update a AAAA record on CloudFlare with your computer's global IPv6 address

cloudflare_ddns_aaaa.py

#!/usr/bin/env python3

import json
import os
import requests
import socket

CF_API_ZONE_BASE = 'https://api.cloudflare.com/client/v4/zones/'


# we could use something like `ip -o -6 addr show scope global`, but urgh.
# if I wanted a bash script, I would've written one
# with thanks to https://stackoverflow.com/a/20710035
def get_host_ipv6():
    with socket.socket(socket.AF_INET6, socket.SOCK_DGRAM) as sock:
        sock.connect(('2001:db8::1234', 9))
        return sock.getsockname()[0]


with open(os.path.expanduser('~/.cloudflare.json')) as f:
    conf = json.loads(f.read())

headers = {
    'X-Auth-Key': conf['key'],
    'X-Auth-Email': conf['email'],
    'Content-Type': 'application/json'
}

zones_resp = requests.get(CF_API_ZONE_BASE, params={'name': conf['zone_name']}, headers=headers).json()
zone = zones_resp['result'][0]
zone_id = zone['id']

print('got zone id', zone_id)
cf_zone_records_endpoint = CF_API_ZONE_BASE + zone_id + '/dns_records/'

hostname = conf['hostname']

dns_records_resp = requests.get(cf_zone_records_endpoint, params={'type': 'AAAA', 'name': hostname}, headers=headers).json()
records = dns_records_resp['result']

print('updating hostname', hostname)
my_ipv6 = get_host_ipv6()
print('current ipv6 is', my_ipv6)

if records:
    print('num records:', len(records))
    record = records[0]
    print('record:', record)

    if record['content'] != my_ipv6:
        new_record = record.copy()
        record_id = record['id']
        new_record['content'] = my_ipv6

        upd_rec_resp = requests.put(cf_zone_records_endpoint + record_id, data=json.dumps(new_record), headers=headers).json()
        success = upd_rec_resp['success']

    else:
        print('already up to date')
        success = True

else:
    print('no records, creating new record')
    new_record = {
        'type': 'AAAA',
        'name': hostname,
        'content': my_ipv6
    }
    create_rec_resp = requests.post(cf_zone_records_endpoint, data=json.dumps(new_record), headers=headers).json()
    success = create_rec_resp['success']

print(('fail', 'success')[success])