From 4efcbc593685286837022e5600d81e67f3e0131c Mon Sep 17 00:00:00 2001
From: Tomi Turtiainen <10324676+tomi@users.noreply.github.com>
Date: Fri, 6 Sep 2024 11:33:53 +0300
Subject: [PATCH] fix: Show a more user friendly error message if initial Db
 connection times out (#10682)

---
 packages/cli/src/databases/config.ts          |  6 +++++
 packages/cli/src/db.ts                        | 25 ++++++++++++++++---
 .../src/errors/db-connection-timeout-error.ts | 14 +++++++++++
 packages/workflow/src/errors/ensure-error.ts  |  9 +++++++
 packages/workflow/src/errors/index.ts         |  2 ++
 5 files changed, 53 insertions(+), 3 deletions(-)
 create mode 100644 packages/workflow/src/errors/db-connection-timeout-error.ts
 create mode 100644 packages/workflow/src/errors/ensure-error.ts

diff --git a/packages/cli/src/databases/config.ts b/packages/cli/src/databases/config.ts
index 9c4562d3d6..51c1c43842 100644
--- a/packages/cli/src/databases/config.ts
+++ b/packages/cli/src/databases/config.ts
@@ -132,3 +132,9 @@ export function getConnectionOptions(): DataSourceOptions {
 			throw new ApplicationError('Database type currently not supported', { extra: { dbType } });
 	}
 }
+
+export function arePostgresOptions(
+	options: DataSourceOptions,
+): options is PostgresConnectionOptions {
+	return options.type === 'postgres';
+}
diff --git a/packages/cli/src/db.ts b/packages/cli/src/db.ts
index e032241426..2645865d0b 100644
--- a/packages/cli/src/db.ts
+++ b/packages/cli/src/db.ts
@@ -3,12 +3,16 @@ import { Container } from 'typedi';
 import type { EntityManager } from '@n8n/typeorm';
 // eslint-disable-next-line n8n-local-rules/misplaced-n8n-typeorm-import
 import { DataSource as Connection } from '@n8n/typeorm';
-import { ErrorReporterProxy as ErrorReporter } from 'n8n-workflow';
+import {
+	DbConnectionTimeoutError,
+	ensureError,
+	ErrorReporterProxy as ErrorReporter,
+} from 'n8n-workflow';
 
 import { inTest } from '@/constants';
 import { wrapMigration } from '@/databases/utils/migration-helpers';
 import type { Migration } from '@/databases/types';
-import { getConnectionOptions } from '@/databases/config';
+import { getConnectionOptions, arePostgresOptions } from '@/databases/config';
 
 let connection: Connection;
 
@@ -54,7 +58,22 @@ export async function init(): Promise<void> {
 	const connectionOptions = getConnectionOptions();
 	connection = new Connection(connectionOptions);
 	Container.set(Connection, connection);
-	await connection.initialize();
+	try {
+		await connection.initialize();
+	} catch (e) {
+		let error = ensureError(e);
+		if (
+			arePostgresOptions(connectionOptions) &&
+			error.message === 'Connection terminated due to connection timeout'
+		) {
+			error = new DbConnectionTimeoutError({
+				cause: error,
+				configuredTimeoutInMs: connectionOptions.connectTimeoutMS!,
+			});
+		}
+
+		throw error;
+	}
 
 	connectionState.connected = true;
 }
diff --git a/packages/workflow/src/errors/db-connection-timeout-error.ts b/packages/workflow/src/errors/db-connection-timeout-error.ts
new file mode 100644
index 0000000000..901b9d36b7
--- /dev/null
+++ b/packages/workflow/src/errors/db-connection-timeout-error.ts
@@ -0,0 +1,14 @@
+import { ApplicationError } from './application.error';
+
+export type DbConnectionTimeoutErrorOpts = {
+	configuredTimeoutInMs: number;
+	cause: Error;
+};
+
+export class DbConnectionTimeoutError extends ApplicationError {
+	constructor(opts: DbConnectionTimeoutErrorOpts) {
+		const numberFormat = Intl.NumberFormat();
+		const errorMessage = `Could not establish database connection within the configured timeout of ${numberFormat.format(opts.configuredTimeoutInMs)} ms. Please ensure the database is configured correctly and the server is reachable. You can increase the timeout by setting the 'DB_POSTGRESDB_CONNECTION_TIMEOUT' environment variable.`;
+		super(errorMessage, { cause: opts.cause });
+	}
+}
diff --git a/packages/workflow/src/errors/ensure-error.ts b/packages/workflow/src/errors/ensure-error.ts
new file mode 100644
index 0000000000..331692d6e8
--- /dev/null
+++ b/packages/workflow/src/errors/ensure-error.ts
@@ -0,0 +1,9 @@
+/** Ensures `error` is an `Error */
+export function ensureError(error: unknown): Error {
+	return error instanceof Error
+		? error
+		: new Error('Error that was not an instance of Error was thrown', {
+				// We should never throw anything except something that derives from Error
+				cause: error,
+			});
+}
diff --git a/packages/workflow/src/errors/index.ts b/packages/workflow/src/errors/index.ts
index b48fecb3bc..5dea5b9e6d 100644
--- a/packages/workflow/src/errors/index.ts
+++ b/packages/workflow/src/errors/index.ts
@@ -16,3 +16,5 @@ export { TriggerCloseError } from './trigger-close.error';
 export { NodeError } from './abstract/node.error';
 export { ExecutionBaseError } from './abstract/execution-base.error';
 export { ExpressionExtensionError } from './expression-extension.error';
+export { DbConnectionTimeoutError } from './db-connection-timeout-error';
+export { ensureError } from './ensure-error';