health-check-library

Expose an health-check API to *-worker or a health-check route for already existing API

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health-check-library
Expose an health-check API to -worker or a health-check route for already existing API

Kubernetes (Google Container Engine, Clever-cloud and so on...) requires every processes to expose an HTTP API so it can ensure the service is up.

<img src="https://cloud.githubusercontent.com/assets/138050/7140277/be87ed10-e2ca-11e4-96ec-b6e086321bac.gif" style="width:1000%" />


Instead of duplicating code everywhere in the code, the health-check-library simply expose a route in a language-agnostic and unified way.
Specification
health-check-library MUST expose a GET /health route that yield a 200 HTTP status code. health-check-library follows semver so any non-backward-compatible change will be a major release.
Features
  • Language agnostic, if it's not supported in your current language simply send a PR that follows the above conventions
  • Framework agnostic, if the framework you use is not supported simply send a PR that follows the above conventions
Currently supported

JavaScript

JavaScript / pure (without an existing HTTP API)

Use this when your NodeJS process (a.k.a worker) does not currently expose an HTTP API.
// Usage
require('health-check-library')(port [, callback]);

If health-check-library was not able to bind to the specified port it will throw an error and make the worker crash (that's a good thing).
var healthy = require('health-check-library/javascript/pure')(8080, function onListening(){

    // do some initializations
    healthy(true); // you are ready
});

JavaScript / hapi

Use this when your NodeJS process already exposes an HTTP API with HAPI. Please note that HAPI should always be used in NodeJS, don't forget to document your API with swaggerize-hapi.
If health-check-library was not able to register itself to the HAPI server it will throw an error and will make the process crash (that's a good thing).
var healthy = require('health-check-library').register(server);

// by default GET /health will yield a 500 error

healthy(true);

// now GET /health yield an 200 success

  • always = 99.9% of the time