| /* |
| * |
| * Copyright 2016 gRPC authors. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| |
| #ifndef GRPC_CORE_LIB_BACKOFF_BACKOFF_H |
| #define GRPC_CORE_LIB_BACKOFF_BACKOFF_H |
| |
| #include <grpc/support/port_platform.h> |
| |
| #include "src/core/lib/iomgr/exec_ctx.h" |
| |
| namespace grpc_core { |
| |
| /// Implementation of the backoff mechanism described in |
| /// doc/connection-backoff.md |
| class BackOff { |
| public: |
| class Options; |
| |
| /// Initialize backoff machinery - does not need to be destroyed |
| explicit BackOff(const Options& options); |
| |
| /// Returns the time at which the next attempt should start. |
| grpc_millis NextAttemptTime(); |
| |
| /// Reset the backoff, so the next value returned by NextAttemptTime() |
| /// will be the time of the second attempt (rather than the Nth). |
| void Reset(); |
| |
| void SetRandomSeed(unsigned int seed); |
| |
| class Options { |
| public: |
| Options& set_initial_backoff(grpc_millis initial_backoff) { |
| initial_backoff_ = initial_backoff; |
| return *this; |
| } |
| Options& set_multiplier(double multiplier) { |
| multiplier_ = multiplier; |
| return *this; |
| } |
| Options& set_jitter(double jitter) { |
| jitter_ = jitter; |
| return *this; |
| } |
| Options& set_max_backoff(grpc_millis max_backoff) { |
| max_backoff_ = max_backoff; |
| return *this; |
| } |
| /// how long to wait after the first failure before retrying |
| grpc_millis initial_backoff() const { return initial_backoff_; } |
| /// factor with which to multiply backoff after a failed retry |
| double multiplier() const { return multiplier_; } |
| /// amount to randomize backoffs |
| double jitter() const { return jitter_; } |
| /// maximum time between retries |
| grpc_millis max_backoff() const { return max_backoff_; } |
| |
| private: |
| grpc_millis initial_backoff_; |
| double multiplier_; |
| double jitter_; |
| grpc_millis max_backoff_; |
| }; // class Options |
| |
| private: |
| const Options options_; |
| uint32_t rng_state_; |
| bool initial_; |
| /// current delay before retries |
| grpc_millis current_backoff_; |
| }; |
| |
| } // namespace grpc_core |
| #endif /* GRPC_CORE_LIB_BACKOFF_BACKOFF_H */ |