feat(EurekaClient.js): Allow an independent EUREKA_ENV env variable. (#151)

* feat(EurekaClient.js): Allow an independent EUREKA_ENV env variable.

This allows developers to select whatever Eureka env/config they need
without having to rely on NODE_ENV.
For example, we can set EUREKA_ENV to 'test', but keep
NODE_ENV='production' for all the middleware and components in our
library.

* docs(README.md): Explained how to use env variables to pick configs

* 4.5.0

Author: anacasner

README.md

@@ -44,7 +44,7 @@ const client = new Eureka({
 });
 ```
 
-The Eureka client searches for the YAML file `eureka-client.yml` in the current working directory. It further searches for environment specific overrides in the environment specific YAML files (e.g. `eureka-client-test.yml`). The environment is typically `development` or `production`, and is determined by the `NODE_ENV` environment variable. The options passed to the constructor overwrite any values that are set in configuration files.
+The Eureka client searches for the YAML file `eureka-client.yml` in the current working directory. It further searches for environment specific overrides in the environment specific YAML files (e.g. `eureka-client-test.yml`). The environment is typically `development` or `production`, and is determined by environment variables in this order: `EUREKA_ENV`, if present, or `NODE_ENV`, if present. Otherwise it defaults to `development`. The options passed to the constructor overwrite any values that are set in configuration files.
 
 You can configure a custom directory to load the configuration files from by specifying a `cwd` option in the object passed to the `Eureka` constructor.
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "eureka-js-client",
-  "version": "4.4.2",
+  "version": "4.5.0",
   "description": "A JavaScript implementation the Netflix OSS service registry, Eureka.",
   "main": "lib/index.js",
   "scripts": {

src/EurekaClient.js

@@ -54,7 +54,7 @@ export default class Eureka extends EventEmitter {
 
     // Load up the current working directory and the environment:
     const cwd = config.cwd || process.cwd();
-    const env = process.env.NODE_ENV || 'development';
+    const env = process.env.EUREKA_ENV || process.env.NODE_ENV || 'development';
 
     const filename = config.filename || 'eureka-client';