Create nginx proxy service

create_nginx_service.sh

#!/usr/bin/env bash

# check if script is run as root
if [ "$EUID" -ne 0 ]; then
  echo "Please run as root: sudo -i"
  exit 1
fi

if [[ "$1" == "clear" && ! -z $2 ]]; then
  echo "Deleting $2 files..."
  rm -rfv /etc/nginx/sites-available/$2.conf /etc/nginx/sites-enabled/$2.conf /etc/letsencrypt/live/$2* /etc/letsencrypt/archive/$2* /etc/letsencrypt/renewal/$2*
  exit 2
fi

# read command line arguments and warn if missing
if [[ -z $1 || -z $2 ]]; then
  echo "WARNING! Please pass URL and SERVICE_ADDRESS as arguments, for example:
./create_nginx_service.sh btcpayserver.mydomain.com http://localhost:8081"
  exit 1
fi
URL=$1
SERVICE_ADDRESS=$2

# check if certbot is installed
if ! which certbot > /dev/null 2>&1 ; then
  echo "installing certbot..."
  apt install certbot -y
fi

# check if nginx is installed
if ! which nginx > /dev/null 2>&1 ; then
  echo "installing nginx..."
  apt install nginx -y
fi

# generate 4096 bit DH params to strengthen the security, may take a while
if [ ! -f '/etc/ssl/certs/dhparam.pem' ]; then
  echo "generate 4096 bit DH params..."
  openssl dhparam -out /etc/ssl/certs/dhparam.pem 4096
fi

# create directory for Let's Encrypt files
if [ ! -d '/var/lib/letsencrypt/.well-known' ]; then
  echo "create directory for Let's Encrypt files..."
  mkdir -p /var/lib/letsencrypt/.well-known
  chgrp www-data /var/lib/letsencrypt
  chmod g+s /var/lib/letsencrypt
fi

# Create a variable mapping to forward the correct protocol setting and check 
# if the Upgrade header is sent by the client
if ! grep -q "map \$http_x_forwarded_proto \$proxy_x_forwarded_proto" /etc/nginx/conf.d/map.conf; then
echo "Create a variable mapping to forward the correct protocol setting..."
cat << EOF >> /etc/nginx/conf.d/map.conf
map $http_x_forwarded_proto $proxy_x_forwarded_proto {
  default $http_x_forwarded_proto;
  ''      $scheme;
}
EOF
fi

if ! grep -q "map \$http_upgrade \$connection_upgrade" /etc/nginx/conf.d/map.conf; then
echo "check if the Upgrade header is sent by the client..."
cat << EOF >> /etc/nginx/conf.d/map.conf
map $http_upgrade $connection_upgrade {
  default upgrade;
  ''      close;
}
EOF
fi

# Exit if a config file for the domain already exists
check_if_file_exists() {
  if [ -f $1 ]; then
    echo "WARNING! The following files exist and will not be modified"
    for i in /etc/nginx/sites-available/$URL.conf /etc/nginx/sites-enabled/$URL.conf /etc/letsencrypt/live/$URL/fullchain.pem /etc/letsencrypt/live/$URL/privkey.pem; do
      if [ -f $i ]; then
        echo $i
      fi
    done
    exit 1
  fi
}

# Create a config file for the domain
check_if_file_exists /etc/nginx/sites-available/$URL.conf
echo "creating a nginx conf: /etc/nginx/sites-available/$URL.conf..."
cat << EOF > /etc/nginx/sites-available/$URL.conf
server {
  listen 80;
  server_name $URL;

  # Let's Encrypt verification requests
  location ^~ /.well-known/acme-challenge/ {
    allow all;
    root /var/lib/letsencrypt/;
    default_type "text/plain";
    try_files \$uri =404;
  }

  # Redirect everything else to https
  location / {
    return 301 https://\$server_name\$request_uri;
  }
}
EOF

# Enable the web server config by creating a symlink and restarting nginx
echo "Enable the web server config by creating a symlink: /etc/nginx/sites-enabled/$URL.conf..."
ln -s /etc/nginx/sites-available/$URL.conf /etc/nginx/sites-enabled/$URL.conf
echo "restarting nginx..."
systemctl restart nginx

# Obtain SSL certificate via Let's Encrypt
check_if_file_exists /etc/letsencrypt/live/$URL/fullchain.pem
check_if_file_exists /etc/letsencrypt/live/$URL/privkey.pem
echo "Obtain SSL certificate via Let's Encrypt..."
if ! certbot certonly --agree-tos --email admin@$URL --webroot -w /var/lib/letsencrypt/ -d $URL; then
  echo "Failed to obtain certificate, removing /etc/nginx/sites-available/$URL.conf and /etc/nginx/sites-enabled/$URL.conf and restarting nginx..."
  rm /etc/nginx/sites-available/$URL.conf /etc/nginx/sites-enabled/$URL.conf
  systemctl restart nginx
  exit 1
fi

# Now that we have a valid SSL certificate, add the https server part at the
# end of /etc/nginx/sites-available/$URL.conf
echo "add the https server part at the end of /etc/nginx/sites-available/$URL.conf..."
cat << EOF >> /etc/nginx/sites-available/$URL.conf
server {
  listen 443 ssl http2;
  server_name $URL;

  # SSL settings
  ssl_stapling on;
  ssl_stapling_verify on;

  ssl_session_timeout 1d;
  ssl_session_cache shared:SSL:10m;
  ssl_session_tickets off;

  # Update this with the path of your certificate files
  ssl_certificate /etc/letsencrypt/live/$URL/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/$URL/privkey.pem;

  ssl_dhparam /etc/ssl/certs/dhparam.pem;
  ssl_protocols TLSv1.2 TLSv1.3;
  ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384;
  ssl_prefer_server_ciphers off;

  resolver 8.8.8.8 8.8.4.4 valid=300s;
  resolver_timeout 30s;

  add_header Strict-Transport-Security "max-age=63072000" always;
  add_header Content-Security-Policy "frame-ancestors 'self';";
  add_header X-Content-Type-Options nosniff;

  # Proxy requests to the socat service
  location / {
    proxy_pass $SERVICE_ADDRESS;
    proxy_http_version 1.1;
    proxy_set_header Host \$host;
    proxy_set_header X-Real-IP \$remote_addr;
    proxy_set_header X-Forwarded-For \$remote_addr;
    proxy_set_header X-Forwarded-Proto \$proxy_x_forwarded_proto;
    proxy_set_header Upgrade \$http_upgrade;
    proxy_set_header Connection \$connection_upgrade;
  }
}
EOF

# Restart nginx once more
echo "Restart nginx once more..."
systemctl restart nginx
echo "Try it: https://$URL"

Maybe this is already available in some other form out there somewhere, but this is all I needed for adding new nginx proxy services on a VPS.