Add support for sharded PubSub (#2373)

* refactor pubsub, add support for sharded pub sub

* run tests in redis 7 only, fix PUBSUB SHARDCHANNELS test

* add some comments and fix some bugs

* PubSubType, not PubSubTypes 🤦‍♂️

* remove test.txt

* fix some bugs, add tests

* add some tests

* fix #2345 - allow PING in PubSub mode (remove client side validation)

* remove .only

* revert changes in cluster/index.ts

* fix tests minimum version

* handle server sunsubscribe

* add 'sharded-channel-moved' event to docs, improve the events section in the main README (fix #2302)

* exit "resubscribe" if pubsub not active

* Update commands-queue.ts

* Release client@1.5.0-rc.0

* WIP

* use `node:util` instead of `node:util/types` (to support node 14)

* run PubSub resharding test with Redis 7+

* fix inconsistency in live resharding test

* add some tests

* fix iterateAllNodes when starting from a replica

* fix iterateAllNodes random

* fix slotNodesIterator

* fix slotNodesIterator

* clear pubSubNode when node in use

* wait for all nodes cluster state to be ok before testing

* `cluster.minimizeConections` tests

* `client.reconnectStrategry = false | 0` tests

* sharded pubsub + cluster 🎉

* add minimum version to sharded pubsub tests

* add cluster sharded pubsub live reshard test, use stable dockers for tests, make sure to close pubsub clients when a node disconnects from the cluster

* fix "ssubscribe & sunsubscribe" test

* lock search docker to 2.4.9

* change numberOfMasters default to 2

* use edge for bloom

* add tests

* add back getMasters and getSlotMaster as deprecated functions

* add some tests

* fix reconnect strategy + docs

* sharded pubsub docs

* Update pub-sub.md

* some jsdoc, docs, cluster topology test

* clean pub-sub docs

Co-authored-by: Simon Prickett <simon@redislabs.com>

* reconnect startegy docs and bug fix

Co-authored-by: Simon Prickett <simon@redislabs.com>

* refine jsdoc and some docs

Co-authored-by: Simon Prickett <simon@redislabs.com>

* I'm stupid

* fix cluster topology test

* fix cluster topology test

* Update README.md

* Update clustering.md

* Update pub-sub.md

Co-authored-by: Simon Prickett <simon@redislabs.com>

README.md

@@ -166,47 +166,7 @@ To learn more about isolated execution, check out the [guide](./docs/isolated-ex
 
 ### Pub/Sub
 
-Subscribing to a channel requires a dedicated stand-alone connection. You can easily get one by `.duplicate()`ing an existing Redis connection.
+See the [Pub/Sub overview](./docs/pub-sub.md).
-
-```typescript
-const subscriber = client.duplicate();
-
-await subscriber.connect();
-```
-
-Once you have one, simply subscribe and unsubscribe as needed:
-
-```typescript
-await subscriber.subscribe('channel', (message) => {
-  console.log(message); // 'message'
-});
-
-await subscriber.pSubscribe('channe*', (message, channel) => {
-  console.log(message, channel); // 'message', 'channel'
-});
-
-await subscriber.unsubscribe('channel');
-
-await subscriber.pUnsubscribe('channe*');
-```
-
-Publish a message on a channel:
-
-```typescript
-await publisher.publish('channel', 'message');
-```
-
-There is support for buffers as well:
-
-```typescript
-await subscriber.subscribe('channel', (message) => {
-  console.log(message); // <Buffer 6d 65 73 73 61 67 65>
-}, true);
-
-await subscriber.pSubscribe('channe*', (message, channel) => {
-  console.log(message, channel); // <Buffer 6d 65 73 73 61 67 65>, <Buffer 63 68 61 6e 6e 65 6c>
-}, true);
-```
 
 ### Scan Iterator
 
@@ -373,15 +333,18 @@ Check out the [Clustering Guide](./docs/clustering.md) when using Node Redis to
 
 The Node Redis client class is an Nodejs EventEmitter and it emits an event each time the network status changes:
 
-| Event name     | Scenes                                                                                                            | Arguments to be passed to the listener                                                                                                         |
+| Name                    | When                                                                               | Listener arguments                                         |
-|----------------|-------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------|
+|-------------------------|------------------------------------------------------------------------------------|------------------------------------------------------------|
-| `connect`      | The client is initiating a connection to the server.                                                              | _No argument_                                                                                                                                  |
+| `connect`               | Initiating a connection to the server                                              | *No arguments*                                             |
-| `ready`        | The client successfully initiated the connection to the server.                                                   | _No argument_                                                                                                                                  |
+| `ready`                 | Client is ready to use                                                             | *No arguments*                                             |
-| `end`          | The client disconnected the connection to the server via `.quit()` or `.disconnect()`.                            | _No argument_                                                                                                                                  |
+| `end`                   | Connection has been closed (via `.quit()` or `.disconnect()`)                      | *No arguments*                                             |
-| `error`        | When a network error has occurred, such as unable to connect to the server or the connection closed unexpectedly. | 1 argument: The error object, such as `SocketClosedUnexpectedlyError: Socket closed unexpectedly` or `Error: connect ECONNREFUSED [IP]:[PORT]` |
+| `error`                 | An error has occurred—usually a network issue such as "Socket closed unexpectedly" | `(error: Error)`                                           |
-| `reconnecting` | The client is trying to reconnect to the server.                                                                  | _No argument_                                                                                                                                  |
+| `reconnecting`          | Client is trying to reconnect to the server                                        | *No arguments*                                             |
+| `sharded-channel-moved` | See [here](./docs/pub-sub.md#sharded-channel-moved-event)                          | See  [here](./docs/pub-sub.md#sharded-channel-moved-event) |
 
-The client will not emit [any other events](./docs/v3-to-v4.md#all-the-removed-events) beyond those listed above.
+> :warning: You **MUST** listen to `error` events. If a client doesn't have at least one `error` listener registered and an `error` occurs, that error will be thrown and the Node.js process will exit. See the [`EventEmitter` docs](https://nodejs.org/api/events.html#events_error_events) for more details.
+
+> The client will not emit [any other events](./docs/v3-to-v4.md#all-the-removed-events) beyond those listed above.
 
 ## Supported Redis versions
 

docs/client-configuration.md

@@ -15,7 +15,7 @@
 | socket.reconnectStrategy | `retries => Math.min(retries * 50, 500)` | A function containing the [Reconnect Strategy](#reconnect-strategy) logic                                                                                                                                                                           |
 | username                 |                                          | ACL username ([see ACL guide](https://redis.io/topics/acl))                                                                                                                                                                                         |
 | password                 |                                          | ACL password or the old "--requirepass" password                                                                                                                                                                                                    |
-| name                     |                                          | Connection name ([see `CLIENT SETNAME`](https://redis.io/commands/client-setname))                                                                                                                                                                  |
+| name                     |                                          | Client name ([see `CLIENT SETNAME`](https://redis.io/commands/client-setname))                                                                                                                                                                      |
 | database                 |                                          | Redis database number (see [`SELECT`](https://redis.io/commands/select) command)                                                                                                                                                                    |
 | modules                  |                                          | Included [Redis Modules](../README.md#packages)                                                                                                                                                                                                     |
 | scripts                  |                                          | Script definitions (see [Lua Scripts](../README.md#lua-scripts))                                                                                                                                                                                    |
@@ -25,29 +25,21 @@
 | readonly                 | `false`                                  | Connect in [`READONLY`](https://redis.io/commands/readonly) mode                                                                                                                                                                                    |
 | legacyMode               | `false`                                  | Maintain some backwards compatibility (see the [Migration Guide](./v3-to-v4.md))                                                                                                                                                                    |
 | isolationPoolOptions     |                                          | See the [Isolated Execution Guide](./isolated-execution.md)                                                                                                                                                                                         |
-| pingInterval             |                                          | Send `PING` command at interval (in ms). Useful with "[Azure Cache for Redis](https://learn.microsoft.com/en-us/azure/azure-cache-for-redis/cache-best-practices-connection#idle-timeout)"                                                          |
+| pingInterval             |                                          | Send `PING` command at interval (in ms). Useful with ["Azure Cache for Redis"](https://learn.microsoft.com/en-us/azure/azure-cache-for-redis/cache-best-practices-connection#idle-timeout)                                                          |
 
 ## Reconnect Strategy
 
-When a network error occurs the client will automatically try to reconnect, following a default linear strategy (the more attempts, the more waiting before trying to reconnect).
+When the socket closes unexpectedly (without calling `.quit()`/`.disconnect()`), the client uses `reconnectStrategy` to decide what to do. The following values are supported:
+1. `false` -> do not reconnect, close the client and flush the command queue.
+2. `number` -> wait for `X` milliseconds before reconnecting.
+3. `(retries: number, cause: Error) => false | number | Error` -> `number` is the same as configuring a `number` directly, `Error` is the same as `false`, but with a custom error.
 
-This strategy can be overridden by providing a `socket.reconnectStrategy` option during the client's creation.
+By default the strategy is `Math.min(retries * 50, 500)`, but it can be overwritten like so:
 
-The `socket.reconnectStrategy` is a function that:
+```javascript
-
+createClient({
-- Receives the number of retries attempted so far.
-- Returns `number | Error`:
-    - `number`: wait time in milliseconds prior to attempting a reconnect.
-    - `Error`: closes the client and flushes internal command queues.
-
-The example below shows the default `reconnectStrategy` and how to override it.
-
-```typescript
-import { createClient } from 'redis';
-
-const client = createClient({
   socket: {
-        reconnectStrategy: (retries) => Math.min(retries * 50, 500)
+    reconnectStrategy: retries => Math.min(retries * 50, 1000)
   }
 });
 ```
@@ -60,7 +52,7 @@ To enable TLS, set `socket.tls` to `true`. Below are some basic examples.
 
 ### Create a SSL client
 
-```typescript
+```javascript
 createClient({
   socket: {
     tls: true,
@@ -72,7 +64,7 @@ createClient({
 
 ### Create a SSL client using a self-signed certificate
 
-```typescript
+```javascript
 createClient({
   socket: {
     tls: true,

docs/clustering.md

@@ -35,6 +35,7 @@ const value = await cluster.get('key');
 | rootNodes              |         | An array of root nodes that are part of the cluster, which will be used to get the cluster topology. Each element in the array is a client configuration object. There is no need to specify every node in the cluster, 3 should be enough to reliably connect and obtain the cluster configuration from the server |
 | defaults               |         | The default configuration values for every client in the cluster.  Use this for example when specifying an ACL user to connect with                                                                                                                                                                                 |
 | useReplicas            | `false` | When `true`, distribute load by executing readonly commands (such as `GET`, `GEOSEARCH`, etc.) across all cluster nodes. When `false`, only use master nodes                                                                                                                                                        |
+| minimizeConnections    | `false` | When `true`, `.connect()` will only discover the cluster topology, without actually connecting to all the nodes. Useful for short-term or Pub/Sub-only connections.                                                                                                                                                 |
 | maxCommandRedirections | `16`    | The maximum number of times a command will be redirected due to `MOVED` or `ASK` errors                                                                                                                                                                                                                             |
 | nodeAddressMap         |         | Defines the [node address mapping](#node-address-map)                                                                                                                                                                                                                                                               |
 | modules                |         | Included [Redis Modules](../README.md#packages)                                                                                                                                                                                                                                                                     |
@@ -59,27 +60,45 @@ createCluster({
 
 ## Node Address Map
 
-A node address map is required when a Redis cluster is configured with addresses that are inaccessible by the machine running the Redis client.
+A mapping between the addresses in the cluster (see `CLUSTER SHARDS`) and the addresses the client should connect to.
-This is a mapping of addresses and ports, with the values being the accessible address/port combination. Example:
+Useful when the cluster is running on a different network to the client.
 
 ```javascript
-createCluster({
+const rootNodes = [{
-  rootNodes: [{
   url: 'external-host-1.io:30001'
 }, {
   url: 'external-host-2.io:30002'
-  }],
+}];
+
+// Use either a static mapping:
+createCluster({
+  rootNodes,
   nodeAddressMap: {
     '10.0.0.1:30001': {
-      host: 'external-host-1.io',
+      host: 'external-host.io',
       port: 30001
     },
     '10.0.0.2:30002': {
-      host: 'external-host-2.io',
+      host: 'external-host.io',
       port: 30002
     }
   }
 });
+
+// or create the mapping dynamically, as a function:
+createCluster({
+  rootNodes,
+  nodeAddressMap(address) {
+    const indexOfDash = address.lastIndexOf('-'),
+      indexOfDot = address.indexOf('.', indexOfDash),
+      indexOfColons = address.indexOf(':', indexOfDot);
+    
+    return {
+      host: `external-host-${address.substring(indexOfDash + 1, indexOfDot)}.io`,
+      port: Number(address.substring(indexOfColons + 1))
+    };
+  }
+});
 ```
 
 > This is a common problem when using ElastiCache. See [Accessing ElastiCache from outside AWS](https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/accessing-elasticache.html) for more information on that.

docs/pub-sub.md

@@ -0,0 +1,86 @@
+# Pub/Sub
+
+The Pub/Sub API is implemented by `RedisClient` and `RedisCluster`.
+
+## Pub/Sub with `RedisClient`
+
+Pub/Sub requires a dedicated stand-alone client. You can easily get one by `.duplicate()`ing an existing `RedisClient`:
+
+```typescript
+const subscriber = client.duplicate();
+subscribe.on('error', err => console.error(err));
+await subscriber.connect();
+```
+
+When working with a `RedisCluster`, this is handled automatically for you.
+
+### `sharded-channel-moved` event
+
+`RedisClient` emits the `sharded-channel-moved` event when the ["cluster slot"](https://redis.io/docs/reference/cluster-spec/#key-distribution-model) of a subscribed [Sharded Pub/Sub](https://redis.io/docs/manual/pubsub/#sharded-pubsub) channel has been moved to another shard.
+
+The event listener signature is as follows:
+```typescript
+(
+  channel: string,
+  listeners: {
+    buffers: Set<Listener>;
+    strings: Set<Listener>;
+  }
+)`.
+```
+
+## Subscribing
+
+```javascript
+const listener = (message, channel) => console.log(message, channel);
+await client.subscribe('channel', listener);
+await client.pSubscribe('channe*', listener);
+// Use sSubscribe for sharded Pub/Sub:
+await client.sSubscribe('channel', listener);
+```
+
+## Publishing
+
+```javascript
+await client.publish('channel', 'message');
+// Use sPublish for sharded Pub/Sub:
+await client.sPublish('channel', 'message');
+```
+
+## Unsubscribing
+
+The code below unsubscribes all listeners from all channels.
+
+```javascript
+await client.unsubscribe();
+await client.pUnsubscribe();
+// Use sUnsubscribe for sharded Pub/Sub:
+await client.sUnsubscribe();
+```
+
+To unsubscribe from specific channels:
+
+```javascript
+await client.unsubscribe('channel');
+await client.unsubscribe(['1', '2']);
+```
+
+To unsubscribe a specific listener:
+
+```javascript
+await client.unsubscribe('channel', listener);
+```
+
+## Buffers
+
+Publishing and subscribing using `Buffer`s is also supported:
+
+```javascript
+await subscriber.subscribe('channel', message => {
+  console.log(message); // <Buffer 6d 65 73 73 61 67 65>
+}, true); // true = subscribe in `Buffer` mode.
+
+await subscriber.publish(Buffer.from('channel'), Buffer.from('message'));
+```
+
+> NOTE: Buffers and strings are supported both for the channel name and the message. You can mix and match these as desired.

packages/client/lib/client/commands-queue.ts

@@ -1,18 +1,18 @@
 import * as LinkedList from 'yallist';
 import { AbortError, ErrorReply } from '../errors';
-import { RedisCommandArgument, RedisCommandArguments, RedisCommandRawReply } from '../commands';
+import { RedisCommandArguments, RedisCommandRawReply } from '../commands';
 import RESP2Decoder from './RESP2/decoder';
 import encodeCommand from './RESP2/encoder';
+import { ChannelListeners, PubSub, PubSubCommand, PubSubListener, PubSubType, PubSubTypeListeners } from './pub-sub';
 
 export interface QueueCommandOptions {
     asap?: boolean;
     chainId?: symbol;
     signal?: AbortSignal;
     returnBuffers?: boolean;
-    ignorePubSubMode?: boolean;
 }
 
-interface CommandWaitingToBeSent extends CommandWaitingForReply {
+export interface CommandWaitingToBeSent extends CommandWaitingForReply {
     args: RedisCommandArguments;
     chainId?: symbol;
     abort?: {
@@ -28,27 +28,9 @@ interface CommandWaitingForReply {
     returnBuffers?: boolean;
 }
 
-export enum PubSubSubscribeCommands {
+const PONG = Buffer.from('pong');
-    SUBSCRIBE = 'SUBSCRIBE',
-    PSUBSCRIBE = 'PSUBSCRIBE'
-}
 
-export enum PubSubUnsubscribeCommands {
+export type OnShardedChannelMoved = (channel: string, listeners: ChannelListeners) => void;
-    UNSUBSCRIBE = 'UNSUBSCRIBE',
-    PUNSUBSCRIBE = 'PUNSUBSCRIBE'
-}
-
-export type PubSubListener<
-    RETURN_BUFFERS extends boolean = false,
-    T = RETURN_BUFFERS extends true ? Buffer : string
-> = (message: T, channel: T) => unknown;
-
-interface PubSubListeners {
-    buffers: Set<PubSubListener<true>>;
-    strings: Set<PubSubListener<false>>;
-}
-
-type PubSubListenersMap = Map<string, PubSubListeners>;
 
 export default class RedisCommandsQueue {
     static #flushQueue<T extends CommandWaitingForReply>(queue: LinkedList<T>, err: Error): void {
@@ -57,65 +39,52 @@ export default class RedisCommandsQueue {
         }
     }
 
-    static #emitPubSubMessage(listenersMap: PubSubListenersMap, message: Buffer, channel: Buffer, pattern?: Buffer): void {
-        const keyString = (pattern ?? channel).toString(),
-            listeners = listenersMap.get(keyString);
-
-        if (!listeners) return;
-
-        for (const listener of listeners.buffers) {
-            listener(message, channel);
-        }
-
-        if (!listeners.strings.size) return;
-
-        const channelString = pattern ? channel.toString() : keyString,
-            messageString = channelString === '__redis__:invalidate' ?
-                // https://github.com/redis/redis/pull/7469
-                // https://github.com/redis/redis/issues/7463
-                (message === null ? null : (message as any as Array<Buffer>).map(x => x.toString())) as any :
-                message.toString();
-        for (const listener of listeners.strings) {
-            listener(messageString, channelString);
-        }
-    }
-
     readonly #maxLength: number | null | undefined;
     readonly #waitingToBeSent = new LinkedList<CommandWaitingToBeSent>();
     readonly #waitingForReply = new LinkedList<CommandWaitingForReply>();
+    readonly #onShardedChannelMoved: OnShardedChannelMoved;
 
-    readonly #pubSubState = {
+    readonly #pubSub = new PubSub();
-        isActive: false,
+
-        subscribing: 0,
+    get isPubSubActive() {
-        subscribed: 0,
+        return this.#pubSub.isActive;
-        unsubscribing: 0,
-        listeners: {
-            channels: new Map(),
-            patterns: new Map()
     }
-    };
-
-    static readonly #PUB_SUB_MESSAGES = {
-        message: Buffer.from('message'),
-        pMessage: Buffer.from('pmessage'),
-        subscribe: Buffer.from('subscribe'),
-        pSubscribe: Buffer.from('psubscribe'),
-        unsubscribe: Buffer.from('unsubscribe'),
-        pUnsubscribe: Buffer.from('punsubscribe')
-    };
 
     #chainInExecution: symbol | undefined;
 
     #decoder = new RESP2Decoder({
         returnStringsAsBuffers: () => {
             return !!this.#waitingForReply.head?.value.returnBuffers ||
-                this.#pubSubState.isActive;
+                this.#pubSub.isActive;
         },
         onReply: reply => {
-            if (this.#handlePubSubReply(reply)) {
+            if (this.#pubSub.isActive && Array.isArray(reply)) {
+                if (this.#pubSub.handleMessageReply(reply as Array<Buffer>)) return;
+                
+                const isShardedUnsubscribe = PubSub.isShardedUnsubscribe(reply as Array<Buffer>);
+                if (isShardedUnsubscribe && !this.#waitingForReply.length) {
+                    const channel = (reply[1] as Buffer).toString();
+                    this.#onShardedChannelMoved(
+                        channel,
+                        this.#pubSub.removeShardedListeners(channel)
+                    );
                     return;
-            } else if (!this.#waitingForReply.length) {
+                } else if (isShardedUnsubscribe || PubSub.isStatusReply(reply as Array<Buffer>)) {
-                throw new Error('Got an unexpected reply from Redis');
+                    const head = this.#waitingForReply.head!.value;
+                    if (
+                        (Number.isNaN(head.channelsCounter!) && reply[2] === 0) ||
+                        --head.channelsCounter! === 0
+                    ) {
+                        this.#waitingForReply.shift()!.resolve();
+                    }
+                    return;
+                }
+                if (PONG.equals(reply[0] as Buffer)) {
+                    const { resolve, returnBuffers } = this.#waitingForReply.shift()!,
+                        buffer = ((reply[1] as Buffer).length === 0 ? reply[0] : reply[1]) as Buffer;
+                    resolve(returnBuffers ? buffer : buffer.toString());
+                    return;
+                }
             }
             
             const { resolve, reject } = this.#waitingForReply.shift()!;
@@ -127,14 +96,16 @@ export default class RedisCommandsQueue {
         }
     });
 
-    constructor(maxLength: number | null | undefined) {
+    constructor(
+        maxLength: number | null | undefined,
+        onShardedChannelMoved: OnShardedChannelMoved
+    ) {
         this.#maxLength = maxLength;
+        this.#onShardedChannelMoved = onShardedChannelMoved;
     }
 
     addCommand<T = RedisCommandRawReply>(args: RedisCommandArguments, options?: QueueCommandOptions): Promise<T> {
-        if (this.#pubSubState.isActive && !options?.ignorePubSubMode) {
+        if (this.#maxLength && this.#waitingToBeSent.length + this.#waitingForReply.length >= this.#maxLength) {
-            return Promise.reject(new Error('Cannot send commands in PubSub mode'));
-        } else if (this.#maxLength && this.#waitingToBeSent.length + this.#waitingForReply.length >= this.#maxLength) {
             return Promise.reject(new Error('The queue is full'));
         } else if (options?.signal?.aborted) {
             return Promise.reject(new AbortError());
@@ -173,158 +144,76 @@ export default class RedisCommandsQueue {
     }
 
     subscribe<T extends boolean>(
-        command: PubSubSubscribeCommands,
+        type: PubSubType,
-        channels: RedisCommandArgument | Array<RedisCommandArgument>,
+        channels: string | Array<string>,
         listener: PubSubListener<T>,
         returnBuffers?: T
-    ): Promise<void> {
+    ) {
-        const channelsToSubscribe: Array<RedisCommandArgument> = [],
+        return this.#pushPubSubCommand(
-            listenersMap = command === PubSubSubscribeCommands.SUBSCRIBE ?
+            this.#pubSub.subscribe(type, channels, listener, returnBuffers)
-                this.#pubSubState.listeners.channels :
+        );
-                this.#pubSubState.listeners.patterns;
-        for (const channel of (Array.isArray(channels) ? channels : [channels])) {
-            const channelString = typeof channel === 'string' ? channel : channel.toString();
-            let listeners = listenersMap.get(channelString);
-            if (!listeners) {
-                listeners = {
-                    buffers: new Set(),
-                    strings: new Set()
-                };
-                listenersMap.set(channelString, listeners);
-                channelsToSubscribe.push(channel);
-            }
-
-            // https://github.com/microsoft/TypeScript/issues/23132
-            (returnBuffers ? listeners.buffers : listeners.strings).add(listener as any);
-        }
-
-        if (!channelsToSubscribe.length) {
-            return Promise.resolve();
-        }
-
-        return this.#pushPubSubCommand(command, channelsToSubscribe);
     }
 
     unsubscribe<T extends boolean>(
-        command: PubSubUnsubscribeCommands,
+        type: PubSubType,
         channels?: string | Array<string>,
         listener?: PubSubListener<T>,
         returnBuffers?: T
-    ): Promise<void> {
+    ) {
-        const listeners = command === PubSubUnsubscribeCommands.UNSUBSCRIBE ?
+        return this.#pushPubSubCommand(
-            this.#pubSubState.listeners.channels :
+            this.#pubSub.unsubscribe(type, channels, listener, returnBuffers)
-            this.#pubSubState.listeners.patterns;
+        );
-
-        if (!channels) {
-            const size = listeners.size;
-            listeners.clear();
-            return this.#pushPubSubCommand(command, size);
     }
 
-        const channelsToUnsubscribe = [];
+    resubscribe(): Promise<any> | undefined {
-        for (const channel of (Array.isArray(channels) ? channels : [channels])) {
+        const commands = this.#pubSub.resubscribe();
-            const sets = listeners.get(channel);
+        if (!commands.length) return;
-            if (!sets) continue;
 
-            let shouldUnsubscribe;
+        return Promise.all(
-            if (listener) {
+            commands.map(command => this.#pushPubSubCommand(command))
-                // https://github.com/microsoft/TypeScript/issues/23132
+        );
-                (returnBuffers ? sets.buffers : sets.strings).delete(listener as any);
-                shouldUnsubscribe = !sets.buffers.size && !sets.strings.size;
-            } else {
-                shouldUnsubscribe = true;
     }
 
-            if (shouldUnsubscribe) {
+    extendPubSubChannelListeners(
-                channelsToUnsubscribe.push(channel);
+        type: PubSubType,
-                listeners.delete(channel);
+        channel: string,
-            }
+        listeners: ChannelListeners
+    ) {
+        return this.#pushPubSubCommand(
+            this.#pubSub.extendChannelListeners(type, channel, listeners)
+        );
     }
 
-        if (!channelsToUnsubscribe.length) {
+    extendPubSubListeners(type: PubSubType, listeners: PubSubTypeListeners) {
-            return Promise.resolve();
+        return this.#pushPubSubCommand(
+            this.#pubSub.extendTypeListeners(type, listeners)
+        );
     }
 
-        return this.#pushPubSubCommand(command, channelsToUnsubscribe);
+    getPubSubListeners(type: PubSubType) {
+        return this.#pubSub.getTypeListeners(type);
     }
 
-    #pushPubSubCommand(command: PubSubSubscribeCommands | PubSubUnsubscribeCommands, channels: number | Array<RedisCommandArgument>): Promise<void> {
+    #pushPubSubCommand(command: PubSubCommand) {
-        return new Promise((resolve, reject) => {
+        if (command === undefined) return;
-            const isSubscribe = command === PubSubSubscribeCommands.SUBSCRIBE || command === PubSubSubscribeCommands.PSUBSCRIBE,
-                inProgressKey = isSubscribe ? 'subscribing' : 'unsubscribing',
-                commandArgs: Array<RedisCommandArgument> = [command];
-
-            let channelsCounter: number;
-            if (typeof channels === 'number') { // unsubscribe only
-                channelsCounter = channels;
-            } else {
-                commandArgs.push(...channels);
-                channelsCounter = channels.length;
-            }
-
-            this.#pubSubState.isActive = true;
-            this.#pubSubState[inProgressKey] += channelsCounter;
 
+        return new Promise<void>((resolve, reject) => {
             this.#waitingToBeSent.push({
-                args: commandArgs,
+                args: command.args,
-                channelsCounter,
+                channelsCounter: command.channelsCounter,
                 returnBuffers: true,
                 resolve: () => {
-                    this.#pubSubState[inProgressKey] -= channelsCounter;
+                    command.resolve();
-                    this.#pubSubState.subscribed += channelsCounter * (isSubscribe ? 1 : -1);
-                    this.#updatePubSubActiveState();
                     resolve();
                 },
                 reject: err => {
-                    this.#pubSubState[inProgressKey] -= channelsCounter * (isSubscribe ? 1 : -1);
+                    command.reject?.();
-                    this.#updatePubSubActiveState();
                     reject(err);
                 }
             });
         });
     }
 
-    #updatePubSubActiveState(): void {
-        if (
-            !this.#pubSubState.subscribed &&
-            !this.#pubSubState.subscribing &&
-            !this.#pubSubState.subscribed
-        ) {
-            this.#pubSubState.isActive = false;
-        }
-    }
-
-    resubscribe(): Promise<any> | undefined {
-        this.#pubSubState.subscribed = 0;
-        this.#pubSubState.subscribing = 0;
-        this.#pubSubState.unsubscribing = 0;
-
-        const promises = [],
-            { channels, patterns } = this.#pubSubState.listeners;
-
-        if (channels.size) {
-            promises.push(
-                this.#pushPubSubCommand(
-                    PubSubSubscribeCommands.SUBSCRIBE,
-                    [...channels.keys()]
-                )
-            );
-        }
-
-        if (patterns.size) {
-            promises.push(
-                this.#pushPubSubCommand(
-                    PubSubSubscribeCommands.PSUBSCRIBE,
-                    [...patterns.keys()]
-                )
-            );
-        }
-
-        if (promises.length) {
-            return Promise.all(promises);
-        }
-    }
-
     getCommandToSend(): RedisCommandArguments | undefined {
         const toSend = this.#waitingToBeSent.shift();
         if (!toSend) return;
@@ -351,39 +240,9 @@ export default class RedisCommandsQueue {
         this.#decoder.write(chunk);
     }
 
-    #handlePubSubReply(reply: any): boolean {
-        if (!this.#pubSubState.isActive || !Array.isArray(reply)) return false;
-
-        if (RedisCommandsQueue.#PUB_SUB_MESSAGES.message.equals(reply[0])) {
-            RedisCommandsQueue.#emitPubSubMessage(
-                this.#pubSubState.listeners.channels,
-                reply[2],
-                reply[1]
-            );
-        } else if (RedisCommandsQueue.#PUB_SUB_MESSAGES.pMessage.equals(reply[0])) {
-            RedisCommandsQueue.#emitPubSubMessage(
-                this.#pubSubState.listeners.patterns,
-                reply[3],
-                reply[2],
-                reply[1]
-            );
-        } else if (
-            RedisCommandsQueue.#PUB_SUB_MESSAGES.subscribe.equals(reply[0]) ||
-            RedisCommandsQueue.#PUB_SUB_MESSAGES.pSubscribe.equals(reply[0]) ||
-            RedisCommandsQueue.#PUB_SUB_MESSAGES.unsubscribe.equals(reply[0]) ||
-            RedisCommandsQueue.#PUB_SUB_MESSAGES.pUnsubscribe.equals(reply[0])
-        ) {
-            if (--this.#waitingForReply.head!.value.channelsCounter! === 0) {
-                this.#waitingForReply.shift()!.resolve();
-            }
-        }
-
-        return true;
-    }
-
     flushWaitingForReply(err: Error): void {
         this.#decoder.reset();
-        this.#pubSubState.isActive = false;
+        this.#pubSub.reset();
         RedisCommandsQueue.#flushQueue(this.#waitingForReply, err);
 
         if (!this.#chainInExecution) return;
@@ -396,6 +255,8 @@ export default class RedisCommandsQueue {
     }
 
     flushAll(err: Error): void {
+        this.#decoder.reset();
+        this.#pubSub.reset();
         RedisCommandsQueue.#flushQueue(this.#waitingForReply, err);
         RedisCommandsQueue.#flushQueue(this.#waitingToBeSent, err);
     }

packages/client/lib/client/commands.ts

@@ -98,6 +98,7 @@ import * as PING from '../commands/PING';
 import * as PUBSUB_CHANNELS from '../commands/PUBSUB_CHANNELS';
 import * as PUBSUB_NUMPAT from '../commands/PUBSUB_NUMPAT';
 import * as PUBSUB_NUMSUB from '../commands/PUBSUB_NUMSUB';
+import * as PUBSUB_SHARDCHANNELS from '../commands/PUBSUB_SHARDCHANNELS';
 import * as RANDOMKEY from '../commands/RANDOMKEY';
 import * as READONLY from '../commands/READONLY';
 import * as READWRITE from '../commands/READWRITE';
@@ -317,6 +318,8 @@ export default {
     pubSubNumPat: PUBSUB_NUMPAT,
     PUBSUB_NUMSUB,
     pubSubNumSub: PUBSUB_NUMSUB,
+    PUBSUB_SHARDCHANNELS,
+    pubSubShardChannels: PUBSUB_SHARDCHANNELS,
     RANDOMKEY,
     randomKey: RANDOMKEY,
     READONLY,

packages/client/lib/client/index.spec.ts

@@ -2,14 +2,20 @@ import { strict as assert } from 'assert';
 import testUtils, { GLOBAL, waitTillBeenCalled } from '../test-utils';
 import RedisClient, { RedisClientType } from '.';
 import { RedisClientMultiCommandType } from './multi-command';
-import { RedisCommandArguments, RedisCommandRawReply, RedisModules, RedisFunctions, RedisScripts } from '../commands';
+import { RedisCommandRawReply, RedisModules, RedisFunctions, RedisScripts } from '../commands';
-import { AbortError, ClientClosedError, ClientOfflineError, ConnectionTimeoutError, DisconnectsClientError, SocketClosedUnexpectedlyError, WatchError } from '../errors';
+import { AbortError, ClientClosedError, ClientOfflineError, ConnectionTimeoutError, DisconnectsClientError, ErrorReply, SocketClosedUnexpectedlyError, WatchError } from '../errors';
 import { defineScript } from '../lua-script';
 import { spy } from 'sinon';
 import { once } from 'events';
 import { ClientKillFilters } from '../commands/CLIENT_KILL';
+import { ClusterSlotStates } from '../commands/CLUSTER_SETSLOT';
 import { promisify } from 'util';
 
+// We need to use 'require', because it's not possible with Typescript to import
+// function that are exported as 'module.exports = function`, without esModuleInterop
+// set to true.
+const calculateSlot = require('cluster-key-slot');
+
 export const SQUARE_SCRIPT = defineScript({
     SCRIPT: 'return ARGV[1] * ARGV[1];',
     NUMBER_OF_KEYS: 0,
@@ -817,7 +823,34 @@ describe('Client', () => {
             }
         }, GLOBAL.SERVERS.OPEN);
 
-        testUtils.testWithClient('should be able to quit in PubSub mode', async client => {
+        testUtils.testWithClient('should be able to PING in PubSub mode', async client => {
+            await client.connect();
+
+            try {
+                await client.subscribe('channel', () => {
+                    // noop
+                });
+                
+                const [string, buffer, customString, customBuffer] = await Promise.all([
+                    client.ping(),
+                    client.ping(client.commandOptions({ returnBuffers: true })),
+                    client.ping('custom'),
+                    client.ping(client.commandOptions({ returnBuffers: true }), 'custom')
+                ]);
+    
+                assert.equal(string, 'pong');
+                assert.deepEqual(buffer, Buffer.from('pong'));
+                assert.equal(customString, 'custom');
+                assert.deepEqual(customBuffer, Buffer.from('custom'));
+            } finally {
+                await client.disconnect();
+            }
+        }, {
+            ...GLOBAL.SERVERS.OPEN,
+            disableClientSetup: true
+        });
+
+        testUtils.testWithClient('should be able to QUIT in PubSub mode', async client => {
             await client.subscribe('channel', () => {
                 // noop
             });
@@ -826,6 +859,122 @@ describe('Client', () => {
 
             assert.equal(client.isOpen, false);
         }, GLOBAL.SERVERS.OPEN);
+
+        testUtils.testWithClient('should reject GET in PubSub mode', async client => {
+            await client.connect();
+
+            try {
+                await client.subscribe('channel', () => {
+                    // noop
+                });
+
+                await assert.rejects(client.get('key'), ErrorReply);
+            } finally {
+                await client.disconnect();
+            }
+        }, {
+            ...GLOBAL.SERVERS.OPEN,
+            disableClientSetup: true
+        });
+
+        describe('shareded PubSub', () => {
+            testUtils.isVersionGreaterThanHook([7]);
+
+            testUtils.testWithClient('should be able to receive messages', async publisher => {
+                const subscriber = publisher.duplicate();
+    
+                await subscriber.connect();
+    
+                try {
+                    const listener = spy();
+                    await subscriber.sSubscribe('channel', listener);
+    
+                    await Promise.all([
+                        waitTillBeenCalled(listener),
+                        publisher.sPublish('channel', 'message')
+                    ]);
+    
+                    assert.ok(listener.calledOnceWithExactly('message', 'channel'));
+    
+                    await subscriber.sUnsubscribe();
+    
+                    // should be able to send commands
+                    await assert.doesNotReject(subscriber.ping());
+                } finally {
+                    await subscriber.disconnect();
+                }
+            }, {
+                ...GLOBAL.SERVERS.OPEN
+            });
+
+            testUtils.testWithClient('should emit sharded-channel-moved event', async publisher => {
+                await publisher.clusterAddSlotsRange({ start: 0, end: 16383 });
+
+                const subscriber = publisher.duplicate();
+    
+                await subscriber.connect();
+    
+                try {
+                    await subscriber.sSubscribe('channel', () => {});
+
+                    await Promise.all([
+                        publisher.clusterSetSlot(
+                            calculateSlot('channel'),
+                            ClusterSlotStates.NODE,
+                            await publisher.clusterMyId()
+                        ),
+                        once(subscriber, 'sharded-channel-moved')
+                    ]);
+                    
+                    assert.equal(
+                        await subscriber.ping(),
+                        'PONG'
+                    );
+                } finally {
+                    await subscriber.disconnect();
+                }
+            }, {
+                serverArguments: ['--cluster-enabled', 'yes']
+            });
+        });
+
+        testUtils.testWithClient('should handle errors in SUBSCRIBE', async publisher => {
+            const subscriber = publisher.duplicate();
+
+            await subscriber.connect();
+
+            try {
+                const listener1 = spy();
+                await subscriber.subscribe('1', listener1);
+
+                await publisher.aclSetUser('default', 'resetchannels');
+
+
+                const listener2 = spy();
+                await assert.rejects(subscriber.subscribe('2', listener2));
+                
+                await Promise.all([
+                    waitTillBeenCalled(listener1),
+                    publisher.aclSetUser('default', 'allchannels'),
+                    publisher.publish('1', 'message'),
+                ]);
+                assert.ok(listener1.calledOnceWithExactly('message', '1'));
+                
+                await subscriber.subscribe('2', listener2);
+
+                await Promise.all([
+                    waitTillBeenCalled(listener2),
+                    publisher.publish('2', 'message'),
+                ]);
+                assert.ok(listener2.calledOnceWithExactly('message', '2'));
+            } finally {
+                await subscriber.disconnect();
+            }
+        }, {
+            // this test change ACL rules, running in isolated server
+            serverArguments: [],
+            minimumDockerVersion: [6 ,2] // ACL PubSub rules were added in Redis 6.2
+        });
     });
 
     testUtils.testWithClient('ConnectionTimeoutError', async client => {

packages/client/lib/client/index.ts

@@ -1,7 +1,7 @@
 import COMMANDS from './commands';
 import { RedisCommand, RedisCommandArguments, RedisCommandRawReply, RedisCommandReply, RedisFunctions, RedisModules, RedisExtensions, RedisScript, RedisScripts, RedisCommandSignature, ConvertArgumentType, RedisFunction, ExcludeMappedString, RedisCommands } from '../commands';
 import RedisSocket, { RedisSocketOptions, RedisTlsSocketOptions } from './socket';
-import RedisCommandsQueue, { PubSubListener, PubSubSubscribeCommands, PubSubUnsubscribeCommands, QueueCommandOptions } from './commands-queue';
+import RedisCommandsQueue, { QueueCommandOptions } from './commands-queue';
 import RedisClientMultiCommand, { RedisClientMultiCommandType } from './multi-command';
 import { RedisMultiQueuedCommand } from '../multi-command';
 import { EventEmitter } from 'events';
@@ -14,23 +14,57 @@ import { Pool, Options as PoolOptions, createPool } from 'generic-pool';
 import { ClientClosedError, ClientOfflineError, DisconnectsClientError } from '../errors';
 import { URL } from 'url';
 import { TcpSocketConnectOpts } from 'net';
+import { PubSubType, PubSubListener, PubSubTypeListeners, ChannelListeners } from './pub-sub';
 
 export interface RedisClientOptions<
     M extends RedisModules = RedisModules,
     F extends RedisFunctions = RedisFunctions,
     S extends RedisScripts = RedisScripts
 > extends RedisExtensions<M, F, S> {
+    /**
+     * `redis[s]://[[username][:password]@][host][:port][/db-number]`
+     * See [`redis`](https://www.iana.org/assignments/uri-schemes/prov/redis) and [`rediss`](https://www.iana.org/assignments/uri-schemes/prov/rediss) IANA registration for more details
+     */
     url?: string;
+    /**
+     * Socket connection properties
+     */
     socket?: RedisSocketOptions;
+    /**
+     * ACL username ([see ACL guide](https://redis.io/topics/acl))
+     */
     username?: string;
+    /**
+     * ACL password or the old "--requirepass" password
+     */
     password?: string;
+    /**
+     * Client name ([see `CLIENT SETNAME`](https://redis.io/commands/client-setname))
+     */
     name?: string;
+    /**
+     * Redis database number (see [`SELECT`](https://redis.io/commands/select) command)
+     */
     database?: number;
+    /**
+     * Maximum length of the client's internal command queue
+     */
     commandsQueueMaxLength?: number;
+    /**
+     * When `true`, commands are rejected when the client is reconnecting.
+     * When `false`, commands are queued for execution after reconnection.
+     */
     disableOfflineQueue?: boolean;
+    /**
+     * Connect in [`READONLY`](https://redis.io/commands/readonly) mode
+     */
     readonly?: boolean;
     legacyMode?: boolean;
     isolationPoolOptions?: PoolOptions;
+    /**
+     * Send `PING` command at interval (in ms).
+     * Useful with Redis deployments that do not use TCP Keep-Alive.
+     */
     pingInterval?: number;
 }
 
@@ -171,6 +205,10 @@ export default class RedisClient<
         return this.#socket.isReady;
     }
 
+    get isPubSubActive() {
+        return this.#queue.isPubSubActive;
+    }
+
     get v4(): Record<string, any> {
         if (!this.#options?.legacyMode) {
             throw new Error('the client is not in "legacy mode"');
@@ -215,7 +253,10 @@ export default class RedisClient<
     }
 
     #initiateQueue(): RedisCommandsQueue {
-        return new RedisCommandsQueue(this.#options?.commandsQueueMaxLength);
+        return new RedisCommandsQueue(
+            this.#options?.commandsQueueMaxLength,
+            (channel, listeners) => this.emit('sharded-channel-moved', channel, listeners)
+        );
     }
 
     #initiateSocket(): RedisSocket {
@@ -377,8 +418,8 @@ export default class RedisClient<
         });
     }
 
-    async connect(): Promise<void> {
+    connect(): Promise<void> {
-        await this.#socket.connect();
+        return this.#socket.connect();
     }
 
     async commandsExecutor<C extends RedisCommand>(
@@ -500,18 +541,9 @@ export default class RedisClient<
 
     select = this.SELECT;
 
-    #subscribe<T extends boolean>(
+    #pubSubCommand(promise: Promise<void> | undefined) {
-        command: PubSubSubscribeCommands,
+        if (promise === undefined) return Promise.resolve();
-        channels: string | Array<string>,
+
-        listener: PubSubListener<T>,
-        bufferMode?: T
-    ): Promise<void> {
-        const promise = this.#queue.subscribe(
-            command,
-            channels,
-            listener,
-            bufferMode
-        );
         this.#tick();
         return promise;
     }
@@ -521,77 +553,127 @@ export default class RedisClient<
         listener: PubSubListener<T>,
         bufferMode?: T
     ): Promise<void> {
-        return this.#subscribe(
+        return this.#pubSubCommand(
-            PubSubSubscribeCommands.SUBSCRIBE,
+            this.#queue.subscribe(
+                PubSubType.CHANNELS,
                 channels,
                 listener,
                 bufferMode
+            )
         );
     }
 
     subscribe = this.SUBSCRIBE;
 
-    PSUBSCRIBE<T extends boolean = false>(
-        patterns: string | Array<string>,
-        listener: PubSubListener<T>,
-        bufferMode?: T
-    ): Promise<void> {
-        return this.#subscribe(
-            PubSubSubscribeCommands.PSUBSCRIBE,
-            patterns,
-            listener,
-            bufferMode
-        );
-    }
-
-    pSubscribe = this.PSUBSCRIBE;
-
-    #unsubscribe<T extends boolean>(
-        command: PubSubUnsubscribeCommands,
-        channels?: string | Array<string>,
-        listener?: PubSubListener<T>,
-        bufferMode?: T
-    ): Promise<void> {
-        const promise = this.#queue.unsubscribe(command, channels, listener, bufferMode);
-        this.#tick();
-        return promise;
-    }
 
     UNSUBSCRIBE<T extends boolean = false>(
         channels?: string | Array<string>,
         listener?: PubSubListener<T>,
         bufferMode?: T
     ): Promise<void> {
-        return this.#unsubscribe(
+        return this.#pubSubCommand(
-            PubSubUnsubscribeCommands.UNSUBSCRIBE,
+            this.#queue.unsubscribe(
+                PubSubType.CHANNELS,
                 channels,
                 listener,
                 bufferMode
+            )
         );
     }
 
     unsubscribe = this.UNSUBSCRIBE;
 
+    PSUBSCRIBE<T extends boolean = false>(
+        patterns: string | Array<string>,
+        listener: PubSubListener<T>,
+        bufferMode?: T
+    ): Promise<void> {
+        return this.#pubSubCommand(
+            this.#queue.subscribe(
+                PubSubType.PATTERNS,
+                patterns,
+                listener,
+                bufferMode
+            )
+        );
+    }
+
+    pSubscribe = this.PSUBSCRIBE;
+
     PUNSUBSCRIBE<T extends boolean = false>(
         patterns?: string | Array<string>,
         listener?: PubSubListener<T>,
         bufferMode?: T
     ): Promise<void> {
-        return this.#unsubscribe(
+        return this.#pubSubCommand(
-            PubSubUnsubscribeCommands.PUNSUBSCRIBE,
+            this.#queue.unsubscribe(
+                PubSubType.PATTERNS,
                 patterns,
                 listener,
                 bufferMode
+            )
         );
     }
 
     pUnsubscribe = this.PUNSUBSCRIBE;
 
+    SSUBSCRIBE<T extends boolean = false>(
+        channels: string | Array<string>,
+        listener: PubSubListener<T>,
+        bufferMode?: T
+    ): Promise<void> {
+        return this.#pubSubCommand(
+            this.#queue.subscribe(
+                PubSubType.SHARDED,
+                channels,
+                listener,
+                bufferMode
+            )
+        );
+    }
+
+    sSubscribe = this.SSUBSCRIBE;
+
+    SUNSUBSCRIBE<T extends boolean = false>(
+        channels?: string | Array<string>,
+        listener?: PubSubListener<T>,
+        bufferMode?: T
+    ): Promise<void> {
+        return this.#pubSubCommand(
+            this.#queue.unsubscribe(
+                PubSubType.SHARDED,
+                channels,
+                listener,
+                bufferMode
+            )
+        );
+    }
+
+    sUnsubscribe = this.SUNSUBSCRIBE;
+
+    getPubSubListeners(type: PubSubType) {
+        return this.#queue.getPubSubListeners(type);
+    }
+
+    extendPubSubChannelListeners(
+        type: PubSubType,
+        channel: string,
+        listeners: ChannelListeners
+    ) {
+        return this.#pubSubCommand(
+            this.#queue.extendPubSubChannelListeners(type, channel, listeners)
+        );
+    }
+
+    extendPubSubListeners(type: PubSubType, listeners: PubSubTypeListeners) {
+        return this.#pubSubCommand(
+            this.#queue.extendPubSubListeners(type, listeners)
+        );
+    }
+
     QUIT(): Promise<string> {
         return this.#socket.quit(async () => {
-            const quitPromise = this.#queue.addCommand<string>(['QUIT'], {
+            const quitPromise = this.#queue.addCommand<string>(['QUIT']);
-                ignorePubSubMode: true
-            });
             this.#tick();
             const [reply] = await Promise.all([
                 quitPromise,

packages/client/lib/client/pub-sub.spec.ts

@@ -0,0 +1,151 @@
+import { strict as assert } from 'assert';
+import { PubSub, PubSubType } from './pub-sub';
+
+describe('PubSub', () => {
+    const TYPE = PubSubType.CHANNELS,
+        CHANNEL = 'channel',
+        LISTENER = () => {};
+
+    describe('subscribe to new channel', () => {
+        function createAndSubscribe() {
+            const pubSub = new PubSub(),
+                command = pubSub.subscribe(TYPE, CHANNEL, LISTENER);
+    
+            assert.equal(pubSub.isActive, true);
+            assert.ok(command);
+            assert.equal(command.channelsCounter, 1);
+            
+            return {
+                pubSub,
+                command
+            };
+        }
+
+        it('resolve', () => {
+            const { pubSub, command } = createAndSubscribe();
+    
+            command.resolve();
+
+            assert.equal(pubSub.isActive, true);
+        });
+
+        it('reject', () => {
+            const { pubSub, command } = createAndSubscribe();
+    
+            assert.ok(command.reject);
+            command.reject();
+
+            assert.equal(pubSub.isActive, false);
+        });
+    });
+
+    it('subscribe to already subscribed channel', () => {
+        const pubSub = new PubSub(),
+            firstSubscribe = pubSub.subscribe(TYPE, CHANNEL, LISTENER);
+        assert.ok(firstSubscribe);
+
+        const secondSubscribe = pubSub.subscribe(TYPE, CHANNEL, LISTENER);
+        assert.ok(secondSubscribe);
+
+        firstSubscribe.resolve();
+
+        assert.equal(
+            pubSub.subscribe(TYPE, CHANNEL, LISTENER),
+            undefined
+        );
+    });
+
+    it('unsubscribe all', () => {
+        const pubSub = new PubSub();
+        
+        const subscribe = pubSub.subscribe(TYPE, CHANNEL, LISTENER);
+        assert.ok(subscribe);
+        subscribe.resolve();
+        assert.equal(pubSub.isActive, true);
+
+        const unsubscribe = pubSub.unsubscribe(TYPE);
+        assert.equal(pubSub.isActive, true);
+        assert.ok(unsubscribe);
+        unsubscribe.resolve();
+        assert.equal(pubSub.isActive, false);
+    });
+
+    describe('unsubscribe from channel', () => {
+        it('when not subscribed', () => {
+            const pubSub = new PubSub(),
+                unsubscribe = pubSub.unsubscribe(TYPE, CHANNEL);
+            assert.ok(unsubscribe);
+            unsubscribe.resolve();
+            assert.equal(pubSub.isActive, false);
+        });
+
+        it('when already subscribed', () => {
+            const pubSub = new PubSub(),
+                subscribe = pubSub.subscribe(TYPE, CHANNEL, LISTENER);
+            assert.ok(subscribe);
+            subscribe.resolve();
+            assert.equal(pubSub.isActive, true);
+    
+            const unsubscribe = pubSub.unsubscribe(TYPE, CHANNEL);
+            assert.equal(pubSub.isActive, true);
+            assert.ok(unsubscribe);
+            unsubscribe.resolve();
+            assert.equal(pubSub.isActive, false);
+        });
+    });
+
+    describe('unsubscribe from listener', () => {
+        it('when it\'s the only listener', () => {
+            const pubSub = new PubSub(),
+                subscribe = pubSub.subscribe(TYPE, CHANNEL, LISTENER);
+            assert.ok(subscribe);
+            subscribe.resolve();
+            assert.equal(pubSub.isActive, true);
+
+            const unsubscribe = pubSub.unsubscribe(TYPE, CHANNEL, LISTENER);
+            assert.ok(unsubscribe);
+            unsubscribe.resolve();
+            assert.equal(pubSub.isActive, false);
+        });
+
+        it('when there are more listeners', () => {
+            const pubSub = new PubSub(),
+                subscribe = pubSub.subscribe(TYPE, CHANNEL, LISTENER);
+            assert.ok(subscribe);
+            subscribe.resolve();
+            assert.equal(pubSub.isActive, true);
+
+            assert.equal(
+                pubSub.subscribe(TYPE, CHANNEL, () => {}),
+                undefined
+            );
+
+            assert.equal(
+                pubSub.unsubscribe(TYPE, CHANNEL, LISTENER),
+                undefined
+            );
+        });
+
+        describe('non-existing listener', () => {
+            it('on subscribed channel', () => {
+                const pubSub = new PubSub(),
+                    subscribe = pubSub.subscribe(TYPE, CHANNEL, LISTENER);
+                assert.ok(subscribe);
+                subscribe.resolve();
+                assert.equal(pubSub.isActive, true);
+
+                assert.equal(
+                    pubSub.unsubscribe(TYPE, CHANNEL, () => {}),
+                    undefined
+                );
+                assert.equal(pubSub.isActive, true);
+            });
+
+            it('on unsubscribed channel', () => {
+                const pubSub = new PubSub();
+                assert.ok(pubSub.unsubscribe(TYPE, CHANNEL, () => {}));
+                assert.equal(pubSub.isActive, false);
+            });
+        });
+    });
+});

packages/client/lib/client/pub-sub.ts

@@ -0,0 +1,408 @@
+import { RedisCommandArgument } from "../commands";
+
+export enum PubSubType {
+    CHANNELS = 'CHANNELS',
+    PATTERNS = 'PATTERNS',
+    SHARDED = 'SHARDED'
+}
+
+const COMMANDS = {
+    [PubSubType.CHANNELS]: {
+        subscribe: Buffer.from('subscribe'),
+        unsubscribe: Buffer.from('unsubscribe'),
+        message: Buffer.from('message')
+    },
+    [PubSubType.PATTERNS]: {
+        subscribe: Buffer.from('psubscribe'),
+        unsubscribe: Buffer.from('punsubscribe'),
+        message: Buffer.from('pmessage')
+    },
+    [PubSubType.SHARDED]: {
+        subscribe: Buffer.from('ssubscribe'),
+        unsubscribe: Buffer.from('sunsubscribe'),
+        message: Buffer.from('smessage')
+    }
+};
+
+export type PubSubListener<
+    RETURN_BUFFERS extends boolean = false
+> = <T extends RETURN_BUFFERS extends true ? Buffer : string>(message: T, channel: T) => unknown;
+
+export interface ChannelListeners {
+    unsubscribing: boolean;
+    buffers: Set<PubSubListener<true>>;
+    strings: Set<PubSubListener<false>>;
+}
+
+export type PubSubTypeListeners = Map<string, ChannelListeners>;
+
+type Listeners = Record<PubSubType, PubSubTypeListeners>;
+
+export type PubSubCommand = ReturnType<
+    typeof PubSub.prototype.subscribe |
+    typeof PubSub.prototype.unsubscribe | 
+    typeof PubSub.prototype.extendTypeListeners
+>;
+
+export class PubSub {
+    static isStatusReply(reply: Array<Buffer>): boolean {
+        return (
+            COMMANDS[PubSubType.CHANNELS].subscribe.equals(reply[0]) ||
+            COMMANDS[PubSubType.CHANNELS].unsubscribe.equals(reply[0]) ||
+            COMMANDS[PubSubType.PATTERNS].subscribe.equals(reply[0]) ||
+            COMMANDS[PubSubType.PATTERNS].unsubscribe.equals(reply[0]) ||
+            COMMANDS[PubSubType.SHARDED].subscribe.equals(reply[0])
+        );
+    }
+
+    static isShardedUnsubscribe(reply: Array<Buffer>): boolean {
+        return COMMANDS[PubSubType.SHARDED].unsubscribe.equals(reply[0]);
+    }
+    
+    static #channelsArray(channels: string | Array<string>) {
+        return (Array.isArray(channels) ? channels : [channels]);
+    }
+
+    static #listenersSet<T extends boolean>(
+        listeners: ChannelListeners,
+        returnBuffers?: T
+    ) {
+        return (returnBuffers ? listeners.buffers : listeners.strings);
+    }
+
+    #subscribing = 0;
+
+    #isActive = false;
+
+    get isActive() {
+        return this.#isActive;
+    }
+
+    #listeners: Listeners = {
+        [PubSubType.CHANNELS]: new Map(),
+        [PubSubType.PATTERNS]: new Map(),
+        [PubSubType.SHARDED]: new Map()
+    };
+
+    subscribe<T extends boolean>(
+        type: PubSubType,
+        channels: string | Array<string>,
+        listener: PubSubListener<T>,
+        returnBuffers?: T
+    ) {
+        const args: Array<RedisCommandArgument> = [COMMANDS[type].subscribe],
+            channelsArray = PubSub.#channelsArray(channels);
+        for (const channel of channelsArray) {
+            let channelListeners = this.#listeners[type].get(channel);
+            if (!channelListeners || channelListeners.unsubscribing) {
+                args.push(channel);
+            }
+        }
+
+        if (args.length === 1) {
+            // all channels are already subscribed, add listeners without issuing a command
+            for (const channel of channelsArray) {
+                PubSub.#listenersSet(
+                    this.#listeners[type].get(channel)!,
+                    returnBuffers
+                ).add(listener);
+            }
+            return;
+        }
+
+        this.#isActive = true;
+        this.#subscribing++;
+        return {
+            args,
+            channelsCounter: args.length - 1,
+            resolve: () => {
+                this.#subscribing--;
+                for (const channel of channelsArray) {
+                    let listeners = this.#listeners[type].get(channel);
+                    if (!listeners) {
+                        listeners = {
+                            unsubscribing: false,
+                            buffers: new Set(),
+                            strings: new Set()
+                        };
+                        this.#listeners[type].set(channel, listeners);
+                    }
+
+                    PubSub.#listenersSet(listeners, returnBuffers).add(listener);
+                }
+            },
+            reject: () => {
+                this.#subscribing--;
+                this.#updateIsActive();
+            }
+        };
+    }
+
+    extendChannelListeners(
+        type: PubSubType,
+        channel: string,
+        listeners: ChannelListeners
+    ) {
+        if (!this.#extendChannelListeners(type, channel, listeners)) return;
+
+        this.#isActive = true;
+        this.#subscribing++;
+        return {
+            args: [
+                COMMANDS[type].subscribe,
+                channel
+            ],
+            channelsCounter: 1,
+            resolve: () => this.#subscribing--,
+            reject: () => {
+                this.#subscribing--;
+                this.#updateIsActive();
+            }
+        };
+    }
+
+    #extendChannelListeners(
+        type: PubSubType,
+        channel: string,
+        listeners: ChannelListeners
+    ) {
+        const existingListeners = this.#listeners[type].get(channel);
+        if (!existingListeners) {
+            this.#listeners[type].set(channel, listeners);
+            return true;
+        }
+
+        for (const listener of listeners.buffers) {
+            existingListeners.buffers.add(listener);
+        }
+
+        for (const listener of listeners.strings) {
+            existingListeners.strings.add(listener);
+        }
+
+        return false;
+    }
+
+    extendTypeListeners(type: PubSubType, listeners: PubSubTypeListeners) {
+        const args: Array<RedisCommandArgument> = [COMMANDS[type].subscribe];
+        for (const [channel, channelListeners] of listeners) {
+            if (this.#extendChannelListeners(type, channel, channelListeners)) {
+                args.push(channel);
+            }
+        }
+
+        if (args.length === 1) return;
+
+        this.#isActive = true;
+        this.#subscribing++;
+        return {
+            args,
+            channelsCounter: args.length - 1,
+            resolve: () => this.#subscribing--,
+            reject: () => {
+                this.#subscribing--;
+                this.#updateIsActive();
+            }
+        };
+    }
+
+    unsubscribe<T extends boolean>(
+        type: PubSubType,
+        channels?: string | Array<string>,
+        listener?: PubSubListener<T>,
+        returnBuffers?: T
+    ) {
+        const listeners = this.#listeners[type];
+        if (!channels) {
+            return this.#unsubscribeCommand(
+                [COMMANDS[type].unsubscribe],
+                // cannot use `this.#subscribed` because there might be some `SUBSCRIBE` commands in the queue
+                // cannot use `this.#subscribed + this.#subscribing` because some `SUBSCRIBE` commands might fail
+                NaN,
+                () => listeners.clear()
+            );
+        }
+
+        const channelsArray = PubSub.#channelsArray(channels);
+        if (!listener) {
+            return this.#unsubscribeCommand(
+                [COMMANDS[type].unsubscribe, ...channelsArray],
+                channelsArray.length,
+                () => {
+                    for (const channel of channelsArray) {
+                        listeners.delete(channel);
+                    }
+                }
+            );
+        }
+
+        const args: Array<RedisCommandArgument> = [COMMANDS[type].unsubscribe];
+        for (const channel of channelsArray) {
+            const sets = listeners.get(channel);
+            if (sets) {
+                let current,
+                    other;
+                if (returnBuffers) {
+                    current = sets.buffers;
+                    other = sets.strings;
+                } else {
+                    current = sets.strings;
+                    other = sets.buffers;
+                }
+
+                const currentSize = current.has(listener) ? current.size - 1 : current.size;
+                if (currentSize !== 0 || other.size !== 0) continue;
+                sets.unsubscribing = true;
+            }
+
+            args.push(channel);
+        }
+
+        if (args.length === 1) {
+            // all channels has other listeners,
+            // delete the listeners without issuing a command
+            for (const channel of channelsArray) {
+                PubSub.#listenersSet(
+                    listeners.get(channel)!,
+                    returnBuffers
+                ).delete(listener);
+            }
+            return;
+        }
+
+        return this.#unsubscribeCommand(
+            args,
+            args.length - 1,
+            () => {
+                for (const channel of channelsArray) {
+                    const sets = listeners.get(channel);
+                    if (!sets) continue;
+
+                    (returnBuffers ? sets.buffers : sets.strings).delete(listener);
+                    if (sets.buffers.size === 0 && sets.strings.size === 0) {
+                        listeners.delete(channel);
+                    }
+                }
+            }
+        );
+    }
+
+    #unsubscribeCommand(
+        args: Array<RedisCommandArgument>,
+        channelsCounter: number,
+        removeListeners: () => void
+    ) {
+        return {
+            args,
+            channelsCounter,
+            resolve: () => {
+                removeListeners();
+                this.#updateIsActive();
+            },
+            reject: undefined // use the same structure as `subscribe`
+        };
+    }
+
+    #updateIsActive() {
+        this.#isActive = (
+            this.#listeners[PubSubType.CHANNELS].size !== 0 ||
+            this.#listeners[PubSubType.PATTERNS].size !== 0 ||
+            this.#listeners[PubSubType.CHANNELS].size !== 0 ||
+            this.#subscribing !== 0
+        );
+    }
+
+    reset() {
+        this.#isActive = false;
+        this.#subscribing = 0;
+    }
+
+    resubscribe(): Array<PubSubCommand> {
+        const commands = [];
+        for (const [type, listeners] of Object.entries(this.#listeners)) {
+            if (!listeners.size) continue;
+
+            this.#isActive = true;
+            this.#subscribing++;
+            const callback = () => this.#subscribing--;
+            commands.push({
+                args: [
+                    COMMANDS[type as PubSubType].subscribe,
+                    ...listeners.keys()
+                ],
+                channelsCounter: listeners.size,
+                resolve: callback,
+                reject: callback
+            });
+        }
+
+        return commands;
+    }
+
+    handleMessageReply(reply: Array<Buffer>): boolean {
+        if (COMMANDS[PubSubType.CHANNELS].message.equals(reply[0])) {
+            this.#emitPubSubMessage(
+                PubSubType.CHANNELS,
+                reply[2],
+                reply[1]
+            );
+            return true;
+        } else if (COMMANDS[PubSubType.PATTERNS].message.equals(reply[0])) {
+            this.#emitPubSubMessage(
+                PubSubType.PATTERNS,
+                reply[3],
+                reply[2],
+                reply[1]
+            );
+            return true;
+        } else if (COMMANDS[PubSubType.SHARDED].message.equals(reply[0])) {
+            this.#emitPubSubMessage(
+                PubSubType.SHARDED,
+                reply[2],
+                reply[1]
+            );
+            return true;
+        }
+
+        return false;
+    }
+
+    removeShardedListeners(channel: string): ChannelListeners {
+        const listeners = this.#listeners[PubSubType.SHARDED].get(channel)!;
+        this.#listeners[PubSubType.SHARDED].delete(channel);
+        this.#updateIsActive();
+        return listeners;
+    }
+    
+    #emitPubSubMessage(
+        type: PubSubType,
+        message: Buffer,
+        channel: Buffer,
+        pattern?: Buffer
+    ): void {
+        const keyString = (pattern ?? channel).toString(),
+            listeners = this.#listeners[type].get(keyString);
+
+        if (!listeners) return;
+
+        for (const listener of listeners.buffers) {
+            listener(message, channel);
+        }
+
+        if (!listeners.strings.size) return;
+
+        const channelString = pattern ? channel.toString() : keyString,
+            messageString = channelString === '__redis__:invalidate' ?
+                // https://github.com/redis/redis/pull/7469
+                // https://github.com/redis/redis/issues/7463
+                (message === null ? null : (message as any as Array<Buffer>).map(x => x.toString())) as any :
+                message.toString();
+        for (const listener of listeners.strings) {
+            listener(messageString, channelString);
+        }
+    }
+
+    getTypeListeners(type: PubSubType): PubSubTypeListeners {
+        return this.#listeners[type];
+    }
+}

packages/client/lib/client/socket.spec.ts

@@ -1,5 +1,6 @@
-import { strict as assert } from 'assert';
+import { strict as assert } from 'node:assert';
 import { spy } from 'sinon';
+import { once } from 'node:events';
 import RedisSocket, { RedisSocketOptions } from './socket';
 
 describe('Socket', () => {
@@ -17,16 +18,42 @@ describe('Socket', () => {
     }
 
     describe('reconnectStrategy', () => {
+        it('false', async () => {
+            const socket = createSocket({
+                host: 'error',
+                connectTimeout: 1,
+                reconnectStrategy: false
+            });
+
+            await assert.rejects(socket.connect());
+
+            assert.equal(socket.isOpen, false);
+        });
+
+        it('0', async () => {
+            const socket = createSocket({
+                host: 'error',
+                connectTimeout: 1,
+                reconnectStrategy: 0
+            });
+
+            socket.connect();
+            await once(socket, 'error');
+            assert.equal(socket.isOpen, true);
+            assert.equal(socket.isReady, false);
+            socket.disconnect();
+            assert.equal(socket.isOpen, false);
+        });
+
         it('custom strategy', async () => {
-            const numberOfRetries = 10;
+            const numberOfRetries = 3;
 
             const reconnectStrategy = spy((retries: number) => {
                 assert.equal(retries + 1, reconnectStrategy.callCount);
 
                 if (retries === numberOfRetries) return new Error(`${numberOfRetries}`);
 
-                const time = retries * 2;
+                return 0;
-                return time;
             });
 
             const socket = createSocket({

packages/client/lib/client/socket.ts

@@ -6,10 +6,26 @@ import { ConnectionTimeoutError, ClientClosedError, SocketClosedUnexpectedlyErro
 import { promiseTimeout } from '../utils';
 
 export interface RedisSocketCommonOptions {
+    /**
+     * Connection Timeout (in milliseconds)
+     */
     connectTimeout?: number;
+    /**
+     * Toggle [`Nagle's algorithm`](https://nodejs.org/api/net.html#net_socket_setnodelay_nodelay)
+     */
     noDelay?: boolean;
+    /**
+     * Toggle [`keep-alive`](https://nodejs.org/api/net.html#net_socket_setkeepalive_enable_initialdelay)
+     */
     keepAlive?: number | false;
-    reconnectStrategy?(retries: number): number | Error;
+    /**
+     * When the socket closes unexpectedly (without calling `.quit()`/`.disconnect()`), the client uses `reconnectStrategy` to decide what to do. The following values are supported:
+     * 1. `false` -> do not reconnect, close the client and flush the command queue.
+     * 2. `number` -> wait for `X` milliseconds before reconnecting.
+     * 3. `(retries: number, cause: Error) => false | number | Error` -> `number` is the same as configuring a `number` directly, `Error` is the same as `false`, but with a custom error.
+     * Defaults to `retries => Math.min(retries * 50, 500)`
+     */
+    reconnectStrategy?: false | number | ((retries: number, cause: Error) => false | Error | number);
 }
 
 type RedisNetSocketOptions = Partial<net.SocketConnectOpts> & {
@@ -83,12 +99,16 @@ export default class RedisSocket extends EventEmitter {
         this.#options = RedisSocket.#initiateOptions(options);
     }
 
-    reconnectStrategy(retries: number): number | Error {
+    #reconnectStrategy(retries: number, cause: Error) {
-        if (this.#options.reconnectStrategy) {
+        if (this.#options.reconnectStrategy === false) {
+            return false;
+        } else if (typeof this.#options.reconnectStrategy === 'number') {
+            return this.#options.reconnectStrategy;
+        } else if (this.#options.reconnectStrategy) {
             try {
-                const retryIn = this.#options.reconnectStrategy(retries);
+                const retryIn = this.#options.reconnectStrategy(retries, cause);
-                if (typeof retryIn !== 'number' && !(retryIn instanceof Error)) {
+                if (retryIn !== false && !(retryIn instanceof Error) && typeof retryIn !== 'number') {
-                    throw new TypeError('Reconnect strategy should return `number | Error`');
+                    throw new TypeError(`Reconnect strategy should return \`false | Error | number\`, got ${retryIn} instead`);
                 }
 
                 return retryIn;
@@ -100,6 +120,21 @@ export default class RedisSocket extends EventEmitter {
         return Math.min(retries * 50, 500);
     }
 
+    #shouldReconnect(retries: number, cause: Error) {
+        const retryIn = this.#reconnectStrategy(retries, cause);
+        if (retryIn === false) {
+            this.#isOpen = false;
+            this.emit('error', cause);
+            return cause;
+        } else if (retryIn instanceof Error) {
+            this.#isOpen = false;
+            this.emit('error', cause);
+            return new ReconnectStrategyError(retryIn, cause);
+        }
+
+        return retryIn;
+    }
+
     async connect(): Promise<void> {
         if (this.#isOpen) {
             throw new Error('Socket already opened');
@@ -109,13 +144,9 @@ export default class RedisSocket extends EventEmitter {
         return this.#connect();
     }
 
-    async #connect(hadError?: boolean): Promise<void> {
+    async #connect(): Promise<void> {
         let retries = 0;
         do {
-            if (retries > 0 || hadError) {
-                this.emit('reconnecting');
-            }
-
             try {
                 this.#socket = await this.#createSocket();
                 this.#writableNeedDrain = false;
@@ -131,17 +162,17 @@ export default class RedisSocket extends EventEmitter {
                 this.#isReady = true;
                 this.emit('ready');
             } catch (err) {
-                const retryIn = this.reconnectStrategy(retries);
+                const retryIn = this.#shouldReconnect(retries, err as Error);
-                if (retryIn instanceof Error) {
+                if (typeof retryIn !== 'number') {
-                    this.#isOpen = false;
+                    throw retryIn;
-                    this.emit('error', err);
-                    throw new ReconnectStrategyError(retryIn, err);
                 }
 
                 this.emit('error', err);
                 await promiseTimeout(retryIn);
             }
+
             retries++;
+            this.emit('reconnecting');
         } while (this.#isOpen && !this.#isReady);
     }
 
@@ -203,9 +234,10 @@ export default class RedisSocket extends EventEmitter {
         this.#isReady = false;
         this.emit('error', err);
 
-        if (!this.#isOpen) return;
+        if (!this.#isOpen || typeof this.#shouldReconnect(0, err) !== 'number') return;
         
-        this.#connect(true).catch(() => {
+        this.emit('reconnecting');
+        this.#connect().catch(() => {
             // the error was already emitted, silently ignore it
         });
     }

packages/client/lib/cluster/cluster-slots.ts

@@ -1,23 +1,17 @@
 import RedisClient, { InstantiableRedisClient, RedisClientType } from '../client';
-import { RedisClusterMasterNode, RedisClusterReplicaNode } from '../commands/CLUSTER_NODES';
 import { RedisClusterClientOptions, RedisClusterOptions } from '.';
 import { RedisCommandArgument, RedisFunctions, RedisModules, RedisScripts } from '../commands';
 import { RootNodesUnavailableError } from '../errors';
+import { ClusterSlotsNode } from '../commands/CLUSTER_SLOTS';
+import { types } from 'node:util';
+import { ChannelListeners, PubSubType, PubSubTypeListeners } from '../client/pub-sub';
+import { EventEmitter } from 'node:stream';
 
 // We need to use 'require', because it's not possible with Typescript to import
 // function that are exported as 'module.exports = function`, without esModuleInterop
 // set to true.
 const calculateSlot = require('cluster-key-slot');
 
-export interface ClusterNode<
-    M extends RedisModules,
-    F extends RedisFunctions,
-    S extends RedisScripts
-> {
-    id: string;
-    client: RedisClientType<M, F, S>;
-}
-
 interface NodeAddress {
     host: string;
     port: number;
@@ -27,132 +21,235 @@ export type NodeAddressMap = {
     [address: string]: NodeAddress;
 } | ((address: string) => NodeAddress | undefined);
 
-interface SlotNodes<
+type ValueOrPromise<T> = T | Promise<T>;
+
+type ClientOrPromise<
+    M extends RedisModules,
+    F extends RedisFunctions,
+    S extends RedisScripts
+> = ValueOrPromise<RedisClientType<M, F, S>>;
+
+export interface Node<
     M extends RedisModules,
     F extends RedisFunctions,
     S extends RedisScripts
 > {
-    master: ClusterNode<M, F, S>;
+    address: string;
-    replicas: Array<ClusterNode<M, F, S>>;
+    client?: ClientOrPromise<M, F, S>;
-    clientIterator: IterableIterator<RedisClientType<M, F, S>> | undefined;
 }
 
-type OnError = (err: unknown) => void;
+export interface ShardNode<
+    M extends RedisModules,
+    F extends RedisFunctions,
+    S extends RedisScripts
+> extends Node<M, F, S> {
+    id: string;
+    host: string;
+    port: number;
+    readonly: boolean;
+}
+
+export interface MasterNode<
+    M extends RedisModules,
+    F extends RedisFunctions,
+    S extends RedisScripts
+> extends ShardNode<M, F, S> {
+    pubSubClient?: ClientOrPromise<M, F, S>;
+}
+
+export interface Shard<
+    M extends RedisModules,
+    F extends RedisFunctions,
+    S extends RedisScripts
+> {
+    master: MasterNode<M, F, S>;
+    replicas?: Array<ShardNode<M, F, S>>;
+    nodesIterator?: IterableIterator<ShardNode<M, F, S>>;
+}
+
+type ShardWithReplicas<
+    M extends RedisModules,
+    F extends RedisFunctions,
+    S extends RedisScripts
+> = Shard<M, F, S> & Required<Pick<Shard<M, F, S>, 'replicas'>>;
+
+export type PubSubNode<
+    M extends RedisModules,
+    F extends RedisFunctions,
+    S extends RedisScripts
+> = Required<Node<M, F, S>>;
+
+type PubSubToResubscribe = Record<
+    PubSubType.CHANNELS | PubSubType.PATTERNS,
+    PubSubTypeListeners
+>;
+
+export type OnShardedChannelMovedError = (
+    err: unknown,
+    channel: string,
+    listeners?: ChannelListeners
+) => void;
 
 export default class RedisClusterSlots<
     M extends RedisModules,
     F extends RedisFunctions,
     S extends RedisScripts
 > {
+    static #SLOTS = 16384;
+
     readonly #options: RedisClusterOptions<M, F, S>;
     readonly #Client: InstantiableRedisClient<M, F, S>;
-    readonly #onError: OnError;
+    readonly #emit: EventEmitter['emit'];
-    readonly #nodeByAddress = new Map<string, ClusterNode<M, F, S>>();
+    slots = new Array<Shard<M, F, S>>(RedisClusterSlots.#SLOTS);
-    readonly #slots: Array<SlotNodes<M, F, S>> = [];
+    shards = new Array<Shard<M, F, S>>();
+    masters = new Array<ShardNode<M, F, S>>();
+    replicas = new Array<ShardNode<M, F, S>>();
+    readonly nodeByAddress = new Map<string, MasterNode<M, F, S> | ShardNode<M, F, S>>();
+    pubSubNode?: PubSubNode<M, F, S>;
 
-    constructor(options: RedisClusterOptions<M, F, S>, onError: OnError) {
+    #isOpen = false;
-        this.#options = options;
+
-        this.#Client = RedisClient.extend(options);
+    get isOpen() {
-        this.#onError = onError;
+        return this.#isOpen;
     }
 
-    async connect(): Promise<void> {
+    constructor(
-        for (const rootNode of this.#options.rootNodes) {
+        options: RedisClusterOptions<M, F, S>,
-            if (await this.#discoverNodes(rootNode)) return;
+        emit: EventEmitter['emit']
+    ) {
+        this.#options = options;
+        this.#Client = RedisClient.extend(options);
+        this.#emit = emit;
+    }
+
+    async connect() {
+        if (this.#isOpen) {
+            throw new Error('Cluster already open');
+        }
+
+        this.#isOpen = true;
+        try {
+            await this.#discoverWithRootNodes();
+        } catch (err) {
+            this.#isOpen = false;
+            throw err;
+        }
+    }
+
+    async #discoverWithRootNodes() {
+        let start = Math.floor(Math.random() * this.#options.rootNodes.length);
+        for (let i = start; i < this.#options.rootNodes.length; i++) {    
+            if (await this.#discover(this.#options.rootNodes[i])) return;
+        }
+
+        for (let i = 0; i < start; i++) {
+            if (await this.#discover(this.#options.rootNodes[i])) return;
         }
 
         throw new RootNodesUnavailableError();
     }
 
-    async #discoverNodes(clientOptions?: RedisClusterClientOptions): Promise<boolean> {
+    #resetSlots() {
-        const client = this.#initiateClient(clientOptions);
+        this.slots = new Array(RedisClusterSlots.#SLOTS);
+        this.shards = [];
+        this.masters = [];
+        this.replicas = [];
+        this.#randomNodeIterator = undefined;
+    }
+
+    async #discover(rootNode?: RedisClusterClientOptions) {
+        this.#resetSlots();
+        const addressesInUse = new Set<string>();
+
+        try {
+            const shards = await this.#getShards(rootNode),
+                promises: Array<Promise<unknown>> = [],
+                eagerConnect = this.#options.minimizeConnections !== true;
+            for (const { from, to, master, replicas } of shards) {
+                const shard: Shard<M, F, S> = {
+                    master: this.#initiateSlotNode(master, false, eagerConnect, addressesInUse, promises)
+                };
+
+                if (this.#options.useReplicas) {
+                    shard.replicas = replicas.map(replica =>
+                        this.#initiateSlotNode(replica, true, eagerConnect, addressesInUse, promises)
+                    );
+                }
+
+                this.shards.push(shard);
+
+                for (let i = from; i <= to; i++) {
+                    this.slots[i] = shard;
+                }
+            }
+
+            if (this.pubSubNode && !addressesInUse.has(this.pubSubNode.address)) {
+                if (types.isPromise(this.pubSubNode.client)) {
+                    promises.push(
+                        this.pubSubNode.client.then(client => client.disconnect())
+                    );
+                    this.pubSubNode = undefined;
+                } else {
+                    promises.push(this.pubSubNode.client.disconnect());
+                    
+                    const channelsListeners = this.pubSubNode.client.getPubSubListeners(PubSubType.CHANNELS),
+                        patternsListeners = this.pubSubNode.client.getPubSubListeners(PubSubType.PATTERNS);
+
+                    if (channelsListeners.size || patternsListeners.size) {
+                        promises.push(
+                            this.#initiatePubSubClient({
+                                [PubSubType.CHANNELS]: channelsListeners,
+                                [PubSubType.PATTERNS]: patternsListeners
+                            })
+                        );
+                    }
+                }
+            }
+
+            for (const [address, node] of this.nodeByAddress.entries()) {
+                if (addressesInUse.has(address)) continue;
+
+                if (node.client) {
+                    promises.push(
+                        this.#execOnNodeClient(node.client, client => client.disconnect())
+                    );
+                }
+
+                const { pubSubClient } = node as MasterNode<M, F, S>;
+                if (pubSubClient) {
+                    promises.push(
+                        this.#execOnNodeClient(pubSubClient, client => client.disconnect())
+                    );
+                }
+
+                this.nodeByAddress.delete(address);
+            }
+
+            await Promise.all(promises);
+
+            return true;
+        } catch (err) {
+            this.#emit('error', err);
+            return false;
+        }
+    }
+
+    async #getShards(rootNode?: RedisClusterClientOptions) {
+        const client = new this.#Client(
+            this.#clientOptionsDefaults(rootNode, true)
+        );
+
+        client.on('error', err => this.#emit('error', err));
 
         await client.connect();
 
         try {
-            await this.#reset(await client.clusterNodes());
+            // using `CLUSTER SLOTS` and not `CLUSTER SHARDS` to support older versions
-            return true;
+            return await client.clusterSlots();
-        } catch (err) {
-            this.#onError(err);
-            return false;
         } finally {
-            if (client.isOpen) {
             await client.disconnect();
         }
     }
-    }
-
-    #runningRediscoverPromise?: Promise<void>;
-
-    async rediscover(startWith: RedisClientType<M, F, S>): Promise<void> {
-        if (!this.#runningRediscoverPromise) {
-            this.#runningRediscoverPromise = this.#rediscover(startWith)
-                .finally(() => this.#runningRediscoverPromise = undefined);
-        }
-
-        return this.#runningRediscoverPromise;
-    }
-
-    async #rediscover(startWith: RedisClientType<M, F, S>): Promise<void> {
-        if (await this.#discoverNodes(startWith.options)) return;
-
-        for (const { client } of this.#nodeByAddress.values()) {
-            if (client === startWith) continue;
-
-            if (await this.#discoverNodes(client.options)) return;
-        }
-
-        throw new Error('None of the cluster nodes is available');
-    }
-
-    async #reset(masters: Array<RedisClusterMasterNode>): Promise<void> {
-        // Override this.#slots and add not existing clients to this.#nodeByAddress
-        const promises: Array<Promise<void>> = [],
-            clientsInUse = new Set<string>();
-        for (const master of masters) {
-            const slot = {
-                master: this.#initiateClientForNode(master, false, clientsInUse, promises),
-                replicas: this.#options.useReplicas ?
-                    master.replicas.map(replica => this.#initiateClientForNode(replica, true, clientsInUse, promises)) :
-                    [],
-                clientIterator: undefined // will be initiated in use
-            };
-
-            for (const { from, to } of master.slots) {
-                for (let i = from; i <= to; i++) {
-                    this.#slots[i] = slot;
-                }
-            }
-        }
-
-        // Remove unused clients from this.#nodeByAddress using clientsInUse
-        for (const [address, { client }] of this.#nodeByAddress.entries()) {
-            if (clientsInUse.has(address)) continue;
-
-            promises.push(client.disconnect());
-            this.#nodeByAddress.delete(address);
-        }
-
-        await Promise.all(promises);
-    }
-
-    #clientOptionsDefaults(options?: RedisClusterClientOptions): RedisClusterClientOptions | undefined {
-        if (!this.#options.defaults) return options;
-
-        return {
-            ...this.#options.defaults,
-            ...options,
-            socket: this.#options.defaults.socket && options?.socket ? {
-                ...this.#options.defaults.socket,
-                ...options.socket
-            } : this.#options.defaults.socket ?? options?.socket
-        };
-    }
-
-    #initiateClient(options?: RedisClusterClientOptions): RedisClientType<M, F, S> {
-        return new this.#Client(this.#clientOptionsDefaults(options))
-            .on('error', this.#onError);
-    }
 
     #getNodeAddress(address: string): NodeAddress | undefined {
         switch (typeof this.#options.nodeAddressMap) {
@@ -164,111 +261,123 @@ export default class RedisClusterSlots<
         }
     }
 
-    #initiateClientForNode(
+    #clientOptionsDefaults(
-        nodeData: RedisClusterMasterNode | RedisClusterReplicaNode,
+        options?: RedisClusterClientOptions,
-        readonly: boolean,
+        disableReconnect?: boolean
-        clientsInUse: Set<string>,
+    ): RedisClusterClientOptions | undefined {
-        promises: Array<Promise<void>>
+        let result: RedisClusterClientOptions | undefined;
-    ): ClusterNode<M, F, S> {
+        if (this.#options.defaults) {
-        const address = `${nodeData.host}:${nodeData.port}`;
+            let socket;
-        clientsInUse.add(address);
+            if (this.#options.defaults.socket) {
+                socket = options?.socket ? {
+                    ...this.#options.defaults.socket,
+                    ...options.socket
+                } : this.#options.defaults.socket;
+            } else {
+                socket = options?.socket;
+            }
 
-        let node = this.#nodeByAddress.get(address);
+            result = {
+                ...this.#options.defaults,
+                ...options,
+                socket
+            };
+        } else {
+            result = options;
+        }
+        
+        if (disableReconnect) {
+            result ??= {};
+            result.socket ??= {};
+            result.socket.reconnectStrategy = false;
+        }
+
+        return result;
+    }
+
+    #initiateSlotNode(
+        { id, ip, port }: ClusterSlotsNode,
+        readonly: boolean,
+        eagerConnent: boolean,
+        addressesInUse: Set<string>,
+        promises: Array<Promise<unknown>>
+    ) {
+        const address = `${ip}:${port}`;
+        addressesInUse.add(address);
+
+        let node = this.nodeByAddress.get(address);
         if (!node) {
             node = {
-                id: nodeData.id,
+                id,
-                client: this.#initiateClient({
+                host: ip,
-                    socket: this.#getNodeAddress(address) ?? {
+                port,
-                        host: nodeData.host,
+                address,
-                        port: nodeData.port
+                readonly,
-                    },
+                client: undefined
-                    readonly
-                })
             };
-            promises.push(node.client.connect());
+            
-            this.#nodeByAddress.set(address, node);
+            if (eagerConnent) {
+                promises.push(this.#createNodeClient(node));
             }
             
+            this.nodeByAddress.set(address, node);
+        }
+
+        (readonly ? this.replicas : this.masters).push(node);
+
         return node;
     }
 
-    getSlotMaster(slot: number): ClusterNode<M, F, S> {
+    async #createClient(
-        return this.#slots[slot].master;
+        node: ShardNode<M, F, S>,
-    }
+        readonly = node.readonly
-
+    ) {
-    *#slotClientIterator(slotNumber: number): IterableIterator<RedisClientType<M, F, S>> {
+        const client = new this.#Client(
-        const slot = this.#slots[slotNumber];
+            this.#clientOptionsDefaults({
-        yield slot.master.client;
+                socket: this.#getNodeAddress(node.address) ?? {
-
+                    host: node.host,
-        for (const replica of slot.replicas) {
+                    port: node.port
-            yield replica.client;
+                },
-        }
+                readonly
-    }
+            })
-
-    #getSlotClient(slotNumber: number): RedisClientType<M, F, S> {
-        const slot = this.#slots[slotNumber];
-        if (!slot.clientIterator) {
-            slot.clientIterator = this.#slotClientIterator(slotNumber);
-        }
-
-        const {done, value} = slot.clientIterator.next();
-        if (done) {
-            slot.clientIterator = undefined;
-            return this.#getSlotClient(slotNumber);
-        }
-
-        return value;
-    }
-
-    #randomClientIterator?: IterableIterator<ClusterNode<M, F, S>>;
-
-    #getRandomClient(): RedisClientType<M, F, S> {
-        if (!this.#nodeByAddress.size) {
-            throw new Error('Cluster is not connected');
-        }
-
-        if (!this.#randomClientIterator) {
-            this.#randomClientIterator = this.#nodeByAddress.values();
-        }
-
-        const {done, value} = this.#randomClientIterator.next();
-        if (done) {
-            this.#randomClientIterator = undefined;
-            return this.#getRandomClient();
-        }
-
-        return value.client;
-    }
-
-    getClient(firstKey?: RedisCommandArgument, isReadonly?: boolean): RedisClientType<M, F, S> {
-        if (!firstKey) {
-            return this.#getRandomClient();
-        }
-
-        const slot = calculateSlot(firstKey);
-        if (!isReadonly || !this.#options.useReplicas) {
-            return this.getSlotMaster(slot).client;
-        }
-
-        return this.#getSlotClient(slot);
-    }
-
-    getMasters(): Array<ClusterNode<M, F, S>> {
-        const masters = [];
-        for (const node of this.#nodeByAddress.values()) {
-            if (node.client.options?.readonly) continue;
-
-            masters.push(node);
-        }
-
-        return masters;
-    }
-
-    getNodeByAddress(address: string): ClusterNode<M, F, S> | undefined {
-        const mappedAddress = this.#getNodeAddress(address);
-        return this.#nodeByAddress.get(
-            mappedAddress ? `${mappedAddress.host}:${mappedAddress.port}` : address
         );
+        client.on('error', err => this.#emit('error', err));
+
+        await client.connect();
+
+        return client;
+    }
+
+    #createNodeClient(node: ShardNode<M, F, S>) {
+        const promise = this.#createClient(node)
+            .then(client => {
+                node.client = client;
+                return client;
+            })
+            .catch(err => {
+                node.client = undefined;
+                throw err;
+            });
+        node.client = promise;
+        return promise;
+    }
+
+    nodeClient(node: ShardNode<M, F, S>) {
+        return node.client ?? this.#createNodeClient(node);
+    }
+
+    #runningRediscoverPromise?: Promise<void>;
+
+    async rediscover(startWith: RedisClientType<M, F, S>): Promise<void> {
+        this.#runningRediscoverPromise ??= this.#rediscover(startWith)
+            .finally(() => this.#runningRediscoverPromise = undefined);
+        return this.#runningRediscoverPromise;
+    }
+
+    async #rediscover(startWith: RedisClientType<M, F, S>): Promise<void> {
+        if (await this.#discover(startWith.options)) return;
+
+        return this.#discoverWithRootNodes();
     }
 
     quit(): Promise<void> {
@@ -280,14 +389,233 @@ export default class RedisClusterSlots<
     }
 
     async #destroy(fn: (client: RedisClientType<M, F, S>) => Promise<unknown>): Promise<void> {
+        this.#isOpen = false;
+
         const promises = [];
-        for (const { client } of this.#nodeByAddress.values()) {
+        for (const { master, replicas } of this.shards) {
-            promises.push(fn(client));
+            if (master.client) {
+                promises.push(
+                    this.#execOnNodeClient(master.client, fn)
+                );
             }
 
-        await Promise.all(promises);
+            if (master.pubSubClient) {
+                promises.push(
+                    this.#execOnNodeClient(master.pubSubClient, fn)
+                );
+            }
 
-        this.#nodeByAddress.clear();
+            if (replicas) {
-        this.#slots.splice(0);
+                for (const { client } of replicas) {
+                    if (client) {
+                        promises.push(
+                            this.#execOnNodeClient(client, fn)
+                        );
+                    }
+                }
+            }
+        }
+
+        if (this.pubSubNode) {
+            promises.push(this.#execOnNodeClient(this.pubSubNode.client, fn));
+            this.pubSubNode = undefined;
+        }
+
+        this.#resetSlots();
+        this.nodeByAddress.clear();
+
+        await Promise.allSettled(promises);
+    }
+
+    #execOnNodeClient(
+        client: ClientOrPromise<M, F, S>,
+        fn: (client: RedisClientType<M, F, S>) => Promise<unknown>
+    ) {
+        return types.isPromise(client) ?
+            client.then(fn) :
+            fn(client);
+    }
+
+    getClient(
+        firstKey: RedisCommandArgument | undefined,
+        isReadonly: boolean | undefined
+    ): ClientOrPromise<M, F, S> {
+        if (!firstKey) {
+            return this.nodeClient(this.getRandomNode());
+        }
+
+        const slotNumber = calculateSlot(firstKey);
+        if (!isReadonly) {
+            return this.nodeClient(this.slots[slotNumber].master);
+        }
+
+        return this.nodeClient(this.getSlotRandomNode(slotNumber));
+    }
+
+    *#iterateAllNodes() {
+        let i = Math.floor(Math.random() * (this.masters.length + this.replicas.length));
+        if (i < this.masters.length) {
+            do {
+                yield this.masters[i];
+            } while (++i < this.masters.length);
+
+            for (const replica of this.replicas) {
+                yield replica;
+            }
+        } else {
+            i -= this.masters.length;
+            do {
+                yield this.replicas[i];
+            } while (++i < this.replicas.length);
+        }
+
+        while (true) {
+            for (const master of this.masters) {
+                yield master;
+            }
+
+            for (const replica of this.replicas) {
+                yield replica;
+            }
+        }
+    }
+
+    #randomNodeIterator?: IterableIterator<ShardNode<M, F, S>>;
+
+    getRandomNode() {
+        this.#randomNodeIterator ??= this.#iterateAllNodes();
+        return this.#randomNodeIterator.next().value as ShardNode<M, F, S>;
+    }
+
+    *#slotNodesIterator(slot: ShardWithReplicas<M, F, S>) {
+        let i = Math.floor(Math.random() * (1 + slot.replicas.length));
+        if (i < slot.replicas.length) {
+            do {
+                yield slot.replicas[i];
+            } while (++i < slot.replicas.length);
+        }
+
+        while (true) {
+            yield slot.master;
+            
+            for (const replica of slot.replicas) {
+                yield replica;
+            }
+        }
+    }
+
+    getSlotRandomNode(slotNumber: number) {
+        const slot = this.slots[slotNumber];
+        if (!slot.replicas?.length) {
+            return slot.master;
+        }
+
+        slot.nodesIterator ??= this.#slotNodesIterator(slot as ShardWithReplicas<M, F, S>);
+        return slot.nodesIterator.next().value as ShardNode<M, F, S>;
+    }
+
+    getMasterByAddress(address: string) {
+        const master = this.nodeByAddress.get(address);
+        if (!master) return;
+
+        return this.nodeClient(master);
+    }
+
+    getPubSubClient() {
+        return this.pubSubNode ?
+            this.pubSubNode.client :
+            this.#initiatePubSubClient();
+    }
+
+    async #initiatePubSubClient(toResubscribe?: PubSubToResubscribe) {
+        const index = Math.floor(Math.random() * (this.masters.length + this.replicas.length)),
+            node = index < this.masters.length ?
+                this.masters[index] :
+                this.replicas[index - this.masters.length];
+    
+        this.pubSubNode = {
+            address: node.address,
+            client: this.#createClient(node, true)
+                .then(async client => {
+                    if (toResubscribe) {
+                        await Promise.all([
+                            client.extendPubSubListeners(PubSubType.CHANNELS, toResubscribe[PubSubType.CHANNELS]),
+                            client.extendPubSubListeners(PubSubType.PATTERNS, toResubscribe[PubSubType.PATTERNS])
+                        ]);
+                    }
+                    
+                    this.pubSubNode!.client = client;
+                    return client;
+                })
+                .catch(err => {
+                    this.pubSubNode = undefined;
+                    throw err;
+                })
+        };
+        
+        return this.pubSubNode.client as Promise<RedisClientType<M, F, S>>;
+    }
+
+    async executeUnsubscribeCommand(
+        unsubscribe: (client: RedisClientType<M, F, S>) => Promise<void>
+    ): Promise<void> {
+        const client = await this.getPubSubClient();
+        await unsubscribe(client);
+
+        if (!client.isPubSubActive) {
+            await client.disconnect();
+            this.pubSubNode = undefined;
+        }
+    }
+
+    getShardedPubSubClient(channel: string) {
+        const { master } = this.slots[calculateSlot(channel)];
+        return master.pubSubClient ?? this.#initiateShardedPubSubClient(master);
+    }
+
+    #initiateShardedPubSubClient(master: MasterNode<M, F, S>) {
+        const promise = this.#createClient(master, true)
+            .then(client => {
+                client.on('server-sunsubscribe', async (channel, listeners) => {
+                    try {
+                        await this.rediscover(client);
+                        const redirectTo = await this.getShardedPubSubClient(channel);
+                        redirectTo.extendPubSubChannelListeners(
+                            PubSubType.SHARDED,
+                            channel,
+                            listeners
+                        );
+                    } catch (err) {
+                        this.#emit('sharded-shannel-moved-error', err, channel, listeners);
+                    }
+                });
+
+                master.pubSubClient = client;
+                return client;
+            })
+            .catch(err => {
+                master.pubSubClient = undefined;
+                throw err;
+            });
+
+        master.pubSubClient = promise;
+
+        return promise;
+    }
+
+    async executeShardedUnsubscribeCommand(
+        channel: string,
+        unsubscribe: (client: RedisClientType<M, F, S>) => Promise<void>
+    ): Promise<void> {
+        const { master } = this.slots[calculateSlot(channel)];
+        if (!master.pubSubClient) return Promise.resolve();
+
+        const client = await master.pubSubClient;
+        await unsubscribe(client);
+
+        if (!client.isPubSubActive) {
+            await client.disconnect();
+            master.pubSubClient = undefined;
+        }
     }
 }

packages/client/lib/cluster/commands.ts

@@ -135,6 +135,7 @@ import * as SORT_RO from '../commands/SORT_RO';
 import * as SORT_STORE from '../commands/SORT_STORE';
 import * as SORT from '../commands/SORT';
 import * as SPOP from '../commands/SPOP';
+import * as SPUBLISH from '../commands/SPUBLISH';
 import * as SRANDMEMBER_COUNT from '../commands/SRANDMEMBER_COUNT';
 import * as SRANDMEMBER from '../commands/SRANDMEMBER';
 import * as SREM from '../commands/SREM';
@@ -483,6 +484,8 @@ export default {
     sort: SORT,
     SPOP,
     sPop: SPOP,
+    SPUBLISH,
+    sPublish: SPUBLISH,
     SRANDMEMBER_COUNT,
     sRandMemberCount: SRANDMEMBER_COUNT,
     SRANDMEMBER,

packages/client/lib/cluster/index.spec.ts

@@ -1,25 +1,29 @@
 import { strict as assert } from 'assert';
-import testUtils, { GLOBAL } from '../test-utils';
+import testUtils, { GLOBAL, waitTillBeenCalled } from '../test-utils';
 import RedisCluster from '.';
 import { ClusterSlotStates } from '../commands/CLUSTER_SETSLOT';
 import { SQUARE_SCRIPT } from '../client/index.spec';
 import { RootNodesUnavailableError } from '../errors';
-
+import { spy } from 'sinon';
-// We need to use 'require', because it's not possible with Typescript to import
+import { promiseTimeout } from '../utils';
-// function that are exported as 'module.exports = function`, without esModuleInterop
+import RedisClient from '../client';
-// set to true.
-const calculateSlot = require('cluster-key-slot');
 
 describe('Cluster', () => {
     testUtils.testWithCluster('sendCommand', async cluster => {
-        await cluster.publish('channel', 'message');
+        assert.equal(
-        await cluster.set('a', 'b');
+            await cluster.sendCommand(undefined, true, ['PING']),
-        await cluster.set('a{a}', 'bb');
+            'PONG'
-        await cluster.set('aa', 'bb');
+        );
-        await cluster.get('aa');
+    }, GLOBAL.CLUSTERS.OPEN);
-        await cluster.get('aa');
+
-        await cluster.get('aa');
+    testUtils.testWithCluster('isOpen', async cluster => {
-        await cluster.get('aa');
+        assert.equal(cluster.isOpen, true);
+        await cluster.disconnect();
+        assert.equal(cluster.isOpen, false);
+    }, GLOBAL.CLUSTERS.OPEN);
+
+    testUtils.testWithCluster('connect should throw if already connected', async cluster => {
+        await assert.rejects(cluster.connect());
     }, GLOBAL.CLUSTERS.OPEN);
 
     testUtils.testWithCluster('multi', async cluster => {
@@ -64,54 +68,279 @@ describe('Cluster', () => {
     });
 
     testUtils.testWithCluster('should handle live resharding', async cluster => {
-        const key = 'key',
+        const slot = 12539,
+            key = 'key',
             value = 'value';
         await cluster.set(key, value);
 
-        const slot = calculateSlot(key),
+        const importing = cluster.slots[0].master,
-            source = cluster.getSlotMaster(slot),
+            migrating = cluster.slots[slot].master,
-            destination = cluster.getMasters().find(node => node.id !== source.id)!;
+            [ importingClient, migratingClient ] = await Promise.all([
-
+                cluster.nodeClient(importing),
-        await Promise.all([
+                cluster.nodeClient(migrating)
-            source.client.clusterSetSlot(slot, ClusterSlotStates.MIGRATING, destination.id),
-            destination.client.clusterSetSlot(slot, ClusterSlotStates.IMPORTING, destination.id)
             ]);
 
-        // should be able to get the key from the source node using "ASKING"
+        await Promise.all([
+            importingClient.clusterSetSlot(slot, ClusterSlotStates.IMPORTING, migrating.id),
+            migratingClient.clusterSetSlot(slot, ClusterSlotStates.MIGRATING, importing.id)
+        ]);
+
+        // should be able to get the key from the migrating node
         assert.equal(
             await cluster.get(key),
             value
         );
 
-        await Promise.all([
+        await migratingClient.migrate(
-            source.client.migrate(
+            importing.host,
-                '127.0.0.1',
+            importing.port,
-                (<any>destination.client.options).socket.port,
             key,
             0,
             10
-            )
+        );
-        ]);
 
-        // should be able to get the key from the destination node using the "ASKING" command
+        // should be able to get the key from the importing node using `ASKING`
         assert.equal(
             await cluster.get(key),
             value
         );
 
-        await Promise.all(
+        await Promise.all([
-            cluster.getMasters().map(({ client }) => {
+            importingClient.clusterSetSlot(slot, ClusterSlotStates.NODE, importing.id),
-                return client.clusterSetSlot(slot, ClusterSlotStates.NODE, destination.id);
+            migratingClient.clusterSetSlot(slot, ClusterSlotStates.NODE, importing.id),
-            })
+        ]);
-        );
 
-        // should handle "MOVED" errors
+        // should handle `MOVED` errors
         assert.equal(
             await cluster.get(key),
             value
         );
     }, {
         serverArguments: [],
-        numberOfNodes: 2
+        numberOfMasters: 2
+    });
+
+    testUtils.testWithCluster('getRandomNode should spread the the load evenly', async cluster => {
+        const totalNodes = cluster.masters.length + cluster.replicas.length,
+            ids = new Set<string>();
+        for (let i = 0; i < totalNodes; i++) {
+            ids.add(cluster.getRandomNode().id);
+        }
+        
+        assert.equal(ids.size, totalNodes);
+    }, GLOBAL.CLUSTERS.WITH_REPLICAS);
+
+    testUtils.testWithCluster('getSlotRandomNode should spread the the load evenly', async cluster => {
+        const totalNodes = 1 + cluster.slots[0].replicas!.length,
+            ids = new Set<string>();
+        for (let i = 0; i < totalNodes; i++) {
+            ids.add(cluster.getSlotRandomNode(0).id);
+        }
+        
+        assert.equal(ids.size, totalNodes);
+    }, GLOBAL.CLUSTERS.WITH_REPLICAS);
+
+    testUtils.testWithCluster('cluster topology', async cluster => {
+        assert.equal(cluster.slots.length, 16384);
+        const { numberOfMasters, numberOfReplicas } = GLOBAL.CLUSTERS.WITH_REPLICAS;
+        assert.equal(cluster.shards.length, numberOfMasters);
+        assert.equal(cluster.masters.length, numberOfMasters);
+        assert.equal(cluster.replicas.length, numberOfReplicas * numberOfMasters);
+        assert.equal(cluster.nodeByAddress.size, numberOfMasters + numberOfMasters * numberOfReplicas);
+    }, GLOBAL.CLUSTERS.WITH_REPLICAS);
+
+    testUtils.testWithCluster('getMasters should be backwards competiable (without `minimizeConnections`)', async cluster => {
+        const masters = cluster.getMasters();
+        assert.ok(Array.isArray(masters));
+        for (const master of masters) {
+            assert.equal(typeof master.id, 'string');
+            assert.ok(master.client instanceof RedisClient);
+        }
+    }, {
+        ...GLOBAL.CLUSTERS.OPEN,
+        clusterConfiguration: {
+            minimizeConnections: undefined // reset to default
+        }
+    });
+
+    testUtils.testWithCluster('getSlotMaster should be backwards competiable (without `minimizeConnections`)', async cluster => {
+        const master = cluster.getSlotMaster(0);
+        assert.equal(typeof master.id, 'string');
+        assert.ok(master.client instanceof RedisClient);
+    }, {
+        ...GLOBAL.CLUSTERS.OPEN,
+        clusterConfiguration: {
+            minimizeConnections: undefined // reset to default
+        }
+    });
+
+    testUtils.testWithCluster('should throw CROSSSLOT error', async cluster => {
+        await assert.rejects(cluster.mGet(['a', 'b']));
+    }, GLOBAL.CLUSTERS.OPEN);
+
+    describe('minimizeConnections', () => {
+        testUtils.testWithCluster('false', async cluster => {
+            for (const master of cluster.masters) {
+                assert.ok(master.client instanceof RedisClient);
+            }
+        }, {
+            ...GLOBAL.CLUSTERS.OPEN,
+            clusterConfiguration: {
+                minimizeConnections: false
+            }
+        });
+
+        testUtils.testWithCluster('true', async cluster => {
+            for (const master of cluster.masters) {
+                assert.equal(master.client, undefined);
+            }
+        }, {
+            ...GLOBAL.CLUSTERS.OPEN,
+            clusterConfiguration: {
+                minimizeConnections: true
+            }
+        });
+    });
+
+    describe('PubSub', () => {
+        testUtils.testWithCluster('subscribe & unsubscribe', async cluster => {
+            const listener = spy();
+
+            await cluster.subscribe('channel', listener);
+
+            await Promise.all([
+                waitTillBeenCalled(listener),
+                cluster.publish('channel', 'message')
+            ]);
+            
+            assert.ok(listener.calledOnceWithExactly('message', 'channel'));
+
+            await cluster.unsubscribe('channel', listener);
+
+            assert.equal(cluster.pubSubNode, undefined);
+        }, GLOBAL.CLUSTERS.OPEN);
+
+        testUtils.testWithCluster('psubscribe & punsubscribe', async cluster => {
+            const listener = spy();
+
+            await cluster.pSubscribe('channe*', listener);
+
+            await Promise.all([
+                waitTillBeenCalled(listener),
+                cluster.publish('channel', 'message')
+            ]);
+            
+            assert.ok(listener.calledOnceWithExactly('message', 'channel'));
+
+            await cluster.pUnsubscribe('channe*', listener);
+
+            assert.equal(cluster.pubSubNode, undefined);
+        }, GLOBAL.CLUSTERS.OPEN);        
+
+        testUtils.testWithCluster('should move listeners when PubSub node disconnects from the cluster', async cluster => {
+            const listener = spy();
+            await cluster.subscribe('channel', listener);
+
+            assert.ok(cluster.pubSubNode);
+            const [ migrating, importing ] = cluster.masters[0].address === cluster.pubSubNode.address ?
+                    cluster.masters :
+                    [cluster.masters[1], cluster.masters[0]],
+                [ migratingClient, importingClient ] = await Promise.all([
+                    cluster.nodeClient(migrating),
+                    cluster.nodeClient(importing)
+                ]);
+
+            const range = cluster.slots[0].master === migrating ? {
+                key: 'bar', // 5061
+                start: 0,
+                end: 8191
+            } : {
+                key: 'foo', // 12182
+                start: 8192,
+                end: 16383
+            };
+
+            await Promise.all([
+                migratingClient.clusterDelSlotsRange(range),
+                importingClient.clusterDelSlotsRange(range),
+                importingClient.clusterAddSlotsRange(range)
+            ]);
+
+            // wait for migrating node to be notified about the new topology
+            while ((await migratingClient.clusterInfo()).state !== 'ok') {
+                await promiseTimeout(50);
+            }
+
+            // make sure to cause `MOVED` error
+            await cluster.get(range.key);
+
+            await Promise.all([
+                cluster.publish('channel', 'message'),
+                waitTillBeenCalled(listener)
+            ]);
+            
+            assert.ok(listener.calledOnceWithExactly('message', 'channel'));
+        }, {
+            serverArguments: [],
+            numberOfMasters: 2,
+            minimumDockerVersion: [7]
+        });
+
+        testUtils.testWithCluster('ssubscribe & sunsubscribe', async cluster => {
+            const listener = spy();
+
+            await cluster.sSubscribe('channel', listener);
+
+            await Promise.all([
+                waitTillBeenCalled(listener),
+                cluster.sPublish('channel', 'message')
+            ]);
+            
+            assert.ok(listener.calledOnceWithExactly('message', 'channel'));
+
+            await cluster.sUnsubscribe('channel', listener);
+
+            // 10328 is the slot of `channel`
+            assert.equal(cluster.slots[10328].master.pubSubClient, undefined);
+        }, {
+            ...GLOBAL.CLUSTERS.OPEN,
+            minimumDockerVersion: [7]
+        });
+
+        testUtils.testWithCluster('should handle sharded-channel-moved events', async cluster => {
+            const SLOT = 10328,
+                migrating = cluster.slots[SLOT].master,
+                importing = cluster.masters.find(master => master !== migrating)!,
+                [ migratingClient, importingClient ] = await Promise.all([
+                    cluster.nodeClient(migrating),
+                    cluster.nodeClient(importing)
+                ]);
+
+            await Promise.all([
+                migratingClient.clusterDelSlots(SLOT),
+                importingClient.clusterDelSlots(SLOT),
+                importingClient.clusterAddSlots(SLOT)
+            ]);
+
+            // wait for migrating node to be notified about the new topology
+            while ((await migratingClient.clusterInfo()).state !== 'ok') {
+                await promiseTimeout(50);
+            }
+
+            const listener = spy();
+
+            // will trigger `MOVED` error
+            await cluster.sSubscribe('channel', listener);
+
+            await Promise.all([
+                waitTillBeenCalled(listener),
+                cluster.sPublish('channel', 'message')
+            ]);
+            
+            assert.ok(listener.calledOnceWithExactly('message', 'channel'));
+        }, {
+            serverArguments: [],
+            minimumDockerVersion: [7]
+        });
     });
 });

packages/client/lib/cluster/index.ts

@@ -1,11 +1,13 @@
 import COMMANDS from './commands';
 import { RedisCommand, RedisCommandArgument, RedisCommandArguments, RedisCommandRawReply, RedisCommandReply, RedisFunctions, RedisModules, RedisExtensions, RedisScript, RedisScripts, RedisCommandSignature, RedisFunction } from '../commands';
 import { ClientCommandOptions, RedisClientOptions, RedisClientType, WithFunctions, WithModules, WithScripts } from '../client';
-import RedisClusterSlots, { ClusterNode, NodeAddressMap } from './cluster-slots';
+import RedisClusterSlots, { NodeAddressMap, ShardNode } from './cluster-slots';
 import { attachExtensions, transformCommandReply, attachCommands, transformCommandArguments } from '../commander';
 import { EventEmitter } from 'events';
 import RedisClusterMultiCommand, { InstantiableRedisClusterMultiCommandType, RedisClusterMultiCommandType } from './multi-command';
 import { RedisMultiQueuedCommand } from '../multi-command';
+import { PubSubListener } from '../client/pub-sub';
+import { ErrorReply } from '../errors';
 
 export type RedisClusterClientOptions = Omit<
     RedisClientOptions,
@@ -17,10 +19,34 @@ export interface RedisClusterOptions<
     F extends RedisFunctions = Record<string, never>,
     S extends RedisScripts = Record<string, never>
 > extends RedisExtensions<M, F, S> {
+    /**
+     * Should contain details for some of the cluster nodes that the client will use to discover 
+     * the "cluster topology". We recommend including details for at least 3 nodes here.
+     */
     rootNodes: Array<RedisClusterClientOptions>;
+    /**
+     * Default values used for every client in the cluster. Use this to specify global values, 
+     * for example: ACL credentials, timeouts, TLS configuration etc.
+     */
     defaults?: Partial<RedisClusterClientOptions>;
+    /**
+     * When `true`, `.connect()` will only discover the cluster topology, without actually connecting to all the nodes.
+     * Useful for short-term or PubSub-only connections.
+     */
+    minimizeConnections?: boolean;
+    /**
+     * When `true`, distribute load by executing readonly commands (such as `GET`, `GEOSEARCH`, etc.) across all cluster nodes. When `false`, only use master nodes.
+     */
     useReplicas?: boolean;
+    /**
+     * The maximum number of times a command will be redirected due to `MOVED` or `ASK` errors.
+     */
     maxCommandRedirections?: number;
+    /**
+     * Mapping between the addresses in the cluster (see `CLUSTER SHARDS`) and the addresses the client should connect to
+     * Useful when the cluster is running on another network
+     * 
+     */
     nodeAddressMap?: NodeAddressMap;
 }
 
@@ -70,14 +96,44 @@ export default class RedisCluster<
     }
 
     readonly #options: RedisClusterOptions<M, F, S>;
+
     readonly #slots: RedisClusterSlots<M, F, S>;
+    
+    get slots() {
+        return this.#slots.slots;
+    }
+
+    get shards() {
+        return this.#slots.shards;
+    }
+
+    get masters() {
+        return this.#slots.masters;
+    }
+
+    get replicas() {
+        return this.#slots.replicas;
+    }
+
+    get nodeByAddress() {
+        return this.#slots.nodeByAddress;
+    }
+
+    get pubSubNode() {
+        return this.#slots.pubSubNode;
+    }
+
     readonly #Multi: InstantiableRedisClusterMultiCommandType<M, F, S>;
 
+    get isOpen() {
+        return this.#slots.isOpen;
+    }
+
     constructor(options: RedisClusterOptions<M, F, S>) {
         super();
 
         this.#options = options;
-        this.#slots = new RedisClusterSlots(options, err => this.emit('error', err));
+        this.#slots = new RedisClusterSlots(options, this.emit.bind(this));
         this.#Multi = RedisClusterMultiCommand.extend(options);
     }
 
@@ -88,7 +144,7 @@ export default class RedisCluster<
         });
     }
 
-    async connect(): Promise<void> {
+    connect() {
         return this.#slots.connect();
     }
 
@@ -188,34 +244,33 @@ export default class RedisCluster<
         executor: (client: RedisClientType<M, F, S>) => Promise<Reply>
     ): Promise<Reply> {
         const maxCommandRedirections = this.#options.maxCommandRedirections ?? 16;
-        let client = this.#slots.getClient(firstKey, isReadonly);
+        let client = await this.#slots.getClient(firstKey, isReadonly);
         for (let i = 0;; i++) {
             try {
                 return await executor(client);
             } catch (err) {
-                if (++i > maxCommandRedirections || !(err instanceof Error)) {
+                if (++i > maxCommandRedirections || !(err instanceof ErrorReply)) {
                     throw err;
                 }
 
                 if (err.message.startsWith('ASK')) {
                     const address = err.message.substring(err.message.lastIndexOf(' ') + 1);
-                    if (this.#slots.getNodeByAddress(address)?.client === client) {
+                    let redirectTo = await this.#slots.getMasterByAddress(address);
-                        await client.asking();
+                    if (!redirectTo) {
-                        continue;
+                        await this.#slots.rediscover(client);
+                        redirectTo = await this.#slots.getMasterByAddress(address);
                     }
 
-                    await this.#slots.rediscover(client);
-                    const redirectTo = this.#slots.getNodeByAddress(address);
                     if (!redirectTo) {
                         throw new Error(`Cannot find node ${address}`);
                     }
 
-                    await redirectTo.client.asking();
+                    await redirectTo.asking();
-                    client = redirectTo.client;
+                    client = redirectTo;
                     continue;
                 } else if (err.message.startsWith('MOVED')) {
                     await this.#slots.rediscover(client);
-                    client = this.#slots.getClient(firstKey, isReadonly);
+                    client = await this.#slots.getClient(firstKey, isReadonly);
                     continue;
                 }
 
@@ -239,14 +294,94 @@ export default class RedisCluster<
 
     multi = this.MULTI;
 
-    getMasters(): Array<ClusterNode<M, F, S>> {
+    async SUBSCRIBE<T extends boolean = false>(
-        return this.#slots.getMasters();
+        channels: string | Array<string>,
+        listener: PubSubListener<T>,
+        bufferMode?: T
+    ) {
+        return (await this.#slots.getPubSubClient())
+            .SUBSCRIBE(channels, listener, bufferMode);
     }
 
-    getSlotMaster(slot: number): ClusterNode<M, F, S> {
+    subscribe = this.SUBSCRIBE;
-        return this.#slots.getSlotMaster(slot);
+
+    async UNSUBSCRIBE<T extends boolean = false>(
+        channels?: string | Array<string>,
+        listener?: PubSubListener<boolean>,
+        bufferMode?: T
+    ) {
+        return this.#slots.executeUnsubscribeCommand(client => 
+            client.UNSUBSCRIBE(channels, listener, bufferMode)
+        );
     }
 
+    unsubscribe = this.UNSUBSCRIBE;
+
+    async PSUBSCRIBE<T extends boolean = false>(
+        patterns: string | Array<string>,
+        listener: PubSubListener<T>,
+        bufferMode?: T
+    ) {
+        return (await this.#slots.getPubSubClient())
+            .PSUBSCRIBE(patterns, listener, bufferMode);
+    }
+
+    pSubscribe = this.PSUBSCRIBE;
+
+    async PUNSUBSCRIBE<T extends boolean = false>(
+        patterns?: string | Array<string>,
+        listener?: PubSubListener<T>,
+        bufferMode?: T
+    ) {
+        return this.#slots.executeUnsubscribeCommand(client => 
+            client.PUNSUBSCRIBE(patterns, listener, bufferMode)
+        );
+    }
+
+    pUnsubscribe = this.PUNSUBSCRIBE;
+
+    async SSUBSCRIBE<T extends boolean = false>(
+        channels: string | Array<string>,
+        listener: PubSubListener<T>,
+        bufferMode?: T
+    ) { 
+        const maxCommandRedirections = this.#options.maxCommandRedirections ?? 16,
+            firstChannel = Array.isArray(channels) ? channels[0] : channels;
+        let client = await this.#slots.getShardedPubSubClient(firstChannel);
+        for (let i = 0;; i++) {
+            try {
+                return await client.SSUBSCRIBE(channels, listener, bufferMode);
+            } catch (err) {
+                if (++i > maxCommandRedirections || !(err instanceof ErrorReply)) {
+                    throw err;
+                }
+
+                if (err.message.startsWith('MOVED')) {
+                    await this.#slots.rediscover(client);
+                    client = await this.#slots.getShardedPubSubClient(firstChannel);
+                    continue;
+                }
+
+                throw err;
+            }
+        }
+    }
+
+    sSubscribe = this.SSUBSCRIBE;
+
+    SUNSUBSCRIBE<T extends boolean = false>(
+        channels: string | Array<string>,
+        listener: PubSubListener<T>,
+        bufferMode?: T
+    ) {
+        return this.#slots.executeShardedUnsubscribeCommand(
+            Array.isArray(channels) ? channels[0] : channels,
+            client => client.SUNSUBSCRIBE(channels, listener, bufferMode)
+        );
+    }
+
+    sUnsubscribe = this.SUNSUBSCRIBE;
+
     quit(): Promise<void> {
         return this.#slots.quit();
     }
@@ -254,6 +389,32 @@ export default class RedisCluster<
     disconnect(): Promise<void> {
         return this.#slots.disconnect();
     }
+
+    nodeClient(node: ShardNode<M, F, S>) {
+        return this.#slots.nodeClient(node); 
+    }
+
+    getRandomNode() {
+        return this.#slots.getRandomNode();
+    }
+
+    getSlotRandomNode(slot: number) {
+        return this.#slots.getSlotRandomNode(slot);
+    }
+
+    /**
+     * @deprecated use `.masters` instead
+     */
+    getMasters() {
+        return this.masters;
+    }
+
+    /**
+     * @deprecated use `.slots[<SLOT>]` instead
+     */
+    getSlotMaster(slot: number) {
+        return this.slots[slot].master;
+    }
 }
 
 attachCommands({

packages/client/lib/commands/CLUSTER_BUMPEPOCH.spec.ts

@@ -11,8 +11,9 @@ describe('CLUSTER BUMPEPOCH', () => {
     });
 
     testUtils.testWithCluster('clusterNode.clusterBumpEpoch', async cluster => {
+        const client = await cluster.nodeClient(cluster.masters[0]);
         assert.equal(
-            typeof await cluster.getSlotMaster(0).client.clusterBumpEpoch(),
+            typeof await client.clusterBumpEpoch(),
             'string'
         );
     }, GLOBAL.SERVERS.OPEN);

packages/client/lib/commands/CLUSTER_COUNT-FAILURE-REPORTS.spec.ts

@@ -11,7 +11,7 @@ describe('CLUSTER COUNT-FAILURE-REPORTS', () => {
     });
 
     testUtils.testWithCluster('clusterNode.clusterCountFailureReports', async cluster => {
-        const { client } = cluster.getSlotMaster(0);
+        const client = await cluster.nodeClient(cluster.masters[0]);
         assert.equal(
             typeof await client.clusterCountFailureReports(
                 await client.clusterMyId()

packages/client/lib/commands/CLUSTER_COUNTKEYSINSLOT.spec.ts

@@ -11,8 +11,9 @@ describe('CLUSTER COUNTKEYSINSLOT', () => {
     });
 
     testUtils.testWithCluster('clusterNode.clusterCountKeysInSlot', async cluster => {
+        const client = await cluster.nodeClient(cluster.masters[0]);
         assert.equal(
-            typeof await cluster.getSlotMaster(0).client.clusterCountKeysInSlot(0),
+            typeof await client.clusterCountKeysInSlot(0),
             'number'
         );
     }, GLOBAL.CLUSTERS.OPEN);

packages/client/lib/commands/CLUSTER_GETKEYSINSLOT.spec.ts

@@ -11,7 +11,8 @@ describe('CLUSTER GETKEYSINSLOT', () => {
     });
 
     testUtils.testWithCluster('clusterNode.clusterGetKeysInSlot', async cluster => {
-        const reply = await cluster.getSlotMaster(0).client.clusterGetKeysInSlot(0, 1);
+        const client = await cluster.nodeClient(cluster.masters[0]),
+            reply = await client.clusterGetKeysInSlot(0, 1);
         assert.ok(Array.isArray(reply));
         for (const item of reply) {
             assert.equal(typeof item, 'string');

packages/client/lib/commands/CLUSTER_INFO.spec.ts

@@ -46,8 +46,9 @@ describe('CLUSTER INFO', () => {
     });
 
     testUtils.testWithCluster('clusterNode.clusterInfo', async cluster => {
+        const client = await cluster.nodeClient(cluster.masters[0]);
         assert.notEqual(
-            await cluster.getSlotMaster(0).client.clusterInfo(),
+            await client.clusterInfo(),
             null
         );
     }, GLOBAL.CLUSTERS.OPEN);

packages/client/lib/commands/CLUSTER_KEYSLOT.spec.ts

@@ -11,8 +11,9 @@ describe('CLUSTER KEYSLOT', () => {
     });
 
     testUtils.testWithCluster('clusterNode.clusterKeySlot', async cluster => {
+        const client = await cluster.nodeClient(cluster.masters[0]);
         assert.equal(
-            typeof await cluster.getSlotMaster(0).client.clusterKeySlot('key'),
+            typeof await client.clusterKeySlot('key'),
             'number'
         );
     }, GLOBAL.CLUSTERS.OPEN);

packages/client/lib/commands/CLUSTER_LINKS.spec.ts

@@ -13,7 +13,8 @@ describe('CLUSTER LINKS', () => {
     });
 
     testUtils.testWithCluster('clusterNode.clusterLinks', async cluster => {
-        const links = await cluster.getSlotMaster(0).client.clusterLinks();
+        const client = await cluster.nodeClient(cluster.masters[0]),
+            links = await client.clusterLinks();
         assert.ok(Array.isArray(links));
         for (const link of links) {
             assert.equal(typeof link.direction, 'string');

packages/client/lib/commands/CLUSTER_MYID.spec.ts

@@ -11,9 +11,11 @@ describe('CLUSTER MYID', () => {
     });
 
     testUtils.testWithCluster('clusterNode.clusterMyId', async cluster => {
+        const [master] = cluster.masters,
+            client = await cluster.nodeClient(master);
         assert.equal(
-            typeof await cluster.getSlotMaster(0).client.clusterMyId(),
+            await client.clusterMyId(),
-            'string'
+            master.id
         );
     }, GLOBAL.CLUSTERS.OPEN);
 });

packages/client/lib/commands/CLUSTER_SAVECONFIG.spec.ts

@@ -11,8 +11,9 @@ describe('CLUSTER SAVECONFIG', () => {
     });
 
     testUtils.testWithCluster('clusterNode.clusterSaveConfig', async cluster => {
+        const client = await cluster.nodeClient(cluster.masters[0]);
         assert.equal(
-            await cluster.getSlotMaster(0).client.clusterSaveConfig(),
+            await client.clusterSaveConfig(),
             'OK'
         );
     }, GLOBAL.CLUSTERS.OPEN);

packages/client/lib/commands/CLUSTER_SLOTS.ts

@@ -13,7 +13,7 @@ type ClusterSlotsRawReply = Array<[
     ...replicas: Array<ClusterSlotsRawNode>
 ]>;
 
-type ClusterSlotsNode = {
+export interface ClusterSlotsNode {
     ip: string;
     port: number;
     id: string;

packages/client/lib/commands/PING.spec.ts

@@ -1,8 +1,24 @@
 import { strict as assert } from 'assert';
 import testUtils, { GLOBAL } from '../test-utils';
-import RedisClient from '../client';
+import { transformArguments } from './PING';
 
 describe('PING', () => {
+    describe('transformArguments', () => {
+        it('default', () => {
+            assert.deepEqual(
+                transformArguments(),
+                ['PING']
+            );
+        });
+
+        it('with message', () => {
+            assert.deepEqual(
+                transformArguments('message'),
+                ['PING', 'message']
+            );
+        });
+    });
+
     describe('client.ping', () => {
         testUtils.testWithClient('string', async client => {
             assert.equal(
@@ -13,7 +29,7 @@ describe('PING', () => {
 
         testUtils.testWithClient('buffer', async client => {
             assert.deepEqual(
-                await client.ping(RedisClient.commandOptions({ returnBuffers: true })),
+                await client.ping(client.commandOptions({ returnBuffers: true })),
                 Buffer.from('PONG')
             );
         }, GLOBAL.SERVERS.OPEN);

packages/client/lib/commands/PING.ts

@@ -1,7 +1,12 @@
-import { RedisCommandArgument } from '.';
+import { RedisCommandArgument, RedisCommandArguments } from '.';
 
-export function transformArguments(): Array<string> {
+export function transformArguments(message?: RedisCommandArgument): RedisCommandArguments {
-    return ['PING'];
+    const args: RedisCommandArguments = ['PING'];
+    if (message) {
+        args.push(message);
+    }
+
+    return args;
 }
 
 export declare function transformReply(): RedisCommandArgument;

packages/client/lib/commands/PUBLISH.ts

@@ -1,5 +1,7 @@
 import { RedisCommandArgument, RedisCommandArguments } from '.';
 
+export const IS_READ_ONLY = true;
+
 export function transformArguments(
     channel: RedisCommandArgument,
     message: RedisCommandArgument

packages/client/lib/commands/PUBSUB_SHARDCHANNELS.spec.ts

@@ -0,0 +1,30 @@
+import { strict as assert } from 'assert';
+import testUtils, { GLOBAL } from '../test-utils';
+import { transformArguments } from './PUBSUB_SHARDCHANNELS';
+
+describe('PUBSUB SHARDCHANNELS', () => {
+    testUtils.isVersionGreaterThanHook([7]);
+    
+    describe('transformArguments', () => {
+        it('without pattern', () => {
+            assert.deepEqual(
+                transformArguments(),
+                ['PUBSUB', 'SHARDCHANNELS']
+            );
+        });
+
+        it('with pattern', () => {
+            assert.deepEqual(
+                transformArguments('patter*'),
+                ['PUBSUB', 'SHARDCHANNELS', 'patter*']
+            );
+        });
+    });
+
+    testUtils.testWithClient('client.pubSubShardChannels', async client => {
+        assert.deepEqual(
+            await client.pubSubShardChannels(),
+            []
+        );
+    }, GLOBAL.SERVERS.OPEN);
+});

packages/client/lib/commands/PUBSUB_SHARDCHANNELS.ts

@@ -0,0 +1,13 @@
+import { RedisCommandArgument, RedisCommandArguments } from '.';
+
+export const IS_READ_ONLY = true;
+
+export function transformArguments(
+    pattern?: RedisCommandArgument
+): RedisCommandArguments {
+    const args: RedisCommandArguments = ['PUBSUB', 'SHARDCHANNELS'];
+    if (pattern) args.push(pattern);
+    return args;
+}
+
+export declare function transformReply(): Array<RedisCommandArgument>;

packages/client/lib/commands/SPUBLISH.spec.ts

@@ -0,0 +1,21 @@
+import { strict as assert } from 'assert';
+import testUtils, { GLOBAL } from '../test-utils';
+import { transformArguments } from './SPUBLISH';
+
+describe('SPUBLISH', () => {
+    testUtils.isVersionGreaterThanHook([7]);
+    
+    it('transformArguments', () => {
+        assert.deepEqual(
+            transformArguments('channel', 'message'),
+            ['SPUBLISH', 'channel', 'message']
+        );
+    });
+
+    testUtils.testWithClient('client.sPublish', async client => {
+        assert.equal(
+            await client.sPublish('channel', 'message'),
+            0
+        );
+    }, GLOBAL.SERVERS.OPEN);
+});

packages/client/lib/commands/SPUBLISH.ts

@@ -0,0 +1,14 @@
+import { RedisCommandArgument, RedisCommandArguments } from '.';
+
+export const IS_READ_ONLY = true;
+
+export const FIRST_KEY_INDEX = 1;
+
+export function transformArguments(
+    channel: RedisCommandArgument,
+    message: RedisCommandArgument
+): RedisCommandArguments {
+    return ['SPUBLISH', channel, message];
+}
+
+export declare function transformReply(): number;

packages/client/lib/commands/generic-transformers.ts

@@ -137,7 +137,6 @@ export function transformSortedSetMemberNullReply(
 export function transformSortedSetMemberReply(
     reply: [RedisCommandArgument, RedisCommandArgument]
 ): ZMember {
-
     return {
         value: reply[0],
         score: transformNumberInfinityReply(reply[1])

packages/client/lib/test-utils.ts

@@ -3,7 +3,6 @@ import { SinonSpy } from 'sinon';
 import { promiseTimeout } from './utils';
 
 export default new TestUtils({
-    defaultDockerVersion: '7.0.2',
     dockerImageName: 'redis',
     dockerImageVersionArgument: 'redis-version'
 });
@@ -31,6 +30,14 @@ export const GLOBAL = {
                     password: 'password'
                 }
             }
+        },
+        WITH_REPLICAS: {
+            serverArguments: [],
+            numberOfMasters: 2,
+            numberOfReplicas: 1,
+            clusterConfiguration: {
+                useReplicas: true
+            }
         }
     }
 };

packages/client/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@redis/client",
-  "version": "1.4.2",
+  "version": "1.5.0",
   "license": "MIT",
   "main": "./dist/index.js",
   "types": "./dist/index.d.ts",

packages/graph/lib/test-utils.ts

@@ -3,8 +3,7 @@ import RedisGraph from '.';
 
 export default new TestUtils({
     dockerImageName: 'redislabs/redisgraph',
-    dockerImageVersionArgument: 'redisgraph-version',
+    dockerImageVersionArgument: 'redisgraph-version'
-    defaultDockerVersion: '2.8.15'
 });
 
 export const GLOBAL = {

packages/json/lib/test-utils.ts

@@ -3,8 +3,7 @@ import RedisJSON from '.';
 
 export default new TestUtils({
     dockerImageName: 'redislabs/rejson',
-    dockerImageVersionArgument: 'rejson-version',
+    dockerImageVersionArgument: 'rejson-version'
-    defaultDockerVersion: '2.0.9'
 });
 
 export const GLOBAL = {

packages/test-utils/lib/dockers.ts

@@ -1,8 +1,8 @@
 import { createConnection } from 'net';
 import { once } from 'events';
-import { RedisModules, RedisFunctions, RedisScripts } from '@redis/client/dist/lib/commands';
+import RedisClient from '@redis/client/dist/lib/client';
-import RedisClient, { RedisClientType } from '@redis/client/dist/lib/client';
 import { promiseTimeout } from '@redis/client/dist/lib/utils';
+import { ClusterSlotsReply } from '@redis/client/dist/lib/commands/CLUSTER_SLOTS';
 import * as path from 'path';
 import { promisify } from 'util';
 import { exec } from 'child_process';
@@ -64,7 +64,7 @@ async function spawnRedisServerDocker({ image, version }: RedisServerDockerConfi
     }
 
     while (await isPortAvailable(port)) {
-        await promiseTimeout(500);
+        await promiseTimeout(50);
     }
 
     return {
@@ -102,17 +102,65 @@ after(() => {
 });
 
 export interface RedisClusterDockersConfig extends RedisServerDockerConfig {
-    numberOfNodes?: number;
+    numberOfMasters?: number;
+    numberOfReplicas?: number;
+}
+
+async function spawnRedisClusterNodeDockers(
+    dockersConfig: RedisClusterDockersConfig,
+    serverArguments: Array<string>,
+    fromSlot: number,
+    toSlot: number
+) {
+    const range: Array<number> = [];
+    for (let i = fromSlot; i < toSlot; i++) {
+        range.push(i);
+    }
+
+    const master = await spawnRedisClusterNodeDocker(
+        dockersConfig,
+        serverArguments
+    );
+
+    await master.client.clusterAddSlots(range);
+
+    if (!dockersConfig.numberOfReplicas) return [master];
+    
+    const replicasPromises: Array<ReturnType<typeof spawnRedisClusterNodeDocker>> = [];
+    for (let i = 0; i < (dockersConfig.numberOfReplicas ?? 0); i++) {
+        replicasPromises.push(
+            spawnRedisClusterNodeDocker(dockersConfig, [
+                ...serverArguments,
+                '--cluster-enabled',
+                'yes',
+                '--cluster-node-timeout',
+                '5000'
+            ]).then(async replica => {
+                await replica.client.clusterMeet('127.0.0.1', master.docker.port);
+
+                while ((await replica.client.clusterSlots()).length === 0) {
+                    await promiseTimeout(50);
+                }
+
+                await replica.client.clusterReplicate(
+                    await master.client.clusterMyId()
+                );
+
+                return replica;
+            })
+        );
+    }
+
+    return [
+        master,
+        ...await Promise.all(replicasPromises)
+    ];
 }
 
 async function spawnRedisClusterNodeDocker(
     dockersConfig: RedisClusterDockersConfig,
-    serverArguments: Array<string>,
+    serverArguments: Array<string>
-    fromSlot: number,
+) {
-    toSlot: number,
-    waitForState: boolean,
-    meetPort?: number
-): Promise<RedisServerDocker> {
     const docker = await spawnRedisServerDocker(dockersConfig, [
             ...serverArguments,
             '--cluster-enabled',
@@ -128,78 +176,64 @@ async function spawnRedisClusterNodeDocker(
 
     await client.connect();
 
-    try {
+    return {
-        const range = [];
+        docker,
-        for (let i = fromSlot; i < toSlot; i++) {
+        client
-            range.push(i);
+    };
-        }
-
-        const promises: Array<Promise<unknown>> = [client.clusterAddSlots(range)];
-
-        if (meetPort) {
-            promises.push(client.clusterMeet('127.0.0.1', meetPort));
-        }
-
-        if (waitForState) {
-            promises.push(waitForClusterState(client));
-        }
-
-        await Promise.all(promises);
-
-        return docker;
-    } finally {
-        await client.disconnect();
-    }
-}
-
-async function waitForClusterState<
-    M extends RedisModules,
-    F extends RedisFunctions,
-    S extends RedisScripts
->(client: RedisClientType<M, F, S>): Promise<void> {
-    while ((await client.clusterInfo()).state !== 'ok') {
-        await promiseTimeout(500);
-    }
 }
 
 const SLOTS = 16384;
 
-async function spawnRedisClusterDockers(dockersConfig: RedisClusterDockersConfig, serverArguments: Array<string>): Promise<Array<RedisServerDocker>> {
+async function spawnRedisClusterDockers(
-    const numberOfNodes = dockersConfig.numberOfNodes ?? 3,
+    dockersConfig: RedisClusterDockersConfig,
-        slotsPerNode = Math.floor(SLOTS / numberOfNodes),
+    serverArguments: Array<string>
-        dockers: Array<RedisServerDocker> = [];
+): Promise<Array<RedisServerDocker>> {
-    for (let i = 0; i < numberOfNodes; i++) {
+    const numberOfMasters = dockersConfig.numberOfMasters ?? 2,
+        slotsPerNode = Math.floor(SLOTS / numberOfMasters),
+        spawnPromises: Array<ReturnType<typeof spawnRedisClusterNodeDockers>> = [];
+    for (let i = 0; i < numberOfMasters; i++) {
         const fromSlot = i * slotsPerNode,
-            [ toSlot, waitForState ] = i === numberOfNodes - 1 ? [SLOTS, true] : [fromSlot + slotsPerNode, false];
+            toSlot = i === numberOfMasters - 1 ? SLOTS : fromSlot + slotsPerNode;
-        dockers.push(
+        spawnPromises.push(
-            await spawnRedisClusterNodeDocker(
+            spawnRedisClusterNodeDockers(
                 dockersConfig,
                 serverArguments,
                 fromSlot,
-                toSlot,
+                toSlot
-                waitForState,
-                i === 0 ? undefined : dockers[i - 1].port
             )
         );
     }
 
-    const client = RedisClient.create({
+    const nodes = (await Promise.all(spawnPromises)).flat(),
-        socket: {
+        meetPromises: Array<Promise<unknown>> = [];
-            port: dockers[0].port
+    for (let i = 1; i < nodes.length; i++) {
-        }
+        meetPromises.push(
-    });
+            nodes[i].client.clusterMeet('127.0.0.1', nodes[0].docker.port)
-
+        );
-    await client.connect();
-
-    try {
-        while ((await client.clusterInfo()).state !== 'ok') {
-            await promiseTimeout(500);
-        }
-    } finally {
-        await client.disconnect();
     }
 
-    return dockers;
+    await Promise.all(meetPromises);
+
+    await Promise.all(
+        nodes.map(async ({ client }) => {
+            while (totalNodes(await client.clusterSlots()) !== nodes.length) {
+                await promiseTimeout(50);
+            }
+        
+            return client.disconnect();
+        })
+    );
+
+    return nodes.map(({ docker }) => docker);
+}
+
+function totalNodes(slots: ClusterSlotsReply) {
+    let total = slots.length;
+    for (const slot of slots) {
+        total += slot.replicas.length;
+    }
+
+    return total;
 }
 
 const RUNNING_CLUSTERS = new Map<Array<string>, ReturnType<typeof spawnRedisClusterDockers>>();

packages/test-utils/lib/index.ts

@@ -9,7 +9,7 @@ import { hideBin } from 'yargs/helpers';
 interface TestUtilsConfig {
     dockerImageName: string;
     dockerImageVersionArgument: string;
-    defaultDockerVersion: string;
+    defaultDockerVersion?: string;
 }
 
 interface CommonTestOptions {
@@ -33,7 +33,8 @@ interface ClusterTestOptions<
 > extends CommonTestOptions {
     serverArguments: Array<string>;
     clusterConfiguration?: Partial<RedisClusterOptions<M, F, S>>;
-    numberOfNodes?: number;
+    numberOfMasters?: number;
+    numberOfReplicas?: number;
 }
 
 interface Version {
@@ -43,7 +44,7 @@ interface Version {
 
 export default class TestUtils {
     static #parseVersionNumber(version: string): Array<number> {
-        if (version === 'edge') return [Infinity];
+        if (version === 'latest' || version === 'edge') return [Infinity];
 
         const dashIndex = version.indexOf('-');
         return (dashIndex === -1 ? version : version.substring(0, dashIndex))
@@ -58,7 +59,7 @@ export default class TestUtils {
             });
     }
 
-    static #getVersion(argumentName: string, defaultVersion: string): Version {
+    static #getVersion(argumentName: string, defaultVersion = 'latest'): Version {
         return yargs(hideBin(process.argv))
             .option(argumentName, {
                 type: 'string',
@@ -163,9 +164,13 @@ export default class TestUtils {
         M extends RedisModules,
         F extends RedisFunctions,
         S extends RedisScripts
-    >(cluster: RedisClusterType<M, F, S>): Promise<void> {
+    >(cluster: RedisClusterType<M, F, S>): Promise<unknown> {
-        await Promise.all(
+        return Promise.all(
-            cluster.getMasters().map(({ client }) => client.flushAll())
+            cluster.masters.map(async ({ client }) => {
+                if (client) {
+                    await (await client).flushAll();
+                }
+            })
         );
     }
 
@@ -186,7 +191,8 @@ export default class TestUtils {
 
                 dockersPromise = spawnRedisCluster({
                     ...dockerImage,
-                    numberOfNodes: options?.numberOfNodes
+                    numberOfMasters: options?.numberOfMasters,
+                    numberOfReplicas: options?.numberOfReplicas 
                 }, options.serverArguments);
                 return dockersPromise;
             });
@@ -197,15 +203,15 @@ export default class TestUtils {
 
             const dockers = await dockersPromise,
                 cluster = RedisCluster.create({
-                    ...options.clusterConfiguration,
                     rootNodes: dockers.map(({ port }) => ({
                         socket: {
                             port
                         }
-                    }))
+                    })),
+                    minimizeConnections: true,
+                    ...options.clusterConfiguration
                 });
 
-
             await cluster.connect();
 
             try {

packages/time-series/lib/test-utils.ts

@@ -3,8 +3,7 @@ import TimeSeries from '.';
 
 export default new TestUtils({
     dockerImageName: 'redislabs/redistimeseries',
-    dockerImageVersionArgument: 'timeseries-version',
+    dockerImageVersionArgument: 'timeseries-version'
-    defaultDockerVersion: '1.8.0'
 });
 
 export const GLOBAL = {