Ruby script to parse ansible host file into hash

ansible_ruby_parser.rb

# The ansible hosts file parser class
class AnsibleHostsFileParser

  HOST_NAME_REGEX = /^\[(.*)\]$/
  IP_ADDR_REGEX = /^((?:[0-9]){1,3}\.){1,3}[0-9]{1,3}$/
  
  def self.load_hosts(hostsfile)
    f = File.open(hostsfile)
    t = f.read
    f.close
    parse_ansible_hosts_info(t)
  end

  # Parses ansible file contents
  # @param [String] hosts_file The location of the host file
  # @return [Hash{ String => List }] A hash containing hostnames as the key
  #   and the list of IP address as the value
  def parse_ansible_hosts_info(text)
    hostname = nil
    text.split(/\n+/).inject({}) do |hosts, el|
      if el.match HOST_NAME_REGEX
        hostname = el.match(HOST_NAME_REGEX)[1]
        unless hosts.has_key?hostname
          hosts[hostname] = Array.new
        end
      elsif el.match IP_ADDR_REGEX
        ip_addr = el.match(IP_ADDR_REGEX)[0]
        hosts[hostname] = hosts[hostname].push(ip_addr)
      end
      hosts
    end

  end
end