This is my simple cloudflare dynamic dns app. It reads a small config file (~/.cloudflare/ddns.cfg) and iterates through all subdomains and the root and points them to your external ip address.
if useIPv6 is set it will do both A and AAAA records.
Example config
token = CLOUDFLARE_TOKEN
zone_name = example.com
subdomains = a b
useIPv6 = 0
Requirements:
dig, libcurl, jsoncpp