A bash script to setup nginx as reverse proxy to $BACKEND

nginx-basic-setup.sh

#!/bin/bash
set -e

# Variable for the backend service address.
BACKEND="127.0.0.1:8000"

# Echo the purpose of this script.
echo "This script installs Nginx, creates a self-signed SSL certificate, and configures Nginx as a reverse proxy to forward HTTPS requests to the backend service at ${BACKEND}."

echo "Updating package index and installing nginx and openssl..."
sudo apt update
sudo apt install -y nginx openssl

echo "Creating SSL directory..."
sudo mkdir -p /etc/nginx/ssl

# Generate a self-signed certificate valid for 365 days.
if [ ! -f /etc/nginx/ssl/nginx-selfsigned.crt ]; then
  echo "Generating self-signed certificate..."
  sudo openssl req -x509 -nodes -days 365 \
    -newkey rsa:2048 \
    -keyout /etc/nginx/ssl/nginx-selfsigned.key \
    -out /etc/nginx/ssl/nginx-selfsigned.crt \
    -subj "/CN=localhost"
fi

echo "Configuring Nginx as a reverse proxy..."
# Use sudo tee to write the configuration file into /etc/nginx/sites-available.
sudo tee /etc/nginx/sites-available/reverse-proxy > /dev/null <<EOF
server {
    listen 80;
    server_name localhost;
    # Redirect all HTTP traffic to HTTPS.
    return 301 https://\$host\$request_uri;
}

server {
    listen 443 ssl;
    server_name localhost;

    # SSL configuration using the self-signed certificate.
    ssl_certificate /etc/nginx/ssl/nginx-selfsigned.crt;
    ssl_certificate_key /etc/nginx/ssl/nginx-selfsigned.key;

    # Reverse proxy configuration.
    location / {
        proxy_pass http://${BACKEND};
        proxy_set_header Host \$host;
        proxy_set_header X-Real-IP \$remote_addr;
        proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
    }
}
EOF

echo "Enabling the new configuration..."
sudo ln -sf /etc/nginx/sites-available/reverse-proxy /etc/nginx/sites-enabled/reverse-proxy

# Optionally remove the default site if it exists.
if [ -f /etc/nginx/sites-enabled/default ]; then
  sudo rm /etc/nginx/sites-enabled/default
fi

echo "Testing Nginx configuration..."
sudo nginx -t

echo "Reloading Nginx..."
sudo systemctl reload nginx

echo "Nginx is now installed and configured as a reverse proxy with a self-signed certificate for the backend at ${BACKEND}."