statistics.hpp

#pragma once
 
#include <array>
#include <atomic>
#include <chrono>
#include <cstddef>
#include <cstdint>
 
#include <grpcpp/support/status.h>
 
#include <userver/utils/fixed_array.hpp>
#include <userver/utils/statistics/fwd.hpp>
#include <userver/utils/statistics/percentile.hpp>
#include <userver/utils/statistics/rate_counter.hpp>
#include <userver/utils/statistics/recentperiod.hpp>
 
#include <userver/ugrpc/impl/static_metadata.hpp>
 
USERVER_NAMESPACE_BEGIN
 
namespace ugrpc::impl {
 
enum class StatisticsDomain { kClient, kServer };
 
std::string_view ToString(StatisticsDomain);
 
class MethodStatistics final {
 public:
  explicit MethodStatistics(StatisticsDomain domain);
 
  void AccountStarted() noexcept;
 
  void AccountStatus(grpc::StatusCode code) noexcept;
 
  void AccountTiming(std::chrono::milliseconds timing) noexcept;
 
  // All errors without gRPC status codes are categorized as "network errors".
  // See server::RpcInterruptedError.
  void AccountNetworkError() noexcept;
 
  // Occurs when the service forgot to finish a request, oftentimes due to a
  // thrown exception. Always indicates a programming error in our service.
  // UNKNOWN status code is automatically returned in this case.
  void AccountInternalError() noexcept;
 
  void AccountCancelledByDeadlinePropagation() noexcept;
 
  void AccountDeadlinePropagated() noexcept;
 
  void AccountCancelled() noexcept;
 
  friend void DumpMetric(utils::statistics::Writer& writer,
                         const MethodStatistics& stats);
 
  std::uint64_t GetStarted() const noexcept;
 
 private:
  using Percentile =
      utils::statistics::Percentile<2000, std::uint32_t, 256, 100>;
  using RateCounter = utils::statistics::RateCounter;
  // StatusCode enum cases have consecutive underlying values, starting from 0.
  // UNAUTHENTICATED currently has the largest value.
  static constexpr std::size_t kCodesCount =
      static_cast<std::size_t>(grpc::StatusCode::UNAUTHENTICATED) + 1;
 
  const StatisticsDomain domain_;
  RateCounter started_{0};
  std::array<RateCounter, kCodesCount> status_codes_{};
  utils::statistics::RecentPeriod<Percentile, Percentile> timings_;
  RateCounter network_errors_{0};
  RateCounter internal_errors_{0};
  RateCounter cancelled_{0};
 
  RateCounter deadline_updated_{0};
  RateCounter deadline_cancelled_{0};
};
 
class ServiceStatistics final {
 public:
  ServiceStatistics(const StaticServiceMetadata& metadata,
                    StatisticsDomain domain);
 
  ~ServiceStatistics();
 
  MethodStatistics& GetMethodStatistics(std::size_t method_id);
  const MethodStatistics& GetMethodStatistics(std::size_t method_id) const;
 
  const StaticServiceMetadata& GetMetadata() const;
 
  std::uint64_t GetStartedRequests() const;
 
  friend void DumpMetric(utils::statistics::Writer& writer,
                         const ServiceStatistics& stats);
 
 private:
  const StaticServiceMetadata metadata_;
  utils::FixedArray<MethodStatistics> method_statistics_;
};
 
}  // namespace ugrpc::impl
 
USERVER_NAMESPACE_END