nexit

Zero Dependency utility to exit NodeJs gracefully

Install

npm install nexit

API

Constructor parameters

| Parameter | Default | Description | | ----------- | ----------- | ----------- | | options.shutdownDelay | 30000 | shutdown delay(ms) | | options.exitDelay | 300 | exit delay(ms) |

Quick Start

const Nexit = require('nexit');

new Nexit.Nexit();

or

import { Nexit } from 'nexit';

new Nexit();

Description

This library aims to delay process exit by a configurable amount of time to let service/traffic orchestrator to stop routing active traffic so that the process can be killed safely.

1. SIGINT, SIGTERM and uncaughtException signals
2. start a timer with shutdownDelay after catching one of the signals above.
3. fire an event with NEXIT_SHUTDOWN to let application know about the state

application can use this event for its healthz route as below.

4. once shutdownDelay timer is expired, start a new timer with exitDelay
5. fire an event with NEXIT_EXIT to let application know about the state
6. at this point, application may exit on its own at any time if node event loop is fully cleared
7. once exitDelay timer is expired, application will be killed forcefully by process.exit command

Usage

Simple healthz route implementation for ExpressJs.

const express = require('express');
const Nexit = require('nexit');

const app = express();

const nexit = new Nexit.Nexit();
nexit.on(Nexit.NEXIT_SHUTDOWN, (err, signal) => {
  console.log(`server is shutting down signal: ${signal}`, err);
  app.set('isShuttingDown', true);
});
nexit.on(Nexit.NEXIT_EXIT, () => {
  console.log('server is exiting...');
});

app.get('/healthz', (req, res) => {
  const isShuttingDown = app.get('isShuttingDown');

  if (isShuttingDown) {
    res.status(503).send({
      message: 'shutting down',
    });
    return;
  }

  res.status(200).send({
    message: 'ok',
  });
});

app.listen(8080);

See ./demo for a working example;

cd ./demo
npm install
node index.js