Update DNSimple subdomain with current public facing IP as returned by ifconfig.me along with a systemd service and timer file

.update-ip-parameters

TOKEN=<DNSIMPLE-TOKEN>
ACCOUNT=<ACCOUNTID>
ZONE=<ZONEID-OR-DOMAINNAME>
RECORD=<RECORDID>

update-ip.service

[Unit]
Description=Update IP Address with DNSimple
Wants=update-ip.timer

[Service]
Type=oneshot
ExecStart=<PATH-TO-SCRIPT>/update-ip.sh -t $TOKEN -a $ACCOUNT -z $ZONE -r $RECORD
EnvironmentFile=<PATH-TO-PARAMETERS-FILE>/.update-ip-parameters

[Install]
WantedBy=multi-user.target

update-ip.sh

#!/bin/zsh

# makes a DNSimple API request to the following URL to update a particular subdomain with the IP returned
# by making a request to ifconfig.me
# https://api.dnsimple.com/v2/{{Account ID}}/zones/{{Zone ID}}/records/{{Zone Record ID}}
# see also https://www.postman.com/cokert/workspace/dnsimple/collection/7188053-d529d5c8-1d38-4e70-bc58-cd41db702711
# for example requests to find the zone and record ids

while getopts a:z:r:t: flag
do
    case "${flag}" in
        a) account_id=${OPTARG};;
        z) zone_id=${OPTARG};;
        r) record_id=${OPTARG};;
        t) token=${OPTARG};;
    esac
done

if [[ -z "$account_id" ||  -z "$zone_id" ||  -z "$record_id" ||  -z "$token" ]]
then
    echo "This script updates a dnsimple hosted domain\'s subdomain with the current public IP as"
    echo "returned by a request to \`ifconfig.me\`"
    echo "    -a: Your account ID (listed in the address bar of dnsimple.com)"
    echo "    -z: The zone id of the domain to update (can be the domain name)"
    echo "    -r: The record ID of the subdomain to update"
    echo "    -t: Your dnsimple user token"
    echo "See https://developer.dnsimple.com/v2/zones/records/ for more info"
    exit 1
fi

public_ip=$(curl ifconfig.me)
# public_ip=31.31.31.34

set -x
curl -H 'Authorization: Bearer '$token'' \
        -H "Content-Type: application/json" \
        -X PATCH \
        -d '{"content": "'"$public_ip"'"}' \
        https://api.dnsimple.com/v2/$account_id/zones/$zone_id/records/$record_id
set +x

update-ip.timer

[Unit]
Description=Update IP Address with DNSimple every 30 minutes
Requires=update-ip.service

[Timer]
Unit=update-ip.service
OnCalendar=*-*-* *:00/30:00

[Install]
WantedBy=timers.target

Note that running the systemd timer like will result in your DNSimple token being logged/visible with journalctl... ¯_(ツ)_/¯