io.opentelemetry.sdk.metrics.internal.view.ExponentialHistogramAggregation Maven / Gradle / Ivy

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/*
 * Copyright The OpenTelemetry Authors
 * SPDX-License-Identifier: Apache-2.0
 */

package io.opentelemetry.sdk.metrics.internal.view;

import static io.opentelemetry.api.internal.Utils.checkArgument;

import io.opentelemetry.sdk.common.Clock;
import io.opentelemetry.sdk.internal.RandomSupplier;
import io.opentelemetry.sdk.metrics.Aggregation;
import io.opentelemetry.sdk.metrics.data.ExemplarData;
import io.opentelemetry.sdk.metrics.internal.aggregator.Aggregator;
import io.opentelemetry.sdk.metrics.internal.aggregator.AggregatorFactory;
import io.opentelemetry.sdk.metrics.internal.aggregator.DoubleExponentialHistogramAggregator;
import io.opentelemetry.sdk.metrics.internal.descriptor.InstrumentDescriptor;
import io.opentelemetry.sdk.metrics.internal.exemplar.ExemplarFilter;
import io.opentelemetry.sdk.metrics.internal.exemplar.ExemplarReservoir;

/**
 * Exponential bucket histogram aggregation configuration.
 *
 * This class is internal and is hence not for public use. Its APIs are unstable and can change
 * at any time.
 */
public final class ExponentialHistogramAggregation implements Aggregation, AggregatorFactory {

  private static final int DEFAULT_MAX_BUCKETS = 160;

  private static final Aggregation DEFAULT =
      new ExponentialHistogramAggregation(DEFAULT_MAX_BUCKETS);

  private final int maxBuckets;

  private ExponentialHistogramAggregation(int maxBuckets) {
    this.maxBuckets = maxBuckets;
  }

  public static Aggregation getDefault() {
    return DEFAULT;
  }

  public static Aggregation create(int maxBuckets) {
    checkArgument(maxBuckets >= 1, "maxBuckets must be > 0");
    return new ExponentialHistogramAggregation(maxBuckets);
  }

  @Override
  @SuppressWarnings("unchecked")
  public  Aggregator createAggregator(
      InstrumentDescriptor instrumentDescriptor, ExemplarFilter exemplarFilter) {
    return (Aggregator)
        new DoubleExponentialHistogramAggregator(
            () ->
                ExemplarReservoir.filtered(
                    exemplarFilter,
                    ExemplarReservoir.doubleFixedSizeReservoir(
                        Clock.getDefault(),
                        Runtime.getRuntime().availableProcessors(),
                        RandomSupplier.platformDefault())),
            maxBuckets);
  }

  @Override
  public boolean isCompatibleWithInstrument(InstrumentDescriptor instrumentDescriptor) {
    switch (instrumentDescriptor.getType()) {
      case COUNTER:
      case HISTOGRAM:
        return true;
      default:
        return false;
    }
  }

  @Override
  public String toString() {
    return "ExponentialHistogramAggregation{maxBuckets=" + maxBuckets + "}";
  }
}