io.opentelemetry.sdk.metrics.internal.state.CallbackRegistration Maven / Gradle / Ivy
/*
* Copyright The OpenTelemetry Authors
* SPDX-License-Identifier: Apache-2.0
*/
package io.opentelemetry.sdk.metrics.internal.state;
import static io.opentelemetry.sdk.internal.ThrowableUtil.propagateIfFatal;
import static java.util.stream.Collectors.toList;
import io.opentelemetry.sdk.internal.ThrottlingLogger;
import io.opentelemetry.sdk.metrics.internal.descriptor.InstrumentDescriptor;
import io.opentelemetry.sdk.metrics.internal.export.RegisteredReader;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* A registered callback.
*
* This class is internal and is hence not for public use. Its APIs are unstable and can change
* at any time.
*/
public final class CallbackRegistration {
private static final Logger logger = Logger.getLogger(CallbackRegistration.class.getName());
private final ThrottlingLogger throttlingLogger = new ThrottlingLogger(logger);
private final List observableMeasurements;
private final Runnable callback;
private final List instrumentDescriptors;
private final boolean hasStorages;
private CallbackRegistration(
List observableMeasurements, Runnable callback) {
this.observableMeasurements = observableMeasurements;
this.callback = callback;
this.instrumentDescriptors =
observableMeasurements.stream()
.map(SdkObservableMeasurement::getInstrumentDescriptor)
.collect(toList());
if (instrumentDescriptors.size() == 0) {
throw new IllegalStateException("Callback with no instruments is not allowed");
}
this.hasStorages =
observableMeasurements.stream()
.flatMap(measurement -> measurement.getStorages().stream())
.findAny()
.isPresent();
}
/**
* Create a callback registration.
*
* The {@code observableMeasurements} define the set of measurements the {@code runnable} may
* record to. The active reader of each {@code observableMeasurements} is set via {@link
* SdkObservableMeasurement#setActiveReader(RegisteredReader, long, long)} before {@code runnable}
* is called, and set to {@code null} afterwards.
*
* @param observableMeasurements the measurements that the runnable may record to
* @param runnable the callback
* @return the callback registration
*/
public static CallbackRegistration create(
List observableMeasurements, Runnable runnable) {
return new CallbackRegistration(observableMeasurements, runnable);
}
@Override
public String toString() {
return "CallbackRegistration{instrumentDescriptors=" + instrumentDescriptors + "}";
}
public void invokeCallback(RegisteredReader reader, long startEpochNanos, long epochNanos) {
// Return early if no storages are registered
if (!hasStorages) {
return;
}
// Set the active reader on each observable measurement so that measurements are only recorded
// to relevant storages
observableMeasurements.forEach(
observableMeasurement ->
observableMeasurement.setActiveReader(reader, startEpochNanos, epochNanos));
try {
callback.run();
} catch (Throwable e) {
propagateIfFatal(e);
throttlingLogger.log(
Level.WARNING, "An exception occurred invoking callback for " + this + ".", e);
} finally {
observableMeasurements.forEach(SdkObservableMeasurement::unsetActiveReader);
}
}
}