use-env

A simple node program for executing commands using an environment from an env file.

Install

npm install use-env or npm install -g use-env

Basic Usage

Environment file ./.env

# This is a comment
ENV1=THANKS
ENV2=FOR ALL
ENV3=THE FISH

Package.json

{
  "scripts": {
    "test": "use-env mocha -R spec"
  }
}

Terminal

./node_modules/.bin/use-env node index.js

Using custom env file path

To use a custom env filename or path, pass the -f flag. This is a major breaking change from prior versions < 9.0.0

Terminal

./node_modules/.bin/use-env -f ./custom/path/.env node index.js

📜 Help

Usage: _ [options] <command> [...args]

Options:
  -v, --version                       output the version number
  -f, --file [path]                   Custom env file path (default path: ./.env)
  -r, --rc-file [path]                Custom rc file path (default path: ./.use-envrc(|.js|.json)
  -e, --environments [env1,env2,...]  The rc file environment(s) to use
  --fallback                          Fallback to default env file path, if custom env file path not found
  --no-override                       Do not override existing environment variables
  --use-shell                         Execute the command in a new shell with the given environment
  -h, --help                          output usage information

🔬 Advanced Usage

.rc file usage

For more complex projects, a .use-envrc file can be defined in the root directory and supports as many environments as you want. Simply use the -e flag and provide which environments you wish to use from the .use-envrc file. Using multiple environment names will merge the environment variables together. Later environments overwrite earlier ones in the list if conflicting environment variables are found.

.rc file ./.use-envrc

{
  "development": {
    "ENV1": "Thanks",
    "ENV2": "For All"
  },
  "test": {
    "ENV1": "No Thanks",
    "ENV3": "!"
  },
  "production": {
    "ENV1": "The Fish"
  }
}

Terminal

./node_modules/.bin/use-env -e production node index.js
# Or for multiple environments (where `production` vars override `test` vars,
# but both are included)
./node_modules/.bin/use-env -e test,production node index.js

--no-override option

Prevents overriding of existing environment variables on process.env and within the current environment.

--fallback file usage option

If the .env file does not exist at the provieded custom path, then use the default fallback location ./.env env file instead.

--use-shell

Executes the command within a new shell environment. This is useful if you want to string multiple commands together that share the same environment variables.

Terminal

./node_modules/.bin/use-env -f ./test/.env --use-shell "npm run lint && npm test"

Asynchronous env file support

EnvCmd supports reading from asynchronous .env files. Instead of using a .env file, pass in a .js file that exports either an object or a Promise resolving to an object ({ ENV_VAR_NAME: value, ... }). Asynchronous .rc files are also supported using .js file extension and resolving to an object with top level environment names ({ production: { ENV_VAR_NAME: value, ... } }).

Terminal

./node_modules/.bin/use-env -f ./async-file.js node index.js

Examples

You can find examples of how to use the various options above by visiting the examples repo use-env-examples.

Environment File Formats

These are the currently accepted environment file formats. If any other formats are desired please create an issue.

• .env as key=value
• .env.json Key/value pairs as JSON
• .env.js JavaScript file exporting an object or a Promise that resolves to an object
• .use-envrc as valid json or .use-envrc.json in execution directory with at least one environment { "dev": { "key1": "val1" } }
• .use-envrc.js JavaScript file exporting an object or a Promise that resolves to an object that contains at least one environment

Path Rules

This lib attempts to follow standard bash path rules. The rules are as followed:

Home Directory = /Users/test

Working Directory = /Users/test/Development/app

| Type | Input Path | Expanded Path | | -- | -- | ------------- | | Absolute | /some/absolute/path.env | /some/absolute/path.env | | Home Directory with ~ | ~/starts/on/homedir/path.env | /Users/test/starts/on/homedir/path.env | | Relative | ./some/relative/path.env or some/relative/path.env | /Users/test/Development/app/some/relative/path.env | | Relative with parent dir | ../some/relative/path.env | /Users/test/Development/some/relative/path.env |

⚒ API Usage

EnvCmd

A function that executes a given command in a new child process with the given environment and options

• options { object }
  • command { string }: The command to execute (node, mocha, ...)
  • commandArgs { string[] }: List of arguments to pass to the command (['-R', 'Spec'])
  • envFile { object }
    • filePath { string }: Custom path to .env file to read from (defaults to: ./.env)
    • fallback { boolean }: Should fall back to default ./.env file if custom path does not exist
  • rc { object }
    • environments { string[] }: List of environment to read from the .rc file
    • filePath { string }: Custom path to the .rc file (defaults to: ./.use-envrc(|.js|.json))
  • options { object }
    • noOverride { boolean }: Prevent .env file vars from overriding existing process.env vars (default: false)
    • useShell { boolean }: Runs command inside a new shell instance (default: false)
  • Returns { Promise<object> }: key is env var name and value is the env var value

GetEnvVars

A function that parses environment variables from a .env or a .rc file

• options { object }
  • envFile { object }
    • filePath { string }: Custom path to .env file to read from (defaults to: ./.env)
    • fallback { boolean }: Should fall back to default ./.env file if custom path does not exist
  • rc { object }
    • environments { string[] }: List of environment to read from the .rc file
    • filePath { string }: Custom path to the .rc file (defaults to: ./.use-envrc(|.js|.json))
• Returns { Promise<object> }: key is env var name and value is the env var value

Why

Because sometimes it is just too cumbersome passing a lot of environment variables to scripts. It is usually just easier to have a file with all the vars in them, especially for development and testing.

🚨Do not commit sensitive environment data to a public git repo! 🚨

Related Projects

cross-env - Cross platform setting of environment scripts

🎊 Special Thanks

Special thanks to cross-env for inspiration (uses the same cross-spawn lib underneath too).

🎉 Contributors

• Eric Lanehart
• Jon Scheiding
• Alexander Praetorius
• Anton Versal

📋 Contributing Guide

I welcome all pull requests. Please make sure you add appropriate test cases for any features added. Before opening a PR please make sure to run the following scripts:

• npm run lint checks for code errors and format according to js-standard
• npm test make sure all tests pass
• npm run test-cover make sure the coverage has not decreased from current master