Refactoring: Extract checkMongoDB function

src/misc/check-mongodb.ts

@@ -0,0 +1,37 @@
+import { nativeDbConn } from '../db/mongodb';
+import { Config } from '../config/types';
+import Logger from './logger';
+import { lessThan } from '../prelude/array';
+
+const requiredMongoDBVersion = [3, 6];
+
+export function checkMongoDB(config: Config, logger: Logger) {
+	return new Promise((res, rej) => {
+		const mongoDBLogger = logger.createSubLogger('db');
+		const u = config.mongodb.user ? encodeURIComponent(config.mongodb.user) : null;
+		const p = config.mongodb.pass ? encodeURIComponent(config.mongodb.pass) : null;
+		const uri = `mongodb://${u && p ? `${u}:****@` : ''}${config.mongodb.host}:${config.mongodb.port}/${config.mongodb.db}`;
+		mongoDBLogger.info(`Connecting to ${uri} ...`);
+
+		nativeDbConn().then(db => {
+			mongoDBLogger.succ('Connectivity confirmed');
+
+			db.admin().serverInfo().then(x => {
+				const version = x.version as string;
+				mongoDBLogger.info(`Version: ${version}`);
+				if (lessThan(version.split('.').map(x => parseInt(x, 10)), requiredMongoDBVersion)) {
+					mongoDBLogger.error(`MongoDB version is less than ${requiredMongoDBVersion.join('.')}. Please upgrade it.`);
+					rej('outdated version');
+				} else {
+					res();
+				}
+			}).catch(err => {
+				mongoDBLogger.error(`Failed to fetch server info: ${err.message}`);
+				rej(err);
+			});
+		}).catch(err => {
+			mongoDBLogger.error(err.message);
+			rej(err);
+		});
+	});
+}