Add support for CLIENT TRACKINGINFO (#2862)

* Initial commit

* Added the CLIENT TRACKINGINFO command

* Implement the final version of the command, add parser utility

* Add some more unit tests. Polishing.

* Implemented dynamic parsing of the result returned from CLIENT TRACKINGINFO

* Fixed conflixt issues

* Addressed Ali's comment on calling the .getDynamicMap only once

* Circle back to using domain objects

* Missed several crucial files

* Remove part of the license that is not needed

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

@@ -389,6 +389,11 @@ public RedisFuture<String> clientTracking(TrackingArgs args) {
         return dispatch(commandBuilder.clientTracking(args));
     }
 
+    @Override
+    public RedisFuture<TrackingInfo> clientTrackinginfo() {
+        return dispatch(commandBuilder.clientTrackinginfo());
+    }
+
     @Override
     public RedisFuture<Long> clientUnblock(long id, UnblockType type) {
         return dispatch(commandBuilder.clientUnblock(id, type));

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

@@ -407,6 +407,11 @@ public Mono<String> clientTracking(TrackingArgs args) {
         return createMono(() -> commandBuilder.clientTracking(args));
     }
 
+    @Override
+    public Mono<TrackingInfo> clientTrackinginfo() {
+        return createMono(commandBuilder::clientTrackinginfo);
+    }
+
     @Override
     public Mono<Long> clientUnblock(long id, UnblockType type) {
         return createMono(() -> commandBuilder.clientUnblock(id, type));

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

@@ -528,6 +528,12 @@ Command<K, V, String> clientTracking(TrackingArgs trackingArgs) {
         return createCommand(CLIENT, new StatusOutput<>(codec), args);
     }
 
+    Command<K, V, TrackingInfo> clientTrackinginfo() {
+        CommandArgs<K, V> args = new CommandArgs<>(codec).add(TRACKINGINFO);
+
+        return new Command<>(CLIENT, new ComplexOutput<>(codec, TrackingInfoParser.INSTANCE), args);
+    }
+
     Command<K, V, Long> clientUnblock(long id, UnblockType type) {
         LettuceAssert.notNull(type, "UnblockType " + MUST_NOT_BE_NULL);
 

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

@@ -0,0 +1,165 @@
+/*
+ * Copyright 2024, Redis Ltd. and Contributors
+ * All rights reserved.
+ *
+ * Licensed under the MIT License.
+ */
+
+package io.lettuce.core;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Objects;
+import java.util.Set;
+import java.util.List;
+
+/**
+ * Contains the output of a <a href="https://redis.io/docs/latest/commands/client-trackinginfo/">CLIENT TRACKINGINFO</a>
+ * command.
+ *
+ * @author Tihomir Mateev
+ * @since 6.5
+ */
+public class TrackingInfo {
+
+    private final Set<TrackingFlag> flags = new HashSet<>();
+
+    private final long redirect;
+
+    private final List<String> prefixes = new ArrayList<>();
+
+    /**
+     * Constructor
+     * 
+     * @param flags a {@link Set} of {@link TrackingFlag}s that the command returned
+     * @param redirect the client ID used for notification redirection, -1 when none
+     * @param prefixes a {@link List} of key prefixes for which notifications are sent to the client
+     *
+     * @see TrackingFlag
+     */
+    public TrackingInfo(Set<TrackingFlag> flags, long redirect, List<String> prefixes) {
+        this.flags.addAll(flags);
+        this.redirect = redirect;
+        this.prefixes.addAll(prefixes);
+    }
+
+    /**
+     * @return set of all the {@link TrackingFlag}s currently enabled on the client connection
+     */
+    public Set<TrackingFlag> getFlags() {
+        return Collections.unmodifiableSet(flags);
+    }
+
+    /**
+     * @return the client ID used for notification redirection, -1 when none
+     */
+    public long getRedirect() {
+        return redirect;
+    }
+
+    /**
+     * @return a {@link List} of key prefixes for which notifications are sent to the client
+     */
+    public List<String> getPrefixes() {
+        return Collections.unmodifiableList(prefixes);
+    }
+
+    @Override
+    public String toString() {
+        return "TrackingInfo{" + "flags=" + flags + ", redirect=" + redirect + ", prefixes=" + prefixes + '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (o == null || getClass() != o.getClass())
+            return false;
+        TrackingInfo that = (TrackingInfo) o;
+        return redirect == that.redirect && Objects.equals(flags, that.flags) && Objects.equals(prefixes, that.prefixes);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(flags, redirect, prefixes);
+    }
+
+    /**
+     * CLIENT TRACKINGINFO flags
+     *
+     * @see <a href="https://redis.io/docs/latest/commands/client-trackinginfo/">CLIENT TRACKINGINFO</a>
+     */
+    public enum TrackingFlag {
+
+        /**
+         * The connection isn't using server assisted client side caching.
+         */
+        OFF,
+        /**
+         * Server assisted client side caching is enabled for the connection.
+         */
+        ON,
+        /**
+         * The client uses broadcasting mode.
+         */
+        BCAST,
+        /**
+         * The client does not cache keys by default.
+         */
+        OPTIN,
+        /**
+         * The client caches keys by default.
+         */
+        OPTOUT,
+        /**
+         * The next command will cache keys (exists only together with optin).
+         */
+        CACHING_YES,
+        /**
+         * The next command won't cache keys (exists only together with optout).
+         */
+        CACHING_NO,
+        /**
+         * The client isn't notified about keys modified by itself.
+         */
+        NOLOOP,
+        /**
+         * The client ID used for redirection isn't valid anymore.
+         */
+        BROKEN_REDIRECT;
+
+        /**
+         * Convert a given {@link String} flag to the corresponding {@link TrackingFlag}
+         * 
+         * @param flag a {@link String} representation of the flag
+         * @return the resulting {@link TrackingFlag} or {@link IllegalArgumentException} if unrecognized
+         */
+        public static TrackingFlag from(String flag) {
+            switch (flag.toLowerCase()) {
+                case "off":
+                    return OFF;
+                case "on":
+                    return ON;
+                case "bcast":
+                    return BCAST;
+                case "optin":
+                    return OPTIN;
+                case "optout":
+                    return OPTOUT;
+                case "caching-yes":
+                    return CACHING_YES;
+                case "caching-no":
+                    return CACHING_NO;
+                case "noloop":
+                    return NOLOOP;
+                case "broken_redirect":
+                    return BROKEN_REDIRECT;
+                default:
+                    throw new RuntimeException("Unsupported flag: " + flag);
+            }
+        }
+
+    }
+
+}

src/main/java/io/lettuce/core/api/async/RedisServerAsyncCommands.java

@@ -30,6 +30,7 @@
 import io.lettuce.core.ShutdownArgs;
 import io.lettuce.core.TrackingArgs;
 import io.lettuce.core.UnblockType;
+import io.lettuce.core.TrackingInfo;
 import io.lettuce.core.protocol.CommandType;
 
 /**
@@ -177,6 +178,14 @@ public interface RedisServerAsyncCommands<K, V> {
      */
     RedisFuture<String> clientTracking(TrackingArgs args);
 
+    /**
+     * Returns information about the current client connection's use of the server assisted client side caching feature.
+     *
+     * @return {@link TrackingInfo}, for more information check the documentation
+     * @since 6.5
+     */
+    RedisFuture<TrackingInfo> clientTrackinginfo();
+
     /**
      * Unblock the specified blocked client.
      *

src/main/java/io/lettuce/core/api/reactive/RedisServerReactiveCommands.java

@@ -28,6 +28,7 @@
 import io.lettuce.core.ShutdownArgs;
 import io.lettuce.core.TrackingArgs;
 import io.lettuce.core.UnblockType;
+import io.lettuce.core.TrackingInfo;
 import io.lettuce.core.protocol.CommandType;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -177,6 +178,14 @@ public interface RedisServerReactiveCommands<K, V> {
      */
     Mono<String> clientTracking(TrackingArgs args);
 
+    /**
+     * Returns information about the current client connection's use of the server assisted client side caching feature.
+     *
+     * @return {@link TrackingInfo}, for more information check the documentation
+     * @since 6.5
+     */
+    Mono<TrackingInfo> clientTrackinginfo();
+
     /**
      * Unblock the specified blocked client.
      *

src/main/java/io/lettuce/core/api/sync/RedisServerCommands.java

@@ -28,6 +28,7 @@
 import io.lettuce.core.KillArgs;
 import io.lettuce.core.ShutdownArgs;
 import io.lettuce.core.TrackingArgs;
+import io.lettuce.core.TrackingInfo;
 import io.lettuce.core.UnblockType;
 import io.lettuce.core.protocol.CommandType;
 
@@ -176,6 +177,14 @@ public interface RedisServerCommands<K, V> {
      */
     String clientTracking(TrackingArgs args);
 
+    /**
+     * Returns information about the current client connection's use of the server assisted client side caching feature.
+     *
+     * @return {@link TrackingInfo}, for more information check the documentation
+     * @since 6.5
+     */
+    TrackingInfo clientTrackinginfo();
+
     /**
      * Unblock the specified blocked client.
      *

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

@@ -19,15 +19,15 @@
  */
 package io.lettuce.core.cluster.api.async;
 
-import java.util.Date;
-import java.util.List;
 import java.util.Map;
-
+import java.util.List;
+import java.util.Date;
 import io.lettuce.core.ClientListArgs;
 import io.lettuce.core.FlushMode;
 import io.lettuce.core.KillArgs;
 import io.lettuce.core.TrackingArgs;
 import io.lettuce.core.UnblockType;
+import io.lettuce.core.TrackingInfo;
 import io.lettuce.core.protocol.CommandType;
 
 /**
@@ -175,6 +175,14 @@ public interface NodeSelectionServerAsyncCommands<K, V> {
      */
     AsyncExecutions<String> clientTracking(TrackingArgs args);
 
+    /**
+     * Returns information about the current client connection's use of the server assisted client side caching feature.
+     *
+     * @return {@link TrackingInfo}, for more information check the documentation
+     * @since 6.5
+     */
+    AsyncExecutions<TrackingInfo> clientTrackinginfo();
+
     /**
      * Unblock the specified blocked client.
      *

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

@@ -28,6 +28,7 @@
 import io.lettuce.core.KillArgs;
 import io.lettuce.core.TrackingArgs;
 import io.lettuce.core.UnblockType;
+import io.lettuce.core.TrackingInfo;
 import io.lettuce.core.protocol.CommandType;
 
 /**
@@ -163,7 +164,7 @@ public interface NodeSelectionServerCommands<K, V> {
      * @return simple-string-reply {@code OK} if the connection name was successfully set.
      * @since 6.3
      */
-    Executions<String> clientSetinfo(String key, V value);
+    Executions<String> clientSetinfo(String key, String value);
 
     /**
      * Enables the tracking feature of the Redis server, that is used for server assisted client side caching. Tracking messages
@@ -175,6 +176,14 @@ public interface NodeSelectionServerCommands<K, V> {
      */
     Executions<String> clientTracking(TrackingArgs args);
 
+    /**
+     * Returns information about the current client connection's use of the server assisted client side caching feature.
+     *
+     * @return {@link TrackingInfo}, for more information check the documentation
+     * @since 6.5
+     */
+    Executions<TrackingInfo> clientTrackinginfo();
+
     /**
      * Unblock the specified blocked client.
      *