feat(core): Make Redis available for backend communication (#6719)

* support redis cluster

* cleanup, fix config schema

* set default prefix to bull

* initial commit

* improve logging

* improve types and refactor

* list support and refactor

* fix redis service and tests

* add comment

* add redis and cache prefix

* use injection

* lint fix

* clean schema comments

* improve naming, tests, cluster client

* merge master

* cache returns unknown instead of T

* update cache service, tests and doc

* remove console.log

* do not cache null or undefined values

* fix merge

* lint fix

packages/cli/src/services/redis/RedisServicePubSubSubscriber.ts

@@ -0,0 +1,46 @@
+import { Service } from 'typedi';
+import { LoggerProxy as Logger } from 'n8n-workflow';
+import {
+	COMMAND_REDIS_CHANNEL,
+	EVENT_BUS_REDIS_CHANNEL,
+	WORKER_RESPONSE_REDIS_CHANNEL,
+} from './RedisServiceHelper';
+import { RedisServiceBaseReceiver } from './RedisServiceBaseClasses';
+
+@Service()
+export class RedisServicePubSubSubscriber extends RedisServiceBaseReceiver {
+	async init(): Promise<void> {
+		await super.init('subscriber');
+
+		this.redisClient?.on('message', (channel: string, message: string) => {
+			this.messageHandlers.forEach((handler: (channel: string, message: string) => void) =>
+				handler(channel, message),
+			);
+		});
+	}
+
+	async subscribe(channel: string): Promise<void> {
+		if (!this.redisClient) {
+			await this.init();
+		}
+		await this.redisClient?.subscribe(channel, (error, count: number) => {
+			if (error) {
+				Logger.error(`Error subscribing to channel ${channel}`);
+			} else {
+				Logger.debug(`Subscribed ${count.toString()} to eventlog channel`);
+			}
+		});
+	}
+
+	async subscribeToEventLog(): Promise<void> {
+		await this.subscribe(EVENT_BUS_REDIS_CHANNEL);
+	}
+
+	async subscribeToCommandChannel(): Promise<void> {
+		await this.subscribe(COMMAND_REDIS_CHANNEL);
+	}
+
+	async subscribeToWorkerResponseChannel(): Promise<void> {
+		await this.subscribe(WORKER_RESPONSE_REDIS_CHANNEL);
+	}
+}