generate_hiera_bindings.rb

require 'puppetclassify'

module Puppet::Parser::Functions
  newfunction(:generate_hiera_bindings, :type => :rvalue, :arity => 1, :doc => <<-EOS
it does stuff
  EOS
) do |args|

  classifier_url = args[0]
  raise ArgumentError, "invalid classifier URI" unless classifier_url =~ URI.regexp('https')

  auth_info = {
    'ca_certificate_path' => Puppet[:localcacert],
    'certificate_path'    => Puppet[:hostcert],
    'private_key_path'    => Puppet[:hostprivkey],
  }

  puppetclassify = PuppetClassify.new(classifier_url, auth_info)
  classes = puppetclassify.classes.get_classes.reject do |klass|
    klass['parameters'].empty?
  end

  response = {}
  classes.each do |klass|
    klass['parameters'].each do |param,val|
      key = "#{klass['name']}::#{param}"
      case val
      when nil # skip params without defaults
        next
      when 'undef'
        next
      when /[a-z]+\(.*\)/ # skip function calls
        next
      when /^\$/ # defer interpolation
        val[0] = ''
        response[key] = "%{#{val}}"
      else
        response[key] = val
      end
    end
  end

  response
  end
end

test.pp

$foo = generate_hiera_bindings("https://master.inf.puppetlabs.demo:4433/classifier-api")
file { '/data.yaml':
  content => inline_template("<%= @foo.to_yaml %>"),
}