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Core module of Micrometer containing instrumentation API and implementation
/*
* Copyright 2019 VMware, 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
*
* https://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.annotation.Incubating;
import io.micrometer.core.annotation.Timed;
import io.micrometer.core.instrument.distribution.CountAtBucket;
import io.micrometer.core.instrument.distribution.HistogramSupport;
import io.micrometer.core.instrument.distribution.ValueAtPercentile;
import io.micrometer.core.instrument.distribution.pause.PauseDetector;
import io.micrometer.core.lang.Nullable;
import java.time.Duration;
import java.util.Arrays;
import java.util.concurrent.Callable;
import java.util.concurrent.TimeUnit;
import java.util.function.Supplier;
/**
* Timer intended to track of a large number of short running events. Example would be
* something like an HTTP request. Though "short running" is a bit subjective the
* assumption is that it should be under a minute.
*
* @author Jon Schneider
* @author Oleksii Bondar
*/
public interface Timer extends Meter, HistogramSupport {
/**
* Start a timing sample using the {@link Clock#SYSTEM System clock}.
* @return A timing sample with start time recorded.
* @since 1.1.0
*/
static Sample start() {
return start(Clock.SYSTEM);
}
/**
* Start a timing sample.
* @param registry A meter registry whose clock is to be used
* @return A timing sample with start time recorded.
*/
static Sample start(MeterRegistry registry) {
return start(registry.config().clock());
}
/**
* Start a timing sample.
* @param clock a clock to be used
* @return A timing sample with start time recorded.
*/
static Sample start(Clock clock) {
return new Sample(clock);
}
static Builder builder(String name) {
return new Builder(name);
}
/**
* @param registry A meter registry against which the timer will be registered.
* @param name The name of the timer.
* @return A timing builder that automatically records a timing on close.
* @since 1.6.0
*/
@Incubating(since = "1.6.0")
static ResourceSample resource(MeterRegistry registry, String name) {
return new ResourceSample(registry, name);
}
/**
* Create a timer builder from a {@link Timed} annotation.
* @param timed The annotation instance to base a new timer on.
* @param defaultName A default name to use in the event that the value attribute is
* empty.
* @return This builder.
*/
static Builder builder(Timed timed, String defaultName) {
if (timed.longTask() && timed.value().isEmpty()) {
// the user MUST name long task timers, we don't lump them in with regular
// timers with the same name
throw new IllegalArgumentException(
"Long tasks instrumented with @Timed require the value attribute to be non-empty");
}
return new Builder(timed.value().isEmpty() ? defaultName : timed.value()).tags(timed.extraTags())
.description(timed.description().isEmpty() ? null : timed.description())
.publishPercentileHistogram(timed.histogram())
.publishPercentiles(timed.percentiles().length > 0 ? timed.percentiles() : null);
}
/**
* Updates the statistics kept by the timer with the specified amount.
* @param amount Duration of a single event being measured by this timer. If the
* amount is less than 0 the value will be dropped.
* @param unit Time unit for the amount being recorded.
*/
void record(long amount, TimeUnit unit);
/**
* Updates the statistics kept by the timer with the specified amount.
* @param duration Duration of a single event being measured by this timer.
*/
default void record(Duration duration) {
record(duration.toNanos(), TimeUnit.NANOSECONDS);
}
/**
* Executes the Supplier {@code f} and records the time taken.
* @param f Function to execute and measure the execution time.
* @param The return type of the {@link Supplier}.
* @return The return value of {@code f}.
*/
@Nullable
T record(Supplier f);
/**
* Executes the callable {@code f} and records the time taken.
* @param f Function to execute and measure the execution time.
* @param The return type of the {@link Callable}.
* @return The return value of {@code f}.
* @throws Exception Any exception bubbling up from the callable.
*/
@Nullable
T recordCallable(Callable f) throws Exception;
/**
* Executes the runnable {@code f} and records the time taken.
* @param f Function to execute and measure the execution time.
*/
void record(Runnable f);
/**
* Wrap a {@link Runnable} so that it is timed when invoked.
* @param f The Runnable to time when it is invoked.
* @return The wrapped Runnable.
*/
default Runnable wrap(Runnable f) {
return () -> record(f);
}
/**
* Wrap a {@link Callable} so that it is timed when invoked.
* @param f The Callable to time when it is invoked.
* @param The return type of the callable.
* @return The wrapped callable.
*/
default Callable wrap(Callable f) {
return () -> recordCallable(f);
}
/**
* Wrap a {@link Supplier} so that it is timed when invoked.
* @param f The {@code Supplier} to time when it is invoked.
* @param The return type of the {@code Supplier} result.
* @return The wrapped supplier.
* @since 1.2.0
*/
default Supplier wrap(Supplier f) {
return () -> record(f);
}
/**
* @return The number of times that stop has been called on this timer.
*/
long count();
/**
* @param unit The base unit of time to scale the total to.
* @return The total time of recorded events.
*/
double totalTime(TimeUnit unit);
/**
* @param unit The base unit of time to scale the mean to.
* @return The distribution average for all recorded events.
*/
default double mean(TimeUnit unit) {
long count = count();
return count == 0 ? 0 : totalTime(unit) / count;
}
/**
* @param unit The base unit of time to scale the max to.
* @return The maximum time of a single event.
*/
double max(TimeUnit unit);
@Override
default Iterable measure() {
return Arrays.asList(new Measurement(() -> (double) count(), Statistic.COUNT),
new Measurement(() -> totalTime(baseTimeUnit()), Statistic.TOTAL_TIME),
new Measurement(() -> max(baseTimeUnit()), Statistic.MAX));
}
/**
* Provides cumulative histogram counts.
* @param valueNanos The histogram bucket to retrieve a count for.
* @return The count of all events less than or equal to the bucket. If valueNanos
* does not match a preconfigured bucket boundary, returns NaN.
* @deprecated Use {@link #takeSnapshot()} to retrieve bucket counts.
*/
@Deprecated
default double histogramCountAtValue(long valueNanos) {
for (CountAtBucket countAtBucket : takeSnapshot().histogramCounts()) {
if ((long) countAtBucket.bucket(TimeUnit.NANOSECONDS) == valueNanos) {
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.
* @param unit The base unit of time to scale the percentile value to.
* @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 bucket counts.
*/
@Deprecated
default double percentile(double percentile, TimeUnit unit) {
for (ValueAtPercentile valueAtPercentile : takeSnapshot().percentileValues()) {
if (valueAtPercentile.percentile() == percentile) {
return valueAtPercentile.value(unit);
}
}
return Double.NaN;
}
/**
* @return The base time unit of the timer to which all published metrics will be
* scaled
*/
TimeUnit baseTimeUnit();
/**
* Maintains state on the clock's start position for a latency sample. Complete the
* timing by calling {@link Sample#stop(Timer)}. Note how the {@link Timer} isn't
* provided until the sample is stopped, allowing you to determine the timer's tags at
* the last minute.
*/
class Sample {
private final long startTime;
private final Clock clock;
Sample(Clock clock) {
this.clock = clock;
this.startTime = clock.monotonicTime();
}
/**
* Records the duration of the operation.
* @param timer The timer to record the sample to.
* @return The total duration of the sample in nanoseconds
*/
public long stop(Timer timer) {
long durationNs = clock.monotonicTime() - startTime;
timer.record(durationNs, TimeUnit.NANOSECONDS);
return durationNs;
}
}
class ResourceSample extends AbstractTimerBuilder implements AutoCloseable {
private final MeterRegistry registry;
private final long startTime;
ResourceSample(MeterRegistry registry, String name) {
super(name);
this.registry = registry;
this.startTime = registry.config().clock().monotonicTime();
}
@Override
public void close() {
long durationNs = registry.config().clock().monotonicTime() - startTime;
registry.timer(new Meter.Id(name, tags, null, description, Type.TIMER), distributionConfigBuilder.build(),
pauseDetector == null ? registry.config().pauseDetector() : pauseDetector)
.record(durationNs, TimeUnit.NANOSECONDS);
}
}
/**
* Fluent builder for timers.
*/
class Builder extends AbstractTimerBuilder {
Builder(String name) {
super(name);
}
@Override
public Builder tags(String... tags) {
return super.tags(tags);
}
@Override
public Builder tags(Iterable tags) {
return super.tags(tags);
}
@Override
public Builder tag(String key, String value) {
return super.tag(key, value);
}
@Override
public Builder publishPercentiles(double... percentiles) {
return super.publishPercentiles(percentiles);
}
@Override
public Builder percentilePrecision(Integer digitsOfPrecision) {
return super.percentilePrecision(digitsOfPrecision);
}
@Override
public Builder publishPercentileHistogram() {
return super.publishPercentileHistogram();
}
@Override
public Builder publishPercentileHistogram(Boolean enabled) {
return super.publishPercentileHistogram(enabled);
}
@SuppressWarnings("deprecation")
@Override
public Builder sla(Duration... sla) {
return super.sla(sla);
}
@Override
public Builder serviceLevelObjectives(Duration... slos) {
return super.serviceLevelObjectives(slos);
}
@Override
public Builder minimumExpectedValue(Duration min) {
return super.minimumExpectedValue(min);
}
@Override
public Builder maximumExpectedValue(Duration max) {
return super.maximumExpectedValue(max);
}
@Override
public Builder distributionStatisticExpiry(Duration expiry) {
return super.distributionStatisticExpiry(expiry);
}
@Override
public Builder distributionStatisticBufferLength(Integer bufferLength) {
return super.distributionStatisticBufferLength(bufferLength);
}
@Override
public Builder pauseDetector(PauseDetector pauseDetector) {
return super.pauseDetector(pauseDetector);
}
@Override
public Builder description(String description) {
return super.description(description);
}
/**
* Add the timer to a single registry, or return an existing timer in that
* registry. The returned timer will be unique for each registry, but each
* registry is guaranteed to only create one timer for the same combination of
* name and tags.
* @param registry A registry to add the timer to, if it doesn't already exist.
* @return A new or existing timer.
*/
public Timer register(MeterRegistry registry) {
// the base unit for a timer will be determined by the monitoring system
// implementation
return registry.timer(new Meter.Id(name, tags, null, description, Type.TIMER),
distributionConfigBuilder.build(),
pauseDetector == null ? registry.config().pauseDetector() : pauseDetector);
}
}
}