Angular NestJs DB connect

import { Injectable, Logger, OnModuleInit } from '@nestjs/common';
import mysql from 'mysql';

@Injectable()
export class WareHouseService implements OnModuleInit {

    private logger = new Logger(WareHouseService.name);
    private connection: mysql.Connection;

    constructor() {
        this.connection = mysql.createConnection({
            host: process.env['WAREHOUSE_DATABASE_URL'],
            port: parseInt(process.env['WAREHOUSE_DATABASE_PORT']),
            database: process.env['WAREHOUSE_DATABASE_NAME'],
            user: process.env['WAREHOUSE_DATABASE_USERNAME'],
            password: process.env['WAREHOUSE_DATABASE_PASSWORD'],
            multipleStatements: true
        })
    }

    onModuleInit() {
        this.connection.query('SELECT version()', (err) => {
            if (err) throw err;
            this.logger.debug('ARESA DATABASE CONNECTION SUCCESS');
        });
    }

    getConnection() {
        return this.connection;
    }
}