@lennoxruk/express-status-monitor

Simple, self-hosted module based on Socket.io and Chart.js to report realtime server metrics for Express-based node servers.

Independent fork notice

This is an independent fork of express-status-monitor with a number of updates. It is detached from the original project as the update has divulged somewhat from the original source. The original structure of the project is still maintained but all source files have been refactored.

Notable changes:

• All security vulnerabilities in package dependencies have been fixed
• Replaced axios with node-fetch-native for commonjs compatibility with packaging tools
• Changed health checker to use node-fetch-native instead of axios
• Fixed issue with health checker for non-200 status code responses
• Fixed event loop showing when set to false in config
• Removed event loop warning on startup when not requested in config
• Removed branding from UI
• Changed all unit tests to jest

Support for other Node.js frameworks

• koa-monitor for Koa
• hapijs-status-monitor for hapi.js

Installation & setup

1. Run npm install @lennoxruk/express-status-monitor --save
2. Before any other middleware or router add following line: app.use(require('@lennoxruk/express-status-monitor')());
3. Run server and go to /status

Note: This plugin works on Node versions > 4.x

Run examples

1. Run npm run example
2. Go to UI at http://0.0.0.0:3000

To run status code tester, whilst example is running,

1. Go to examples folder cd examples
2. Run node tester.js
3. View UI for status code updates at random intervals

Options

Monitor can be configured by passing options object into expressMonitor constructor.

Default config:

title: 'Express Status',  // Default title
theme: 'default.css',     // Default styles
path: '/status',
socketPath: '/socket.io', // In case you use a custom path
websocket: existingSocketIoInstance,
spans: [{
  interval: 1,            // Every second
  retention: 60           // Keep 60 datapoints in memory
}, {
  interval: 5,            // Every 5 seconds
  retention: 60
}, {
  interval: 15,           // Every 15 seconds
  retention: 60
}],
chartVisibility: {
  cpu: true,
  mem: true,
  load: true,
  eventLoop: true,
  heap: true,
  responseTime: true,
  rps: true,
  statusCodes: true
},
healthChecks: [],
ignoreStartsWith: '/admin'

Health Checks

You can add a series of health checks to the configuration that will appear below the other stats. The health check will be considered successful if the endpoint returns a 200 status code.

// config
healthChecks: [{
  protocol: 'http',
  host: 'localhost',
  path: '/admin/health/ex1',
  port: '3000'
}, {
  protocol: 'http',
  host: 'localhost',
  path: '/admin/health/ex2',
  port: '3000'
}]

Securing endpoint

The HTML page handler is exposed as a pageRoute property on the main middleware function. So the middleware is mounted to intercept all requests while the HTML page handler will be authenticated.

Example using https://www.npmjs.com/package/connect-ensure-login

const ensureLoggedIn = require('connect-ensure-login').ensureLoggedIn()

const statusMonitor = require('express-status-monitor')();
app.use(statusMonitor);
app.get('/status', ensureLoggedIn, statusMonitor.pageRoute)

Credits to @mattiaerre

Example using http-auth

const auth = require('http-auth');
const basic = auth.basic({realm: 'Monitor Area'}, function(user, pass, callback) {
  callback(user === 'username' && pass === 'password');
});

// Set '' to config path to avoid middleware serving the html page (path must be a string not equal to the wanted route)
const statusMonitor = require('express-status-monitor')({ path: '' });
app.use(statusMonitor.middleware); // use the "middleware only" property to manage websockets
app.get('/status', basic.check(statusMonitor.pageRoute)); // use the pageRoute property to serve the dashboard html page

Using module with socket.io in project

If you're using socket.io in your project, this module could break your project because this module by default will spawn its own socket.io instance. To mitigate that, fill websocket parameter with your main socket.io instance as well as port parameter.

Tests and coverage

In order to run test and coverage use the following npm commands:

npm test
npm run coverage

License

MIT License