EXAMPLE.md

Example

• Example
  • ExpressJS
  • Fastify
  • Koa
  • HTTP Server

ExpressJS

The library works with the default HTTP NodeJS object. So, when you're using Express you can't pass directly the app object from Express. But, you can easily generate an HTTP NodeJS object from the app object.

Just follow the bottom example:

const express = require('express')
const helmet = require('helmet')
const http = require('http')
const GracefulServer = require('@gquittet/graceful-server')
const { connectToDb, closeDbConnection } = require('./db')

const app = express()
const server = http.createServer(app)
const gracefulServer = GracefulServer(server, { closePromises: [closeDbConnection] })

app.use(helmet())

app.get('/test', (_, res) => {
  return res.send({ uptime: process.uptime() | 0 })
})

gracefulServer.on(GracefulServer.READY, () => {
  console.log('Server is ready')
})

gracefulServer.on(GracefulServer.SHUTTING_DOWN, () => {
  console.log('Server is shutting down')
})

gracefulServer.on(GracefulServer.SHUTDOWN, error => {
  console.log('Server is down because of', error.message)
})

server.listen(8080, async () => {
  await connectToDb()
  gracefulServer.setReady()
})

As you can see, we're using the app object from Express to set up the endpoints and middleware. But it can't listen (you can do it but app hasn't any liveness or readiness). The listening of HTTP calls need to be done by the default NodeJS HTTP object (aka server).

Fastify

const fastify = require('fastify')({ logger: true })
const GracefulServer = require('@gquittet/graceful-server')

const gracefulServer = GracefulServer(fastify.server)

gracefulServer.on(GracefulServer.READY, () => {
  console.log('Server is ready')
})

gracefulServer.on(GracefulServer.SHUTTING_DOWN, () => {
  console.log('Server is shutting down')
})

gracefulServer.on(GracefulServer.SHUTDOWN, error => {
  console.log('Server is down because of', error.message)
})

// Declare a route
fastify.get('/', async (request, reply) => {
  return { hello: 'world' }
})

// Run the server!
const start = async () => {
  try {
    await fastify.listen({ port: 3000 })
    fastify.log.info(`server listening on ${fastify.server.address().port}`)
    gracefulServer.setReady()
  } catch (err) {
    fastify.log.error(err)
    process.exit(1)
  }
}
start()

Be careful, if you are using Fastify v4.x.x with Node 16 and below, you have to use

await fastify.listen({ port: 3000, host: '0.0.0.0' })

because Node 16 and below does not support multiple addresses binding.

See: fastify/fastify#3536

Koa

const GracefulServer = require('@gquittet/graceful-server')
const Koa = require('koa')
const http = require('http')
const Router = require('koa-router')

const app = new Koa()
const router = new Router()

const server = http.createServer(app.callback())
gracefulServer = GracefulServer(server)

router.get('/test')
app.use(router.routes())

// response
app.use(ctx => {
  ctx.body = 'Hello Koa'
})

gracefulServer.on(GracefulServer.READY, () => {
  console.log('Server is ready')
})

gracefulServer.on(GracefulServer.SHUTTING_DOWN, () => {
  console.log('Server is shutting down')
})

gracefulServer.on(GracefulServer.SHUTDOWN, error => {
  console.log('Server is down because of', error.message)
})

server.listen(8080, async () => {
  gracefulServer.setReady()
})

As you can see, we're using the app object from Express to set up the endpoints and middleware. But it can't listen (you can do it but app hasn't any liveness or readiness). The listening of HTTP calls need to be done by the default NodeJS HTTP object (aka server).

HTTP Server

import http from 'http'
import url from 'url'
import GracefulServer from '@gquittet/graceful-server'
import { connectToDb, closeDbConnection } from './db'

const server = http.createServer((req, res) => {
  if (req.url === '/test' && req.method === 'GET') {
    res.statusCode = 200
    res.setHeader('Content-Type', 'application/json')
    return res.end(JSON.stringify({ uptime: process.uptime() | 0 }))
  }
  res.statusCode = 404
  return res.end()
})

const gracefulServer = GracefulServer(server, { closePromises: [closeDbConnection] })

gracefulServer.on(GracefulServer.READY, () => {
  console.log('Server is ready')
})

gracefulServer.on(GracefulServer.SHUTTING_DOWN, () => {
  console.log('Server is shutting down')
})

gracefulServer.on(GracefulServer.SHUTDOWN, error => {
  console.log('Server is down because of', error.message)
})

server.listen(8080, async () => {
  await connectToDb()
  gracefulServer.setReady()
})