package org.apache.helix.manager.zk;
/*
* 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.List;
import org.I0Itec.zkclient.exception.ZkInterruptedException;
import org.apache.helix.ClusterMessagingService;
import org.apache.helix.HelixConnection;
import org.apache.helix.HelixController;
import org.apache.helix.HelixDataAccessor;
import org.apache.helix.HelixException;
import org.apache.helix.HelixManager;
import org.apache.helix.HelixTimerTask;
import org.apache.helix.InstanceType;
import org.apache.helix.PropertyKey;
import org.apache.helix.api.accessor.ClusterAccessor;
import org.apache.helix.api.id.ClusterId;
import org.apache.helix.api.id.ControllerId;
import org.apache.helix.api.id.Id;
import org.apache.helix.controller.GenericHelixController;
import org.apache.helix.healthcheck.HealthStatsAggregationTask;
import org.apache.helix.healthcheck.HealthStatsAggregator;
import org.apache.helix.messaging.DefaultMessagingService;
import org.apache.helix.messaging.handling.MessageHandlerFactory;
import org.apache.helix.model.LiveInstance;
import org.apache.helix.monitoring.StatusDumpTask;
import org.apache.log4j.Logger;
public class ZkHelixController implements HelixController {
private static Logger LOG = Logger.getLogger(ZkHelixController.class);
final ZkHelixConnection _connection;
final ClusterId _clusterId;
final ControllerId _controllerId;
final GenericHelixController _pipeline;
final DefaultMessagingService _messagingService;
final List<HelixTimerTask> _timerTasks;
final ClusterAccessor _clusterAccessor;
final HelixDataAccessor _accessor;
final HelixManager _manager;
final ZkHelixLeaderElection _leaderElection;
public ZkHelixController(ZkHelixConnection connection, ClusterId clusterId, ControllerId controllerId) {
_connection = connection;
_clusterId = clusterId;
_controllerId = controllerId;
_pipeline = new GenericHelixController();
_clusterAccessor = connection.createClusterAccessor(clusterId);
_accessor = connection.createDataAccessor(clusterId);
_messagingService = (DefaultMessagingService) connection.createMessagingService(this);
_timerTasks = new ArrayList<HelixTimerTask>();
_manager = new HelixConnectionAdaptor(this);
_leaderElection = new ZkHelixLeaderElection(this, _pipeline);
_timerTasks.add(new HealthStatsAggregationTask(new HealthStatsAggregator(_manager)));
_timerTasks.add(new StatusDumpTask(clusterId, _manager.getHelixDataAccessor()));
}
void startTimerTasks() {
for (HelixTimerTask task : _timerTasks) {
task.start();
}
}
void stopTimerTasks() {
for (HelixTimerTask task : _timerTasks) {
task.stop();
}
}
@Override
public HelixConnection getConnection() {
return _connection;
}
@Override
public void startAsync() {
_connection.addConnectionStateListener(this);
onConnected();
}
@Override
public void stopAsync() {
_connection.removeConnectionStateListener(this);
onDisconnecting();
}
void reset() {
/**
* reset all handlers, make sure cleanup completed for previous session
* disconnect if fail to cleanup
*/
_connection.resetHandlers(this);
}
void init() {
/**
* from here on, we are dealing with new session
* init handlers
*/
if (!_clusterAccessor.isClusterStructureValid()) {
throw new HelixException("Cluster structure is not set up for cluster: " + _clusterId);
}
/**
* leader-election listener should be reset/init before all other controller listeners;
* it's ok to add a listener multiple times, since we check existence in
* ZkHelixConnection#addXXXListner()
*/
_connection.addControllerListener(this, _leaderElection, _clusterId);
/**
* ok to init message handler and controller handlers twice
* the second init will be skipped (see CallbackHandler)
*/
_connection.initHandlers(this);
}
@Override
public void onConnected() {
reset();
init();
}
@Override
public void onDisconnecting() {
LOG.info("disconnecting " + _controllerId + "(" + getType() + ") from " + _clusterId);
reset();
}
@Override
public ClusterMessagingService getMessagingService() {
return _messagingService;
}
@Override
public ClusterId getClusterId() {
return _clusterId;
}
@Override
public ControllerId getControllerId() {
return _controllerId;
}
@Override
public Id getId() {
return getControllerId();
}
@Override
public InstanceType getType() {
return InstanceType.CONTROLLER;
}
@Override
public boolean isLeader() {
PropertyKey.Builder keyBuilder = _accessor.keyBuilder();
try {
LiveInstance leader = _accessor.getProperty(keyBuilder.controllerLeader());
if (leader != null) {
String leaderName = leader.getInstanceName();
String sessionId = leader.getSessionId();
if (leaderName != null && leaderName.equals(_controllerId.stringify()) && sessionId != null
&& sessionId.equals(_connection.getSessionId().stringify())) {
return true;
}
}
} catch (Exception e) {
// log
}
return false;
}
void addListenersToController(GenericHelixController pipeline) {
try {
/**
* setup controller message listener and register message handlers
*/
_connection.addControllerMessageListener(this, _messagingService.getExecutor(),
_clusterId);
MessageHandlerFactory defaultControllerMsgHandlerFactory =
new DefaultControllerMessageHandlerFactory();
_messagingService.getExecutor().registerMessageHandlerFactory(
defaultControllerMsgHandlerFactory.getMessageType(), defaultControllerMsgHandlerFactory);
MessageHandlerFactory defaultSchedulerMsgHandlerFactory =
new DefaultSchedulerMessageHandlerFactory(_manager);
_messagingService.getExecutor().registerMessageHandlerFactory(
defaultSchedulerMsgHandlerFactory.getMessageType(), defaultSchedulerMsgHandlerFactory);
MessageHandlerFactory defaultParticipantErrorMessageHandlerFactory =
new DefaultParticipantErrorMessageHandlerFactory(_manager);
_messagingService.getExecutor().registerMessageHandlerFactory(
defaultParticipantErrorMessageHandlerFactory.getMessageType(),
defaultParticipantErrorMessageHandlerFactory);
/**
* setup generic-controller
*/
_connection.addConfigChangeListener(this, pipeline, _clusterId);
_connection.addLiveInstanceChangeListener(this, pipeline, _clusterId);
_connection.addIdealStateChangeListener(this, pipeline, _clusterId);
_connection.addControllerListener(this, pipeline, _clusterId);
} catch (ZkInterruptedException e) {
LOG.warn("zk connection is interrupted during addListenersToController()"
+ e);
} catch (Exception e) {
LOG.error("Error addListenersToController", e);
}
}
void removeListenersFromController(GenericHelixController pipeline) {
PropertyKey.Builder keyBuilder = new PropertyKey.Builder(_manager.getClusterName());
/**
* reset generic-controller
*/
_connection.removeListener(this, pipeline, keyBuilder.instanceConfigs());
_connection.removeListener(this, pipeline, keyBuilder.liveInstances());
_connection.removeListener(this, pipeline, keyBuilder.idealStates());
_connection.removeListener(this, pipeline, keyBuilder.controller());
/**
* reset controller message listener and unregister all message handlers
*/
_connection.removeListener(this, _messagingService.getExecutor(),
keyBuilder.controllerMessages());
}
HelixManager getManager() {
return _manager;
}
}