fix(core)!: Bind worker server to IPv4 (#11087)

packages/@n8n/config/src/configs/scaling-mode.config.ts

@@ -6,9 +6,13 @@ class HealthConfig {
 	@Env('QUEUE_HEALTH_CHECK_ACTIVE')
 	active: boolean = false;
 
-	/** Port for worker to respond to health checks requests on, if enabled. */
+	/** Port for worker server to listen on. */
 	@Env('QUEUE_HEALTH_CHECK_PORT')
 	port: number = 5678;
+
+	/** IP address for worker server to listen on. */
+	@Env('N8N_WORKER_SERVER_ADDRESS')
+	address: string = '0.0.0.0';
 }
 
 @Config

packages/@n8n/config/test/config.test.ts

@@ -198,6 +198,7 @@ describe('GlobalConfig', () => {
 			health: {
 				active: false,
 				port: 5678,
+				address: '0.0.0.0',
 			},
 			bull: {
 				redis: {

packages/cli/BREAKING-CHANGES.md

@@ -2,6 +2,16 @@
 
 This list shows all the versions which include breaking changes and how to upgrade.
 
+# 1.63.0
+
+### What changed?
+
+The worker server used to bind to IPv6 by default. It now binds to IPv4 by default.
+
+### When is action necessary?
+
+If you experience a port conflict error when starting a worker server using its default port, set a different port for the worker server with `QUEUE_HEALTH_CHECK_PORT`.
+
 ## 1.57.0
 
 ### What changed?

packages/cli/src/errors/port-taken.error.ts

@@ -1,9 +0,0 @@
-import { ApplicationError } from 'n8n-workflow';
-
-export class PortTakenError extends ApplicationError {
-	constructor(port: number) {
-		super(
-			`Port ${port} is already in use. Do you already have the n8n main process running on that port?`,
-		);
-	}
-}

packages/cli/src/scaling/__tests__/worker-server.test.ts

@@ -5,7 +5,6 @@ import type { InstanceSettings } from 'n8n-core';
 import { AssertionError } from 'node:assert';
 import * as http from 'node:http';
 
-import { PortTakenError } from '@/errors/port-taken.error';
 import type { ExternalHooks } from '@/external-hooks';
 import type { PrometheusMetricsService } from '@/metrics/prometheus-metrics.service';
 import { bodyParser, rawBodyReader } from '@/middlewares';
@@ -34,7 +33,7 @@ describe('WorkerServer', () => {
 	beforeEach(() => {
 		globalConfig = mock<GlobalConfig>({
 			queue: {
-				health: { active: true, port: 5678 },
+				health: { active: true, port: 5678, address: '0.0.0.0' },
 			},
 			credentials: {
 				overwrite: { endpoint: '' },
@@ -59,8 +58,11 @@ describe('WorkerServer', () => {
 			).toThrowError(AssertionError);
 		});
 
-		it('should throw if port taken', async () => {
+		it('should exit if port taken', async () => {
 			const server = mock<http.Server>();
+			const procesExitSpy = jest
+				.spyOn(process, 'exit')
+				.mockImplementation(() => undefined as never);
 
 			jest.spyOn(http, 'createServer').mockReturnValue(server);
 
@@ -69,18 +71,19 @@ describe('WorkerServer', () => {
 				return server;
 			});
 
-			expect(
+			new WorkerServer(
-				() =>
+				globalConfig,
-					new WorkerServer(
+				mock(),
-						globalConfig,
+				mock(),
-						mock(),
+				mock(),
-						mock(),
+				externalHooks,
-						mock(),
+				instanceSettings,
-						externalHooks,
+				prometheusMetricsService,
-						instanceSettings,
+			);
-						prometheusMetricsService,
+
-					),
+			expect(procesExitSpy).toHaveBeenCalledWith(1);
-			).toThrowError(PortTakenError);
+
+			procesExitSpy.mockRestore();
 		});
 	});
 
@@ -89,8 +92,9 @@ describe('WorkerServer', () => {
 			const server = mock<http.Server>();
 			jest.spyOn(http, 'createServer').mockReturnValue(server);
 
-			server.listen.mockImplementation((_port, callback: () => void) => {
+			server.listen.mockImplementation((...args: unknown[]) => {
-				callback();
+				const callback = args.find((arg) => typeof arg === 'function');
+				if (callback) callback();
 				return server;
 			});
 
@@ -123,8 +127,9 @@ describe('WorkerServer', () => {
 			const server = mock<http.Server>();
 			jest.spyOn(http, 'createServer').mockReturnValue(server);
 
-			server.listen.mockImplementation((_port, callback: () => void) => {
+			server.listen.mockImplementation((...args: unknown[]) => {
-				callback();
+				const callback = args.find((arg) => typeof arg === 'function');
+				if (callback) callback();
 				return server;
 			});
 
@@ -177,8 +182,9 @@ describe('WorkerServer', () => {
 				prometheusMetricsService,
 			);
 
-			server.listen.mockImplementation((_port, callback: () => void) => {
+			server.listen.mockImplementation((...args: unknown[]) => {
-				callback();
+				const callback = args.find((arg) => typeof arg === 'function');
+				if (callback) callback();
 				return server;
 			});
 

packages/cli/src/scaling/worker-server.ts

@@ -12,7 +12,6 @@ import { CredentialsOverwrites } from '@/credentials-overwrites';
 import * as Db from '@/db';
 import { CredentialsOverwritesAlreadySetError } from '@/errors/credentials-overwrites-already-set.error';
 import { NonJsonBodyError } from '@/errors/non-json-body.error';
-import { PortTakenError } from '@/errors/port-taken.error';
 import { ServiceUnavailableError } from '@/errors/response-errors/service-unavailable.error';
 import { ExternalHooks } from '@/external-hooks';
 import type { ICredentialsOverwrite } from '@/interfaces';
@@ -40,6 +39,8 @@ export type WorkerServerEndpointsConfig = {
 export class WorkerServer {
 	private readonly port: number;
 
+	private readonly address: string;
+
 	private readonly server: Server;
 
 	private readonly app: Application;
@@ -66,9 +67,15 @@ export class WorkerServer {
 		this.server = http.createServer(this.app);
 
 		this.port = this.globalConfig.queue.health.port;
+		this.address = this.globalConfig.queue.health.address;
 
 		this.server.on('error', (error: NodeJS.ErrnoException) => {
-			if (error.code === 'EADDRINUSE') throw new PortTakenError(this.port);
+			if (error.code === 'EADDRINUSE') {
+				this.logger.error(
+					`Port ${this.port} is already in use, possibly by the n8n main process server. Please set a different port for the worker server.`,
+				);
+				process.exit(1);
+			}
 		});
 	}
 
@@ -79,7 +86,7 @@ export class WorkerServer {
 
 		await this.mountEndpoints();
 
-		await new Promise<void>((resolve) => this.server.listen(this.port, resolve));
+		await new Promise<void>((resolve) => this.server.listen(this.port, this.address, resolve));
 
 		await this.externalHooks.run('worker.ready');