The steps are meant to turn a generic Ubuntu server into an Django server hosting the RAT-Mekong tool with PostgreSQL, Nginx, Gunicorn and Virtualenv

About RAT-Mekong Tool

The RAT-Mekong is a web application for Predicting Hydrologic Impact and Operating Pattern of Existing and Planned Reservoirs of the Lower Mekong Region.

Update Ubuntu Server

sudo apt update
sudo apt upgrade
sudo apt clean

Install necessary packages

sudo apt install python3-pip python3-dev libpq-dev postgresql postgresql-contrib nginx curl

Git installation and configuration

sudo apt install git-core
sudo apt clean
git config --global user.name "< your_username >"
git config --global user.email "< your_email >"

Create PostgreSQL database and user

// Log into an interactive Postgres session by typing:

sudo -u postgres psql

// Create database for the tool

postgres# CREATE DATABASE "< your_databasename >";

// Create a database user 

postgres# CREATE USER "< name_of_databaseuser >" WITH PASSWORD '< password_for_databseuser >';

// Settingup default encoding, transaction and timezone

postgres# ALTER ROLE "< name_of_databaseuser >" SET client_encoding TO 'utf8';
postgres# ALTER ROLE "< name_of_databaseuser >" SET default_transaction_isolation TO 'read committed';
postgres# ALTER ROLE "< name_of_databaseuser >" SET timezone TO 'UTC';

// Provide database user to administrative privilege

postgres# GRANT ALL PRIVILEGES ON DATABASE "< your_databasename >" TO "< name_of_databaseuser >";

// Exit out of the PostgreSQL prompt by typing:

postgres# \q

[Reference - Additional Informations](https://www.digitalocean.com/community/tutorials/how-to-set-up-django-with-postgres-nginx-and-gunicorn-on-ubuntu-20-04)

Install Python Virtual Environment

// First upgrade pip version
sudo -H pip3 install --upgrade pip

// Install virtual environment using pip
sudo -H pip3 install virtualenv

Create an empty directory for rattool

mkdir /home/ubuntu/rattool

Create a Python3 Virtual Environment

// Navigate to rattool directory
cd /home/ubuntu/rattool

// Create a virtual environment name rat_env
python3 -m venv rat_env

// Now activate the virtual environment
source rat_env/bin/activate

Download and setup the rat_mekong from git

// git clone rat_mekong_github_address
git clone https://github.com/Servir-Mekong/rat_mekong.git

// Change directory
cd rat_mekong

// Install dependencies from the requirements.txt
pip install -r requirements.txt

Install Gunicorn

pip install gunicorn

Create and config local_settings.py file

// Navigate to rat directory
cd rat

// Open an empty python file
sudo nano local_settings.py

// Add Secret Key, Allowed Hosts, Debug and Database details
SECRET_KEY = "< your_sevcet_key >"

DEBUG = True

ALLOWED_HOSTS = ["Your_server_domain_or_IP_address"]

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2',
        'NAME': '< name_of_your_database >',
        'USER': '< your_database_user >',
        'PASSWORD': 'password',
        'HOST': 'localhost',
        'PORT': '5432',
    }
}

Migrate database and create superuser to access Django admin panel

// Back to rat_mekong directory
cd ..

// Now migrate by
python manage.py makemigrations
pythton mange.py migrate

// Create superuser
python manage.py createsuperuser

#You will have to select a username, provide an email address, and choose and confirm a password.

Collect static files to static directory

python manage.py collectstatic

#It will collect all of the static files in a static directory defined in the settings.py

Test Django server

// Allow 8000 port to UFW firewall
sudo UFW allow 8000

// Check server by 
python manage.py runserver 0.0.0.0:8000

// Now open a browser and check the development server by typing
http://server_domain_or_IP:8000

Testing Gunicorn’s Ability to Serve the Project

gunicorn --bind 0.0.0.0:8000 rat.wsgi

// Now open a browser and check the development server with gunicorn by typing
http://server_domain_or_IP:8000

// Now deactivate the development server by typing
deactivate

Creating systemd Socket File for Gunicorn

// Open gunicorn.socket file using sudo
sudo nano /etc/systemd/system/gunicorn.socket

// Edit the gunicorn.socket file
[Unit]
Description=gunicorn socket

[Socket]
ListenStream=/run/gunicorn.sock

[Install]
WantedBy=sockets.target

//Now save and exit

Creating systemd Service File for Gunicorn

// Open gunicorn.service file using sudo
sudo nano /etc/systemd/system/gunicorn.service

// Edit the gunicorn.service file
[Unit]
Description=gunicorn daemon
Requires=gunicorn.socket
After=network.target

[Service]
PIDFile=/run/gunicorn/pid
User=ubuntu
Group=ubuntu
RuntimeDirectory=gunicorn
WorkingDirectory=/home/ubuntu/rattool/rat_mekong
ExecStart=/home/ubuntu/rattool/rat_env/bin/gunicorn \
          --access-logfile - \
          --workers 3 \
          --bind unix:/run/gunicorn.sock \
         rat.wsgi:application
ExecReload=/bin/kill -s HUP $MAINPID
ExecStop=/bin/kill -s TERM $MAINPID
PrivateTmp=true

// Now save and exit

Start, enable and check gunicorn

sudo systemctl start gunicorn.socket
sudo systemctl enable gunicorn.socket
sudo systemctl status gunicorn.socket

Configure Nginx to Proxy Pass to Gunicorn

// Start by creating and opening a new server block in Nginx’s sites-available directory:
sudo nano /etc/nginx/sites-available/rat_mekong

// Edit the file
server {
    listen 80;
    server_name "< your_server_domain_or_IP_address >";

    location = /favicon.ico { access_log off; log_not_found off; }
    location /static/ {
        root /home/ubuntu/rattool;
    }

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

// Now save and exit

// Enable the file by linking it to the sites-enabled directory
sudo ln -s /etc/nginx/sites-available/rat_mekong /etc/nginx/sites-enabled

Test and configure NGINX

// Test NGINX  Server
sudo nginx -t

// Restart NGINX Server
sudo systemctl restart nginx

// Delete 8000 port access
sudo ufw delete allow 8000

// Allow NGINX Full to access port 80
sudo ufw allow 'Nginx Full'

// Finally, restart everything
sudo systemctl daemon-reload
sudo systemctl restart gunicorn.socket gunicorn.service
sudo nginx -t && sudo systemctl restart nginx