NestJS-如何在主应用程序模块文件中使用.env变量进行数据库连接 [英] NestJS - How to use .env variables in main app module file for database connection

问题描述

我正在开发我的第一个NestJS应用程序，该应用程序在 app.module.ts 中的硬编码数据库连接字符串上工作正常。

I am working on my first NestJS application, which was working fine with hardcoded database connecting string in app.module.ts.

但是根据我们的要求，我不得不从环境文件中选择数据库配置值。为此，我遵循了nestjs文档网站上的配置文档- https://docs.nestjs.com/技术/配置

But then as per our requirements, I had to pick the database config values from environment files. For that, I followed the configuration documentation on the nestjs documentation website - https://docs.nestjs.com/techniques/configuration

但是问题是我需要在同一文件中使用.env变量进行数据库连接，这是失败的。

But the issue is that I need to use the .env variables inside the same file for database connection, which is failing.

这是我的原始代码，效果很好：

Here is my original code that was working fine:

@Module({
  imports: [
    MongooseModule.forRoot(`mongodb+srv://myusername:[e-mail]?retryWrites=true&w=majority&db=dbname`, { useNewUrlParser: true, dbName: 'dbname' }),
    ProductModule,
    CategoryModule,
  ],
  controllers: [
    AppController,
    HealthCheckController,
  ],
  providers: [AppService, CustomLogger],
})

现在，我想从.env文件中选择那些数据库值，例如 local.env ， dev.env 等，具体取决于在环境上。现在，我的代码无法正常工作：

Now, I wanted to pick those DB values from .env files which are like local.env, dev.env etc. depending on the environment. Now, my this code is not working:

@Module({
  imports: [
    ConfigModule.forRoot({ envFilePath: `${process.env.NODE_ENV}.env` }),
    MongooseModule.forRoot(`mongodb+srv://${ConfigModule.get('DB_USER')}:${ConfigModule.get('DB_PASS')}@myhost.net?retryWrites=true&w=majority&db=dbname`, { useNewUrlParser: true, dbName: 'dbname' }),
    ProductModule,
    CategoryModule,
  ],
  controllers: [
    AppController,
    HealthCheckController,
  ],
  providers: [AppService, CustomLogger],
})

推荐答案

1。使用 dotenv

1. Using dotenv

npm install dotenv

在您的 package.json 中添加一些脚本来设置您的环境

Add some scripts to your package.json to set what env you are in.

"scripts": {
  ...
  "start:local": "NODE_ENV=local npm run start"
  "start:dev": "NODE_ENV=dev npm run start"
}

在<$ c $中导入 dotenv c> main.ts 文件。确保在文件顶部执行该操作。

Import dotenv in main.ts file. Make sure you do it at the top of the file.

require('dotenv').config({ path: `../${process.env.NODE_ENV}.env` });

2。使用 env-cmd

2. Using env-cmd

您可以使用 env-cmd npm软件包。

You can use env-cmd npm package.

npm install env-cmd

并在 package.json 中添加一些用于不同环境的命令，例如：

And add some commands for different envs in package.json, for example:

"scripts": {
  ...
  "start:local": "env-cmd -f local.env npm run start"
  "start:dev": "env-cmd -f dev.env npm run start"
}
...

---

现在您可以使用env变量，例如：

---

Now you can use the env variables, for example:

MongooseModule.forRoot(`mongodb+srv://${process.env.DB_USER}:${process.env.DB_PASS}@myhost.net?retryWrites=true&w=majority&db=dbname`, { useNewUrlParser: true, dbName: 'dbname' })

process.env.MONGO_CONNECTION_STRING

这篇关于NestJS-如何在主应用程序模块文件中使用.env变量进行数据库连接的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！