1 files changed, 161 insertions, 0 deletions
diff --git a/src/main/java/com/att/dmf/mr/backends/kafka/KafkaLiveLockAvoider2.java b/src/main/java/com/att/dmf/mr/backends/kafka/KafkaLiveLockAvoider2.java
new file mode 100644
index 0000000..805701a
--- /dev/null
+++ b/src/main/java/com/att/dmf/mr/backends/kafka/KafkaLiveLockAvoider2.java
@@ -0,0 +1,161 @@
+/*******************************************************************************
+ *  ============LICENSE_START=======================================================
+ *  org.onap.dmaap
+ *  ================================================================================
+ *  Copyright © 2017 AT&T Intellectual Property. All rights reserved.
+ *  ================================================================================
+ *  Licensed 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.
+ *  ============LICENSE_END=========================================================
+ *  
+ *  ECOMP is a trademark and service mark of AT&T Intellectual Property.
+ *  
+ *******************************************************************************/
+package com.att.dmf.mr.backends.kafka;
+
+
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import javax.annotation.PostConstruct;
+
+import org.apache.curator.framework.CuratorFramework;
+import org.apache.curator.framework.recipes.locks.InterProcessMutex;
+import org.apache.zookeeper.CreateMode;
+import org.apache.zookeeper.Watcher;
+import com.att.eelf.configuration.EELFLogger;
+import com.att.eelf.configuration.EELFManager;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.stereotype.Component;
+import org.springframework.stereotype.Service;
+
+//@ComponentScan(basePackages="com.att.dmf.mr.backends.kafka")
+@Component
+public class KafkaLiveLockAvoider2 {
+	
+	public static final String ZNODE_ROOT = "/live-lock-avoid";
+	public static final String ZNODE_LOCKS = "/locks";
+	public static final String ZNODE_UNSTICK_TASKS ="/unstick-tasks";
+	
+	private static String locksPath = ZNODE_ROOT+ZNODE_LOCKS;
+	private static String tasksPath = ZNODE_ROOT+ZNODE_UNSTICK_TASKS;
+	private static final EELFLogger log = EELFManager.getInstance().getLogger(KafkaLiveLockAvoider2.class.getName());
+	
+	@Autowired
+	@Qualifier("curator")	
+	private CuratorFramework curatorFramework;
+	
+   @PostConstruct
+	public void init() {
+	System.out.println("Welcome......................................................................................");
+	try {
+		if (curatorFramework.checkExists().forPath(locksPath) == null) {
+			curatorFramework.create().creatingParentsIfNeeded().forPath(locksPath);
+		}
+		if (curatorFramework.checkExists().forPath(tasksPath) == null) {
+			curatorFramework.create().creatingParentsIfNeeded().forPath(tasksPath);
+		}
+		
+	} catch (Exception e) {
+		//e.printStackTrace();
+		log.error("Error during creation of permanent Znodes under /live-lock-avoid ",e);
+		
+	}
+	
+		
+	}
+	public void unlockConsumerGroup(String appId, String groupName) throws Exception {
+		
+		log.info("Signalling unlock to all conumsers of in group [{}] now, " ,  groupName);
+		
+		String fullLockPath = String.format("%s/%s", locksPath, groupName );
+		String fullTasksPath = null;
+		
+		try {
+
+			//Use the Curator recipe for a Mutex lock, only one process can be broadcasting unlock instructions for a group
+			InterProcessMutex lock = new InterProcessMutex(curatorFramework, fullLockPath);
+			if ( lock.acquire(100L, TimeUnit.MILLISECONDS) ) 
+			{
+				try 
+				{
+					List<String> taskNodes = curatorFramework.getChildren().forPath(tasksPath);
+					for (String taskNodeName : taskNodes) {
+						if(!taskNodeName.equals(appId)) {
+							
+							fullTasksPath = String.format("%s/%s/%s", tasksPath, taskNodeName, groupName);
+							log.info("Writing groupName {} to path {}",groupName, fullTasksPath);
+							
+							
+							if(curatorFramework.checkExists().forPath(fullTasksPath) != null) {
+								curatorFramework.delete().forPath(fullTasksPath);
+							}
+							curatorFramework.create().withMode(CreateMode.EPHEMERAL).forPath(fullTasksPath);
+						}
+					}
+					
+
+				}
+				finally
+				{
+					//Curator lock recipe requires a acquire() to be followed by a release()
+					lock.release();
+				}
+			}else {
+				log.info("Could not obtain the avoider lock, another process has the avoider lock? {}", !lock.isAcquiredInThisProcess() );
+			}
+
+
+		} catch (Exception e) {
+			log.error("Error setting up either lock ZNode {} or task  ZNode {}",fullLockPath, fullTasksPath,e);
+			throw e;
+		}
+		
+		
+	}
+	
+	/*
+	 * Shoud be called once per MR server instance.
+	 * 
+	 */
+	public void startNewWatcherForServer(String appId, LiveLockAvoidance avoidanceCallback) {
+		LockInstructionWatcher instructionWatcher = new LockInstructionWatcher(curatorFramework,avoidanceCallback,this);
+		assignNewProcessNode(appId, instructionWatcher);
+		
+	}
+	
+	
+	protected void assignNewProcessNode(String appId, Watcher processNodeWatcher ) {
+		
+		String taskHolderZnodePath = ZNODE_ROOT+ZNODE_UNSTICK_TASKS+"/"+appId;
+		//Watcher processNodeWatcher = createWatcher();
+		
+		try {
+			
+			if(curatorFramework.checkExists().forPath(taskHolderZnodePath) != null) {
+				curatorFramework.delete().deletingChildrenIfNeeded().forPath(taskHolderZnodePath);
+
+			}
+			curatorFramework.create().forPath(taskHolderZnodePath);
+			//setup the watcher
+			curatorFramework.getChildren().usingWatcher(processNodeWatcher).inBackground().forPath(taskHolderZnodePath);
+			log.info("Done creating task holder and watcher for APP name: {}",appId);
+			
+		} catch (Exception e) {
+			log.error("Could not add new processing node for name {}", appId, e);
+		}
+				
+	}
+
+	
+}