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/**
*
* 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.hadoop.hbase.executor;
import java.io.IOException;
import java.io.Writer;
import java.lang.management.ThreadInfo;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.executor.EventHandler.EventHandlerListener;
import org.apache.hadoop.hbase.monitoring.ThreadMonitoring;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.util.concurrent.ThreadFactoryBuilder;
/**
* This is a generic executor service. This component abstracts a
* threadpool, a queue to which {@link EventType}s can be submitted,
* and a Runnable that handles the object that is added to the queue.
*
* In order to create a new service, create an instance of this class and
* then do: instance.startExecutorService("myService");. When done
* call {@link #shutdown()}.
*
*
In order to use the service created above, call
* {@link #submit(EventHandler)}. Register pre- and post- processing listeners
* by registering your implementation of {@link EventHandler.EventHandlerListener}
* with {@link #registerListener(EventType, EventHandler.EventHandlerListener)}. Be sure
* to deregister your listener when done via {@link #unregisterListener(EventType)}.
*/
@InterfaceAudience.Private
public class ExecutorService {
private static final Log LOG = LogFactory.getLog(ExecutorService.class);
// hold the all the executors created in a map addressable by their names
private final ConcurrentHashMap executorMap =
new ConcurrentHashMap();
// listeners that are called before and after an event is processed
private ConcurrentHashMap eventHandlerListeners =
new ConcurrentHashMap();
// Name of the server hosting this executor service.
private final String servername;
/**
* Default constructor.
* @param servername Name of the hosting server.
*/
public ExecutorService(final String servername) {
super();
this.servername = servername;
}
/**
* Start an executor service with a given name. If there was a service already
* started with the same name, this throws a RuntimeException.
* @param name Name of the service to start.
*/
@VisibleForTesting
public void startExecutorService(String name, int maxThreads) {
if (this.executorMap.get(name) != null) {
throw new RuntimeException("An executor service with the name " + name +
" is already running!");
}
Executor hbes = new Executor(name, maxThreads, this.eventHandlerListeners);
if (this.executorMap.putIfAbsent(name, hbes) != null) {
throw new RuntimeException("An executor service with the name " + name +
" is already running (2)!");
}
LOG.debug("Starting executor service name=" + name +
", corePoolSize=" + hbes.threadPoolExecutor.getCorePoolSize() +
", maxPoolSize=" + hbes.threadPoolExecutor.getMaximumPoolSize());
}
boolean isExecutorServiceRunning(String name) {
return this.executorMap.containsKey(name);
}
public void shutdown() {
for(Entry entry: this.executorMap.entrySet()) {
List wasRunning =
entry.getValue().threadPoolExecutor.shutdownNow();
if (!wasRunning.isEmpty()) {
LOG.info(entry.getValue() + " had " + wasRunning + " on shutdown");
}
}
this.executorMap.clear();
}
Executor getExecutor(final ExecutorType type) {
return getExecutor(type.getExecutorName(this.servername));
}
Executor getExecutor(String name) {
Executor executor = this.executorMap.get(name);
return executor;
}
@VisibleForTesting
public ThreadPoolExecutor getExecutorThreadPool(final ExecutorType type) {
return getExecutor(type).getThreadPoolExecutor();
}
public void startExecutorService(final ExecutorType type, final int maxThreads) {
String name = type.getExecutorName(this.servername);
if (isExecutorServiceRunning(name)) {
LOG.debug("Executor service " + toString() + " already running on " +
this.servername);
return;
}
startExecutorService(name, maxThreads);
}
public void submit(final EventHandler eh) {
Executor executor = getExecutor(eh.getEventType().getExecutorServiceType());
if (executor == null) {
// This happens only when events are submitted after shutdown() was
// called, so dropping them should be "ok" since it means we're
// shutting down.
LOG.error("Cannot submit [" + eh + "] because the executor is missing." +
" Is this process shutting down?");
} else {
executor.submit(eh);
}
}
/**
* Subscribe to updates before and after processing instances of
* {@link EventType}. Currently only one listener per
* event type.
* @param type Type of event we're registering listener for
* @param listener The listener to run.
*/
public void registerListener(final EventType type,
final EventHandlerListener listener) {
this.eventHandlerListeners.put(type, listener);
}
/**
* Stop receiving updates before and after processing instances of
* {@link EventType}
* @param type Type of event we're registering listener for
* @return The listener we removed or null if we did not remove it.
*/
public EventHandlerListener unregisterListener(final EventType type) {
return this.eventHandlerListeners.remove(type);
}
public Map getAllExecutorStatuses() {
Map ret = Maps.newHashMap();
for (Map.Entry e : executorMap.entrySet()) {
ret.put(e.getKey(), e.getValue().getStatus());
}
return ret;
}
/**
* Executor instance.
*/
static class Executor {
// how long to retain excess threads
static final long keepAliveTimeInMillis = 1000;
// the thread pool executor that services the requests
final TrackingThreadPoolExecutor threadPoolExecutor;
// work queue to use - unbounded queue
final BlockingQueue q = new LinkedBlockingQueue();
private final String name;
private final Map eventHandlerListeners;
private static final AtomicLong seqids = new AtomicLong(0);
private final long id;
protected Executor(String name, int maxThreads,
final Map eventHandlerListeners) {
this.id = seqids.incrementAndGet();
this.name = name;
this.eventHandlerListeners = eventHandlerListeners;
// create the thread pool executor
this.threadPoolExecutor = new TrackingThreadPoolExecutor(
maxThreads, maxThreads,
keepAliveTimeInMillis, TimeUnit.MILLISECONDS, q);
// name the threads for this threadpool
ThreadFactoryBuilder tfb = new ThreadFactoryBuilder();
tfb.setNameFormat(this.name + "-%d");
this.threadPoolExecutor.setThreadFactory(tfb.build());
}
/**
* Submit the event to the queue for handling.
* @param event
*/
void submit(final EventHandler event) {
// If there is a listener for this type, make sure we call the before
// and after process methods.
EventHandlerListener listener =
this.eventHandlerListeners.get(event.getEventType());
if (listener != null) {
event.setListener(listener);
}
this.threadPoolExecutor.execute(event);
}
TrackingThreadPoolExecutor getThreadPoolExecutor() {
return threadPoolExecutor;
}
@Override
public String toString() {
return getClass().getSimpleName() + "-" + id + "-" + name;
}
public ExecutorStatus getStatus() {
List queuedEvents = Lists.newArrayList();
for (Runnable r : q) {
if (!(r instanceof EventHandler)) {
LOG.warn("Non-EventHandler " + r + " queued in " + name);
continue;
}
queuedEvents.add((EventHandler)r);
}
List running = Lists.newArrayList();
for (Map.Entry e :
threadPoolExecutor.getRunningTasks().entrySet()) {
Runnable r = e.getValue();
if (!(r instanceof EventHandler)) {
LOG.warn("Non-EventHandler " + r + " running in " + name);
continue;
}
running.add(new RunningEventStatus(e.getKey(), (EventHandler)r));
}
return new ExecutorStatus(this, queuedEvents, running);
}
}
/**
* A subclass of ThreadPoolExecutor that keeps track of the Runnables that
* are executing at any given point in time.
*/
static class TrackingThreadPoolExecutor extends ThreadPoolExecutor {
private ConcurrentMap running = Maps.newConcurrentMap();
public TrackingThreadPoolExecutor(int corePoolSize, int maximumPoolSize,
long keepAliveTime, TimeUnit unit, BlockingQueue workQueue) {
super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue);
}
@Override
protected void afterExecute(Runnable r, Throwable t) {
super.afterExecute(r, t);
running.remove(Thread.currentThread());
}
@Override
protected void beforeExecute(Thread t, Runnable r) {
Runnable oldPut = running.put(t, r);
assert oldPut == null : "inconsistency for thread " + t;
super.beforeExecute(t, r);
}
/**
* @return a map of the threads currently running tasks
* inside this executor. Each key is an active thread,
* and the value is the task that is currently running.
* Note that this is not a stable snapshot of the map.
*/
public ConcurrentMap getRunningTasks() {
return running;
}
}
/**
* A snapshot of the status of a particular executor. This includes
* the contents of the executor's pending queue, as well as the
* threads and events currently being processed.
*
* This is a consistent snapshot that is immutable once constructed.
*/
public static class ExecutorStatus {
final Executor executor;
final List queuedEvents;
final List running;
ExecutorStatus(Executor executor,
List queuedEvents,
List running) {
this.executor = executor;
this.queuedEvents = queuedEvents;
this.running = running;
}
/**
* Dump a textual representation of the executor's status
* to the given writer.
*
* @param out the stream to write to
* @param indent a string prefix for each line, used for indentation
*/
public void dumpTo(Writer out, String indent) throws IOException {
out.write(indent + "Status for executor: " + executor + "\n");
out.write(indent + "=======================================\n");
out.write(indent + queuedEvents.size() + " events queued, " +
running.size() + " running\n");
if (!queuedEvents.isEmpty()) {
out.write(indent + "Queued:\n");
for (EventHandler e : queuedEvents) {
out.write(indent + " " + e + "\n");
}
out.write("\n");
}
if (!running.isEmpty()) {
out.write(indent + "Running:\n");
for (RunningEventStatus stat : running) {
out.write(indent + " Running on thread '" +
stat.threadInfo.getThreadName() +
"': " + stat.event + "\n");
out.write(ThreadMonitoring.formatThreadInfo(
stat.threadInfo, indent + " "));
out.write("\n");
}
}
out.flush();
}
}
/**
* The status of a particular event that is in the middle of being
* handled by an executor.
*/
public static class RunningEventStatus {
final ThreadInfo threadInfo;
final EventHandler event;
public RunningEventStatus(Thread t, EventHandler event) {
this.threadInfo = ThreadMonitoring.getThreadInfo(t);
this.event = event;
}
}
}