io.micrometer.core.instrument.DistributionSummary Maven / Gradle / Ivy
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/**
* Copyright 2017 Pivotal Software, Inc.
*
* 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.
*/
package io.micrometer.core.instrument;
import io.micrometer.core.instrument.distribution.CountAtBucket;
import io.micrometer.core.instrument.distribution.DistributionStatisticConfig;
import io.micrometer.core.instrument.distribution.HistogramSupport;
import io.micrometer.core.instrument.distribution.ValueAtPercentile;
import io.micrometer.core.lang.Nullable;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.TimeUnit;
/**
* Track the sample distribution of events. An example would be the response sizes for requests
* hitting and http server.
*
* @author Jon Schneider
*/
public interface DistributionSummary extends Meter, HistogramSupport {
static Builder builder(String name) {
return new Builder(name);
}
/**
* Updates the statistics kept by the summary with the specified amount.
*
* @param amount Amount for an event being measured. For example, if the size in bytes of responses
* from a server. If the amount is less than 0 the value will be dropped.
*/
void record(double amount);
/**
* @return The number of times that record has been called since this timer was created.
*/
long count();
/**
* @return The total amount of all recorded events.
*/
double totalAmount();
/**
* @return The distribution average for all recorded events.
*/
default double mean() {
return count() == 0 ? 0 : totalAmount() / count();
}
/**
* @return The maximum time of a single event.
*/
double max();
/**
* Provides cumulative histogram counts.
*
* @param value The histogram bucket to retrieve a count for.
* @return The count of all events less than or equal to the bucket. If value does not
* match a preconfigured bucket boundary, returns NaN.
* @deprecated Use {@link #takeSnapshot()} to retrieve bucket counts.
*/
@Deprecated
default double histogramCountAtValue(long value) {
for (CountAtBucket countAtBucket : takeSnapshot().histogramCounts()) {
if ((long) countAtBucket.bucket(TimeUnit.NANOSECONDS) == value) {
return countAtBucket.count();
}
}
return Double.NaN;
}
/**
* @param percentile A percentile in the domain [0, 1]. For example, 0.5 represents the 50th percentile of the
* distribution.
* @return The latency at a specific percentile. This value is non-aggregable across dimensions. Returns NaN if
* percentile is not a preconfigured percentile that Micrometer is tracking.
* @deprecated Use {@link #takeSnapshot()} to retrieve percentiles.
*/
@Deprecated
default double percentile(double percentile) {
for (ValueAtPercentile valueAtPercentile : takeSnapshot().percentileValues()) {
if (valueAtPercentile.percentile() == percentile) {
return valueAtPercentile.value();
}
}
return Double.NaN;
}
@Override
default Iterable measure() {
return Arrays.asList(
new Measurement(() -> (double) count(), Statistic.COUNT),
new Measurement(this::totalAmount, Statistic.TOTAL)
);
}
/**
* Fluent builder for distribution summaries.
*/
class Builder {
private final String name;
private final List tags = new ArrayList<>();
private DistributionStatisticConfig.Builder distributionConfigBuilder = DistributionStatisticConfig.builder();
@Nullable
private String description;
@Nullable
private String baseUnit;
private double scale = 1.0;
private Builder(String name) {
this.name = name;
}
/**
* @param tags Must be an even number of arguments representing key/value pairs of tags.
* @return The distribution summmary builder with added tags.
*/
public Builder tags(String... tags) {
return tags(Tags.of(tags));
}
/**
* @param tags Tags to add to the eventual distribution summary.
* @return The distribution summary builder with added tags.
*/
public Builder tags(Iterable tags) {
tags.forEach(this.tags::add);
return this;
}
/**
* @param key The tag key.
* @param value The tag value.
* @return The distribution summary builder with a single added tag.
*/
public Builder tag(String key, String value) {
tags.add(Tag.of(key, value));
return this;
}
/**
* @param description Description text of the eventual distribution summary.
* @return The distribution summary builder with added description.
*/
public Builder description(@Nullable String description) {
this.description = description;
return this;
}
/**
* @param unit Base unit of the eventual distribution summary.
* @return The distribution summary builder with added base unit.
*/
public Builder baseUnit(@Nullable String unit) {
this.baseUnit = unit;
return this;
}
/**
* Produces an additional time series for each requested percentile. This percentile
* is computed locally, and so can't be aggregated with percentiles computed across other
* dimensions (e.g. in a different instance). Use {@link #publishPercentileHistogram()}
* to publish a histogram that can be used to generate aggregable percentile approximations.
*
* @param percentiles Percentiles to compute and publish. The 95th percentile should be expressed as {@code 0.95}.
* @return This builder.
*/
public Builder publishPercentiles(@Nullable double... percentiles) {
this.distributionConfigBuilder.percentiles(percentiles);
return this;
}
/**
* Determines the number of digits of precision to maintain on the dynamic range histogram used to compute
* percentile approximations. The higher the degrees of precision, the more accurate the approximation is at the
* cost of more memory.
*
* @param digitsOfPrecision The digits of precision to maintain for percentile approximations.
* @return This builder.
*/
public Builder percentilePrecision(int digitsOfPrecision) {
this.distributionConfigBuilder.percentilePrecision(digitsOfPrecision);
return this;
}
/**
* Adds histogram buckets used to generate aggregable percentile approximations in monitoring
* systems that have query facilities to do so (e.g. Prometheus' {@code histogram_quantile},
* Atlas' {@code :percentiles}).
*
* @return This builder.
*/
public Builder publishPercentileHistogram() {
return publishPercentileHistogram(true);
}
/**
* Adds histogram buckets used to generate aggregable percentile approximations in monitoring
* systems that have query facilities to do so (e.g. Prometheus' {@code histogram_quantile},
* Atlas' {@code :percentiles}).
*
* @param enabled Determines whether percentile histograms should be published.
* @return This builder.
*/
public Builder publishPercentileHistogram(@Nullable Boolean enabled) {
this.distributionConfigBuilder.percentilesHistogram(enabled);
return this;
}
/**
* Publish at a minimum a histogram containing your defined SLA boundaries. When used in conjunction with
* {@link Builder#publishPercentileHistogram()}, the boundaries defined here are included alongside
* other buckets used to generate aggregable percentile approximations.
*
* @param sla Publish SLA boundaries in the set of histogram buckets shipped to the monitoring system.
* @return This builder.
*/
public Builder sla(@Nullable long... sla) {
this.distributionConfigBuilder.sla(sla);
return this;
}
/**
* Sets the minimum value that this distribution summary is expected to observe. Sets a lower bound
* on histogram buckets that are shipped to monitoring systems that support aggregable percentile approximations.
*
* @param min The minimum value that this distribution summary is expected to observe.
* @return This builder.
*/
public Builder minimumExpectedValue(@Nullable Long min) {
this.distributionConfigBuilder.minimumExpectedValue(min);
return this;
}
/**
* Sets the maximum value that this distribution summary is expected to observe. Sets an upper bound
* on histogram buckets that are shipped to monitoring systems that support aggregable percentile approximations.
*
* @param max The maximum value that this distribution summary is expected to observe.
* @return This builder.
*/
public Builder maximumExpectedValue(@Nullable Long max) {
this.distributionConfigBuilder.maximumExpectedValue(max);
return this;
}
/**
* Statistics emanating from a distribution summary like max, percentiles, and histogram counts decay over time to
* give greater weight to recent samples (exception: histogram counts are cumulative for those systems that expect cumulative
* histogram buckets). Samples are accumulated to such statistics in ring buffers which rotate after
* this expiry, with a buffer length of {@link #distributionStatisticBufferLength(Integer)}.
*
* @param expiry The amount of time samples are accumulated to a histogram before it is reset and rotated.
* @return This builder.
*/
public Builder distributionStatisticExpiry(@Nullable Duration expiry) {
this.distributionConfigBuilder.expiry(expiry);
return this;
}
/**
* Statistics emanating from a distribution summary like max, percentiles, and histogram counts decay over time to
* give greater weight to recent samples (exception: histogram counts are cumulative for those systems that expect cumulative
* histogram buckets). Samples are accumulated to such statistics in ring buffers which rotate after
* {@link #distributionStatisticExpiry(Duration)}, with this buffer length.
*
* @param bufferLength The number of histograms to keep in the ring buffer.
* @return This builder.
*/
public Builder distributionStatisticBufferLength(@Nullable Integer bufferLength) {
this.distributionConfigBuilder.bufferLength(bufferLength);
return this;
}
/**
* Multiply values recorded to the distribution summary by a scaling factor.
*
* @param scale Factor to scale each recorded value by.
* @return This builder.
*/
public Builder scale(double scale) {
this.scale = scale;
return this;
}
/**
* Add the distribution summary to a single registry, or return an existing distribution summary in that registry. The returned
* distribution summary will be unique for each registry, but each registry is guaranteed to only create one distribution summary
* for the same combination of name and tags.
*
* @param registry A registry to add the distribution summary to, if it doesn't already exist.
* @return A new or existing distribution summary.
*/
public DistributionSummary register(MeterRegistry registry) {
return registry.summary(new Meter.Id(name, tags, baseUnit, description, Type.DISTRIBUTION_SUMMARY), distributionConfigBuilder.build(), scale);
}
}
}