBuilderUnitTests

Author: thachlp

src/main/java/io/lettuce/core/AbstractRedisAsyncCommands.java

@@ -3189,6 +3189,11 @@ public RedisFuture<Long> zunionstore(K destination, ZStoreArgs zStoreArgs, K...
         return dispatch(commandBuilder.zunionstore(destination, zStoreArgs, keys));
     }
 
+    @Override
+    public RedisFuture<List<Map<String, Object>>> clusterLinks() {
+        return dispatch(commandBuilder.clusterLinks());
+    }
+
     private byte[] encodeFunction(String functionCode) {
         LettuceAssert.notNull(functionCode, "Function code must not be null");
         LettuceAssert.notEmpty(functionCode, "Function code script must not be empty");

src/main/java/io/lettuce/core/AbstractRedisReactiveCommands.java

@@ -3257,6 +3257,11 @@ public Mono<Long> zunionstore(K destination, ZStoreArgs zStoreArgs, K... keys) {
         return createMono(() -> commandBuilder.zunionstore(destination, zStoreArgs, keys));
     }
 
+    @Override
+    public Mono<List<Map<String, Object>>> clusterLinks() {
+        return createMono(commandBuilder::clusterLinks);
+    }
+
     private byte[] encodeFunction(String functionCode) {
         LettuceAssert.notNull(functionCode, "Function code must not be null");
         LettuceAssert.notEmpty(functionCode, "Function code script must not be empty");

src/main/java/io/lettuce/core/RedisCommandBuilder.java

@@ -4433,6 +4433,11 @@ Command<K, V, Long> zunionstore(K destination, ZAggregateArgs aggregateArgs, K..
         return createCommand(ZUNIONSTORE, new IntegerOutput<>(codec), args);
     }
 
+    Command<K, V, List<Map<String, Object>>> clusterLinks() {
+        CommandArgs<K, V> args = new CommandArgs<>(codec).add(LINKS);
+        return createCommand(CLUSTER, (CommandOutput) new ObjectOutput<>(StringCodec.UTF8), args);
+    }
+
     private boolean allElementsInstanceOf(Object[] objects, Class<?> expectedAssignableType) {
 
         for (Object object : objects) {

src/main/java/io/lettuce/core/cluster/api/async/RedisClusterAsyncCommands.java

@@ -380,4 +380,11 @@ public interface RedisClusterAsyncCommands<K, V> extends BaseRedisAsyncCommands<
      */
     RedisFuture<String> readWrite();
 
+    /**
+     * Retrieves information about the TCP links between nodes in a Redis Cluster.
+     * 
+     * @return List of maps containing attributes and values for each peer link.
+     */
+    RedisFuture<List<Map<String, Object>>> clusterLinks();
+
 }

src/main/java/io/lettuce/core/cluster/api/reactive/RedisClusterReactiveCommands.java

@@ -21,6 +21,7 @@
 
 import java.time.Duration;
 import java.util.List;
+import java.util.Map;
 
 import io.lettuce.core.Range;
 import io.lettuce.core.api.reactive.*;
@@ -368,4 +369,11 @@ public interface RedisClusterReactiveCommands<K, V> extends BaseRedisReactiveCom
      */
     Mono<String> readWrite();
 
+    /**
+     * Retrieves information about the TCP links between nodes in a Redis Cluster.
+     * 
+     * @return List of maps containing attributes and values for each peer link.
+     */
+    Mono<List<Map<String, Object>>> clusterLinks();
+
 }

src/main/java/io/lettuce/core/cluster/api/sync/RedisClusterCommands.java

@@ -21,6 +21,7 @@
 
 import java.time.Duration;
 import java.util.List;
+import java.util.Map;
 
 import io.lettuce.core.Range;
 import io.lettuce.core.api.sync.*;
@@ -368,4 +369,11 @@ public interface RedisClusterCommands<K, V> extends BaseRedisCommands<K, V>, Red
     @Override
     String readWrite();
 
+    /**
+     * Retrieves information about the TCP links between nodes in a Redis Cluster.
+     * 
+     * @return List of maps containing attributes and values for each peer link.
+     */
+    List<Map<String, Object>> clusterLinks();
+
 }

src/main/java/io/lettuce/core/protocol/CommandKeyword.java

@@ -39,7 +39,7 @@ public enum CommandKeyword implements ProtocolKeyword {
 
     FAILOVER, FORGET, FIELDS, FLAGS, FLUSH, FORCE, FREQ, FLUSHSLOTS, GENPASS, GETNAME, GETUSER, GETKEYSINSLOT, GETREDIR, GROUP, GROUPS, HTSTATS, ID, IDLE, INFO,
 
-    IDLETIME, JUSTID, KILL, KEYSLOT, LEFT, LEN, LIMIT, LIST, LOAD, LOG, MATCH,
+    IDLETIME, JUSTID, KILL, KEYSLOT, LEFT, LEN, LIMIT, LINKS, LIST, LOAD, LOG, MATCH,
 
     MAX, MAXLEN, MEET, MIN, MINID, MOVED, NO, NOACK, NOCOMMANDS, NODE, NODES, NOMKSTREAM, NOPASS, NOSAVE, NOT, NOVALUES, NUMSUB, SHARDCHANNELS, SHARDNUMSUB, NUMPAT, NX, OFF, ON, ONE, OR, PAUSE, PREFIXES,
 

src/test/java/io/lettuce/core/RedisCommandBuilderUnitTests.java

@@ -7,6 +7,8 @@
 import org.junit.jupiter.api.Test;
 
 import java.nio.charset.StandardCharsets;
+import java.util.List;
+import java.util.Map;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -168,4 +170,14 @@ void shouldCorrectlyConstructClusterMyshardid() {
                 .isEqualTo("*2\r\n" + "$7\r\n" + "CLUSTER\r\n" + "$9\r\n" + "MYSHARDID\r\n");
     }
 
+    @Test
+    void shouldCorrectlyConstructClusterLinks() {
+
+        Command<String, String, List<Map<String, Object>>> command = sut.clusterLinks();
+        ByteBuf buf = Unpooled.directBuffer();
+        command.encode(buf);
+
+        assertThat(buf.toString(StandardCharsets.UTF_8)).isEqualTo("*2\r\n$7\r\nCLUSTER\r\n$5\r\nLINKS\r\n");
+    }
+
 }

src/test/java/io/lettuce/core/cluster/ClusterCommandIntegrationTests.java

@@ -5,6 +5,7 @@
 
 import java.time.Duration;
 import java.util.List;
+import java.util.Map;
 
 import javax.inject.Inject;
 
@@ -271,6 +272,26 @@ void clusterReplicas() {
         assertThat(result.size()).isGreaterThan(0);
     }
 
+    @Test
+    void testClusterLinks() {
+        List<Map<String, Object>> values = sync.clusterLinks();
+        assertThat(values).isNotEmpty();
+        for (Map<String, Object> value : values) {
+            assertThat(value).containsKeys("direction", "node", "create-time", "events", "send-buffer-allocated",
+                    "send-buffer-used");
+        }
+    }
+
+    @Test
+    void testClusterLinksAsync() throws Exception {
+        RedisFuture<List<Map<String, Object>>> futureLinks = async.clusterLinks();
+        List<Map<String, Object>> values = futureLinks.get();
+        for (Map<String, Object> value : values) {
+            assertThat(value).containsKeys("direction", "node", "create-time", "events", "send-buffer-allocated",
+                    "send-buffer-used");
+        }
+    }
+
     private void prepareReadonlyTest(String key) {
 
         async.set(key, value);

src/test/java/io/lettuce/core/cluster/ClusterReactiveCommandIntegrationTests.java

@@ -3,6 +3,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.List;
+import java.util.Map;
 
 import javax.inject.Inject;
 
@@ -97,4 +98,13 @@ void clusterSlaves() {
         assertThat(result.size()).isGreaterThan(0);
     }
 
+    @Test
+    void testClusterLinks() {
+        List<Map<String, Object>> values = reactive.clusterLinks().block();
+        for (Map<String, Object> value : values) {
+            assertThat(value).containsKeys("direction", "node", "create-time", "events", "send-buffer-allocated",
+                    "send-buffer-used");
+        }
+    }
+
 }