/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.s4.core.staging;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import org.apache.s4.core.util.S4Metrics;
import com.google.common.util.concurrent.ThreadFactoryBuilder;
import com.google.inject.Inject;
import com.google.inject.name.Named;
/**
* <p>
* Load shedding factory for the event processing stage executors.
* <p>
* It provides optional parallelism, when the processing activity requires blocking I/O operations, or is CPU-bound.
* <p>
* It drops events when work queue is full.
* <p>
* More customized load shedding strategies can be defined based on this simple implementation.
*
*/
public class LoadSheddingStreamExecutorServiceFactory implements StreamExecutorServiceFactory {
private final int workQueueSize;
@Inject
private S4Metrics metrics;
@Inject
public LoadSheddingStreamExecutorServiceFactory(@Named("s4.stream.workQueueSize") int workQueueSize) {
this.workQueueSize = workQueueSize;
}
@Override
public ExecutorService create(int parallelism, final String name, final ClassLoader classLoader) {
ThreadFactory threadFactory = new ThreadFactoryBuilder().setDaemon(true)
.setNameFormat("stream-" + name + "-%d").setThreadFactory(new ThreadFactory() {
@Override
public Thread newThread(Runnable r) {
Thread t = new Thread(r);
t.setContextClassLoader(classLoader);
return t;
}
}).build();
RejectedExecutionHandler rejectedExecutionHandler = new RejectedExecutionHandler() {
@Override
public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {
metrics.droppedEvent(name);
}
};
ThreadPoolExecutor tpe = new ThreadPoolExecutor(parallelism, parallelism, 60, TimeUnit.SECONDS,
new ArrayBlockingQueue<Runnable>(workQueueSize), threadFactory, rejectedExecutionHandler);
tpe.allowCoreThreadTimeOut(true);
return tpe;
}
}