mariocesar · November 25, 2012 06:08 · Nov 25, 2012
diff --git a/dyndns_route53.py b/dyndns_route53.py
@@ -0,0 +1,107 @@
+"""
+ Requeriments:
+
+     $ sudo pip install boto dnspython
+
+ Edit ~/.boto to use your AWS credentials
+
+"""
+import time
+import sys
+import urllib2
+import dns.resolver
+from boto.route53.connection import Route53Connection
+from boto.route53.exception import DNSServerError
+from boto.route53.record import ResourceRecordSets
+import logging
+
+logger = logging.getLogger(__name__)
+handler = logging.FileHandler('dyndns_route53.log')
+formatter = logging.Formatter('%(asctime)s %(levelname)s %(message)s')
+handler.setFormatter(formatter)
+logger.addHandler(handler) 
+logger.setLevel(logging.INFO)
+
+# Settings, Change me!
+HOSTED_ZONE = 'ZXQU10000001'
+DOMAIN_NAME = 'home.mydomain.com'
+
+
+get_change_id = lambda response: response['ChangeInfo']['Id'].split('/')[-1]
+get_change_status = lambda response: response['ChangeInfo']['Status']
+
+def resolve_name_ip(name):
+    resolver = dns.resolver.Resolver()
+    resolver.nameservers = [
+        '8.8.8.8',
+        '8.8.4.4'
+    ]
+    answer = resolver.query(name)
+
+    """
+    >>> answer.response.answer[0].to_text()
+    home.mydomain.com. 60 IN A 192.168.0.2'
+    >>> answer.response.answer[0].items
+    [<DNS IN A rdata: 192.168.0.2>]
+    >>> answer.response.answer[0].items[0].address
+    '192.168.0.2'
+    """
+    return answer.response.answer[0].items[0].address
+
+def main():
+
+    # Get your ip using a public service
+    current_ip = urllib2.urlopen('http://ip.42.pl/raw').read()
+
+    # Avoid to hit the Route53 API if is not necessary.
+    # so compare first to a DNS server if the IP changed
+    resolved_ip = resolve_name_ip(DOMAIN_NAME)
+    if resolved_ip == current_ip:
+        logger.debug('DNS response (%s) and public IP (%s) are the same, nothing to do' % (resolved_ip, current_ip))
+        return
+
+    conn = Route53Connection()
+
+    try:
+        zone = conn.get_hosted_zone(HOSTED_ZONE)
+    except DNSServerError:
+        logger.error('%s Zone Not Found' % HOSTED_ZONE)
+        sys.exit(1)
+
+    response = conn.get_all_rrsets(HOSTED_ZONE, 'A', DOMAIN_NAME, maxitems=1)[0]
+
+    if current_ip not in response.resource_records:
+        logger.info('Found new IP: %s' % current_ip)
+
+        # Delete the old record, and create a new one.
+        # This code is from route53.py script, the change record command
+        changes = ResourceRecordSets(conn, HOSTED_ZONE, '')
+        change1 = changes.add_change("DELETE", DOMAIN_NAME, 'A', response.ttl)
+        for old_value in response.resource_records:
+            change1.add_value(old_value)
+        change2 = changes.add_change("CREATE", DOMAIN_NAME, 'A', response.ttl)
+        change2.add_value(current_ip)
+
+        try:
+            commit = changes.commit()
+            logger.debug('%s' % commit)
+        except:
+            logger.error("Changes can't be made: %s" % commit)
+            sys.exit(1)
+        else:
+
+            change = conn.get_change(get_change_id(commit['ChangeResourceRecordSetsResponse']))
+            logger.debug('%s' % change)
+
+            while get_change_status(change['GetChangeResponse']) == 'PENDING':
+                time.sleep(2)
+                change = conn.get_change(get_change_id(change['GetChangeResponse']))
+                logger.debug('%s' % change)                
+            if get_change_status(change['GetChangeResponse']) == 'INSYNC':
+                logger.info('Change %s A de %s -> %s' % (DOMAIN_NAME, response.resource_records[0], current_ip))
+            else:
+                logger.warning('Unknow status for the change: %s' % change)
+                logger.debug('%s' % change)
+
+if __name__ == '__main__':
+    main()