Check the IPv4 and IPv6 address and bind to Google Cloud DNS

main.py

#!/usr/bin/env python3

import os
import time
import socket

import requests
from google.cloud import dns

# pip install google-cloud-dns requests

os.environ["GOOGLE_APPLICATION_CREDENTIALS"] = "/gcp-service-account.json"  # don't forget this file!

GET_IP_API = "https://domains.google.com/checkip"
GCP_PROJECT_ID = "project-XXXXXX"
DEFAULT_TTL = 60

DOMAINS = {
    "aaa.com.": [
        "home.aaa.com.",
        "*.home.aaa.com.",
    ],
    "bbb.me.": [
        "bbb.me.",
    ],
    "ccc.net.": [
        "ccc.net.",
        "*.ccc.net.",
    ],
}


def get_family4():
    return socket.AF_INET


def get_family6():
    return socket.AF_INET6


def get_current_ip(get_family):
    requests.packages.urllib3.util.connection.allowed_gai_family = get_family
    r = requests.get(GET_IP_API)
    return r.text.strip()


def get_current_ipv4():
    return get_current_ip(get_family4)


def get_current_ipv6():
    return get_current_ip(get_family6)


def get_ips():
    return get_current_ipv4(), get_current_ipv6()


def set_ip(zone, domain, rtype, ip):
    records = [
        record for record in zone.list_resource_record_sets() if record.name == domain and record.record_type == rtype
    ]

    if len(records) == 0:
        add_record(zone, domain, rtype, ip)
    else:
        matched = False
        for record in records:
            if len(record.rrdatas) != 1 or record.rrdatas[0] != ip:
                del_changes = zone.changes()
                del_changes.delete_record_set(record)
                del_changes.create()
            else:
                matched = True
        if not matched:
            add_record(zone, domain, rtype, ip)


def add_record(zone, domain, rtype, ip):
    add_changes = zone.changes()
    add_changes.add_record_set(zone.resource_record_set(domain, rtype, DEFAULT_TTL, [ip]))
    add_changes.create()


def main():
    client = dns.Client(project=GCP_PROJECT_ID)

    while True:
        for zone in client.list_zones():
            for root, domains in DOMAINS.items():
                if zone.dns_name == root:
                    ipv4, ipv6 = get_ips()
                    for domain in domains:
                        set_ip(zone, domain, "A", ipv4)
                        set_ip(zone, domain, "AAAA", ipv6)

        time.sleep(120)


if __name__ == "__main__":
    main()