#pragma once

#include "envoy/common/optref.h"

#include "envoy/common/pure.h"

namespace Envoy {

namespace Config {

/**

 * A provider for extension configurations obtained either statically or via

 * the extension configuration discovery service. Dynamically updated extension

 * configurations may share subscriptions across extension config providers.

 */

template <class FactoryCallback> class ExtensionConfigProvider {

public:

  /**

   * Get the extension configuration resource name.

   **/

  virtual const std::string& name() PURE;

  /**

   * @return FactoryCallback an extension factory callback. Note that if the

   * provider has not yet performed an initial configuration load and no

   * default is provided, an empty optional will be returned. The factory

   * callback is the latest version of the extension configuration, and should

   * generally apply only to new requests and connections.

   */

  virtual OptRef<FactoryCallback> config() PURE;

};

} // namespace Config

} // namespace Envoy