dotenv-that-plays-nice

dotenv-that-plays-nice

dotenv-that-plays-nice is a zero-dependency module that loads environment variables from a .env file into process.env. Storing configuration in the environment separate from code is based on The Twelve-Factor App methodology.

This module is based on the original dotenv module. Since that module was written, however, the rest of the world has adopted similar and done it one better. Most dotenv implementations understand that environment variables are largely the province of shell scripts and things that shell scripts call, and so they ignore shell-style comments (# foo) and correctly handle variable assignations prepended with export. The dotenv folks seem oddly resistant to this, claiming that .env is an "INI file". And given that they delete-on-sight polite "please reconsider so you aren't surprising and wasting folks' time", I guess it's probably best forked. So, here we go: dotenv-that-plays-nice.

(I don't really have any illusions that this is going to take over the world, but I want it for me.)

Install

# with npm
npm install dotenv-that-plays-nice

# or with Yarn
yarn add dotenv-that-plays-nice

Usage

As early as possible in your application, require and configure dotenv.

require('dotenv-that-plays-nice').config()

Create a .env file in the root directory of your project. Add environment-specific variables on new lines in the form of NAME=VALUE. For example:

DB_HOST=localhost
DB_USER=root
DB_PASS=s1mpl3

process.env now has the keys and values you defined in your .env file.

const db = require('db')
db.connect({
  host: process.env.DB_HOST,
  username: process.env.DB_USER,
  password: process.env.DB_PASS
})

Preload

You can use the --require (-r) command line option to preload dotenv. By doing this, you do not need to require and load dotenv in your application code. This is the preferred approach when using import instead of require.

$ node -r dotenv-that-plays-nice/config your_script.js

The configuration options below are supported as command line arguments in the format dotenv_config_<option>=value

$ node -r dotenv-that-plays-nice/config your_script.js dotenv_config_path=/custom/path/to/your/env/vars

Additionally, you can use environment variables to set configuration options. Command line arguments will precede these.

$ DOTENV_CONFIG_<OPTION>=value node -r dotenv-that-plays-nice/config your_script.js

$ DOTENV_CONFIG_ENCODING=latin1 node -r dotenv-that-plays-nice/config your_script.js dotenv_config_path=/custom/path/to/.env

Config

config will read your .env file, parse the contents, assign it to process.env, and return an Object with a parsed key containing the loaded content or an error key if it failed.

const result = dotenv.config()

if (result.error) {
  throw result.error
}

console.log(result.parsed)

You can additionally, pass options to config.

Options

Path

Default: path.resolve(process.cwd(), '.env')

You may specify a custom path if your file containing environment variables is located elsewhere.

require('dotenv-that-plays-nice').config({ path: '/full/custom/path/to/your/env/vars' })

Encoding

Default: utf8

You may specify the encoding of your file containing environment variables.

require('dotenv-that-plays-nice').config({ encoding: 'latin1' })

Debug

Default: false

You may turn on logging to help debug why certain keys or values are not being set as you expect.

require('dotenv-that-plays-nice').config({ debug: process.env.DEBUG })

Parse

The engine which parses the contents of your file containing environment variables is available to use. It accepts a String or Buffer and will return an Object with the parsed keys and values.

const dotenv = require('dotenv-that-plays-nice')
const buf = Buffer.from('BASIC=basic')
const config = dotenv.parse(buf) // will return an object
console.log(typeof config, config) // object { BASIC : 'basic' }

Options

Debug

Default: false

You may turn on logging to help debug why certain keys or values are not being set as you expect.

const dotenv = require('dotenv-that-plays-nice')
const buf = Buffer.from('hello world')
const opt = { debug: true }
const config = dotenv.parse(buf, opt)
// expect a debug message because the buffer is not in KEY=VAL form

Rules

The parsing engine currently supports the following rules:

• BASIC=basic becomes {BASIC: 'basic'}
• empty lines are skipped
• empty values become empty strings (EMPTY= becomes {EMPTY: ''})
• inner quotes are maintained (think JSON) (JSON={"foo": "bar"} becomes {JSON:"{\"foo\": \"bar\"}")
• whitespace is removed from both ends of unquoted values (see more on trim) (FOO= some value becomes {FOO: 'some value'})
• single and double quoted values are escaped (SINGLE_QUOTE='quoted' becomes {SINGLE_QUOTE: "quoted"})
• single and double quoted values maintain whitespace from both ends (FOO=" some value " becomes {FOO: ' some value '})
• double quoted values expand new lines (MULTILINE="new\nline" becomes

{MULTILINE: 'new
line'}

• (new to dotenv-that-plays-nice): lines beginning with # are treated as comments instead of turning into debug barf
• (new to dotenv-that-plays-nice): lines beginning with export are parsed as if the export wasn't there

FAQ

Should I commit my .env file?

No. We strongly recommend against committing your .env file to version control. It should only include environment-specific values such as database passwords or API keys. Your production database should have a different password than your development database.

Should I have multiple .env files?

No. We strongly recommend against having a "main" .env file and an "environment" .env file like .env.test. Your config should vary between deploys, and you should not be sharing values between environments.

In a twelve-factor app, env vars are granular controls, each fully orthogonal to other env vars. They are never grouped together as “environments”, but instead are independently managed for each deploy. This is a model that scales up smoothly as the app naturally expands into more deploys over its lifetime.

– The Twelve-Factor App

What happens to environment variables that were already set?

We will never modify any environment variables that have already been set. In particular, if there is a variable in your .env file which collides with one that already exists in your environment, then that variable will be skipped. This behavior allows you to override all .env configurations with a machine-specific environment, although it is not recommended.

If you want to override process.env you can do something like this:

const fs = require('fs')
const dotenv = require('dotenv-that-plays-nice')
const envConfig = dotenv.parse(fs.readFileSync('.env.override'))
for (let k in envConfig) {
  process.env[k] = envConfig[k]
}

Can I customize/write plugins for dotenv?

For dotenv@2.x.x: Yes. dotenv.config() now returns an object representing the parsed .env file. This gives you everything you need to continue setting values on process.env. For example:

const dotenv = require('dotenv-that-plays-nice')
const variableExpansion = require('dotenv-expand')
const myEnv = dotenv.config()
variableExpansion(myEnv)

How do I use dotenv with import?

ES2015 and beyond offers modules that allow you to export any top-level function, class, var, let, or const.

When you run a module containing an import declaration, the modules it imports are loaded first, then each module body is executed in a depth-first traversal of the dependency graph, avoiding cycles by skipping anything already executed.

– ES6 In Depth: Modules

You must run dotenv.config() before referencing any environment variables. Here's an example of problematic code:

errorReporter.js:

import { Client } from 'best-error-reporting-service'

export const client = new Client(process.env.BEST_API_KEY)

index.js:

import dotenv from 'dotenv-that-plays-nice'
import errorReporter from './errorReporter'

dotenv.config()
errorReporter.client.report(new Error('faq example'))

client will not be configured correctly because it was constructed before dotenv.config() was executed. There are (at least) 3 ways to make this work.

1. Preload dotenv: node --require dotenv-that-plays-nice/config index.js (Note: you do not need to import dotenv with this approach)
2. Import dotenv-that-plays-nice/config instead of dotenv-that-plays-nice (Note: you do not need to call dotenv.config() and must pass options via the command line or environment variables with this approach)
3. Create a separate file that will execute config first as outlined in this comment on the parent project's #133

Contributing Guide

See CONTRIBUTING.md

Change Log

See CHANGELOG.md

Changelog

8.1.1

• Added support for optional export prepending to entries in .env.
• (There is no public v8.1.0; packaging snafu.)