Fastify Ready Checks

Ready checks plugin for fastify Node.js web app framework

Usage

Basic usage

import fastify from 'fastify';
import plugin from 'fastify-ready-checks';
const app = fastify();
app.register(plugin);

An endpoint /live which will respond with 200 Server live will be added to your app An endpoint /ready which will respond with 500 Server not ready will be added to your app

Setting fixed boolean responses

app.register(plugin, { live: true, ready: true });

An endpoint /live which will respond with 200 Server live will be added to your app An endpoint /ready which will respond with 200 Server ready will be added to your app

Passing functions

app.register(plugin, { live: () => true, ready: () => true });

An endpoint /live will be added to your app which will first call the given live function and then respond with 200 Server live since return value of the function is truthy An endpoint /ready will be added to your app which will first call the given ready function and then respond with 200 Server ready since return value of the function is truthy

Passing functions that return promises

app.register(plugin, {
    live: () => Promise.resolve(),
    ready: () => Promise.reject(),
});

An endpoint /live will be added to your app which will first call the given live function, then await the returned promise and then respond with 200 Server live since the promise did not reject. An endpoint /ready will be added to your app which will first call the given ready function, then await the returned promise and then respond with 500 Server not ready since the promise rejected.

Passing promises

app.register(plugin, {
    live: Promise.resolve(),
    ready: Promise.reject(),
});

An endpoint /live will be added to your app which will await the given promise and then respond with 200 Server live since the promise did not reject. An endpoint /ready will be added to your app which will await the given promise and then respond with 500 Server not ready since the promise rejected.

Setting pathnames

app.register(plugin, {
    livePathname: '/_/health',
    readyPathname: '/_/ready',
    ready: true,
});

An endpoint /_/health will be added to your app which will respond with 200 Server live An endpoint /_/ready will be added to your app which will respond with 500 Server ready

Plugin options

app.register(plugin, {
    logger,
    livePathname,
    readyPathname,
    live,
    ready,
});

name	description	type	default
logger	log4j compatible logger (usually pino) to use for logging.	object
live	Either boolean value, function or promise used to determine if app is live	boolean or function => boolean or promise or function => promise	true
ready	Either boolean value, function or promise used to determine if app is ready	boolean or function => boolean or promise or function => promise	false
livePathname	Pathname for endpoint where live checks will be served	string	/live
readyPathname	Pathname for endpoint where ready checks will be served	string	/ready