Python script to add/update an A record at amazon area53 DNS service, using current IP. (ie, dyndns replacement)

dyndns53.py

from area53 import route53
from boto.route53.exception import DNSServerError
import requests
import sys
from datetime import datetime

# Modified from https://markcaudill.me/blog/2012/07/dynamic-route53-dns-updating-with-python/

domain = 'domain.tld'
subdomain = 'subdomain_name'

def get_public_ip():
    r = requests.get('http://icanhazip.com')
    return r.text.rstrip()

fqdn = '%s.%s' % (subdomain, domain)
zone = route53.get_zone(domain)
arec = zone.get_a(fqdn)
new_value = get_public_ip()
datestr = '"Last update %s."' % datetime.utcnow().strftime('%Y-%m-%d %H:%M')

if arec:
        old_value = arec.resource_records[0]

        if old_value == new_value:
                print '%s is current. (%s)' % (fqdn, new_value)
                sys.exit(0)

        print 'Updating %s: %s -> %s' % (fqdn, old_value, new_value)

        try:
                zone.update_a(fqdn, new_value, 900)
                zone.update_txt(fqdn, datestr, 900)

        except DNSServerError:
                # This can happen if the record did not already exist. Let's
                # try to add_a in case that's the case here.
                zone.add_a(fqdn, new_value, 900)
                zone.add_txt(fqdn, datestr, 900)
else:
        zone.add_a(fqdn, new_value, 900)
        zone.add_txt(fqdn, datestr, 900)

I use the AWS CLI for this in a simple shell script:

#!/bin/sh
export AWS_ACCESS_KEY_ID="redacted"
export AWS_SECRET_ACCESS_KEY="redacted"

AWS_ROUTE53_ZONEID="redacted"
HOSTNAME="sub.domain.com"
TTL="600"
IP=`curl http://ifconfig.co/ 2>/dev/null`

/path/to/aws route53 change-resource-record-sets --hosted-zone-id $AWS_ROUTE53_ZONEID --change-batch "{ \"Changes\": [ { \"Action\": \"UPSERT\", \"ResourceRecordSet\": { \"Name\": \"$HOSTNAME\", \"Type\": \"A\", \"TTL\": $TTL, \"ResourceRecords\": [ { \"Value\": \"$IP\" } ] } } ] }"
echo "Updated the DNS Zone to $IP"

You'll need to make sure that the AWS user you're using has route53:ChangeResourceRecordSets access allowed.