Manage environment variables with dotenv in Node.js applications

Last Edited: May 29, 2019 5:09 PM

I was recently writing a Node.js web application in WebStorm. A part of the local development was creating and managing environment variables and prevented them from storing in the source control (e.g. Git). Here are some notes of the process I followed:

Install the dotenv package

    # use npm
    npm install dotenv

Require and configure dotenv at the very top of the root app.js file

    require('dotenv').config();

Create a .env file in the root directory of the project, and add environment variables in the format NAME=VALUE. For example, in my project, I added the keys below. Note that no quotation marks needed for the value if there is no space between words:

    DB_URL=mongodb://localhost:27017/[put the project name]
    GEOCODER_API_KEY=[Put the secret key here]

Now process.env can access the environment variables (keys and values) defined in .env. For example, I used MongoDB in this project and connected mongoose with DB_URL:

    mongoose.connect(process.env.DB_URL, {
      useNewUrlParser: true,
      useCreateIndex: true
    }).then(() => {
      console.log('Connected to DB');
    }).catch(err => {
      console.log('ERROR:', err.message);
    });

I also set up Google Maps API with the key GEOCODER_API_KEY and used geocoder in the later code:

    var options = {
        provider: 'google',
        httpAdapter: 'https',
        apiKey: process.env.GEOCODER_API_KEY,
        formatter: null
    };
    var geocoder = NodeGeocoder(options);

On the same level of .env, you may want to add .gitignore file to intentionally specify all directories and files that you want Git to ignore so that they are not exposed on your repo. Mine looks like this:

    # Ignore files related to API keys
    .env
    
    # Ignore node_modules folder
    node_modules/
    
    # Ignore Mac system files
    .DS_store

If the app is hosted remotely: define all the environment variables everywhere where the app is hosted/started. In my case, I added the env variables to heroku where my app is hosted (note: here heroku is already set up):

    $ cd my app
    $ heroku config:set KEY=VALUE    # e.g. GITHUB_USERNAME=JANEDOE

• You can view all current variables or remove any variable:

    $ heroku config    # View all variables
    GITHUB_USERNAME: JANEDOE
    
    heroku config:get GITHUB_USERNAME    # Check value to the key
    JANEDOE

DONE!

References

1. Configuration and Config Vars
2. dotenv Setup