Popular:
 Building Resilient Systems on AWS: Learn how to design and implement a resilient, highly available, fault-tolerant infrastructure on AWS.

Get and Set Environment Variables in Node.js

By  on  

One of the best ways to use sensitive information in open source repositories without hard-coding the information within publicly available repositories is setting environment variables.  Set the environment variables on the server, retrieve them by key within your application.

When using Node.js, you can retrieve environment variables by key from the process.env object:

var mode = process.env.mode; // 'PRODUCTION', for example

var apiKey = process.env.apiKey; // '38294729347392432'

There are time when you may want to set environment variables while you run your node app -- these are set temporarily while the process is still running.  A common case is simulating environment variables during testing.  You can temporarily set these variables by pegging items onto the process.env object:

process.env.mode = 'TESTING';

// Now app code knows not to do destructive transactions!

Simple enough but worth documenting for future use!

Request Metrics real user monitoring
Request Metrics real user monitoring
Request Metrics real user monitoring
Request Metrics real user monitoring

Recent Features

  • By
    An Interview with Eric Meyer

    Your early CSS books were instrumental in pushing my love for front end technologies. What was it about CSS that you fell in love with and drove you to write about it? At first blush, it was the simplicity of it as compared to the table-and-spacer...

  • By
    JavaScript Promise API

    While synchronous code is easier to follow and debug, async is generally better for performance and flexibility. Why "hold up the show" when you can trigger numerous requests at once and then handle them when each is ready?  Promises are becoming a big part of the JavaScript world...

Incredible Demos

  • By
    Create an Animated Sliding Button Using MooTools

    Buttons (or links) are usually the elements on our sites that we want to draw a lot of attention to. Unfortunately many times they end up looking the most boring. You don't have to let that happen though! I recently found a...

  • By
    CSS Kwicks

    One of the effects that made me excited about client side and JavaScript was the Kwicks effect.  Take a list of items and react to them accordingly when hovered.  Simple, sweet.  The effect was originally created with JavaScript but come five years later, our...

Discussion

  1. Kristjan

    I believe it’s more common to use process.env.NODE_ENV instead of process.env.mode

  2. Blaine

    This is an interesting problem. What if you are using aws or heroku for hosting? You could have your deployment script setup the keys, but you’d need to prompt each time you create a new instance.

    I encrypted the keys in a json file with AES 256 and in my run/deploy script it prompts for a password and decrypts it running the rest of the application with env variables. It’s not perfected yet, but this might be a good way to put it on github.

  3. Caleb

    Are these variables just being set via the command line?

  4. Ola

    I have had great success with json-configurator (https://www.npmjs.com/package/json-configurator). Use it with process.env.NODE_ENV as a input.

    require('json-configurator')(configJson, process.env.NODE_ENV ).userEndpoint;
  5. xgqfrms
    # Windows:

SET NODE_ENV=development
# or
set NODE_ENV=development


# OS X / Linux:

export NODE_ENV=development



# Windows CMD
set NODE_ENV=production


# Windows PowerShell:
$env:NODE_ENV="production"

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!