tlbmc/configs/rate_limiter_config.h

#ifndef THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_CONFIGS_RATE_LIMITER_CONFIG_H_
#define THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_CONFIGS_RATE_LIMITER_CONFIG_H_

#include <string>
#include <string_view>

#include "absl/base/no_destructor.h"
#include "absl/base/thread_annotations.h"
#include "absl/status/status.h"
#include "absl/synchronization/mutex.h"
#include "central_config.pb.h"

namespace milotic_tlbmc {

// Provides configuration for RedfishRateLimiterModule.
// It loads the base configuration from TlbmcConfig and merges it with
// an overlay configuration from overlay_path if it exists.
class RateLimiterConfig {
 public:
  // Initializes the config directory. Must be called before GetConfig() to use
  // a custom directory. If not called, GetConfig() will use the default
  // directory. Should only be called once during program initialization.
  static void Init(std::string_view config_dir);

  // Returns the current configuration.
  static RedfishRateLimiterModule GetConfig();

  // Merges the given patch data with the current configuration and saves it
  // to the overlay file.
  // If replace_bypass_uris is true, the bypass_uri list in the overlay will be
  // replaced by the one in patch_data (if any), instead of appended.
  // Note: While the configuration is updated, consumers of this configuration
  // may need to be re-initialized to use the new values. For example, the
  // crow::RateLimiter in BmcWebServer is initialized with the config but won't
  // automatically pick up changes made via UpdateConfiguration.
  static absl::Status UpdateConfiguration(
      const RedfishRateLimiterModule& patch_data,
      bool replace_bypass_uris = false);

  // Resets the singleton instance for testing.
 protected:
  RateLimiterConfig();
  static void Reset();

 private:
  // Returns singleton instance.
  static RateLimiterConfig& Instance();

  void InitImpl(std::string_view config_dir);
  RedfishRateLimiterModule GetConfigImpl() const;
  absl::Status UpdateConfigurationImpl(
      const RedfishRateLimiterModule& patch_data, bool replace_bypass_uris);

  void ResetImpl();
  // Loads configuration from the given path.
  // This function is not thread-safe and must be called with mutex_ held or
  // during construction.
  void LoadConfigLocked(std::string_view overlay_file_path)
      ABSL_EXCLUSIVE_LOCKS_REQUIRED(mutex_);

  static absl::Status SaveConfigToFile(const RedfishRateLimiterModule& config,
                                       std::string_view overlay_file_path);

  mutable absl::Mutex mutex_;
  RedfishRateLimiterModule config_ ABSL_GUARDED_BY(mutex_);
  RedfishRateLimiterModule overlay_config_ ABSL_GUARDED_BY(mutex_);
  std::string overlay_file_path_ ABSL_GUARDED_BY(mutex_);

  friend class absl::NoDestructor<RateLimiterConfig>;
};

}  // namespace milotic_tlbmc

#endif  // THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_CONFIGS_RATE_LIMITER_CONFIG_H_