[Hitless Upgrades] Zero-server-side configuration with client-side opt-in (redis#3380)

* Support for Client-side opt-in

 A client can tell the server if it wants to receive maintenance push notifications via the following command:

 CLIENT MAINT_NOTIFICATIONS <ON | OFF> [parameter value parameter value ...]

* update maintenance events to latest format

 - MIGRATING <seq_number> <time> <shard_id-s>: A shard migration is going to start within <time> seconds.
 - MIGRATED <seq_number> <shard_id-s>: A shard migration ended.
 - FAILING_OVER <seq_number> <time> <shard_id-s>: A shard failover of a healthy shard started.
 - FAILED_OVER <seq_number> <shard_id-s>: A shard failover of a healthy shard ended.
 - MOVING <seq_number> <time> <endpoint>: A specific endpoint is going to move to another node within <time> seconds

* clean up

* Update FAILED_OVER & MIGRATED to include additional time field

* update is private reserver check & add unit tests

update is private reserver check

* add unit tests for handshake with enabled maintenance events

* add missing copyrights/docs

* format

* address review comments

* Revert address after rebind operation expires

* Update event's validation spec

  - MIGRATING <seq_number> <time> <shard_id-s>: A shard migration is going to start within <time> seconds.
  - MIGRATED <seq_number> <shard_id-s>: A shard migration ended.
  - FAILING_OVER <seq_number> <time> <shard_id-s>: A shard failover of a healthy shard started.
  - FAILED_OVER <seq_number> <shard_id-s>: A shard failover of a healthy shard ended.
  - MOVING <seq_number> <time> <endpoint>: A specific endpoint is going to move to another node within <time> seconds

* rebase

* format after rebase

* Apply suggestions from code review

Co-authored-by: Tihomir Krasimirov Mateev <tihomir.mateev@redis.com>

* javadoc updated

* Update src/main/java/io/lettuce/core/internal/NetUtils.java

Co-authored-by: Tihomir Krasimirov Mateev <tihomir.mateev@redis.com>

---------

Co-authored-by: Tihomir Krasimirov Mateev <tihomir.mateev@redis.com>

Author: ggivo

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

@@ -20,6 +20,8 @@
 package io.lettuce.core;
 
 import java.io.Closeable;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 import java.time.Duration;
 import java.util.ArrayList;
@@ -34,6 +36,7 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 
+import io.lettuce.core.MaintenanceEventsOptions.AddressTypeSource;
 import reactor.core.publisher.Mono;
 import io.lettuce.core.event.command.CommandListener;
 import io.lettuce.core.event.connection.ConnectEvent;
@@ -629,8 +632,16 @@ private CompletableFuture<Void> closeClientResources(long quietPeriod, long time
     }
 
     protected RedisHandshake createHandshake(ConnectionState state) {
+        AddressTypeSource source = null;
+        if (clientOptions.getMaintenanceEventsOptions().supportsMaintenanceEvents()) {
+            LettuceAssert.notNull(clientOptions.getMaintenanceEventsOptions().getAddressTypeSource(),
+                    "Address type source must not be null");
+
+            source = clientOptions.getMaintenanceEventsOptions().getAddressTypeSource();
+        }
+
         return new RedisHandshake(clientOptions.getConfiguredProtocolVersion(), clientOptions.isPingBeforeActivateConnection(),
-                state);
+                state, source);
     }
 
 }

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

@@ -52,7 +52,7 @@ public class ClientOptions implements Serializable {
 
     public static final boolean DEFAULT_AUTO_RECONNECT = true;
 
-    public static final boolean DEFAULT_SUPPORT_MAINTENANCE_EVENTS = false;
+    public static final MaintenanceEventsOptions DEFAULT_MAINTENANCE_EVENTS_OPTIONS = MaintenanceEventsOptions.disabled();
 
     public static final Predicate<RedisCommand<?, ?, ?>> DEFAULT_REPLAY_FILTER = (cmd) -> false;
 
@@ -98,7 +98,7 @@ public class ClientOptions implements Serializable {
 
     private final boolean autoReconnect;
 
-    private final boolean supportMaintenanceEvents;
+    private final MaintenanceEventsOptions maintenanceEventsOptions;
 
     private final Predicate<RedisCommand<?, ?, ?>> replayFilter;
 
@@ -136,7 +136,7 @@ public class ClientOptions implements Serializable {
 
     protected ClientOptions(Builder builder) {
         this.autoReconnect = builder.autoReconnect;
-        this.supportMaintenanceEvents = builder.supportMaintenanceEvents;
+        this.maintenanceEventsOptions = builder.maintenanceEventsOptions;
         this.replayFilter = builder.replayFilter;
         this.cancelCommandsOnReconnectFailure = builder.cancelCommandsOnReconnectFailure;
         this.decodeBufferPolicy = builder.decodeBufferPolicy;
@@ -158,7 +158,7 @@ protected ClientOptions(Builder builder) {
 
     protected ClientOptions(ClientOptions original) {
         this.autoReconnect = original.isAutoReconnect();
-        this.supportMaintenanceEvents = original.supportsMaintenanceEvents();
+        this.maintenanceEventsOptions = original.getMaintenanceEventsOptions();
         this.replayFilter = original.getReplayFilter();
         this.cancelCommandsOnReconnectFailure = original.isCancelCommandsOnReconnectFailure();
         this.decodeBufferPolicy = original.getDecodeBufferPolicy();
@@ -213,7 +213,7 @@ public static class Builder {
 
         private boolean autoReconnect = DEFAULT_AUTO_RECONNECT;
 
-        private boolean supportMaintenanceEvents = DEFAULT_SUPPORT_MAINTENANCE_EVENTS;
+        private MaintenanceEventsOptions maintenanceEventsOptions = DEFAULT_MAINTENANCE_EVENTS_OPTIONS;
 
         private Predicate<RedisCommand<?, ?, ?>> replayFilter = DEFAULT_REPLAY_FILTER;
 
@@ -268,14 +268,14 @@ public Builder autoReconnect(boolean autoReconnect) {
          * Configure whether the driver should listen for server events that notify on current maintenance activities. When
          * enabled, this option will help with the connection handover and reduce the number of failed commands. This feature
          * requires the server to support maintenance events. Defaults to {@code false}. See
-         * {@link #DEFAULT_SUPPORT_MAINTENANCE_EVENTS}.
+         * {@link #DEFAULT_MAINTENANCE_EVENTS_OPTIONS}.
          *
-         * @param supportEvents true/false
+         * @param maintenanceEventsOptions true/false
          * @return {@code this}
          * @since 7.0
          */
-        public Builder supportMaintenanceEvents(boolean supportEvents) {
-            this.supportMaintenanceEvents = supportEvents;
+        public Builder supportMaintenanceEvents(MaintenanceEventsOptions maintenanceEventsOptions) {
+            this.maintenanceEventsOptions = maintenanceEventsOptions;
             return this;
         }
 
@@ -574,7 +574,7 @@ public ClientOptions build() {
     public ClientOptions.Builder mutate() {
         Builder builder = new Builder();
 
-        builder.autoReconnect(isAutoReconnect()).supportMaintenanceEvents(supportsMaintenanceEvents())
+        builder.autoReconnect(isAutoReconnect()).supportMaintenanceEvents(getMaintenanceEventsOptions())
                 .cancelCommandsOnReconnectFailure(isCancelCommandsOnReconnectFailure()).replayFilter(getReplayFilter())
                 .decodeBufferPolicy(getDecodeBufferPolicy()).disconnectedBehavior(getDisconnectedBehavior())
                 .reauthenticateBehavior(getReauthenticateBehaviour()).readOnlyCommands(getReadOnlyCommands())
@@ -601,15 +601,15 @@ public boolean isAutoReconnect() {
     }
 
     /**
-     * Returns whether the client supports maintenance events.
+     * Returns the {@link MaintenanceEventsOptions} to listen for server events that notify on current maintenance activities.
      *
-     * @return {@code true} if maintenance events are supported.
+     * @return {@link MaintenanceEventsOptions}
      * @since 7.0
-     * @see #DEFAULT_SUPPORT_MAINTENANCE_EVENTS
-     * @see #supportsMaintenanceEvents()
+     * @see #DEFAULT_MAINTENANCE_EVENTS_OPTIONS
+     * @see #getMaintenanceEventsOptions()
      */
-    public boolean supportsMaintenanceEvents() {
-        return supportMaintenanceEvents;
+    public MaintenanceEventsOptions getMaintenanceEventsOptions() {
+        return maintenanceEventsOptions;
     }
 
     /**

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

@@ -155,7 +155,7 @@ protected ConnectionWatchdog createConnectionWatchdog() {
         LettuceAssert.assertState(socketAddressSupplier != null, "SocketAddressSupplier must be set for autoReconnect=true");
 
         ConnectionWatchdog watchdog;
-        if (clientOptions.supportsMaintenanceEvents()) {
+        if (clientOptions.getMaintenanceEventsOptions().supportsMaintenanceEvents()) {
             watchdog = new MaintenanceAwareConnectionWatchdog(clientResources.reconnectDelay(), clientOptions, bootstrap,
                     clientResources.timer(), clientResources.eventExecutorGroup(), socketAddressSupplier, reconnectionListener,
                     connection, clientResources.eventBus(), endpoint);

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

@@ -11,6 +11,8 @@ class ConnectionMetadata {
 
     private volatile String libraryVersion;
 
+    private volatile boolean sslEnabled;
+
     public ConnectionMetadata() {
     }
 
@@ -23,13 +25,15 @@ public void apply(RedisURI redisURI) {
         setClientName(redisURI.getClientName());
         setLibraryName(redisURI.getLibraryName());
         setLibraryVersion(redisURI.getLibraryVersion());
+        setSslEnabled(redisURI.isSsl());
     }
 
     public void apply(ConnectionMetadata metadata) {
 
         setClientName(metadata.getClientName());
         setLibraryName(metadata.getLibraryName());
         setLibraryVersion(metadata.getLibraryVersion());
+        setSslEnabled(metadata.isSslEnabled());
     }
 
     protected void setClientName(String clientName) {
@@ -56,4 +60,12 @@ String getLibraryVersion() {
         return libraryVersion;
     }
 
+    boolean isSslEnabled() {
+        return sslEnabled;
+    }
+
+    void setSslEnabled(boolean sslEnabled) {
+        this.sslEnabled = sslEnabled;
+    }
+
 }