module Fluent::Compat::SetTagKeyMixin

def configure(conf)
  @include_tag_key = false
  super
  if s = conf['include_tag_key']
    include_tag_key = Fluent::Config.bool_value(s)
    raise Fluent::ConfigError, "Invalid boolean expression '#{s}' for include_tag_key parameter" if include_tag_key.nil?
    @include_tag_key = include_tag_key
  end
  @tag_key = conf['tag_key'] || 'tag' if @include_tag_key
end

def filter_record(tag, time, record)
  super
  record[@tag_key] = tag if @include_tag_key
end