This simple script will retrieve the IP of your server and update it on CloudFlare.
It can be used as a service that launches at startup, which would correctly set your IP every time it changes.
The script can come handy if you are using Google Cloud with a scheduled start and stop or any other provider with a dynamic IP address.
An example config.json file has been provided. You'll need your project ID and a CloudFlare API Token with Zone.Zone and Zone.DNS permissions.