Use with cron to maintain a dynamic IP in an NPM access list.

update-public-ip-acl.sh

#!/bin/bash

helpFunction()
{
	echo ""
	echo "Usage: $0 -i <ACL IP ID> -p <PATH TO NPM /data folder>"
	echo -e "\t-i This ID can be found by querying the database"
	echo -e "\t-p The path to the NPM /data folder."
	echo -e "\t-d The name of the docker container running NPM."
	exit 1
}

while getopts "i:p:d:" opt
do
	case "$opt" in
		i) acl_ip_id="$OPTARG" ;;
		p) data_path="$OPTARG" ;;
		d) container_name="$OPTARG" ;;
		?) helpFunction ;;
	esac
done


if [ -z "$acl_ip_id" ] || [ -z "$data_path" ]; then
	helpFunction
fi

db_path="${data_path}/database.sqlite"
proxy_host_path="${data_path}/nginx/proxy_host"

old_ip=$(sqlite3 "${db_path}" "select address from access_list_client where id=${acl_ip_id};")
if [ -z $old_ip ]; then
        echo "Couldn't fetch existing IP"
        exit 1
fi


ip=$(curl -s ifconfig.me)

if [ -z $ip ]; then
        echo "Couldn't fetch IP"
        exit 1
fi

if ! [[ $ip =~ ^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
  echo "Retrieved IP is invalid"
  exit 1
fi

for i in 1 2 3 4; do
        if [ $(echo "$ip" | cut -d. -f$i) -gt 255 ]; then
                echo "Invalid IP fetched: ($ip)"
                exit 1
        fi
done

if [[ $old_ip == $ip ]]; then
	echo "No change in IP"
	exit 0
fi

sqlite3 "${db_path}" "update access_list_client SET address = '${ip}' where id = ${acl_ip_id};"
sed -i "s%${old_ip}%${ip}%g" "${proxy_host_path}/${acl_ip_id}.conf"
docker exec $container_name nginx -s reload
echo "IP updated"
exit 0