a simple alternative to something like dyn-dns for remoting into home servers

update-ip

#!/usr/bin/env bash

# requires the google-cloud-sdk

# to activate key
# google-cloud-sdk/bin/gcloud auth activate-service-account --key-file foobar.json

# be sure to run the above as root user as well for cron use

# to fix timeskew
# sudo service ntp stop
# sudo ntpd -gq
# sudo service ntp start

# this needs to be owned by root
# sudo chown root update-ip
# and be 755 in order to be run by cron
# sudo chmod 755 update-ip

# move or symlink into /etc/cron.daily/
# sudo ln -s `readlink -f update-ip` /etc/cron.daily/

F=/tmp/current-ip
LOCATION="gs://BUCKET/FILENAME"

if curl ipinfo.io/ip > "$F"; then
	if grep '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}' "$F"; then
		gsutil cp "$F" "$LOCATION"
	else
		echo "Was not an ip"
	fi
else
	echo "curl failed"
fi

update-ip.service

[Unit]
Description=update ip

[Service]
ExecStart=/bin/bash /home/pi/update-ip

update-ip.timer

[Unit]
Description=Run update-ip weekly

[Timer]
OnCalendar=daily
Persistent=true     
 
[Install]
WantedBy=timers.target

systemd files go in /etc/systemd/user/
then do

systemctl --user enable update-ip.timer
systemctl --user start update-ip.timer