Ruby script to update or create DNS A record in Rackspace DNS service

rs_add_or_update_dns.rb

#!/usr/bin/env ruby
require 'json'

username = ENV['OS_USERNAME']
tenant   = ENV['OS_TENANT_NAME']
password = ENV['OS_PASSWORD']

# Get the fqdn of the server
fqdn = `facter fqdn`.strip
puts fqdn

# Get the IP address of eth0
ip_address = `facter ipaddress_eth0`.strip
puts ip_address

# Get the domain name
domain = fqdn.split('.')[-2..-1].join('.')
puts domain

# Get an auth token
token = `curl -s -I -H "X-Auth-Key: #{password}" -H "X-Auth-User: #{username}" https://auth.api.rackspacecloud.com/v1.0 | grep ^X-Auth-Token | cut -d: -f2`.strip

# Get the records for domain
domains = JSON.parse(`curl -s -H "X-Auth-Token: #{token}" https://dns.api.rackspacecloud.com/v1.0/#{tenant}/domains`)

domain_id = nil
domains['domains'].each do |d|
  if d['name'] == domain
    domain_id = d['id']
  end
end

# Get the records for the domain
records = JSON.parse(`curl -s -H "X-Auth-Token: #{token}" https://dns.api.rackspacecloud.com/v1.0/#{tenant}/domains/#{domain_id}`)

found = nil
records['recordsList']['records'].each do |r|
  if r['name'] == fqdn
    # Record found
    found = r['id']
  end
end

if found
  data = { :name => fqdn, :data => ip_address }
  data = data.to_json
  result = `curl -D - -X PUT -d '#{data}' -H "Content-Type: application/json" -H "X-Auth-Token: #{token}" https://dns.api.rackspacecloud.com/v1.0/#{tenant}/domains/#{domain_id}/records/#{found}`
else
  data = { :records => [ { :name => fqdn, :data => ip_address, :type => 'A' } ] }
  data = data.to_json
  result = `curl -D - -X POST -d '#{data}' -H "Content-Type: application/json" -H "X-Auth-Token: #{token}" https://dns.api.rackspacecloud.com/v1.0/#{tenant}/domains/#{domain_id}/records`
end

puts result