package org.apache.helix.taskexecution;
/*
* 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.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import org.apache.helix.ExternalViewChangeListener;
import org.apache.helix.HelixAdmin;
import org.apache.helix.HelixManager;
import org.apache.helix.NotificationContext;
import org.apache.helix.model.ExternalView;
public abstract class Task implements ExternalViewChangeListener {
CountDownLatch parentDependencyLatch;
Set<String> completedParentTasks;
private static final int TIMEOUT_SECONDS = 5;
protected final Set<String> parentIds;
protected final String id;
private final HelixManager helixManager;
protected final TaskResultStore resultStore;
public Task(String id, Set<String> parentIds, HelixManager helixManager, TaskResultStore resultStore) {
this.id = id;
this.parentIds = parentIds;
this.helixManager = helixManager;
this.resultStore = resultStore;
parentDependencyLatch = new CountDownLatch(1);
completedParentTasks = new HashSet<String>();
}
@Override
public void onExternalViewChange(List<ExternalView> externalViewList,
NotificationContext changeContext) {
if(areParentTasksDone(externalViewList)) {
parentDependencyLatch.countDown();
}
}
private boolean areParentTasksDone(List<ExternalView> externalViewList) {
if(parentIds == null || parentIds.size() == 0) {
return true;
}
for (ExternalView ev : externalViewList) {
String resourceName = ev.getResourceName();
if (parentIds.contains(resourceName)) {
if (isParentTaskDone(ev)) {
completedParentTasks.add(resourceName);
}
}
}
return parentIds.equals(completedParentTasks);
}
private boolean isParentTaskDone(ExternalView ev) {
Set<String> partitionSet = ev.getPartitionSet();
if(partitionSet.isEmpty()) {
return false;
}
for (String partition : partitionSet) {
Map<String, String> stateMap = ev.getStateMap(partition);
for (String instance : stateMap.keySet()) {
if (!stateMap.get(instance).equalsIgnoreCase("Online")) {
return false;
}
}
}
return true;
}
private List<ExternalView> getExternalViews() {
String clusterName = helixManager.getClusterName();
List<ExternalView> externalViewList = new ArrayList<ExternalView>();
HelixAdmin helixAdmin = helixManager.getClusterManagmentTool();
List<String> resourcesInCluster = helixAdmin.getResourcesInCluster(clusterName);
for(String resourceName : resourcesInCluster) {
ExternalView ev = helixManager.getClusterManagmentTool().getResourceExternalView(clusterName, resourceName);
if(ev != null) {
externalViewList.add(ev);
}
}
return externalViewList;
}
public final void execute(String resourceName, int numPartitions, int partitionNum) throws Exception {
if (!areParentTasksDone(getExternalViews())) {
if (!parentDependencyLatch.await(TIMEOUT_SECONDS, TimeUnit.SECONDS)) {
Set<String> pendingTasks = new HashSet<String>();
pendingTasks.addAll(parentIds);
pendingTasks.removeAll(completedParentTasks);
throw new Exception(id + " timed out while waiting for the following parent tasks to finish : " + pendingTasks);
}
}
executeImpl(resourceName, numPartitions, partitionNum);
}
protected abstract void executeImpl(String resourceName, int numPartitions, int partitionNum) throws Exception;
}