Uptime Event Emitter

An uptime event emitter for http, tcp, and udp servers.

Installation

npm install ping-monitor

Documentation

• Uptime Event Emitter
  • Installation
  • Documentation
  • How to use
  • Methods
  • Options
    • Expect Object
    • Config Object
  • Emitted Events
  • Response object
  • State object
  • Website Example
  • TCP Example
  • UDP Example
  • Change log
    • v0.8.2
    • v0.8.1
      • Threshold Example
    • v0.8.0
    • v0.7.0
    • v0.6.1
    • v0.6.0
    • v0.5.2
    • v0.5.1
    • v0.5.0
    • v0.4.4
    • v0.4.3
    • v0.4.2
    • v0.4.1
    • v0.4.0
    • v0.3.1
    • v0.3.0
    • v0.2.0
  • Testing
    • License

How to use

const Monitor = require('ping-monitor');

const myWebsite = new Monitor(options);

myWebsite.on(event, function(response, state) {
    // Do something with the response
});

Alternatively, you can subscribe to the Monitor's events through a notification channel. Click to see some demo nofitication channels.

const Monitor = require('ping-monitor');
const SlackChannel = require('@ping-monitor/slack');
const EmailChannel = require('@ping-monitor/email');

const myWebsite = new Monitor(options);
const slacker = new SlackChannel({...config});
const mailer = new EmailChannel({...config});

myWebsite.addNotificationChannel(slacker);
myWebsite.addNotificationChannel(mailer);

Methods

• stop - stop an active monitor
• restart - stop and start an active monitor
• addNotificationChannel (or addChannel) - adds a notification channel that subscribes to the monitor's events

Options

• address - Server address to be monitored
• protocol - (defaults to http) request protocol (http/s, tcp, udp)
• port - Server port (optional).
• interval (defaults to 15) - time interval for polling requests.
• httpOptions - allows you to define your http/s request with more control. A full list of the options can be found here: https://nodejs.org/api/http.html#http_http_request_url_options_callback
• expect { statusCode , contentSearch } - allows you define what kind of a response you expect from your endpoint.
  • statusCode defines the expected http response status code.
  • contentSearch defines a substring to be expected from the response body.
• config { intervalUnits } - configuration for your Monitor, currently supports one property, intervalUnits. intervalUnits specifies which to time unit you want your Monitor to use. There are 4 options, milliseconds, seconds, minutes (default), and hours.
• ignoreSSL - ignore broken/expired certificates
• threshold (defaults to 1) - an integer specifying the number of tries before a down/error/timeout event is emitted

Expect Object

expect {
  statusCode: Integer, // http status codes
  contentSearch: String
}

Config Object

config {
  intervalUnits: String
}

// http Get
const myApi = new Monitor({
    address: 'https://api.ragingflame.co.za',
    title: 'Raging Flame',
    interval: 5,
    protocol: 'http', // http/s, tcp, udp
    config: {
      intervalUnits: 'minutes' // seconds, milliseconds, minutes {default}, hours
    },

    httpOptions: {
      path: '/users',
      method: 'get',
      query: {
        id: 3
      }
    },
    expect: {
      statusCode: 200
    }
});

// http Post
const myApi = new Monitor({
    address: 'http://api.ragingflame.co.za',
    title: 'Raging Flame',
    interval: 10,
    protocol: 'http',
    config: {
      intervalUnits: 'minutes' // seconds, milliseconds, minutes {default}, hours
    },

    httpOptions: {
      path: '/users',
      method: 'post',
      query: {
        first_name: 'Que',
        last_name: 'Fire'
      },
      body: {content:'Hello World!'}
    },
    expect: {
      statusCode: 200
    }
});

Emitted Events

• up - All is good server is up.
• down - Not good, server is down.
• stop - Fired when the monitor has stopped.
• error - Fired when there's an error
• timeout - Fired when the http request times out
• restored - Fired server is up after being down
• retry - Fired when the monitor is retrying a failed request

Response object

• object.website (deprecated) - website being monitored .
• object.address - server address
• object.port - server port
• object.time - (deprecated use responseTime) request response time
• object.responseMessage - http response code message
• object.responseTime - response time in milliseconds
• object.httpResponse - native http/s response object

State object

• object.id null - monitor id, useful when persistence.
• object.title null - monitor label for humans.
• object.isUp true - flag to indicate if monitored server is up or down.
• object.created_at <Date.now()> - monitor creation date.
• object.port null - server port.
• object.totalRequests 0 - total requests made.
• object.totalDownTimes 0 - total number of downtimes.
• object.lastDownTime <Date.now()> - time of last downtime.
• object.lastRequest <Date.now()> - time of last request.
• object.interval 5 - polling interval in minutes
• object.website null - (deprecated) website being monitored.
• object.address null - server address being monitored.
• object.port null - server port.
• object.paused false - monitor paused flag
• object.httpOptions - monitor httpOptions options
• object.threshold (default to ) - an integer specifying the number of tries before a down/error/timeout event is emitted
• object.shouldAlertDown true - flag to indicate if down/error/timeout events should be emitted

Website Example

'use strict';

const Monitor = require('ping-monitor');


const myMonitor = new Monitor({
  address: 'http://www.ragingflame.co.za',
  title: 'Raging Flame',
  interval: 10 // minutes
  //protocol: 'http'
});


myMonitor.on('up', function (res, state) {
    console.log('Yay!! ' + state.address + ' is up.');
});


myMonitor.on('down', function (res, state) {
  console.log('Oh Snap!! ' + state.address + ' is down! ' + state.responseMessage);
});


myMonitor.on('restored', function (res, state) {
  console.log(state.address + ' has been restore');
});


myMonitor.on('stop', function (res, state) {
  console.log(state.address + ' monitor has stopped.');
});


myMonitor.on('timeout', function (error, res) {
  console.log(error);
});


myMonitor.on('error', function (error) {
  console.log(error);
});

TCP Example

'use strict';

const Monitor = require('ping-monitor');


const myMonitor = new Monitor({
  address: '162.13.124.139',
  port: 8080,
  interval: 5, // minutes
  protocol: 'tcp'
});


myMonitor.on('up', function (res, state) {
  console.log('Yay!! ' + state.address + ':' + state.port + ' is up.');
});


myMonitor.on('down', function (res, state) {
  console.log('Oh Snap!! ' + state.address + ':' + state.port + ' is down! ');
});


myMonitor.on('restored', function (res, state) {
  console.log('Yay!! ' + state.address + ':' + state.port + ' has been restored! ');
});


myMonitor.on('stop', function (res, state) {
  console.log(state.address + ' monitor has stopped.');
});


myMonitor.on('error', function (error, res) {
  console.log(error);
});


myMonitor.on('timeout', function (error, res) {
  console.log(error);
});

UDP Example

'use strict';

const Monitor = require('ping-monitor');


const myMonitor = new Monitor({
  address: '32.13.124.139',
  port: 8080,
  interval: 5,
  protocol: 'udp'
});


myMonitor.on('up', function (res, state) {
  console.log('Yay!! ' + state.address + ':' + state.port + ' is up.');
});


myMonitor.on('down', function (res, state) {
  console.log('Oh Snap!! ' + state.address + ':' + state.port + ' is down! ');
});


myMonitor.on('restored', function (res, state) {
  console.log('Yay!! ' + state.address + ':' + state.port + ' has been restored! ');
});


myMonitor.on('stop', function (res, state) {
  console.log(state.address + ' monitor has stopped.');
});


myMonitor.on('error', function (error, res) {
  console.log(error);
});


myMonitor.on('timeout', function (error, res) {
  console.log(error);
});

Change log

v0.8.2

Changes

• Added new property, contentSearchMatches, to the Monitor class. This property is designed to take care of any content-specific querying tasks. Pull request #58 courtesy of @deferdie

v0.8.1

Changes

• Added threshold property to the Monitor Options. Pull request #53 courtesy of @rixtrayker
• Added the retry event which is emitted when the monitor is retrying a failed request
• Moved Monitor.isUp mutation to before an event is emitted instead of after

Threshold Example

'use strict';

const Monitor = require('ping-monitor');


const myMonitor = new Monitor({
  address: 'http://www.ragingflame.co.za',
  title: 'Raging Flame',
  interval: 10, // minutes
  protocol: 'http',
  threshold: 5
});

myMonitor.on('up', function (res, state) {
  console.log('Yay!! ' + state.address + ' is up.');
});

myMonitor.on('down', function (res, state) {
  // emitted after 5 tries
});

myMonitor.on('retry', function (error, res) {
  // emitted on every retry
});

v0.8.0

Changes

• Added protocol property to the Monitor Options object
• Added support for UDP servers. To monitor a UDP server, set the protocol property to udp
• Added the restored event which is emitted once when a server is up after beign down
• Depracated website property on the Monitor Options object. Only use address
• Refactored some code

  const ping = new Monitor({
    address: '34.22.237.1',
    port: 1234,
    interval: 10,
    protocol: 'udp',
  });

  ping.on('up', function (res, state) {
    console.log('Yay!! Service is up');
  });

  ping.on('down', function (res, state) {
    console.log(':( Service is down!');
  });

  ping.on('restored', function (res, state) {
    console.log('Yay!! Service has been restored');
  });

  ping.on('error', function (error, res) {
    console.error(error);
  });

v0.7.0

Changes

• Dependencies update.
• Added addNotificationChannel method to Monitor.
• Added addChannel method to Monitor. This method is an alias of the addNotificationChannel method.

  /*** 
   * Channel class 
   * methods: up, down, stop, error, timeout 
   * properties: name
   ***/
  class Logger {

    constructor(config = {}) {
      // do something with the config
    }

    name = 'logger';

    up(res, state) {
      console.log(`#${this.name}: ${res.address} is up`);
    }

    down(res, state) {
      console.log(`#${this.name}: ${res.address} is down`);
    }

    stop(res, state) {
      console.log(`#${this.name}: ${res.address} monitor stopped`);
    }

    error(error, res, state) {
      console.log(`#${this.name}: ${res.address} monitor returned an error`);
    }

    timeout(error, res, state) {
      console.log(`#${this.name}: ${res.address} timed out`);
    }

    restored(error, res, state) {
      console.log(`#${this.name}: ${res.address} has been restored`);
    }
  }


  const ping = new Monitor({
    address: 'https://google.com',
    interval: 30,
    protocol: 'http',
    config: {
      intervalUnits: 'seconds',
    }
  });

  const logger = new Logger();

  ping.addNotificationChannel(logger);

  // you can multiple notification channels
  // ping.addNotificationChannel(mailer)
  // ping.addNotificationChannel(slack)

v0.6.1

Changes

• Added auto id generation opt-out

  let ping = new Monitor({
    address: 'https://google.com',
    interval: 5,
    protocol: 'http',
    config: {
      intervalUnits: 'minutes',
      generateId: false // defaults is true
    }
  });

  ping.on('up', function (res, state) {
    //state.id === null
    console.log('Yay!! Google is up');
  });


  ping.on('error', function (error, res) {
    console.error(error);
  });

v0.6.0

Changes

• Code refactoring
• Removed active from props (redundant)
• Removed host from props (not used)
• Added ignoreSSL to support websites with expired certificates

  let ping = new Monitor({
    address: 'https://wrong.host.badssl.com',
    interval: 1,
    protocol: 'http',
    config: {
      intervalUnits: 'minutes' // seconds, milliseconds, minutes {default}, hours
    },
    ignoreSSL: true
  });

  ping.on('up', function (res, state) {
    console.log('Yay!! Service is up');
  });


  ping.on('error', function (error, res) {
    console.error(error);
  });

v0.5.2

Changes

• Added support for configuring interval units

  let ping = new Monitor({
    address: 'https://webservice.com',
    interval: 1,
    protocol: 'http',
    config: {
      intervalUnits: 'minutes'
    }
  });

  ping.on('up', function (res, state) {
    console.log('Yay!! Service is up');
  });


  ping.on('error', function (error, res) {
    console.error(error);
  });

v0.5.1

Changes

• Added Support for content search in HTTP/HTTPS - courtesy of @pbombnz

  let ping = new Monitor({
    address: 'https://ecommorce-shop.com/playstation5',
    interval: 1,
    protocol: 'http',
    expect: {
      contentSearch: 'In stock'
    }
  });

  ping.on('up', function (res, state) {
    console.log('Yay!! Content cantains the phrase "In stock"');
  });


  ping.on('error', function (error, res) {
    console.error(error);
  });

v0.5.0

Changes

• Added timeout event to Monitor instance. This event is passed from the htt/s module.

  myMonitor.on('timeout', function (error, res) {
    console.log(error);
  });

  // also make sure that you are handling the error event
  myMonitor.on('error', function (error, res) {
    console.log(error);
  });

• Dependencies update

Please note: When the timeout event is fired, it is followed by the error event which is created when we manually abort the http request.

v0.4.4

Dependencies update

v0.4.3

Changes

• Added the native http/s response object in the Monitor response object
• Added Post support in your Monitor instances.

You can now include a body in your httpOptions:

// http Post
const myApi = new Monitor({
    address: 'http://api.ragingflame.co.za',
    title: 'Raging Flame',
    interval: 10 // minutes
    protocol: 'http',

    // new options
    httpOptions: {
      path: '/users',
      method: 'post',
      query: {
        type: 'customer',
      },
      body: {
        name: 'Que',
        email: 'que@test.com'  
      }
    },
    expect: {
      statusCode: 200
    }
});

myApi.on('up', function (res, state) {
  /*
    response {
      responseTime <Integer> milliseconds
      responseMessage <String> response code message
      address <String> url being monitored.
      address <String> server address being monitored
      port <Integer>
      httpResponse <Object> native http/s response object
    }

    state {
      created_at <Date.now()>
      isUp <Boolean>
      port: <Integer>
      totalRequests <Integer>
      lastDownTime <Date.now()>
      lastRequest <Date.now()>
      interval <Integer>
    }
  */
});

v0.4.2

Changes

Added some utility methods used when updating a monitor and added immediate ping on monitor creation.

• Added pause method to Monitor.
• Added unpause method to Monitor.

Tip: See options section to learn how they work.

v0.4.1

Changes

Changes in v0.4.1 give you more control to define your http requests and what response to expect.

• Added httpOptions prop to Monitor instance options.
• Added expect prop for naming your your monitor.

Tip: See options section to learn how they work.

v0.4.0

Changes

Most of the changes introduced in this version were introduced to support database persistence.

• Added id prop, useful when you add database persistence.
• Added title prop for naming your your monitor.
• Added active prop to flag if monitoring is active.
• Added totalDownTimes prop for keeping record of total downtimes.
• Added isUp prop to indicate if monitored server is up or down.
• Added website, address, totalDownTimes, active, active props to the emitted state object
• Added eslinting (2015) and cleaned up the code a bit
• *breaking change: * the stop event now takes a callback that accepts 2 arguments, response && state (same as the up and down events).

v0.3.1

New Feature

• Added a state object in the response that returns useful monitoring data

• State object

  const Monitor = require('ping-monitor');

  const myMonitor = new Monitor(options);

  myMonitor.on(event, function(response, state) {
    /*
      response {...}
      state {
        created_at <Date.now()>
        isUp <Boolean>
        port: <Integer>
        totalRequests <Integer>
        lastDownTime <Date.now()>
        lastRequest <Date.now()>
        interval <Integer>
      }
    */
  });

Changes made

• The event handler now accepts to arguments response and state, please see above examples.

v0.3.0

• Brought back error event - required for handling module usage related errors
• Added responseTime to the response object
• Added support for tcp servers

v0.2.0

• Code cleanup and upgrade to ES6
• Removed the error event - now being handled internally
• Bug fixed: Unreachable resource not handled #9

Testing

npm test

License

(MIT License)

Copyright (c) 2013 - 2018 Qawelesizwe Mlilo qawemlilo@gmail.com

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.