package org.apache.helix.messaging.handling;
/*
* 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.
*/
import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import org.apache.helix.ConfigAccessor;
import org.apache.helix.model.ConfigScope;
import org.apache.helix.model.builder.ConfigScopeBuilder;
import org.apache.helix.HelixConstants;
import org.apache.helix.HelixDataAccessor;
import org.apache.helix.HelixException;
import org.apache.helix.HelixManager;
import org.apache.helix.MessageListener;
import org.apache.helix.NotificationContext;
import org.apache.helix.NotificationContext.MapKey;
import org.apache.helix.PropertyKey;
import org.apache.helix.NotificationContext.Type;
import org.apache.helix.PropertyKey.Builder;
import org.apache.helix.model.CurrentState;
import org.apache.helix.model.Message;
import org.apache.helix.model.Message.MessageState;
import org.apache.helix.model.Message.MessageType;
import org.apache.helix.monitoring.ParticipantMonitor;
import org.apache.helix.participant.HelixStateMachineEngine;
import org.apache.helix.util.StatusUpdateUtil;
import org.apache.log4j.Logger;
public class HelixTaskExecutor implements MessageListener, TaskExecutor
{
// TODO: we need to further design how to throttle this.
// From storage point of view, only bootstrap case is expensive
// and we need to throttle, which is mostly IO / network bounded.
public static final int DEFAULT_PARALLEL_TASKS = 40;
// TODO: create per-task type threadpool with customizable pool size
protected final Map<String, MessageTaskInfo> _taskMap;
private final Object _lock;
private final StatusUpdateUtil _statusUpdateUtil;
private final ParticipantMonitor _monitor;
public static final String MAX_THREADS =
"maxThreads";
final ConcurrentHashMap<String, MessageHandlerFactory> _handlerFactoryMap =
new ConcurrentHashMap<String, MessageHandlerFactory>();
final ConcurrentHashMap<String, ExecutorService> _executorMap;
private static Logger LOG =
Logger.getLogger(HelixTaskExecutor.class);
Map<String, Integer> _resourceThreadpoolSizeMap =
new ConcurrentHashMap<String, Integer>();
// timer for schedule timeout tasks
final Timer _timer;
public HelixTaskExecutor()
{
_taskMap = new ConcurrentHashMap<String, MessageTaskInfo>();
_executorMap = new ConcurrentHashMap<String, ExecutorService>();
_lock = new Object();
_statusUpdateUtil = new StatusUpdateUtil();
_monitor = new ParticipantMonitor();
_timer = new Timer(true); // created as a daemon timer thread to handle task timeout
startMonitorThread();
}
@Override
public void registerMessageHandlerFactory(String type, MessageHandlerFactory factory)
{
registerMessageHandlerFactory(type, factory, DEFAULT_PARALLEL_TASKS);
}
@Override
public void registerMessageHandlerFactory(String type,
MessageHandlerFactory factory,
int threadpoolSize)
{
if (!_handlerFactoryMap.containsKey(type))
{
if (!type.equalsIgnoreCase(factory.getMessageType()))
{
throw new HelixException("Message factory type mismatch. Type: " + type
+ " factory : " + factory.getMessageType());
}
_handlerFactoryMap.put(type, factory);
ExecutorService executorSvc = Executors.newFixedThreadPool(threadpoolSize);
_executorMap.put(type, executorSvc);
LOG.info("Added msg-factory for type: " + type + ", threadpool size "
+ threadpoolSize);
}
else
{
LOG.warn("Fail to register msg-handler-factory for type: " + type
+ ", pool-size: " + threadpoolSize + ", factory: " + factory);
}
}
public ParticipantMonitor getParticipantMonitor()
{
return _monitor;
}
private void startMonitorThread()
{
// start a thread which monitors the completions of task
}
void checkResourceConfig(String resourceName, HelixManager manager)
{
if (!_resourceThreadpoolSizeMap.containsKey(resourceName))
{
int threadpoolSize = -1;
ConfigAccessor configAccessor = manager.getConfigAccessor();
if (configAccessor != null)
{
ConfigScope scope =
new ConfigScopeBuilder().forCluster(manager.getClusterName())
.forResource(resourceName)
.build();
String threadpoolSizeStr = configAccessor.get(scope, MAX_THREADS);
try
{
if (threadpoolSizeStr != null)
{
threadpoolSize = Integer.parseInt(threadpoolSizeStr);
}
}
catch (Exception e)
{
LOG.error("", e);
}
}
if (threadpoolSize > 0)
{
String key = MessageType.STATE_TRANSITION.toString() + "." + resourceName;
_executorMap.put(key, Executors.newFixedThreadPool(threadpoolSize));
LOG.info("Added per resource threadpool for resource: " + resourceName
+ " with size: " + threadpoolSize);
}
_resourceThreadpoolSizeMap.put(resourceName, threadpoolSize);
}
}
/**
* Find the executor service for the message. A message can have a per-statemodelfactory
* executor service, or per-message type executor service.
*
**/
ExecutorService findExecutorServiceForMsg(Message message)
{
ExecutorService executorService = _executorMap.get(message.getMsgType());
if (message.getMsgType().equals(MessageType.STATE_TRANSITION.toString()))
{
String resourceName = message.getResourceName();
if (resourceName != null)
{
String key = message.getMsgType() + "." + resourceName;
if (_executorMap.containsKey(key))
{
LOG.info("Find per-resource thread pool with key: " + key);
executorService = _executorMap.get(key);
}
}
}
return executorService;
}
// ExecutorService impl's in JDK are thread-safe
@Override
public List<Future<HelixTaskResult>> invokeAllTasks(List<MessageTask> tasks, long timeout, TimeUnit unit) throws InterruptedException
{
if (tasks == null || tasks.size() == 0) {
return null;
}
// check all tasks use the same executor-service
ExecutorService exeSvc = findExecutorServiceForMsg(tasks.get(0).getMessage());
for (int i = 1; i < tasks.size(); i++) {
MessageTask task = tasks.get(i);
ExecutorService curExeSvc = findExecutorServiceForMsg(task.getMessage());
if (curExeSvc != exeSvc) {
LOG.error("Fail to invoke all tasks because they are not using the same executor-service");
return null;
}
}
// TODO: check if any of the task has already been scheduled
// this is a blocking call
List<Future<HelixTaskResult>> futures = exeSvc.invokeAll(tasks, timeout, unit);
return futures;
}
@Override
public boolean cancelTimeoutTask(MessageTask task)
{
synchronized(_lock) {
String taskId = task.getTaskId();
if (_taskMap.containsKey(taskId)) {
MessageTaskInfo info = _taskMap.get(taskId);
if (info._timerTask != null) {
info._timerTask.cancel();
}
return true;
}
return false;
}
}
@Override
public boolean scheduleTask(MessageTask task)
{
String taskId = task.getTaskId();
Message message = task.getMessage();
NotificationContext notificationContext = task.getNotificationContext();
try
{
if (message.getMsgType().equals(MessageType.STATE_TRANSITION.toString()))
{
checkResourceConfig(message.getResourceName(), notificationContext.getManager());
}
LOG.info("Scheduling message: " + taskId);
// System.out.println("sched msg: " + message.getPartitionName() + "-"
// + message.getTgtName() + "-" + message.getFromState() + "-"
// + message.getToState());
_statusUpdateUtil.logInfo(message,
HelixTaskExecutor.class,
"Message handling task scheduled",
notificationContext.getManager().getHelixDataAccessor());
// this sync guarantees that ExecutorService.submit() task and put taskInfo into map are sync'ed
synchronized (_lock)
{
if (!_taskMap.containsKey(taskId))
{
ExecutorService exeSvc = findExecutorServiceForMsg(message);
Future<HelixTaskResult> future = exeSvc.submit(task);
TimerTask timerTask = null;
if (message.getExecutionTimeout() > 0)
{
timerTask = new MessageTimeoutTask(this, task);
_timer.schedule(timerTask, message.getExecutionTimeout());
LOG.info("Message starts with timeout " + message.getExecutionTimeout()
+ " MsgId: " + task.getTaskId());
}
else
{
LOG.debug("Message does not have timeout. MsgId: " + task.getTaskId());
}
_taskMap.put(taskId, new MessageTaskInfo(task, future, timerTask));
LOG.info("Message: " + taskId + " handling task scheduled");
return true;
}
else
{
_statusUpdateUtil.logWarning(message,
HelixTaskExecutor.class,
"Message handling task already sheduled for "
+ taskId,
notificationContext.getManager()
.getHelixDataAccessor());
}
}
}
catch (Exception e)
{
LOG.error("Error while executing task. " + message, e);
_statusUpdateUtil.logError(message,
HelixTaskExecutor.class,
e,
"Error while executing task " + e,
notificationContext.getManager()
.getHelixDataAccessor());
}
return false;
}
@Override
public boolean cancelTask(MessageTask task)
{
Message message = task.getMessage();
NotificationContext notificationContext = task.getNotificationContext();
String taskId = task.getTaskId();
synchronized(_lock)
{
if (_taskMap.containsKey(taskId))
{
MessageTaskInfo taskInfo = _taskMap.get(taskId);
// cancel timeout task
if (taskInfo._timerTask != null) {
taskInfo._timerTask.cancel();
}
// cancel task
Future<HelixTaskResult> future = taskInfo.getFuture();
_statusUpdateUtil.logInfo(message,
HelixTaskExecutor.class,
"Canceling task: " + taskId,
notificationContext.getManager().getHelixDataAccessor());
// If the thread is still running it will be interrupted if cancel(true)
// is called. So state transition callbacks should implement logic to
// return
// if it is interrupted.
if (future.cancel(true))
{
_statusUpdateUtil.logInfo(message, HelixTaskExecutor.class, "Canceled task: "
+ taskId, notificationContext.getManager().getHelixDataAccessor());
_taskMap.remove(taskId);
return true;
}
else
{
_statusUpdateUtil.logInfo(message,
HelixTaskExecutor.class,
"fail to cancel task: " + taskId,
notificationContext.getManager()
.getHelixDataAccessor());
}
}
else
{
_statusUpdateUtil.logWarning(message,
HelixTaskExecutor.class,
"fail to cancel task: " + taskId + ", future not found",
notificationContext.getManager()
.getHelixDataAccessor());
}
}
return false;
}
@Override
public void finishTask(MessageTask task)
{
Message message = task.getMessage();
String taskId = task.getTaskId();
LOG.info("message finished: " + taskId + ", took "
+ (new Date().getTime() - message.getExecuteStartTimeStamp()));
synchronized (_lock)
{
if (_taskMap.containsKey(taskId))
{
MessageTaskInfo info = _taskMap.remove(taskId);
if (info._timerTask != null) {
// ok to cancel multiple times
info._timerTask.cancel();
}
}
else
{
LOG.warn("message " + taskId + " not found in task map");
}
}
}
private void updateMessageState(List<Message> readMsgs,
HelixDataAccessor accessor,
String instanceName)
{
Builder keyBuilder = accessor.keyBuilder();
List<PropertyKey> readMsgKeys = new ArrayList<PropertyKey>();
for (Message msg : readMsgs)
{
readMsgKeys.add(msg.getKey(keyBuilder, instanceName));
}
accessor.setChildren(readMsgKeys, readMsgs);
}
@Override
public void onMessage(String instanceName,
List<Message> messages,
NotificationContext changeContext)
{
// If FINALIZE notification comes, reset all handler factories
// and terminate all the thread pools
// TODO: see if we should have a separate notification call for resetting
if (changeContext.getType() == Type.FINALIZE)
{
LOG.info("Get FINALIZE notification");
for (MessageHandlerFactory factory : _handlerFactoryMap.values())
{
factory.reset();
}
// Cancel all scheduled tasks
synchronized (_lock)
{
for (MessageTaskInfo info : _taskMap.values())
{
cancelTask(info._task);
}
_taskMap.clear();
}
return;
}
if (messages == null || messages.size() == 0)
{
LOG.info("No Messages to process");
return;
}
// sort message by creation timestamp, so message created earlier is processed first
Collections.sort(messages, Message.CREATE_TIME_COMPARATOR);
HelixManager manager = changeContext.getManager();
HelixDataAccessor accessor = manager.getHelixDataAccessor();
Builder keyBuilder = accessor.keyBuilder();
// message handlers created
List<MessageHandler> handlers = new ArrayList<MessageHandler>();
// message read
List<Message> readMsgs = new ArrayList<Message>();
String sessionId = manager.getSessionId();
List<String> curResourceNames =
accessor.getChildNames(keyBuilder.currentStates(instanceName, sessionId));
List<PropertyKey> createCurStateKeys = new ArrayList<PropertyKey>();
List<CurrentState> metaCurStates = new ArrayList<CurrentState>();
Set<String> createCurStateNames = new HashSet<String>();
for (Message message : messages)
{
// nop messages are simply removed. It is used to trigger onMessage() in
// situations such as register a new message handler factory
if (message.getMsgType().equalsIgnoreCase(MessageType.NO_OP.toString()))
{
LOG.info("Dropping NO-OP message. mid: " + message.getId() + ", from: "
+ message.getMsgSrc());
accessor.removeProperty(message.getKey(keyBuilder, instanceName));
continue;
}
String tgtSessionId = message.getTgtSessionId();
// sessionId mismatch normally means message comes from expired session, just remove it
if (!sessionId.equals(tgtSessionId) && !tgtSessionId.equals("*"))
{
String warningMessage =
"SessionId does NOT match. expected sessionId: " + sessionId
+ ", tgtSessionId in message: " + tgtSessionId + ", messageId: "
+ message.getMsgId();
LOG.warn(warningMessage);
accessor.removeProperty(message.getKey(keyBuilder, instanceName));
_statusUpdateUtil.logWarning(message,
HelixStateMachineEngine.class,
warningMessage,
accessor);
continue;
}
// don't process message that is of READ or UNPROCESSABLE state
if (MessageState.NEW != message.getMsgState())
{
// It happens because we don't delete message right after
// read. Instead we keep it until the current state is updated.
// We will read the message again if there is a new message but we
// check for the status and ignore if its already read
if (LOG.isTraceEnabled()) {
LOG.trace("Message already read. msgId: " + message.getMsgId());
}
continue;
}
// create message handlers, if handlers not found, leave its state as NEW
try
{
MessageHandler createHandler = createMessageHandler(message, changeContext);
if (createHandler == null)
{
continue;
}
handlers.add(createHandler);
}
catch (Exception e)
{
LOG.error("Failed to create message handler for " + message.getMsgId(), e);
String error =
"Failed to create message handler for " + message.getMsgId()
+ ", exception: " + e;
_statusUpdateUtil.logError(message,
HelixStateMachineEngine.class,
e,
error,
accessor);
message.setMsgState(MessageState.UNPROCESSABLE);
accessor.removeProperty(message.getKey(keyBuilder, instanceName));
LOG.error("Message cannot be proessed: " + message.getRecord(), e);
continue;
}
// update msgState to read
message.setMsgState(MessageState.READ);
message.setReadTimeStamp(new Date().getTime());
message.setExecuteSessionId(changeContext.getManager().getSessionId());
_statusUpdateUtil.logInfo(message,
HelixStateMachineEngine.class,
"New Message",
accessor);
readMsgs.add(message);
// batch creation of all current state meta data
// do it for non-controller and state transition messages only
if (!message.isControlerMsg()
&& message.getMsgType().equals(Message.MessageType.STATE_TRANSITION.toString()))
{
String resourceName = message.getResourceName();
if (!curResourceNames.contains(resourceName)
&& !createCurStateNames.contains(resourceName))
{
createCurStateNames.add(resourceName);
createCurStateKeys.add(keyBuilder.currentState(instanceName,
sessionId,
resourceName));
CurrentState metaCurState = new CurrentState(resourceName);
metaCurState.setBucketSize(message.getBucketSize());
metaCurState.setStateModelDefRef(message.getStateModelDef());
metaCurState.setSessionId(sessionId);
metaCurState.setBatchMessageMode(message.getBatchMessageMode());
String ftyName = message.getStateModelFactoryName();
if (ftyName != null)
{
metaCurState.setStateModelFactoryName(ftyName);
}
else
{
metaCurState.setStateModelFactoryName(HelixConstants.DEFAULT_STATE_MODEL_FACTORY);
}
metaCurStates.add(metaCurState);
}
}
}
// batch create curState meta
if (createCurStateKeys.size() > 0)
{
try
{
accessor.createChildren(createCurStateKeys, metaCurStates);
}
catch (Exception e)
{
LOG.error("fail to create cur-state znodes for messages: " + readMsgs, e);
}
}
// update message state to READ in batch and schedule all read messages
if (readMsgs.size() > 0)
{
updateMessageState(readMsgs, accessor, instanceName);
for (MessageHandler handler : handlers)
{
HelixTask task = new HelixTask(handler._message, changeContext, handler, this);
scheduleTask(task);
}
}
}
public MessageHandler createMessageHandler(Message message,
NotificationContext changeContext)
{
String msgType = message.getMsgType().toString();
MessageHandlerFactory handlerFactory = _handlerFactoryMap.get(msgType);
// Fail to find a MessageHandlerFactory for the message
// we will keep the message and the message will be handled when
// the corresponding MessageHandlerFactory is registered
if (handlerFactory == null)
{
LOG.warn("Fail to find message handler factory for type: " + msgType + " msgId: "
+ message.getMsgId());
return null;
}
// pass the executor to msg-handler since batch-msg-handler needs task-executor to schedule sub-msgs
changeContext.add(MapKey.TASK_EXECUTOR.toString(), this);
return handlerFactory.createHandler(message, changeContext);
}
@Override
public void shutdown()
{
LOG.info("shutting down TaskExecutor");
_timer.cancel();
synchronized (_lock)
{
for (String msgType : _executorMap.keySet())
{
List<Runnable> tasksLeft = _executorMap.get(msgType).shutdownNow();
LOG.info(tasksLeft.size() + " tasks are still in the threadpool for msgType "
+ msgType);
}
for (String msgType : _executorMap.keySet())
{
try
{
if (!_executorMap.get(msgType).awaitTermination(200, TimeUnit.MILLISECONDS))
{
LOG.warn(msgType + " is not fully termimated in 200 MS");
System.out.println(msgType + " is not fully termimated in 200 MS");
}
}
catch (InterruptedException e)
{
LOG.error("Interrupted", e);
}
}
}
_monitor.shutDown();
LOG.info("shutdown finished");
}
}