Monody - a simple sensors manager

Features

Monody has 2 simple features:

1. provide some basic sensors to get informations like the CPU usage, memory usage, disk usage
2. allow for regular interrogation of those sensors

Stability

This package is in a prototyping stage and sensors support only Ubuntu hosts. Contact me for other platforms. I DO NOT recommend using this in production for now since there might be some breaking changes.

Node compatibility

Tested starting 4.4.0.

Installation

Install using npm:

npm install monody

Create a server.js file:

// file server.js
const monody = require('monody');
const sensors = require('monody/sensors');

// standalone usage of a sensor
sensors.cpu((cpu) => {
  console.log("current cpu usage", cpu);
});

// template for custom sensors
function customSensorTime(cb, options, taskStatus) {
  const responseData = {
    status: true,
    data: {
      time: new Date()
    },
    msg: "",
    extra: null
  }
  
  cb(responseData, "time");
}

// options for a http sensor
var options = {
  method: 'GET',
  host: 'nodejs.org',
  path: '/en/',
  port: 443
}

// general callback function to display data from the sensors
function callback(data, sensorName, taskStatus) {
  console.log(sensorName, data);
}

// tested with Ubuntu only 
// be carefull and give your sensors enough time to execute
monody.addTask(customSensorTime, callback, 1000);
monody.addTask(sensors.cpu, callback, 5000);
monody.addTask(sensors.mem, callback, 5000);
monody.addTask([sensors.http, options], callback, 5000);

// examples to get disk info and file size
// monody.addTask([sensors.disk, '/dev/sda'], callback, 5000);
// monody.addTask([sensors.fileInfo, 'your_file_name_here'], callback, 5000);

monody.start();

Launch with node server.js.

Anatomy of a sensor

A Monody sensor is a function that accepts two parameters:

• a callback function
• an options object

Monody will pass 3 parameters to the callback function:

• a response object:
  • a status (boolean or string)
  • a data object
  • a string message generally used for informations about errors
  • an extra parameter which can be of any type
• a tag name (string) used by the scheduler to identify the sensor
• a taskStatus object

Let's see an example that can be used as a template for your own custom sensors.

function sensorTime(cb) {
  
  const responseData = {
    status: true,
    data: {
      time: new Date()
    },
    msg: "",
    extra: null
  }
   
  // monody will inject the task status as 3rd argument to the sensor function
  // therefore we will use the arguments array to pass it to the callback
  cb(responseData, "time", arguments[2]);
}

Available sensors

The package offers the following sensors:

• cpu: cpu usage (float)
• mem: mem usage (object)
• disk: disk usage (float)
• fileInfo: file informations(object)
• (NEW) http: executes a http call (using node http.request) and returns the native response object

Roadmap

• improve documentation
• add more sensors
• error handling
• more examples

Contribute

The interest of this package will grow with the number of sensors. If you are interested in publishing new sensors, contact me: [email protected].

Changelog

• 0.0.25 / 2016-09-04: improved http sensor. Returns req and res objects, body, statusCode and statusMessage
• 0.0.24 / 2016-09-04: added a tonic example
• 0.0.23 / 2016-09-04: added compatibility for node 4.4.x and greater
• 0.0.22 / 2016-09-04: added new functions: pauseTask, resumeTask, addTaskAndLaunch, repetitions
• 0.0.17 / 2016-09-01: documentation update
• 0.0.16 / 2016-09-01: bug corrections
• 0.0.15 / 2016-09-01: minor corrections
• 0.0.14 / 2016-09-01: new http sensor, all sensors return a standard response object
• 0.0.13 / 2016-08-29: documentation improvements