feat: Separate task runner server from main http server (no-changelog) (#11062)

packages/@n8n/config/src/configs/runners.config.ts

@@ -11,4 +11,12 @@ export class TaskRunnersConfig {
 
 	@Env('N8N_RUNNERS_AUTH_TOKEN')
 	authToken: string = '';
+
+	/** IP address task runners server should listen on */
+	@Env('N8N_RUNNERS_SERVER_PORT')
+	port: number = 5679;
+
+	/** IP address task runners server should listen on */
+	@Env('N8N_RUNNERS_SERVER_LISTEN_ADDRESS')
+	listen_address: string = '127.0.0.1';
 }

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

@@ -225,6 +225,8 @@ describe('GlobalConfig', () => {
 			disabled: true,
 			path: '/runners',
 			authToken: '',
+			listen_address: '127.0.0.1',
+			port: 5679,
 		},
 		sentry: {
 			backendDsn: '',

packages/@n8n/task-runner-node-js/src/start.ts

@@ -1,4 +1,6 @@
 import * as a from 'node:assert/strict';
+import { ensureError } from 'n8n-workflow';
+
 import { JsTaskRunner } from './code';
 import { authenticate } from './authenticator';
 
@@ -39,6 +41,10 @@ void (async function start() {
 		});
 	}
 
-	const wsUrl = `ws://${config.n8nUri}/rest/runners/_ws`;
+	const wsUrl = `ws://${config.n8nUri}/runners/_ws`;
 	_runner = new JsTaskRunner('javascript', wsUrl, grantToken, 5);
-})();
+})().catch((e) => {
+	const error = ensureError(e);
+	console.error('Task runner failed to start', { error });
+	process.exit(1);
+});

packages/cli/src/abstract-server.ts

@@ -119,8 +119,6 @@ export abstract class AbstractServer {
 
 	protected setupPushServer() {}
 
-	protected setupRunnerServer() {}
-
 	private async setupHealthCheck() {
 		// main health check should not care about DB connections
 		this.app.get('/healthz', async (_req, res) => {
@@ -184,10 +182,6 @@ export abstract class AbstractServer {
 		if (!inTest) {
 			await this.setupErrorHandlers();
 			this.setupPushServer();
-
-			if (!this.globalConfig.taskRunners.disabled) {
-				this.setupRunnerServer();
-			}
 		}
 
 		this.setupCommonMiddlewares();

packages/cli/src/commands/start.ts

@@ -225,6 +225,10 @@ export class Start extends BaseCommand {
 
 		if (!this.globalConfig.taskRunners.disabled) {
 			Container.set(TaskManager, new SingleMainTaskManager());
+			const { TaskRunnerServer } = await import('@/runners/task-runner-server');
+			const taskRunnerServer = Container.get(TaskRunnerServer);
+			await taskRunnerServer.start();
+
 			const { TaskRunnerProcess } = await import('@/runners/task-runner-process');
 			const runnerProcess = Container.get(TaskRunnerProcess);
 			await runnerProcess.start();

packages/cli/src/constants.ts

@@ -168,6 +168,8 @@ export const ARTIFICIAL_TASK_DATA = {
 	],
 };
 
+/** Lowest priority, meaning shut down happens after other groups */
 export const LOWEST_SHUTDOWN_PRIORITY = 0;
 export const DEFAULT_SHUTDOWN_PRIORITY = 100;
+/** Highest priority, meaning shut down happens before all other groups */
 export const HIGHEST_SHUTDOWN_PRIORITY = 200;

packages/cli/src/runners/task-runner-process.ts

@@ -44,7 +44,7 @@ export class TaskRunnerProcess {
 			env: {
 				PATH: process.env.PATH,
 				N8N_RUNNERS_GRANT_TOKEN: grantToken,
-				N8N_RUNNERS_N8N_URI: `localhost:${this.globalConfig.port}`,
+				N8N_RUNNERS_N8N_URI: `localhost:${this.globalConfig.taskRunners.port}`,
 			},
 		});
 

packages/cli/src/runners/task-runner-server.ts

@@ -0,0 +1,201 @@
+import { GlobalConfig } from '@n8n/config';
+import compression from 'compression';
+import express from 'express';
+import * as a from 'node:assert/strict';
+import { randomBytes } from 'node:crypto';
+import { ServerResponse, type Server, createServer as createHttpServer } from 'node:http';
+import type { AddressInfo, Socket } from 'node:net';
+import { parse as parseUrl } from 'node:url';
+import { Service } from 'typedi';
+import { Server as WSServer } from 'ws';
+
+import { inTest, LOWEST_SHUTDOWN_PRIORITY } from '@/constants';
+import { OnShutdown } from '@/decorators/on-shutdown';
+import { Logger } from '@/logging/logger.service';
+import { bodyParser, rawBodyReader } from '@/middlewares';
+import { send } from '@/response-helper';
+import { TaskRunnerAuthController } from '@/runners/auth/task-runner-auth.controller';
+import type {
+	TaskRunnerServerInitRequest,
+	TaskRunnerServerInitResponse,
+} from '@/runners/runner-types';
+import { TaskRunnerService } from '@/runners/runner-ws-server';
+
+/**
+ * Task Runner HTTP & WS server
+ */
+@Service()
+export class TaskRunnerServer {
+	private server: Server | undefined;
+
+	private wsServer: WSServer | undefined;
+
+	readonly app: express.Application;
+
+	public get port() {
+		return (this.server?.address() as AddressInfo)?.port;
+	}
+
+	private get upgradeEndpoint() {
+		return `${this.getEndpointBasePath()}/_ws`;
+	}
+
+	constructor(
+		private readonly logger: Logger,
+		private readonly globalConfig: GlobalConfig,
+		private readonly taskRunnerAuthController: TaskRunnerAuthController,
+		private readonly taskRunnerService: TaskRunnerService,
+	) {
+		this.app = express();
+		this.app.disable('x-powered-by');
+
+		if (!this.globalConfig.taskRunners.authToken) {
+			// Generate an auth token if one is not set
+			this.globalConfig.taskRunners.authToken = randomBytes(32).toString('hex');
+		}
+	}
+
+	async start(): Promise<void> {
+		await this.setupHttpServer();
+
+		this.setupWsServer();
+
+		if (!inTest) {
+			await this.setupErrorHandlers();
+		}
+
+		this.setupCommonMiddlewares();
+
+		this.configureRoutes();
+	}
+
+	@OnShutdown(LOWEST_SHUTDOWN_PRIORITY)
+	async stop(): Promise<void> {
+		if (this.wsServer) {
+			this.wsServer.close();
+			this.wsServer = undefined;
+		}
+		if (this.server) {
+			await new Promise<void>((resolve) => this.server?.close(() => resolve()));
+			this.server = undefined;
+		}
+	}
+
+	/** Creates an HTTP server and listens to the configured port */
+	private async setupHttpServer() {
+		const { app } = this;
+
+		this.server = createHttpServer(app);
+
+		const {
+			taskRunners: { port, listen_address: address },
+		} = this.globalConfig;
+
+		this.server.on('error', (error: Error & { code: string }) => {
+			if (error.code === 'EADDRINUSE') {
+				this.logger.info(
+					`n8n Task Runner's port ${port} is already in use. Do you have another instance of n8n running already?`,
+				);
+				process.exit(1);
+			}
+		});
+
+		await new Promise<void>((resolve) => {
+			a.ok(this.server);
+			this.server.listen(port, address, () => resolve());
+		});
+
+		this.logger.info(`n8n Task Runner server ready on ${address}, port ${port}`);
+	}
+
+	/** Creates WebSocket server for handling upgrade requests */
+	private setupWsServer() {
+		const { authToken } = this.globalConfig.taskRunners;
+		a.ok(authToken);
+		a.ok(this.server);
+
+		this.wsServer = new WSServer({ noServer: true });
+		this.server.on('upgrade', this.handleUpgradeRequest);
+	}
+
+	private async setupErrorHandlers() {
+		const { app } = this;
+
+		// Augment errors sent to Sentry
+		const {
+			Handlers: { requestHandler, errorHandler },
+		} = await import('@sentry/node');
+		app.use(requestHandler());
+		app.use(errorHandler());
+	}
+
+	private setupCommonMiddlewares() {
+		// Compress the response data
+		this.app.use(compression());
+
+		this.app.use(rawBodyReader);
+		this.app.use(bodyParser);
+	}
+
+	private configureRoutes() {
+		this.app.use(
+			this.upgradeEndpoint,
+			// eslint-disable-next-line @typescript-eslint/unbound-method
+			this.taskRunnerAuthController.authMiddleware,
+			(req: TaskRunnerServerInitRequest, res: TaskRunnerServerInitResponse) =>
+				this.taskRunnerService.handleRequest(req, res),
+		);
+
+		const authEndpoint = `${this.getEndpointBasePath()}/auth`;
+		this.app.post(
+			authEndpoint,
+			send(async (req) => await this.taskRunnerAuthController.createGrantToken(req)),
+		);
+	}
+
+	private handleUpgradeRequest = (
+		request: TaskRunnerServerInitRequest,
+		socket: Socket,
+		head: Buffer,
+	) => {
+		if (parseUrl(request.url).pathname !== this.upgradeEndpoint) {
+			socket.write('HTTP/1.1 404 Not Found\r\n\r\n');
+			socket.destroy();
+			return;
+		}
+
+		if (!this.wsServer) {
+			// This might happen if the server is shutting down and we receive an upgrade request
+			socket.write('HTTP/1.1 503 Service Unavailable\r\n\r\n');
+			socket.destroy();
+			return;
+		}
+
+		this.wsServer.handleUpgrade(request, socket, head, (ws) => {
+			request.ws = ws;
+
+			const response = new ServerResponse(request);
+			response.writeHead = (statusCode) => {
+				if (statusCode > 200) ws.close(100);
+				return response;
+			};
+
+			// @ts-expect-error Delegate the request to the express app. This function is not exposed
+			// eslint-disable-next-line @typescript-eslint/no-unsafe-call
+			this.app.handle(request, response);
+		});
+	};
+
+	/** Returns the normalized base path for the task runner endpoints */
+	private getEndpointBasePath() {
+		let path = this.globalConfig.taskRunners.path;
+		if (!path.startsWith('/')) {
+			path = `/${path}`;
+		}
+		if (path.endsWith('/')) {
+			path = path.slice(-1);
+		}
+
+		return path;
+	}
+}

packages/cli/src/server.ts

@@ -31,7 +31,6 @@ import { isApiEnabled, loadPublicApiVersions } from '@/public-api';
 import { setupPushServer, setupPushHandler, Push } from '@/push';
 import type { APIRequest } from '@/requests';
 import * as ResponseHelper from '@/response-helper';
-import { setupRunnerServer, setupRunnerHandler } from '@/runners/runner-ws-server';
 import type { FrontendService } from '@/services/frontend.service';
 import { OrchestrationService } from '@/services/orchestration.service';
 
@@ -202,10 +201,6 @@ export class Server extends AbstractServer {
 		const { restEndpoint, app } = this;
 		setupPushHandler(restEndpoint, app);
 
-		if (!this.globalConfig.taskRunners.disabled) {
-			setupRunnerHandler(restEndpoint, app);
-		}
-
 		const push = Container.get(Push);
 		if (push.isBidirectional) {
 			const { CollaborationService } = await import('@/collaboration/collaboration.service');
@@ -405,9 +400,4 @@ export class Server extends AbstractServer {
 		const { restEndpoint, server, app } = this;
 		setupPushServer(restEndpoint, server, app);
 	}
-
-	protected setupRunnerServer(): void {
-		const { restEndpoint, server, app } = this;
-		setupRunnerServer(restEndpoint, server, app);
-	}
 }

packages/cli/test/integration/runners/task-runner-process.test.ts

@@ -4,20 +4,30 @@ import Container from 'typedi';
 import { TaskRunnerService } from '@/runners/runner-ws-server';
 import { TaskBroker } from '@/runners/task-broker.service';
 import { TaskRunnerProcess } from '@/runners/task-runner-process';
+import { TaskRunnerServer } from '@/runners/task-runner-server';
 import { retryUntil } from '@test-integration/retry-until';
-import { setupTaskRunnerTestServer } from '@test-integration/utils/task-runner-test-server';
 
 describe('TaskRunnerProcess', () => {
 	const authToken = 'token';
 	const globalConfig = Container.get(GlobalConfig);
 	globalConfig.taskRunners.authToken = authToken;
-	const testServer = setupTaskRunnerTestServer({});
-	globalConfig.port = testServer.port;
+	globalConfig.taskRunners.port = 0; // Use any port
+	const taskRunnerServer = Container.get(TaskRunnerServer);
 
 	const runnerProcess = Container.get(TaskRunnerProcess);
 	const taskBroker = Container.get(TaskBroker);
 	const taskRunnerService = Container.get(TaskRunnerService);
 
+	beforeAll(async () => {
+		await taskRunnerServer.start();
+		// Set the port to the actually used port
+		globalConfig.taskRunners.port = taskRunnerServer.port;
+	});
+
+	afterAll(async () => {
+		await taskRunnerServer.stop();
+	});
+
 	afterEach(async () => {
 		await runnerProcess.stop();
 	});

packages/cli/test/integration/shared/utils/task-runner-test-server.ts

@@ -1,43 +0,0 @@
-import { GlobalConfig } from '@n8n/config';
-import cookieParser from 'cookie-parser';
-import type { Application } from 'express';
-import express from 'express';
-import type { Server } from 'node:http';
-import type { AddressInfo } from 'node:net';
-import Container from 'typedi';
-
-import { rawBodyReader } from '@/middlewares';
-import { setupRunnerHandler, setupRunnerServer } from '@/runners/runner-ws-server';
-
-export interface TaskRunnerTestServer {
-	app: Application;
-	httpServer: Server;
-	port: number;
-}
-
-/**
- * Sets up a task runner HTTP & WS server for testing purposes
- */
-export const setupTaskRunnerTestServer = ({}): TaskRunnerTestServer => {
-	const app = express();
-	app.use(rawBodyReader);
-	app.use(cookieParser());
-
-	const testServer: TaskRunnerTestServer = {
-		app,
-		httpServer: app.listen(0),
-		port: 0,
-	};
-
-	testServer.port = (testServer.httpServer.address() as AddressInfo).port;
-
-	const globalConfig = Container.get(GlobalConfig);
-	setupRunnerServer(globalConfig.endpoints.rest, testServer.httpServer, testServer.app);
-	setupRunnerHandler(globalConfig.endpoints.rest, testServer.app);
-
-	afterAll(async () => {
-		testServer.httpServer.close();
-	});
-
-	return testServer;
-};