vGrid's AreYouReady Module

This is a very simple module to include in your node projects to provide HTTP Readiness/Liveness checks to clusters (such as Kubernetes) or load-balancers (nginx/haproxy/etc)

We found other great projects that provided similar functionality, but way too much bloat for our use case - so we wrote this!

Install

npm install --save @vgrid/areyouready

Usage

import AreYouReady from '@vgrid/areyouready';
const ayr = new AreYouReady({ port: 9999 }); // 9999 is default if none supplied

// Do your application logic
// .....

ayr.signalReady(true); // Signal that the app is ready
ayr.signalLive(true); // Signal that the app is now live

// Some while later
// .....
ayr.signalLive(false); // Signal that the app is NOT live
ayr.signalReady(false); // Signal that the app is NOT ready

Set up your cluster / load-balancers to check the following URLs:

http://service:9999/live and http://service:9999/ready

API

Only two methods exist, signalLive and signalReady which independently toggle the ready and live states:

signalLive (state: boolean): void;
signalReady (state: boolean): void;

The app will respond with one of the following response codes:

• live/ready: 200 - 'OK'
• not live / not ready: 500 - 'NOT_LIVE' / 'NOT_READY'
• other url: 404 - 'UNKNOWN'

Contributing

Any contributions are more than welcome!