refactor(core): Simplify webhook pubsub message handler (#11048)

packages/cli/src/scaling/pubsub/subscriber.service.ts

@@ -1,7 +1,10 @@
 import type { Redis as SingleNodeClient, Cluster as MultiNodeClient } from 'ioredis';
+import debounce from 'lodash/debounce';
+import { jsonParse } from 'n8n-workflow';
 import { Service } from 'typedi';
 
 import config from '@/config';
+import { EventService } from '@/events/event.service';
 import { Logger } from '@/logging/logger.service';
 import { RedisClientService } from '@/services/redis-client.service';
 
@@ -21,6 +24,7 @@ export class Subscriber {
 	constructor(
 		private readonly logger: Logger,
 		private readonly redisClientService: RedisClientService,
+		private readonly eventService: EventService,
 	) {
 		// @TODO: Once this class is only ever initialized in scaling mode, throw in the next line instead.
 		if (config.getEnv('executions.mode') !== 'queue') return;
@@ -62,4 +66,39 @@ export class Subscriber {
 	}
 
 	// #endregion
+
+	// #region Commands
+
+	setCommandMessageHandler() {
+		const handlerFn = debounce((str: string) => {
+			const msg = this.parseCommandMessage(str);
+			if (msg) this.eventService.emit(msg.command, msg.payload);
+		}, 300);
+
+		this.setMessageHandler('n8n.commands', handlerFn);
+	}
+
+	private parseCommandMessage(str: string) {
+		const msg = jsonParse<PubSub.Command | null>(str, { fallbackValue: null });
+
+		if (!msg) {
+			this.logger.debug('Received invalid string via command channel', { message: str });
+
+			return null;
+		}
+
+		this.logger.debug('Received message via command channel', msg);
+
+		const queueModeId = config.getEnv('redis.queueModeId');
+
+		if (msg.senderId === queueModeId || (msg.targets && !msg.targets.includes(queueModeId))) {
+			this.logger.debug('Disregarding message - not for this instance', msg);
+
+			return null;
+		}
+
+		return msg;
+	}
+
+	// #endregion
 }