includes/prometheus/histogram.h

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/*
 * SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 * SPDX-License-Identifier: Apache-2.0
 *
 * 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.
 */
 
#pragma once
 
#include <mutex>
#include <vector>
 
#include "prometheus/client_metric.h"
#include "prometheus/counter.h"
#include "prometheus/detail/builder.h"  // IWYU pragma: export
#include "prometheus/detail/core_export.h"
#include "prometheus/gauge.h"
#include "prometheus/metric_type.h"
 
namespace prometheus {
 
class PROMETHEUS_CPP_CORE_EXPORT Histogram {
 public:
  using BucketBoundaries = std::vector<double>;
 
  static const MetricType metric_type{MetricType::Histogram};
 
  explicit Histogram(const BucketBoundaries& buckets);
 
  explicit Histogram(BucketBoundaries&& buckets);
 
  void Observe(double value);
 
  void ObserveMultiple(const std::vector<double>& bucket_increments,
                       double sum_of_values);
 
  void Reset();
 
  ClientMetric Collect() const;
 
 private:
  BucketBoundaries bucket_boundaries_;
  mutable std::mutex mutex_;
  std::vector<Counter> bucket_counts_;
  Gauge sum_;
};
 
PROMETHEUS_CPP_CORE_EXPORT detail::Builder<Histogram> BuildHistogram();
 
}  // namespace prometheus