Fail Gatsby build if environment variable missing

Question

I have experimented with adding environment variables to my Gatsby project using .env.development and .env.production files and it's working great.

I would like to have my builds fail if one of the environment variables is missing, however I can't seem to see how to enable this functionality.

I have read through the Gatsby environment variables documentation, but can't seem to see how this would work? is this possible?

I believe it uses dotenv/webpack define plugin under the hood.

Answer 1

I’m sure there are other ways to do this, but with some quick tests, this approach seems to be working well for me.

In your gatsby-config.js file, you can choose to explicitly require the dotenv, so you can use those environment variables in your config.

I added the following, and now the Gatsby build will fail unless the specified environment variables are present.

// Load the environment variables, per
// https://www.gatsbyjs.org/docs/environment-variables/#server-side-nodejs
require('dotenv').config({
  path: `.env.${process.env.NODE_ENV}`,
})

function checkEnv(envName) {
  if (typeof process.env[envName] === 'undefined' || process.env[envName] === '') {
    throw `Missing required environment variables: ${envName}`
  }
}

try {
  checkEnv('NODE_ENV')
  checkEnv('EXAMPLE_MISSING_ENV')
  checkEnv('EXAMPLE_API_KEY')
} catch (e) {
  throw new Error(e)
}

// The rest of the config file

I could imagine customizing this further, ex. logging a warning for a variable with a fallback versus throwing an error for one that is required by your content sourcing plugin or theme. Hope this is helpful as a starting point!