Configuration::ServerFactoryContext& server_factory_context) {

  Regex::EnginePtr regex_engine;

  if (bootstrap.has_default_regex_engine()) {

    const auto& default_regex_engine = bootstrap.default_regex_engine();

    Regex::EngineFactory& factory =

        Config::Utility::getAndCheckFactory<Regex::EngineFactory>(default_regex_engine);

    auto config = Config::Utility::translateAnyToFactoryConfig(default_regex_engine.typed_config(),

                                                               validation_visitor, factory);

    regex_engine = factory.createEngine(*config, server_factory_context);

  } else {

    regex_engine = std::make_shared<Regex::GoogleReEngine>();

  }

  return regex_engine;

}