/tools

Tools for Coding

MySQL

MySQL is a popular open-source relational database management system. Below is a video link for installing MySQL:

Ubuntu

MySQL is a popular open-source relational database management system. Below is a video link for installing MySQL:

AWS

Amazon Web Services or AWS, commonly known in the tech industry, is the world’s most reliable cloud computing platform. It provides hundreds of unique services which are all cloud-based, ranging from databases to virtual servers.

AWS S3 storage

Object-based cloud storage service to store and retrieve data from anywhere on the web

Render Platform

Object-based cloud storage service to store and retrieve data from anywhere on the web

Django

Python framework for server-side application

Setting Up and Using Python on Ubuntu

Most Ubuntu distributions come with Python 3 pre-installed. To check your Python version, open your terminal and run:

python3 --version

First, update your package list, then install Python 3 if Python is not installed:

sudo apt update
sudo apt install python3

Python on Windows comes with pip pre-installed, but on Ubuntu, you may need to install it separately

sudo apt install python3-pip

Virtual environments in Ubuntu may need manual setup. To install the Python venv package:

sudo apt install python3-venv

To create a new virtual environment named myenv:

python3 -m venv myenv

To activate the virtual environment on Ubuntu:

source myenv/bin/activate

To deactivate the virtual environment:

deactivate

Managing and installing versions

  sudo add-apt-repository ppa:deadsnakes/ppa
  133  sudo apt update
  135  sudo apt install python3.12 -y
  136  clear
  137  sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.10 1
  138  sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.12 2
  139  sudo update-alternatives --config python3

Creating systemd Socket and Service Files for Gunicorn

Step 1: Create systemd Socket File

sudo nano /etc/systemd/system/shopy.socket

Paste the code below

[Unit]
Description=gunicorn socket

[Socket]
ListenStream=/run/shopy.sock

[Install]
WantedBy=sockets.target

Step 2: Create systemd Service File

sudo nano /etc/systemd/system/shopy.service

Paste this code below

[Unit]
Description=gunicorn daemon
Requires=shopy.socket
After=network.target
[Service]
User=ubuntu
Group=www-data
WorkingDirectory=/home/ubuntu/Style_Hub
ExecStart=/home/ubuntu/Style_Hub/venv/bin/gunicorn \
          --access-logfile - \
          --workers 3 \
          --bind unix:/run/shopy.sock \
          style_hub.wsgi:application
[Install]
WantedBy=multi-user.target

Step 3: Start and Enable Gunicorn Socket

sudo systemctl start shopy.socket
sudo systemctl enable shopy.socket
sudo systemctl status shopy.socket

Check socket Status

sudo systemctl status shopy.socket

you should see this output

● shopy.socket - gunicorn socket
     Loaded: loaded (/etc/systemd/system/shopy.socket; enabled; vendor preset: enabled)
     Active: active (listening) since Sat 2024-05-04 18:30:12 UTC; 22min ago
   Triggers: ● shopy.service
     Listen: /run/shopy.sock (Stream)
     CGroup: /system.slice/shopy.socket

May 04 18:30:12 ip-172-31-1-254 systemd[1]: Listening on gunicorn socket
Apr 18 17:53:25 django systemd[1]: Listening on gunicorn socket.

Reload deamon services as shown below

sudo systemctl daemon-reload
sudo systemctl restart gunicorn

Step 4: Configure Nginx to Proxy Pass to Gunicorn

sudo nano /etc/nginx/sites-available/shopy
server {
    listen *:80;
    server_name 54.206.41.225;

    location = /favicon.ico { access_log off; log_not_found off; }
    location /static/ {
       alias /home/ubuntu/Shopy/static/;
    }

    location /{
        include proxy_params;
        proxy_pass http://unix:/run/shopy.sock;

    }
}

Step 5: Link the sites-available to sites-enabled

sudo ln -s /etc/nginx/sites-available/shopy /etc/nginx/sites-enabled

Sockets as Communication Endpoints

Sockets are endpoints for sending and receiving data across a network. They can be used for inter-process communication (IPC) on the same host or across different hosts over a network.

Types of Sockets

Unix Sockets (also known as Unix Domain Sockets)

These are used for IPC on the same host. They use file paths in the file system as their address namespace.

TCP Sockets

These are used for communication over a network using the TCP/IP protocol suite. They use IP addresses and port numbers as their address namespace.

Communication Between Processes on the Same Host

When two processes on the same host need to communicate, they can use Unix sockets. This method is efficient because it avoids the overhead of network protocols.

Socket File

A Unix socket is represented by a special file in the file system. This file is created when the socket is initialized and is used by processes to connect to the socket.

Initialization and Boot-Up

A socket file can be created and initialized at boot-up by a service manager (like systemd on Linux). This socket file acts as a listening endpoint for connections.

Service Bound to the Socket

A service can be bound to a socket, meaning it will start and listen for incoming connections on this socket. When another process wants to communicate, it connects to this socket file.

Example Workflow

  • Process A: Creates a Unix socket file (e.g., /tmp/socket_file) and starts listening for connections.
  • Process B: Knows the path to the socket file and connects to it to communicate with Process A.
  • Service Execution: When a connection is made to the socket file, the bound service (Process A) handles the communication, executing its logic based on the data received.

Nginx and Gunicorn as Separate Processes

Nginx

Acts as a reverse proxy server. It handles incoming HTTP requests from clients.

Gunicorn

Is a WSGI server that runs your web application (e.g., a Django or Flask app) and handles the application logic.

Communication Through a Unix Socket

Nginx and Gunicorn communicate via a Unix socket, which is a file-based communication endpoint.

Unix Socket File

The Unix socket file (e.g., /run/shopy.sock) is created and listened to by Gunicorn. This file acts as the address for the socket.

Gunicorn is bound to this socket file, meaning it listens for connections on this socket.

Nginx Configuration

In the Nginx configuration, the proxy_pass http://unix:/run/shopy.sock; directive tells Nginx to forward incoming HTTP requests to the Unix socket file where Gunicorn is listening.

Startup and Initialization

Typically, the Unix socket file is created and Gunicorn starts listening on it when the system boots up or when the service is started.

Request Handling Workflow

  • Client Request: A client sends an HTTP request to Nginx.
  • Nginx Receives Request: Nginx processes the request and, based on its configuration, forwards it to the Unix socket file specified in the proxy_pass directive.
  • Gunicorn Receives Request: Gunicorn, which is bound to the Unix socket, receives the request, processes it using the web application, and sends back a response.
  • Nginx Forwards Response: Nginx receives the response from Gunicorn through the Unix socket and forwards it back to the client.