file_lookup_key.rb

Puppet::Functions.create_function(:file_lookup_key) do
  dispatch :file_lookup_key do
    param 'String[1]', :key
    param 'Hash[String[1],Any]', :options
    param 'Puppet::LookupContext', :context
  end

  def file_lookup_key(key, options, context)
    # Set interpolate = true by default and override it with the value of
    # options['interpolate'], if set.
    interpolate = true
    interpolate = options['interpolate'] unless options['interpolate'].nil?

    context.explain { "Setting interpolate = #{interpolate}" }

    return context.cached_value(key) if context.cache_has_key(key)

    data_file_path = File.join(options['path'], key)
    data = nil
    context.explain { "Looking for #{key} at #{data_file_path}" }
    begin
      raw_data = context.cached_file_data(data_file_path)
      if interpolate == true
        data = context.interpolate(raw_data)
      else
        data = raw_data
      end
      context.explain { "Found #{key} at #{data_file_path}" }
    rescue Errno::ENOENT
      context.not_found
    end

    context.cache(key, data)
  end
end