update53.rb

require "net/http"
require "uri"
require "aws-sdk"

target_domain=ARGV[0]

zone_name=target_domain.split(".")[-2, 2].join(".") + "."

# Get global IP address
uri = URI.parse("https://ifconfig.co/ip")
ipaddr = Net::HTTP.get_response(uri).body.strip

client = Aws::Route53::Client.new
zone = client.list_hosted_zones.hosted_zones.find{|z| z.name == zone_name}
resp = client.change_resource_record_sets({
  change_batch: {
    changes: [
      {
        action: "UPSERT", 
        resource_record_set: {
          name: TARGET_DOMAIN, 
          resource_records: [
            {
              value: ipaddr, 
            }, 
          ], 
          ttl: 60, 
          type: "A", 
        }, 
      }, 
    ], 
  }, 
  hosted_zone_id: zone.id, 
})