Front end of puppy monitoring application

This is the front end of Puppy monitoring application. It is responsible for managing the Command Line Interface, sending requests to the back end and displaying informations.

Learn more in PUPPY.md

Table of Contents:

Launch the front end in development environment
Usage
Architecture of the front end
Tests

Use the front end in development environment

The front end requires the back end containers to run on the same computer to be functional. Please start by running the back end (see README.md in Puppy back end repository)

To use the front end

Install Node.js, if it is not already done
Open a terminal at the front end folder
Run npm install to install dependencies
Run node puppy to display the welcome message from puppy

Now you can run puppy commands using the syntax node puppy <command> For instance, run node puppy --help to see the list of available commands

Communicate with the back end using Windows and Docker Toolbox

On Windows, you can run the back end using Docker Toolbox. The containers will run on a Docker Virtual Machine which has a different IP adresse than localhost. Container ports are mapped to the Docker VM IP adresse and not to the localhost.

Therefore, to be able to communicate with the back end, you have to do the following modification:

Run docker-machine ip to get the IP adress of the docker machine
Copy this IP adress
Open config.json file
Replace localhost by the docker-machine IP adress

Make puppy command global

Open a terminal at the front end folder
Run sudo npm link to make puppy a global command
Run puppy to display welcome message from puppy

Now you can run puppy commands using the syntax puppy <command> For instance, run puppy --help to see the list of available commands

Usage

The global syntax is node puppy [options] [command] or puppy [options] [command] if you set up the global command. You can get more information using node puppy --help.

Here is a list of all the commands of Puppy:

add <website> <url> <check_interval> : Add a website to monitoring <website> [string] the name of the website <url> [string] the url of the website <check_interval> [number] the time interval between each website check (in second)
list : List all monitored websites
update [options] <website> : Update the given fields of the website -n --name [string] the new name of the website -u --url [string] the new url of the website -i --interval [number] the new time interval between website checks (in seconds)
remove <website> : Remove the website given by its name
check : Start the checking of all the websites on the remote server Warning: the checking will not stop until stop command is run, even if this shell is closed
stop : Stop the checking of all websites
monitor : Start the monitoring of websites. End the monitoring by pressing Escape, q or CTRL+C in this shell.
history: Get the history of past alerts
test : Add the alert and the response codes test routes to the website list.

Architecture of the front end

The front end run with Node.js. It is based on a few modules such as:

Commander for the CLI
Axios for the HTTP requests
Blessed for the custom terminal interface

The front end mainly consist of several commands. These commands are defined in the puppy.js file. Each command calls a function defined in a file located in src/.

Displayers are the functions responsible for displaying the informations sent by the back end. They can be found in the src/displayer/ folder.

The puppy monitor command line uses blessed module to render a customized terminal interface which display alerts and statistics. It uses box components defined in the src/blessedComponent folder.

Tests

When puppy monitor command is running, the back end send alerts to the front end:

DOWN alerts are sent when the availability of a website goes under 80% for the last 2 minutes
UP alerts are sent when the availability of a website goes back over 80% for the last 2 minutes

To test the alerts, the back end exposes a route. It simulates a website that periodically breaks and goes back up. While monitoring this route, the back end will regularly send down and up alerts.

There is also a response codes test route. It generates random status codes in the response. The back end will record the number of each codes and send it in the statistics.

To monitor these routes, use the following commands:

puppy test to add the tests route
puppy monitor to start monitoring the websites