Quick script to dynamically configure my digital ocean dns for home IP rotation

dynamicdns.py

#!/usr/bin/env python3
import json
import os
from pathlib import Path
from urllib.request import Request, urlopen

DOMAIN = os.environ["DOMAIN"]  # hostname, like google.com
SUBDOMAIN = os.environ["SUB_DOMAIN"]  # subdomain, like mail<.google.com>
DO_TOKEN = os.environ["DIGITALOCEAN_TOKEN"]  # token for digital ocean


def current_ip() -> str:
    with urlopen("https://checkip.amazonaws.com") as r:
        return r.read().strip().decode()


def current_dns_ip(domain: str, subdomain: str, do_token: str) -> str:
    req = Request(
        f"https://api.digitalocean.com/v2/domains/{domain}/records",
        headers={
            "Authorization": f"Bearer {do_token}",
        },
    )
    with urlopen(req) as r:
        records = json.load(r)
    for record in records["domain_records"]:
        if record["name"] == subdomain:
            return record
    return {}


def create_a_record(ip: str, domain: str, subdomain: str, do_token: str) -> dict:
    req = Request(
        f"https://api.digitalocean.com/v2/domains/{domain}/records",
        headers={
            "Authorization": f"Bearer {do_token}",
            "Content-Type": "application/json",
        },
        data=json.dumps({
            "type": "A",
            "name": subdomain,
            "data": ip,
            "priority": None,
            "port": None,
            "ttl": 1800,
            "weight": None,
        }).encode(),
        method="POST",
    )
    with urlopen(req) as r:
        return json.load(r)["domain_record"]


def update_record(record: dict, domain: str, do_token: str) -> dict:
    req = Request(
        f"https://api.digitalocean.com/v2/domains/{domain}/records/{record['id']}",
        headers={
            "Authorization": f"Bearer {do_token}",
            "Content-Type": "application/json",
        },
        data=json.dumps(record).encode(),
        method="PUT",
    )
    with urlopen(req) as r:
        return json.load(r)["domain_record"]


def main():
    home_ip = current_ip()
    print("Home IP:", home_ip)

    dns_record = current_dns_ip(DOMAIN, SUBDOMAIN, DO_TOKEN)
    if dns_record and dns_record["data"] == home_ip:
        print("Existing record OK")
    elif dns_record:
        print(f"Updating existing record (old: {dns_record['data']}, new: {home_ip})")
        dns_record["data"] = home_ip
        record = update_record(dns_record, DOMAIN, DO_TOKEN)
        print(record)
    else:
        print("No existing record, creating...")
        record = create_a_record(home_ip, DOMAIN, SUBDOMAIN, DO_TOKEN)
        print(record)


if __name__ == "__main__":
    main()