@godaddy/terminus

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2.2.1
Source
npm

Version published: 6 years ago

Weekly downloads: 177K; decreased by-6.53%

Maintainers: 6

Weekly downloads

Created: 7 years ago

What is @godaddy/terminus?

@godaddy/terminus is a Node.js package that helps manage graceful shutdowns and health checks for your applications. It ensures that your application can handle termination signals properly, allowing for clean shutdowns and preventing data corruption or loss. It also provides endpoints for health checks to monitor the application's status.

What are @godaddy/terminus's main functionalities?

Graceful Shutdown

This feature allows the application to handle termination signals gracefully. When a termination signal (e.g., SIGINT) is received, the `onSignal` function is called to perform any necessary cleanup before the server shuts down.

const http = require('http');
const { createTerminus } = require('@godaddy/terminus');

const server = http.createServer((req, res) => {
  res.end('Hello world!');
});

function onSignal() {
  console.log('Server is starting cleanup');
  // start cleanup of resource, like databases or file descriptors
  return Promise.resolve();
}

function onShutdown() {
  console.log('Cleanup finished, server is shutting down');
}

createTerminus(server, {
  signal: 'SIGINT',
  onSignal,
  onShutdown
});

server.listen(3000);

Health Checks

This feature provides a health check endpoint that can be used to monitor the application's status. The `onHealthCheck` function can include logic to determine if the application is healthy and return a promise that resolves if it is.

const http = require('http');
const { createTerminus } = require('@godaddy/terminus');

const server = http.createServer((req, res) => {
  res.end('Hello world!');
});

function onHealthCheck() {
  return Promise.resolve(); // optionally include a health check here
}

createTerminus(server, {
  healthChecks: {
    '/healthcheck': onHealthCheck
  }
});

server.listen(3000);

Other packages similar to @godaddy/terminus

terminus

Adds graceful shutdown and Kubernetes readiness / liveness checks for any HTTP applications.

Installation

Install via npm:

$ npm i @godaddy/terminus --save

Usage

const http = require('http');
const terminus = require('@godaddy/terminus');

function onSignal () {
  console.log('server is starting cleanup');
  return Promise.all([
    // your clean logic, like closing database connections
  ]);
}

function onShutdown () {
  console.log('cleanup finished, server is shutting down');
}

const server = http.createServer((request, response) => {
  response.end(
    `<html>
      <body>
        <h1>Hello, World!</h1>
       </body>
     </html>`
   );
})

const options = {
  // healtcheck options
  healthChecks: {
    '/healthcheck': check          // a promise returning function indicating service health
  },

  // cleanup options
  timeout: 1000,                   // [optional = 1000] number of milliseconds before forcefull exiting
  signal,                          // [optional = 'SIGTERM'] what signal to listen for relative to shutdown
  beforeShutdown,                  // [optional] called before the HTTP server starts its shutdown
  onSignal,                        // [optional] cleanup function, returning a promise (used to be onSigterm)
  onShutdown,                      // [optional] called right before exiting

  // both
  logger                           // [optional] logger function to be called with errors
};

terminus(server, options);

server.listen(PORT || 3000);

With express

const http = require('http');
const app = express();

app.get('/', (req, res) => {
  res.send('ok');
});

const server = http.createServer(app);

const options = {
  // opts
};

terminus(server, options);

server.listen(PORT || 3000);

With koa

const http = require('http');
const Koa = require('koa');
const app = new Koa();

const server = http.createServer(app.callback());

const options = {
  // opts
};

terminus(server, options);

server.listen(PORT || 3000);

Limited Windows support

Due to inherent platform limitations, terminus has limited support for Windows. You can expect SIGINT to work, as well as SIGBREAK and to some extent SIGHUP. However SIGTERM will never work on Windows because killing a process in the task manager is unconditional, i.e., there's no way for an application to detect or prevent it. Here's some relevant documentation from libuv to learn more about what SIGINT, SIGBREAK etc. signify and what's supported on Windows - http://docs.libuv.org/en/v1.x/signal.html. Also see https://nodejs.org/api/process.html#process_signal_events.

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Package last updated on 08 Jun 2018

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