express-internal-monitor

Monitoring internal expressjs functions such as Handles and Router and connect resource to InfluxDB

The middleware express-internal-monitor allows to trace and record performance measurements of expressjs's internals Handles and Layers (Router). Data points are stored in a plaintext file but the tool can send these points to InfluxDB and then it is possible to monitor the Express Application Server with Grafana.

Example Configuration

const express = require('express')
const expressInternalMonitor = require('express-internal-monitor')

var app = express()

// initialize the monitor
expressInternalMonitor(app, {
  // optionnal
	influxDB: {
		url: 'http://localhost:8086',
		db: 'monitor'
	}
});

// static handle
app.use(express.static(__dirname + '/static'));

// slow route
app.get('/next', function (req, res) {
	setTimeout(() => {
		res.send('Hello World! next')
	}, 1000)
})

app.get('/', function (req, res) {
	res.send('Hello World!')
})

app.listen(3000, function () {
	console.log('Example app listening on port 3000!')
})

Out of the box you will get statistics for:

• Internal Handle measurement
• Internal Router measurement (per Layer)

Two examples are available in test1.json and test2.json

Configuration Options

const expressInternalMonitor = require('express-internal-monitor')

// initialize the monitor
expressInternalMonitor(app, {
  // optionnal
	influxDB: {
		url: 'http://localhost:8086',
		db: 'monitor'
	}
});

In the example expressInternalMonitor(app, options) takes the ExpressJS's Application pointer and options.

Options are:

• path: Change working path. Default to current working path
• influxDB: Setup InfluxDB options (see bellow)
• logFile: Activate file logging for data points (default true)
• statHandle: Activate statistics for ExpressJS Handles (default true)
• statRouter: Activate statistics for ExpressJS Router (default true)
• serverName: Set current server name

For influxDB options are:

• url: InfluxDB URL for example http://user:pass@localhost:8086..
• db: Database to store data points
• concurrent: Amount of concurrent insertion of data points, default to 2000
• heartbeat: Setup application heartbeat, default to true
• heartbeatTimer: Set application heartbeat timer in milliseconds, default to 1000 (1 second)

InfluxDB Integration

A database must be created in order to store data points.

Connect to your InfluxDB administration interface (example: http://localhost:8083/) and create a new database calls monitor:

CREATE DATABASE "monitor"

If you running InfluxDB > v1.3 use the CLI to create the database:

influx -precision rfc3339

Grafana Integration

• First add your InfluxDB data source in Grafana and goto Administration > Data Sources
• Fill informations as following (working example)

• Goto new Import Dashboard
• Paste the grafana.json data (or upload it)
• Well done!

Credits

• Michael Vergoz
• @mykiimike on Github and Twitter

Package under MIT license