dotenv
Dotenv 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.
Install
npm install dotenv --save
Usage
As early as possible in your application, require and configure dotenv.
require('dotenv').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
That's it.
process.env
now has the keys and values you defined in your .env
file.
var db = require('db')
db.connect({
host: process.env.DB_HOST,
username: process.env.DB_USER,
password: process.env.DB_PASS
})
Preload
If you are using iojs-v1.6.0 or later, 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.
$ node -r dotenv/config your_script.js
The configuration options below are supported as command line arguments in the format dotenv_config_<option>=value
$ node -r dotenv/config your_script.js dotenv_config_path=/custom/path/to/your/env/vars
Config
Alias: load
config
will read your .env file, parse the contents, and assign it to
process.env
. You can additionally, pass options to
config
.
Options
Silent
Default: false
Dotenv outputs a warning to your console if missing a .env
file. Suppress
this warning using silent.
require('dotenv').config({silent: true})
Path
Default: .env
You can specify a custom path if your file containing environment variables is named or located differently.
require('dotenv').config({path: '/custom/path/to/your/env/vars'})
Encoding
Default: utf8
You may specify the encoding of your file containing environment variables using this option.
require('dotenv').config({encoding: 'base64'})
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.
var dotenv = require('dotenv')
var buf = new Buffer('BASIC=basic')
var config = dotenv.parse(buf) // will return an object
console.log(typeof config, config) // object { BASIC : 'basic' }
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: ''}
) - single and double quoted values are escaped (
SINGLE_QUOTE='quoted'
becomes{SINGLE_QUOTE: "quoted"}
) - new lines are expanded if in double quotes (
MULTILINE="new\nline"
becomes
{MULTILINE: 'new
line'}
- inner quotes are maintained (think JSON) (
JSON={"foo": "bar"}
becomes{JSON:"{\"foo\": \"bar\"}"
)
FAQ
.env
file?
Should I commit my 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.
.env
files?
Should I have multiple 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.
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')
const envConfig = dotenv.parse(fs.readFileSync('.env.override'))
for (var 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:
var dotenv = require('dotenv')
var variableExpansion = require('dotenv-expand')
const myEnv = dotenv.config()
variableExpansion(myEnv)
What about variable expansion?
For dotenv@2.x.x
: Use dotenv-expand.
For dotenv@1.x.x
: We haven't been presented with a compelling use case for expanding variables and believe it leads to env vars that are not "fully orthogonal" as The Twelve-Factor App outlines.[1][2] Please open an issue if you have a compelling use case.
Contributing Guide
See CONTRIBUTING.md
Change Log
See CHANGELOG.md
License
See LICENSE
Who's using dotenv
Here's just a few of many repositories using dotenv:
Go well with dotenv
Here's some projects that expand on dotenv. Check them out.