poor man's dyndns using route53

dyndns.py

from __future__ import print_function
import boto3
import botocore
import requests
import re
import sys

ip = requests.get("https://api.ipify.org").text
if not re.match(r"^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$",ip):
    print("Fail getting the ip", file=sys.stderr)
    exit(1)

client = boto3.client('route53')

hzs = client.list_hosted_zones()
hz = next(h for h in hzs["HostedZones"] if h['Name'] == 'enriclluelles.com.')

hosted_zone_id = hz['Id']

rs = client.list_resource_record_sets(
        HostedZoneId=hosted_zone_id)

record_set = next((r for r in rs["ResourceRecordSets"] if r["Name"] == "pi.enriclluelles.com."),None)

if record_set:
    values = map(lambda r: r["Value"], record_set["ResourceRecords"])

    if ip in values:
        exit(0)

print("{} is not there, updating".format(ip))

status = client.change_resource_record_sets(
        HostedZoneId=hosted_zone_id,
        ChangeBatch={
            "Comment": "update pi",
            "Changes": [{
                "Action":"UPSERT",
                "ResourceRecordSet":{
                    "Name": "pi.enriclluelles.com.",
                    "Type":"A",
                    "TTL": 600,
                    "ResourceRecords":[{
                        "Value": ip
                    }]
                }
            }]
        })