A *really* basic AWS Route 53 Dynamic DNS Updater in Perl

dhcp_update_route53.pl

#!/usr/bin/perl
#
# AWS Route 53 Dynamic DNS Updater
# (c)2014 Mark Page [[email protected]]
# Wed Dec 31 08:35:56 CST 2014
#
use strict;
use warnings;
use LWP::Simple qw(!head);
use WebService::Amazon::Route53;

my $app_home   = '/opt/aws-tools';
my @domains    = ('some.tld.','someother.tld.','yetanother.tld.',); # note the trailing dots!
my $outside_ip = get_outside_ip();

if ($outside_ip->{'error'}) { die $outside_ip->{'error'}; }

if ($outside_ip->{'info'}) {
  print $outside_ip->{'info'};
  if ($outside_ip->{'info'} =~ m/unchanged/i) { exit 0; }
}

my $r53 = WebService::Amazon::Route53->new (
  'id'  => '__YOUR_AWS_ID__',
  'key' => '__YOUR_AWS_SECRET__',
);

for my $d (0 .. (scalar(@domains) - 1)) {
  my $response = $r53->find_hosted_zone('name' => $domains[$d]);
  my $zone     = $response->{'hosted_zone'};
  my $result   = $r53->change_resource_record_sets(
    zone_id => $zone->{'id'},
    changes => [{
      action => 'upsert',
      name => $domains[$d],
      type => 'A',
      ttl => 300,
      records => [$outside_ip->{'ip'},],
    }]
  );
  
  if ($result->{'status'}) { print localtime(time) . ': INFO: ' . $domains[$d] . ' [' . $result->{'status'} . ': ' . $result->{'id'} . "]\n"; }
  if ($r53->error->{'message'}) { print localtime(time) . ': ERROR: ' . $r53->error->{'message'} . "\n"; }
}

exit;

sub get_outside_ip {
  my ($args) = @_;
  my ($_return);
  my $last_ip = '';

  if ($_return->{'ip'} = LWP::Simple::get("https://icanhazip.com/")) {
    $_return->{'ip'} =~ s/\n|\r//g;
    $_return->{'info'} .= localtime(time) . ': INFO: Got external IP: ' . $_return->{'ip'} . "\n";

    if (stat("$app_home/last_ip")) {
      open (my $in_cache,'<',"$app_home/last_ip"); $last_ip = join('',<$in_cache>); close ($in_cache);
    }
  }
  else {
    $_return->{'error'} = localtime(time) . ': ERROR: Could not get external IP!' . "\n";
  }
  
  if ($_return->{'ip'} eq $last_ip) {
    $_return->{'info'} .= localtime(time) . ': INFO: IP Address unchanged (' . $_return->{'ip'} . ')' . "\n";
  }
  
  open (my $out_cache,'>',"$app_home/last_ip"); print $out_cache $_return->{'ip'}; close ($out_cache);
  
  return $_return;
}