This app will fetch your current public IP address and update records in cloudflare with that address. You can easily stick this in a cronjob to automate the updates.
There are other tools out there similar but I didn't see one in golang and wanted to write some golang.
basic usage is:
./bin/cfdyndns --api-key=bacon --email=person@example.com --zone=example.com
More flags can be found in ./bin/cfdyndns --help
To build the app you have to have go 1.11 install and make. You can do a simple make after checkout which
will create the binary in ./bin