Bash script to manage Wireguard dynamic IP endpoint

wg-watch.sh

#!/usr/bin/env bash

# Settings
WG_IFACE=wg0
WG_PEER=<peer_id>
WG_PORT=12345
HOSTNAME=yourhostname.dynamicip.example.com

# File to store the last IP
last_ip_file="/tmp/last_ip.txt"

# Initialize last IP
if [ ! -f "$last_ip_file" ]; then
    echo "0.0.0.0" > "$last_ip_file"
fi

# Fetch current IP
current_ip=$(dig +short $HOSTNAME)

# Read last IP
last_ip=$(cat "$last_ip_file")

# Compare with the last IP
if [ "$current_ip" != "$last_ip" ]; then
    echo "IP has changed to '$current_ip'. Restarting wg0."
    wg set $WG_IFACE peer $WG_PEER endpoint $current_ip:$WG_PORT
    echo "$current_ip" > "$last_ip_file"
fi