Intro
First, Check out these articles for
Custom Database Setup for Sequelize: https://www.freecodecamp.org/news/build-web-apis-with-nestjs-beginners-guide/
Custom Database Setup for MongoDB: https://dev.to/10xtarun/create-custom-database-module-in-nestjs-4kim
I got a lot of inspiration from these articles especially from the first by Victor
Setup Project
We Create new nest project as,
$ nest new custom-db-project
We will also install all we need,
$ npm install --save @nestjs/typeorm @nestjs/config typeorm mysql2 dotenv
Now generate the custom database module as,
$ nest generate module core/database
...
Let's Code
Database Interface
Inside the database folder, create an interfaces folder, then create a dbConfig.interface.ts file inside it. This is for the database configuration interface.
Each of the database environments should optionally have the following properties.
export interface IDatabaseConfigAttributes {
username?: string;
password?: string;
database?: string;
host?: string;
port?: number;
type?: string;
urlDatabase?: string;
entities?: string[];
migrationsTableName?: string;
migrations?: string[];
cli?: {
migrationsDir?: string;
}
synchronize?: boolean;
}
export interface IDatabaseConfig {
development: IDatabaseConfigAttributes;
test: IDatabaseConfigAttributes;
production: IDatabaseConfigAttributes;
}
Database Configuration
Now, let’s create a database environment configuration. Inside the database folder, create a database.config.ts file.
import * as dotenv from 'dotenv';
import { IDatabaseConfig } from './interfaces/dbConfig.interface';
dotenv.config();
let entities = [__dirname + '/**/*.entity{.ts,.js}']
let migrationsDir = 'src/migration';
let migrations = [migrationsDir + '/*.ts']
export const databaseConfig: IDatabaseConfig = {
development: {
username: process.env.DB_USER,
password: process.env.DB_PASS,
database: process.env.DB_NAME_DEVELOPMENT,
host: process.env.DB_HOST,
port: +process.env.DB_PORT,
type: process.env.DB_DIALECT,
entities: entities,
migrationsTableName: process.env.DB_MIGRATION_TABLE_NAME,
migrations: migrations,
cli: {
migrationsDir: migrationsDir
},
synchronize: true
},
test: {
username: process.env.DB_USER,
password: process.env.DB_PASS,
database: process.env.DB_NAME_TEST,
host: process.env.DB_HOST,
port: +process.env.DB_PORT,
type: process.env.DB_DIALECT,
entities: entities,
migrationsTableName: process.env.DB_MIGRATION_TABLE_NAME,
migrations: migrations,
cli: {
migrationsDir: migrationsDir
},
synchronize: true
},
production: {
username: process.env.DB_USER,
password: process.env.DB_PASS,
database: process.env.DB_NAME_PRODUCTION,
host: process.env.DB_HOST,
port: +process.env.DB_PORT,
type: process.env.DB_DIALECT,
entities: entities,
migrationsTableName: process.env.DB_MIGRATION_TABLE_NAME,
migrations: migrations,
cli: {
migrationsDir: migrationsDir
},
synchronize: true
},
};
The environment will determine which configuration should be used.
.env file
On our project root folder, create a .env file
DB_HOST=localhost
DB_PORT=3306
DB_USER=database_user_name
DB_PASS=database_password
DB_DIALECT=postgres
DB_NAME_TEST=test_database_name
DB_NAME_DEVELOPMENT=development_database_name
DB_NAME_PRODUCTION=production_database_name
DB_MIGRATION_TABLE_NAME=migration
Don't forget to add .env to your .gitignore file.
Import the @nestjs/config
Import the @nestjs/config into your app root module:
import { Module } from '@nestjs/common';
import { ConfigModule } from '@nestjs/config';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { DatabaseModule } from './core/database/database.module';
@Module({
imports: [
ConfigModule.forRoot({ isGlobal: true }),
DatabaseModule
],
controllers: [AppController],
providers: [AppService],
})
export class AppModule {}
Victor Pointed out that Setting the ConfigModule.forRoot({ isGlobal: true }) to isGlobal: true will make the .env properties available throughout the application.
Database Provider
Let’s create a database provider. Inside the database folder, create a file called database.providers.ts.
The core directory will contain all our core setups, configuration, shared modules, pipes, guards, and middlewares.
In the database.providers.ts let's add
import { TypeOrmModule } from '@nestjs/typeorm';
import { TYPEORM ,DEVELOPMENT, TEST, PRODUCTION } from '../constants';
import { databaseConfig } from './database.config';
export const databaseProviders = [{
provide: TYPEORM,
useFactory: async () => {
let config;
switch (process.env.NODE_ENV) {
case DEVELOPMENT:
config = databaseConfig.development;
break;
case TEST:
config = databaseConfig.test;
break;
case PRODUCTION:
config = databaseConfig.production;
break;
default:
config = databaseConfig.development;
}
const typeOrm = TypeOrmModule.forRoot(config);
return typeOrm
},
}];
Here, the application decides what environment we are currently running on and then chooses the environment configuration.
Best practice: It is a good idea to keep all string values in a constant file and export it to avoid misspelling those values. You'll also have a single place to change things.
Inside the core folder, create a constants folder and inside it create an index.ts file. Paste the following code:
export const TYPEORM = 'TYPEORM';
export const DEVELOPMENT = 'development';
export const TEST = 'test';
export const PRODUCTION = 'production';
I hope this article helps someone. Check out the article by Victor to get started with Nestjs
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