Hey there,

You’ll need to do some basic bash scripting. There are a few sites that will return just the requesting IP address from a curl command.

Here’s a quick example of a script:

#!/bin/bash

PUBLIC_IPV4=$(curl ifconfig.co)

curl -X PUT -H "Content-Type: application/json" -H "Authorization: Bearer MY_API_ACCESS_TOKEN" -d '{"data":"${PUBLIC_IPV4}"}' "https://api.digitalocean.com/v2/domains/MY_DOMAIN/records/DOMAIN_ID_NUMBER"

You’d want to make a file that contains the code from the gist link. The file will also need to be executable (chmod o+x filename.sh).

Technically you can run a cronjob on that script file to run once an hour. Here’s a tutorial that talks about how to use cron.

However, “cron” is not the modern way to schedule events on OS X. Technically you want to use launchd, however that is quite a bit more complex. Here is a link on how you would do that and a link to a tool that can generate launchd plist files.

Happy coding,

Jon Schwenn
Platform Support Specialist
DigitalOcean

Here’s an alternative I wrote, which I think is much more secure.

https://github.com/benyanke/configScripts/tree/master/dns-update-server

In this case, the DO api key only exists on a single central API server with this script, and every other host can connect to this api server to inform it of it’s IP. This means your DO keys (which provide complete access to your DO account) are not spread around on multiple hosts.

Just to expand the script above and prevent on each cron trigger to call DO API if IP wasn’t changed:

#!/bin/bash

PUBLIC_IPV4=$(curl ifconfig.co)
SAVED_IPV4=`cat current_ip.txt`

if [ "$PUBLIC_IPV4" != "$SAVED_IPV4" ]
then
echo ${PUBLIC_IPV4} > "current_ip.txt"
curl -X PUT -H "Content-Type: application/json" -H "Authorization: Bearer MY_API_ACCESS_TOKEN" -d '{"data":"'"${PUBLIC_IPV4}"'"}' "https://api.digitalocean.com/v2/domains/MY_DOMAIN/records/DOMAIN_ID_NUMBER"
fi