refactor(core): Simplify webhook pubsub message handler

packages/cli/src/commands/webhook.ts

@@ -4,7 +4,8 @@ import { Container } from 'typedi';
 
 import { ActiveExecutions } from '@/active-executions';
 import config from '@/config';
-import { OrchestrationHandlerWebhookService } from '@/services/orchestration/webhook/orchestration.handler.webhook.service';
+import { PubSubHandler } from '@/scaling/pubsub/pubsub-handler';
+import { Subscriber } from '@/scaling/pubsub/subscriber.service';
 import { OrchestrationWebhookService } from '@/services/orchestration/webhook/orchestration.webhook.service';
 import { WebhookServer } from '@/webhooks/webhook-server';
 
@@ -110,6 +111,11 @@ export class Webhook extends BaseCommand {
 
 	async initOrchestration() {
 		await Container.get(OrchestrationWebhookService).init();
-		await Container.get(OrchestrationHandlerWebhookService).init();
+
+		const subscriber = Container.get(Subscriber);
+		await subscriber.subscribe('n8n.commands');
+		subscriber.setCommandMessageHandler();
+
+		Container.get(PubSubHandler).init();
 	}
 }

packages/cli/src/scaling/__tests__/pubsub-handler.test.ts

@@ -0,0 +1,142 @@
+import { mock } from 'jest-mock-extended';
+import type { InstanceSettings } from 'n8n-core';
+
+import type { MessageEventBus } from '@/eventbus/message-event-bus/message-event-bus';
+import { EventService } from '@/events/event.service';
+import type { ExternalSecretsManager } from '@/external-secrets/external-secrets-manager.ee';
+import type { License } from '@/license';
+import type { CommunityPackagesService } from '@/services/community-packages.service';
+
+import { PubSubHandler } from '../pubsub/pubsub-handler';
+
+describe('PubSubHandler', () => {
+	const eventService = new EventService();
+	const license = mock<License>();
+	const eventbus = mock<MessageEventBus>();
+	const externalSecretsManager = mock<ExternalSecretsManager>();
+	const communityPackagesService = mock<CommunityPackagesService>();
+
+	describe('in webhook process', () => {
+		const instanceSettings = mock<InstanceSettings>({ instanceType: 'webhook' });
+
+		it('should set up handlers in webhook process', () => {
+			// @ts-expect-error Spying on private method
+			const setupWebhookHandlersSpy = jest.spyOn(PubSubHandler.prototype, 'setupWebhookHandlers');
+
+			new PubSubHandler(
+				eventService,
+				instanceSettings,
+				license,
+				eventbus,
+				externalSecretsManager,
+				communityPackagesService,
+			).init();
+
+			expect(setupWebhookHandlersSpy).toHaveBeenCalled();
+		});
+
+		it('should reload license on `reload-license` event', () => {
+			new PubSubHandler(
+				eventService,
+				instanceSettings,
+				license,
+				eventbus,
+				externalSecretsManager,
+				communityPackagesService,
+			).init();
+
+			eventService.emit('reload-license');
+
+			expect(license.reload).toHaveBeenCalled();
+		});
+
+		it('should restart event bus on `restart-event-bus` event', () => {
+			new PubSubHandler(
+				eventService,
+				instanceSettings,
+				license,
+				eventbus,
+				externalSecretsManager,
+				communityPackagesService,
+			).init();
+
+			eventService.emit('restart-event-bus');
+
+			expect(eventbus.restart).toHaveBeenCalled();
+		});
+
+		it('should reload providers on `reload-external-secrets-providers` event', () => {
+			new PubSubHandler(
+				eventService,
+				instanceSettings,
+				license,
+				eventbus,
+				externalSecretsManager,
+				communityPackagesService,
+			).init();
+
+			eventService.emit('reload-external-secrets-providers');
+
+			expect(externalSecretsManager.reloadAllProviders).toHaveBeenCalled();
+		});
+
+		it('should install community package on `community-package-install` event', () => {
+			new PubSubHandler(
+				eventService,
+				instanceSettings,
+				license,
+				eventbus,
+				externalSecretsManager,
+				communityPackagesService,
+			).init();
+
+			eventService.emit('community-package-install', {
+				packageName: 'test-package',
+				packageVersion: '1.0.0',
+			});
+
+			expect(communityPackagesService.installOrUpdateNpmPackage).toHaveBeenCalledWith(
+				'test-package',
+				'1.0.0',
+			);
+		});
+
+		it('should update community package on `community-package-update` event', () => {
+			new PubSubHandler(
+				eventService,
+				instanceSettings,
+				license,
+				eventbus,
+				externalSecretsManager,
+				communityPackagesService,
+			).init();
+
+			eventService.emit('community-package-update', {
+				packageName: 'test-package',
+				packageVersion: '1.0.0',
+			});
+
+			expect(communityPackagesService.installOrUpdateNpmPackage).toHaveBeenCalledWith(
+				'test-package',
+				'1.0.0',
+			);
+		});
+
+		it('should uninstall community package on `community-package-uninstall` event', () => {
+			new PubSubHandler(
+				eventService,
+				instanceSettings,
+				license,
+				eventbus,
+				externalSecretsManager,
+				communityPackagesService,
+			).init();
+
+			eventService.emit('community-package-uninstall', {
+				packageName: 'test-package',
+			});
+
+			expect(communityPackagesService.removeNpmPackage).toHaveBeenCalledWith('test-package');
+		});
+	});
+});

packages/cli/src/scaling/pubsub/pubsub-handler.ts

@@ -0,0 +1,61 @@
+import { InstanceSettings } from 'n8n-core';
+import { Service } from 'typedi';
+
+import { MessageEventBus } from '@/eventbus/message-event-bus/message-event-bus';
+import { EventService } from '@/events/event.service';
+import type { PubSubEventMap } from '@/events/maps/pub-sub.event-map';
+import { ExternalSecretsManager } from '@/external-secrets/external-secrets-manager.ee';
+import { License } from '@/license';
+import { CommunityPackagesService } from '@/services/community-packages.service';
+
+/**
+ * Responsible for handling events emitted from messages received via a pubsub channel.
+ */
+@Service()
+export class PubSubHandler {
+	constructor(
+		private readonly eventService: EventService,
+		private readonly instanceSettings: InstanceSettings,
+		private readonly license: License,
+		private readonly eventbus: MessageEventBus,
+		private readonly externalSecretsManager: ExternalSecretsManager,
+		private readonly communityPackagesService: CommunityPackagesService,
+	) {}
+
+	init() {
+		if (this.instanceSettings.instanceType === 'webhook') this.setupWebhookHandlers();
+	}
+
+	private setupHandlers<EventNames extends keyof PubSubEventMap>(
+		map: {
+			[EventName in EventNames]?: (event: PubSubEventMap[EventName]) => void | Promise<void>;
+		},
+	) {
+		for (const [eventName, handlerFn] of Object.entries(map) as Array<
+			[EventNames, (event: PubSubEventMap[EventNames]) => void | Promise<void>]
+		>) {
+			this.eventService.on(eventName, async (event) => {
+				await handlerFn(event);
+			});
+		}
+	}
+
+	// #region Webhook process
+
+	private setupWebhookHandlers() {
+		this.setupHandlers({
+			'reload-license': async () => await this.license.reload(),
+			'restart-event-bus': async () => await this.eventbus.restart(),
+			'reload-external-secrets-providers': async () =>
+				await this.externalSecretsManager.reloadAllProviders(),
+			'community-package-install': async ({ packageName, packageVersion }) =>
+				await this.communityPackagesService.installOrUpdateNpmPackage(packageName, packageVersion),
+			'community-package-update': async ({ packageName, packageVersion }) =>
+				await this.communityPackagesService.installOrUpdateNpmPackage(packageName, packageVersion),
+			'community-package-uninstall': async ({ packageName }) =>
+				await this.communityPackagesService.removeNpmPackage(packageName),
+		});
+	}
+
+	// #endregion
+}

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
 }