Park-ranger NPM

park-ranger

This repository contains the source code for a Node module that helps with the management of environment-specific dependencies such as environment variables, configuration files and SSL certificate files.

Setup

To include this module in your package, simply run:

npm install park-ranger --save

Then add the following to your code:

var ranger = require('park-ranger')();

Environment name

By default, Park Ranger will load dependencies for the app depending on the value of environment variable ENV_NAME (with no spaces). As such, you can optionally call your app with the following assignment to make this variable available upfront:

ENV_NAME=example node index.js

The name will be used to determine the files that Park Ranger attempts to locate in your project's base directory and use as dependencies.

Dependency	Filename (no ENV_NAME)	Filename (ENV_NAME=example)
Environment variables file	.env	.env-example
Configuration file	.config.json	.config-example.json
SSL certificate directory	.cert	.cert-example

Environment variables

Environment variable files can be made available in INI format. By default, all variables found in these files will be applied automatically to process.env upon load of Park Ranger as a module. They will also be made available as the env property of the ranger.

Variables already available in process.env will be overwritten by any of those in the file with the same name. All variables will also be made available in the env property of the ranger.

If the ranger is loaded with true as a parameter, then the environment variables will not be applied automatically to process.env but just the env property of the ranger. This is useful for accessing the environment variables in a task runner but not incurring the unintended consequence of setting them prematurely for tasks themselves.

Example #1 – no ENV_NAME

.env file

FOO=BAR
WHIZ=BANG

index.js file

var ranger = require('park-ranger')();
console.log(ranger.env.FOO);
console.log(process.env.WHIZ);

command

node index.js

output

BAR
BANG

Example #2 – ENV_NAME=test

.env-test file

DB_NAME=test-db
SEND_EMAIL=false

index.js file

var ranger = require('park-ranger')();
console.log(ranger.env.DB_NAME);
console.log(process.env.SEND_EMAIL);
console.log(ranger.env.ENV_NAME);

command

ENV_NAME=test node index.js

output

test-db
false
test

Example #3 – local environment variables only

.env-task-runner file

FOO=BAR
WHIZ=BANG

index.js file

var ranger = require('park-ranger')(true);
console.log(ranger.env.FOO);
console.log(process.env.FOO);
console.log(ranger.env.ENV_NAME);

command

ENV_NAME=task-runner node index.js

output

BAR
undefined
task-runner

Configuration files

Configuration files can be made available in JSON format and must have ".json" as an extension. Their format should be documented in the parent repository using MSON and will get loaded by the ranger into its config property.

These files have an advantage over environment variable files since they can nest properties and generally represent more complex settings. However, they are not applied to process.env and therefore rely on the ranger object for access.

Example

.config.json file

{
  "foo": "bar",
  "things": [ 1, 2, 3 ]
}

index.js file

var ranger = require('park-ranger')();
console.log(ranger.config.foo);
console.log(ranger.config.things.length);

command

node index.js

output

bar
3

SSL certificate files

Certificate files can be made available in a directory and should correspond to a given certificate's private key, intermediate certificate authority (CA) and server certificate.

The names of these files can vary, with the following filenames supported:

Certificate file	Filenames supported
Private key	key, privkey.pem
Intermediate CA	ca, chain.pem
Server certificate	crt, cert.pem

The content of these files will be loaded into the cert property of the ranger with corresponding properties "key", "ca" and "crt" representing the file contents. As such, the cert property can be used to create an HTTPS server without additional file parsing.

Example

.cert directory

privkey.pem
chain.pem
cert.pem

index.js file

var ranger = require('park-ranger')();
require('https').createServer(ranger.cert, function(req, res) { ... }).listen(443, () => {
  console.log('listening!');
});