grpc/include/grpcpp/resource_quota.h

/*
 *
 * 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 GRPCPP_RESOURCE_QUOTA_H
#define GRPCPP_RESOURCE_QUOTA_H

struct grpc_resource_quota;

#include <grpcpp/impl/grpc_library.h>
#include <grpcpp/support/config.h>

namespace grpc {

/// ResourceQuota represents a bound on memory and thread usage by the gRPC
/// library. A ResourceQuota can be attached to a server (via \a ServerBuilder),
/// or a client channel (via \a ChannelArguments).
/// gRPC will attempt to keep memory and threads used by all attached entities
/// below the ResourceQuota bound.
class ResourceQuota final : private grpc::internal::GrpcLibrary {
 public:
  /// \param name - a unique name for this ResourceQuota.
  explicit ResourceQuota(const std::string& name);
  ResourceQuota();
  ~ResourceQuota() override;

  /// Resize this \a ResourceQuota to a new size. If \a new_size is smaller
  /// than the current size of the pool, memory usage will be monotonically
  /// decreased until it falls under \a new_size.
  /// No time bound is given for this to occur however.
  ResourceQuota& Resize(size_t new_size);

  /// Set the max number of threads that can be allocated from this
  /// ResourceQuota object.
  ///
  /// If the new_max_threads value is smaller than the current value, no new
  /// threads are allocated until the number of active threads fall below
  /// new_max_threads. There is no time bound on when this may happen i.e none
  /// of the current threads are forcefully destroyed and all threads run their
  /// normal course.
  ResourceQuota& SetMaxThreads(int new_max_threads);

  grpc_resource_quota* c_resource_quota() const { return impl_; }

 private:
  ResourceQuota(const ResourceQuota& rhs);
  ResourceQuota& operator=(const ResourceQuota& rhs);

  grpc_resource_quota* const impl_;
};

}  // namespace grpc

#endif  // GRPCPP_RESOURCE_QUOTA_H