How do you configure environment specific configuration of a nodejs app

1) Using Config module

Install in your app directory, and edit the default config file.

$ npm install config

$ mkdir config

$ vi config/default.json

{

  // Customer module configs

  "Customer": {

    "dbConfig": {

      "host": "localhost",

      "port": 5984,

      "dbName": "customers"

    },

    "credit": {

      "initialLimit": 100,

      // Set low for development

      "initialDays": 1

    }

  }

}

Edit config overrides for production deployment:

 $ vi config/production.json

{

  "Customer": {

    "dbConfig": {

      "host": "prod-db-server"

    },

    "credit": {

      "initialDays": 30

    }

  }

}

Use configs in your code:

const config = require('config');

//...

const dbConfig = config.get('Customer.dbConfig');

db.connect(dbConfig, ...);

 

if (config.has('optionalFeature.detail')) {

  const detail = config.get('optionalFeature.detail');

  //...

}

config.get() will throw an exception for undefined keys to help catch typos and missing values. Use config.has() to test if a configuration value is defined.

Start your app server:

$ export NODE_ENV=production

$ node my-app.js

Running in this configuration, the port and dbName elements of dbConfig will come from the default.json file, and the host element will come from the production.jsonoverride file.

2) Using custom-env module

Installation

npm install custom-env

Usage

Place this at the top of your application

require('custom-env').env()

This by default loads configuration from the .env file and assumes the app is in development enviroment mode.

Create a .env file in your app's root directory and add the environment variables each on new line:

APP_ENV=dev
DB_HOST=localhost
DB_USER=root
DB_PASS=root

Simple! The process.env is now loaded with the environment variables above.

Example

console.log(process.env.APP_ENV)
console.log(process.env.DB_HOST)
console.log(process.env.DB_USER)
console.log(process.env.DB_PASS)

Expected Output

dev
localhost
root
root

If you want to load from a particular environment, use:

// This loads configuration from staging environment
require('custom-env').env('staging')

Create a .env.staging file in your app's root directory and add the environment variables each on new line:

APP_ENV=staging
DB_HOST=localhost
DB_USER=root
DB_PASS=root

The process.env is now loaded with the environment variables above. Try it out:

NODE_ENV=staging node index.js

Example

console.log(process.env.APP_ENV)
console.log(process.env.DB_HOST)
console.log(process.env.DB_USER)
console.log(process.env.DB_PASS)

Expected Output

staging
localhost
root
root

Loading from the current environment

You can load configuration from the current environment with custom-env, just pass first argument of the env() method as true (note: this must be a type Boolean type true) and that's all:

// This Loads the configuration dynamically from to the current enviroment
// Defaults to _dev_ if the environment was set
require('custom-env').env(true)

The env() method

The env() method holds two (2) optional arguments envname, path which defaults to devand current working directory respectively. If you wish to set a different path rather than the current working directory, pass your path as the second argument of the env() method.