Route53 Dynamic DNS Updater

dyndns53.py

#!/usr/bin/env python
# Adapted from http://joseph.is/1HPHiOE

import sys
import inspect
from datetime import datetime
from syslog import syslog, LOG_ERR

from area53 import route53
from boto.route53.exception import DNSServerError
from requests import get
from requests.exceptions import ConnectionError, HTTPError, Timeout


domain = "domain.tld"
subdomain = "subdomain"


def get_public_ip():
    try:
        args = {"timeout": 5}
        r = get("http://icanhazip.com", **args)
    except (ConnectionError, HTTPError, Timeout) as e:
        print "%s: Error getting public IP" % (filename)
        syslog(LOG_ERR, "%s: Error getting public IP" % (filename))
        sys.exit(1)
    return r.text.rstrip()


filename = inspect.getfile(inspect.currentframe())
new_value = get_public_ip()
fqdn = "%s.%s" % (subdomain, domain)
datestr = '"Last update: %s"' % datetime.utcnow().strftime('%Y-%m-%d %H:%M')

try:
    zone = route53.get_zone(domain)
    arec = zone.get_a(fqdn)
except DNSServerError:
    print "Error finding %s" % (fqdn)
    syslog(LOG_ERR, "%s: Error finding %s" % (filename, fqdn))
    sys.exit(1)

if arec:
    old_value = arec.resource_records[0]

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

    print "Updating %s: %s -> %s" % (fqdn, old_value, new_value)
    syslog("%s: Updating %s: %s -> %s" % (filename, fqdn, old_value, new_value))

    try:
        zone.update_a(fqdn, new_value, 300)
        zone.update_txt(fqdn, datestr, 300)

    except DNSServerError:
        print "Error updating %s" % (fqdn)
        syslog(LOG_ERR, "%s: Error updating %s" % (filename, fqdn))
        sys.exit(1)
else:
    print "Error finding %s" % (fqdn)
    syslog(LOG_ERR, "%s: Error finding %s" % (filename, fqdn))
    sys.exit(1)