This project is set up to demonstrate the concepts of unit testing, continuous integration, continuous delivery, and continuous deployment. Furthermore, the application itself demonstrates the syntax and settings of Javascript, in particular, one written using Node.js and ES6 Javascript syntax.
The following tools are used:
- Git - for version control
- Node.js - for application code
- ESLint - for Javascript syntax and style checking
- Mocha - unit testing
- Babel - transpiling of written Javascript from ES6 to ES5 syntax
- Nodemon - auto-restart the node app every time the code changes in dev mode
- PM2 - manage node processes in deployment
- Travis CI - for continuous integration (we use both Travis CI and Circle CI just to provide an example of each)
- Circle CI - for continuous integration (we use both Travis CI and Circle CI just to provide an example of each)
- GitHub webhooks - for for continuous delivery/deployment
- Digital Ocean Droplet - deployment target hosting provider
Should you desire to build this application on your own machine. Do the following:
- Clone the source code to your local machine using git
- Navigate to the directory where the source code now resides
- Type
npm installto install all dependencies outlined in the package.json file - Run the application with
npm start, test it withnpm test, and see code coverage analysis withnpm run test-with-coverage. - Enjoy!
Should you desire to understand how to set up the application code in this project from scratch using npm's configuration and dependency management capabilities:
The following instructions are compiled from:
Assuming you have instantiated a Digital Ocean Ubuntu Droplet, first log in to remote Digital Ocean Droplet via SSH, then...
Enable common network apps so they gets through the firewall
sudo ufw allow http
sudo ufw allow https
sudo ufw allow OpenSSH
sudo ufw allow 'NGINX HTTP
sudo ufw allow 'NGINX HTTPS
Turn on the firewall... turning it off is disable as you'd expect
sudo ufw enable
list the status of firewall
sudo ufw status
List all apps the firewall knows about
sudo ufw app list
The following instructions are compiled from:
General purpose Javascript programming environment for server and client-side applications.
Install nodejs and npm using the APT package manager. First, get latest package list
sudo apt-get update
Install nodejs
sudo apt-get install nodejs
Install npm
sudo apt-get install npm
Check the version of npm
npm -v
Check the version of node:
node -v
The following instructions are compiled from:
Web server and reverse proxy.
Install nginx using the APT package manager. First, get the latest package list:
sudo apt update
Then install nginx
sudo apt install nginx
Check whether nginx is running
systemctl status nginx
It should be started by default, but if it's not, do the following... to stop or restart, replace start with stop or restart, respectively
sudo systemctl start nginx
Find the IP address of the local machine
ip addr show eth0 | grep inet | awk '{ print $2; }' | sed 's/\/.*$//'
Try connecting to the nginx server from a web browser using the http protocol and the IP adress resulting from the above command.
The following instructions are taken, in part, from:
This account will be used for deployment, and will not have admin privileges
sudo adduser deploy
give some root-level access to this account
usermod -aG sudo deploy
Following instructions here:
The following instructions are taken, in part, from:
In GitHub repository settings, add webhook
- set it up as JSON sent to a URL on your Droplet on port 8080, and a secret passkey
On your Droplet...
Clone the GitHub repository into a directory in the droplet account home dir
Create a new 'webhooks' directory in the Droplet also within the droplet accoun home dir (but outside the clone dir)
Put the following into a file called 'webhook.js' in this webhooks directory
var secret = "your_webhook_secret_here"; //secret from GitHub webhook
var repo = "~/your_repo_dir_name"; //path to the clone repo on the Droplet
let http = require('http');
let crypto = require('crypto');
const exec = require('child_process').exec;
http.createServer(function (req, res) {
req.on('data', function(chunk) {
let sig = "sha1=" + crypto.createHmac('sha1', secret).update(chunk.toString()).digest('hex');
if (req.headers['x-hub-signature'] == sig) {
exec('cd ' + repo + ' && git pull');
}
});
res.end();
}).listen(8080);
Allow traffic on this port
sudo ufw allow 8080/tcp
Test it out
cd ~/webhooks
node webhook.js
Check out the GitHub repo's settings for this webhook
- the Recent Deliveries section should show a log of the connection
Now make your node webhook app always run as a background process.
Add a system service:
sudo emacs /etc/systemd/system/webhook.service
Enter this into that webhook.service file:
[Unit]
Description=Github webhook
After=network.target
[Service]
Environment=NODE_PORT=8080
Type=simple
User=deploy
ExecStart=/usr/bin/node /home/deploy/webhooks/webhook.js
Restart=on-failure
[Install]
WantedBy=multi-user.target
Enable the new service so it starts when the system boots:
sudo systemctl enable webhook.service
Now start the service:
sudo systemctl start webhook
Ensure the service is started:
sudo systemctl status webhook
Note that this does not yet deploy the code, but has rather delivered it.... deployment is a small extra step to restart the deployed node app from the webhook script, using npm restart or some such thing.