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Script for dynamically updating a route53 record when your external ip changes.
#!/usr/bin/python
import boto.route53
import os
import sys
import urllib2
import time
def get_zone_id(r53, zone_name):
zone_result = r53.get_hosted_zone_by_name(zone_name)
if not zone_result:
print "%s not found" % (zone_name,)
return None
zone = zone_result["GetHostedZoneResponse"]["HostedZone"]
zone_id = zone["Id"].split("/")[2]
return zone_id
def get_current_record(r53, zone_id, host):
records = r53.get_all_rrsets(zone_id, name=host)
records = [record for record in records if record.name.startswith(host)]
if len(records) == 0:
print "no record found"
return None
record = records[0]
if record.type != "A":
print "not an A record"
return None
return record
def get_external_ip():
current_ip = urllib2.urlopen("http://znaptag.com/~emil/ip.php").read()
return current_ip
def monitor(r53, zone_id, host):
while True:
try:
record = get_current_record(r53, zone_id, host)
if record:
record_ip = record.resource_records[0]
else:
record_ip = "not set"
print "no record currently exists for " + host
current_ip = get_external_ip()
if record_ip != current_ip:
print "ip missmatch, changing"
print "current ip: " + current_ip
print "record ip: " + record_ip
change = boto.route53.record.ResourceRecordSets(connection=r53,
hosted_zone_id=zone_id)
if record:
change.add_change_record("DELETE", record)
change.add_change_record("CREATE",
boto.route53.record.Record(name=host,
type="A",
resource_records=[current_ip],
alias_hosted_zone_id=zone_id))
change.commit()
print "record changed"
except urllib2.URLError as e:
print repr(e)
except boto.route53.exception.DNSServerError as e:
print repr(e)
time.sleep(600)
if __name__ == "__main__":
access_key = os.environ["AMAZON_ACCESS_KEY_ID"]
secret_key = os.environ["AMAZON_SECRET_ACCESS_KEY"]
if len(sys.argv) != 2:
print "usage: %s host" % (sys.argv,)
sys.exit(0)
host = sys.argv[1]
zone_name = ".".join(host.split(".")[-2:])
r53 = boto.route53.connection.Route53Connection(aws_access_key_id=access_key,
aws_secret_access_key=secret_key)
zone_id = get_zone_id(r53, zone_name)
if not zone_id:
print "zone not found: " + zone_name
sys.exit(1)
print "zone id: " + zone_id
print "monitoring..."
try:
monitor(r53, zone_id, host)
except KeyboardInterrupt: pass
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