io.shardingsphere.opentracing.sampling.SamplingService Maven / Gradle / Ivy
/*
* Copyright 2016-2018 shardingsphere.io.
*
* 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.shardingsphere.opentracing.sampling;
import lombok.AccessLevel;
import lombok.NoArgsConstructor;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.TimeUnit;
/**
* Sampling control service.
*
* @author chenqingyang
*/
@NoArgsConstructor(access = AccessLevel.PRIVATE)
public final class SamplingService {
private static final SamplingService INSTANCE = new SamplingService();
private int sampleNumPM;
private volatile boolean on;
private volatile AtomicInteger samplingCount;
private volatile ScheduledFuture scheduledFuture;
/**
* Get sampling service instance.
*
* @return sampling service instance
*/
public static SamplingService getInstance() {
return INSTANCE;
}
/**
* sampling service init.
*
* @param sampleNumPM sampling num in one minutes
*/
public void init(final int sampleNumPM) {
this.sampleNumPM = sampleNumPM;
if (scheduledFuture != null) {
scheduledFuture.cancel(true);
}
if (this.sampleNumPM > 0) {
on = true;
this.resetSamplingFactor();
ScheduledExecutorService service = Executors.newSingleThreadScheduledExecutor(new ThreadFactory() {
private final AtomicInteger threadIndex = new AtomicInteger(0);
@Override
public Thread newThread(final Runnable r) {
Thread thread = new Thread(r);
thread.setName("Sharding-opentracing-sampling" + threadIndex.incrementAndGet());
thread.setDaemon(true);
return thread;
}
});
scheduledFuture = service.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
resetSamplingFactor();
}
}, 0, 1, TimeUnit.MINUTES);
}
}
/**
* Is sampling allowed.
*
* @return true, if sampling mechanism is on.
*/
public boolean trySampling() {
return !on || samplingCount.get() <= sampleNumPM;
}
/**
* sampling count.
*/
public void samplingAdd() {
if (on) {
samplingCount.getAndIncrement();
}
}
private void resetSamplingFactor() {
samplingCount = new AtomicInteger(0);
}
}