ENV

Env is a plugin that loads environment variables from a .env file into process.env (opens new window). Storing configuration in the environment separate from code is based on The Twelve-Factor App (opens new window) methodology.

Usage

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

require('rovel.js').env.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 (opens new window) 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 rovel.js/plugins/env/config your_script.js

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

$ node -r rovel.js/plugins/env/config your_script.js dotenv_config_path=/custom/path/to/.env

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

$ DOTENV_CONFIG_<OPTION>=value node -r rovel.js/plugins/env/config your_script.js

$ DOTENV_CONFIG_ENCODING=latin1 node -r rovel.js/plugins/env/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 (opens new window), and return an Object with a parsed key containing the loaded content or an error key if it failed.

//rovel is the full pkg, require("rovel.js") and then env is taken out of it.
const result = rovel.env.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("rovel.js").env.config({ path: '/custom/path/to/.env' })

Encoding

Default: utf8

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

require('rovel.js').env.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("rovel.js").env.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 env = require('rovel.js').env;
const buf = Buffer.from('BASIC=basic')
const config = env.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 env = require('rovel.js').env
const buf = Buffer.from('hello world')
const opt = { debug: true }
const config = env.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
• lines beginning with # are treated as comments
• 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 (opens new window)) (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'}

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 (opens new window)

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 env = require('rovel.js').env
const envConfig = env.parse(fs.readFileSync('.env.override'))
for (const k in envConfig) {
  process.env[k] = envConfig[k]
}

Can I customize/write more features for env?

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 env = require('rovel.js').env
const variableExpansion = require('env-expand')
const myEnv = env.config()
variableExpansion(myEnv)