feat: Graceful termination of task runner (no-changelog) (#11009)

packages/@n8n/task-runner/src/task-runner.ts

@@ -359,4 +359,36 @@ export abstract class TaskRunner {
 		}
 		return rpcObject;
 	}
+
+	/** Close the connection gracefully and wait until has been closed */
+	async stop() {
+		this.stopTaskOffers();
+
+		await this.waitUntilAllTasksAreDone();
+
+		await this.closeConnection();
+	}
+
+	private async closeConnection() {
+		// 1000 is the standard close code
+		// https://www.rfc-editor.org/rfc/rfc6455.html#section-7.1.5
+		this.ws.close(1000, 'Shutting down');
+
+		await new Promise((resolve) => {
+			this.ws.once('close', resolve);
+		});
+	}
+
+	private async waitUntilAllTasksAreDone(maxWaitTimeInMs = 30_000) {
+		// TODO: Make maxWaitTimeInMs configurable
+		const start = Date.now();
+
+		while (this.runningTasks.size > 0) {
+			if (Date.now() - start > maxWaitTimeInMs) {
+				throw new ApplicationError('Timeout while waiting for tasks to finish');
+			}
+
+			await new Promise((resolve) => setTimeout(resolve, 100));
+		}
+	}
 }