gulp-env

Add or modify variables in your process.env.

Purpose

Often, two processes running at the same time need different environmental variables (for example: running tests and a server from the same gulp process). gulp-env helps simplify that problem, by letting you establish your env vars whenever you'd like, in a simpler interface. You can set values from an external .json, .ini, or other file, or programmatically set them directly by using env({vars:{}}) or env.set(vars).

Install

npm i --save-dev gulp-env

The TypeScript definition file is available in gulp-env.d.ts within the base directory.

Usage

Example

Nodemon server:

// gulpfile.js
var gulp = require('gulp');
var nodemon = require('gulp-nodemon');
var env = require('gulp-env');
 
gulp.task('nodemon', function() {
  env({
    file: '.env.json',
    vars: {
      // any variables you want to overwrite
    }
  });
 
  nodemon({
    script: 'server.js',
    ext: 'js html'
    // other config ...
  });
});
 
gulp.task('default', ['nodemon']);

ES6 web development:

import gulp from 'gulp';
import browserify from 'browserify';
import transform from 'vinyl-transform';
import babel from 'gulp-babel';
import concat from 'gulp-concat';
import jshint from 'gulp-jshint';
import uglify from 'gulp-uglify';
import sourcemaps from 'gulp-sourcemaps';
 
gulp.task('debug', () => {
  const envs = env.set({
    NODE_ENV: 'debug'
  });
  return gulp.src('src/main.js')
    .pipe(envs)
    .pipe(babel({optional: [
      'utility.inlineEnvironmentVariables'
    ]}))
    .pipe(uglify())
    .pipe(transform(file => browserify(file).bundle()))
    .pipe(envs.reset)
    .pipe(gulp.dest('dist'));
});

Simple CoffeeScript library's gulpfile:

gulp = require 'gulp'
coffee = require 'gulp-coffee'
mocha = require 'gulp-mocha'
env = require 'gulp-env'
CSON = require 'cson-safe'
 
gulp.task 'compile', ->
  gulp.src('src')
    .pipe coffee()
    .pipe gulp.dest('dest')
 
gulp.task 'test', ['compile'], ->
  gulp.src('test')
    .pipe envs = env
      file: 'config.cson'
      handler: CSON.parse
    .pipe mocha()
    .pipe envs.reset

Details

gulp-env has full test coverage for JSON files, JS modules, INI files, and custom handlers. The entire API below is covered as well. It can also be used in the middle of a Gulp pipeline, where this returns a no-op stream. Note that the process.env changes happen synchronously, at the time when the function is called.

Read a file and set process.env accordingly. Both of these forms are equivalent.

env(file: string) => EnvStream
env({file: string}) => EnvStream

Set one or more hardcoded values in process.env directly.

env({vars: Object}) => EnvStream
env.set(vars: Object) => EnvStream

Parse a file, overriding some of its variables.

env({
  // file to read
  file: string,
 
  // overrides
  vars: Object,
}) => EnvStream

Parse a file with a custom parser.

env({
  // file to read
  file: string,
 
  // custom handling, `contents` is the file's contents
  handler: (contents: string) => Object,
 
  // optional overrides
  vars?: Object,
}) => EnvStream

Parse a file as a different type.

env({
  // file to read
  file: string,
 
  // Treat it like this type. See `options.type` for limitations.
  type: string,
 
  // overrides
  vars?: Object,
}) => EnvStream

file, options.file

The file option loads the file's contents automatically, calling require if it isn't a .ini file or if there is no handler. You can omit the extension as far as require allows if it's already registered, since this uses require under the hood as a fallback.

// .env.json
{
  MONGO_URI: "mongodb://localhost:27017/testdb"
}
 
// .env.js
module.exports = {
  MONGO_URI: "mongodb://localhost:27017/testdb",
};
 
// gulpfile.js
var env = require('gulp-env');
 
process.env.MONGO_URI === "mongodb://localhost:27017/testdb"; // maybe false
 
// Any of these will work:
env(".env"); // if the file can be found via `require`
env(".env.json");
env({file: ".env"}); // if the file can be found via `require`
env({file: ".env.json"});
 
process.env.MONGO_URI === "mongodb://localhost:27017/testdb"; // true

options.vars

Properties on this object overwrite all existing external properties given by file loading, handlers, etc. All of these will also be added to process.env.

// gulpfile.js
var env = require('gulp-env');
env({
  file: 'env.ini',
  vars: {
    MONGO_URI: "mongodb://localhost:27017/testdb-for-british-eyes-only",
    PORT: 9001
  }
});

For the case of just setting environment variables programmatically, you can use env.set.

// These two are equivalent. They both can also be used in Gulp streams.
env({vars: vars});
env.set(vars);

options.handler

This customizes the parsing of the file. If this is given, the extension name is ignored, and the handler itself is directly called. This is very useful in cases where this module doesn't already support the format. Internally, the module uses this hook for its INI and JSON readers.

The function, if given, is called with two arguments:

• contents - the file's contents
• filename - the file's name

Notes:

• You don't need this if the file type itself is already registered in require.extensions.
• If the file doesn't exist, then contents is undefined. filename is still passed, though.
• If the extension is omitted, then filename reflects that, i.e. the extension is omitted.

# CSON is frequently used in CoffeeScript projects. Why not use that? 
env = require 'gulp-env'
CSON = require 'cson-safe'
 
env
  file: '.env.cson'
  handler: (contents) -> CSON.parse contents

// Or, why can't we use YAML?
var env = require('gulp-env');
var jsyaml = require('js-yaml');
 
env({
  file: '.env.yaml',
  handler: function(contents, filename) {
    return jsyaml.safeLoad(contents, {filename: filename});
  },
});

options.type

Treats the file input as if its extension was type. It doesn't work for required files, since Node.js doesn't have hooks to do that, but it currently works for json and ini types. Others may potentially be added over time. If you think another one should be added, please, by all means, submit a PR.

var env = require('gulp-env');
 
env({
  file: '.env',
  type: 'ini',
});
 
// You can also specify it as an extension, as opposed to a type.
env({
  file: '.env',
  type: '.ini',
});

EnvStream

Instances of this interface are returned for env() and env.set(). These are standard through2 object streams with the following extra methods:

• Reset the environment to its former state synchronously. This is designed to be most useful outside of gulpfiles. It returns a boolean, true if any properties were reset, false otherwise. Pass a truthy value as an argument to forcefully restore, i.e. ignore conflicts.

  envs.restore(force?: boolean) => boolean

• Reset the environment to its former state. Similar to .restore(), but is called after the incoming stream is flushed, i.e. after all previous Gulp plugins have had their effect on the stream. This is otherwise a no-op through2 object stream. The second version is analogous to envs.restore(true)

  envs.reset => stream.Readable, stream.Writable
  envs.reset.force => stream.Readable, stream.Writable

Note that such environments can be nested. For example, the following will work:

process.env.NODE_ENV // undefined
var env1 = env.set({NODE_ENV: "whatever"});
process.env.NODE_ENV // "whatever"
var env2 = env.set({NODE_ENV: "something else"});
process.env.NODE_ENV // "something else"
env2.restore();
process.env.NODE_ENV // "whatever"
env1.restore();
process.env.NODE_ENV // undefined

Now, if two settings are restored out of order, conflicting keys (where the currently set value is not the same as the originally set for that version) are simply left as-is. This is the same with externally changed environment variables.

// unbalanced modifications
process.env.NODE_ENV // undefined
var env1 = env.set({NODE_ENV: "whatever"});
process.env.NODE_ENV // "whatever"
var env2 = env.set({NODE_ENV: "something else"});
process.env.NODE_ENV // "something else"
env1.restore();
process.env.NODE_ENV // "something else"
env2.restore();
process.env.NODE_ENV // "whatever"
 
// external modifications
process.env.NODE_ENV // undefined
var env1 = env.set({NODE_ENV: "whatever"});
process.env.NODE_ENV // "whatever"
process.env.NODE_ENV = "something else";
env1.restore();
process.env.NODE_ENV // "something else"

Issues

Submit a new issue here in the issue tracker

Contributing

This aims for full test coverage. If you see something missing, please, by all means, send a PR.

To run the tests, run npm test. The tests and their dependencies are written in test/**.