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/*******************************************************************************
* ============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.nsa.cambria.backends.kafka;
import java.io.IOException;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import java.util.Map.Entry;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import org.I0Itec.zkclient.exception.ZkException;
import org.I0Itec.zkclient.exception.ZkInterruptedException;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.imps.CuratorFrameworkState;
import org.apache.curator.framework.recipes.cache.ChildData;
import org.apache.curator.framework.recipes.cache.PathChildrenCache;
import org.apache.curator.framework.recipes.cache.PathChildrenCacheEvent;
import org.apache.curator.framework.recipes.cache.PathChildrenCacheListener;
import org.apache.curator.framework.state.ConnectionState;
import org.apache.curator.framework.state.ConnectionStateListener;
import org.apache.curator.utils.EnsurePath;
import org.apache.curator.utils.ZKPaths;
import org.apache.http.annotation.NotThreadSafe;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.NoNodeException;
//import org.slf4j.Logger;
//import org.slf4j.LoggerFactory;
import com.att.eelf.configuration.EELFLogger;
import com.att.eelf.configuration.EELFManager;
import com.att.ajsc.filemonitor.AJSCPropertiesMap;
import com.att.nsa.cambria.backends.Consumer;
import com.att.nsa.cambria.backends.MetricsSet;
import com.att.nsa.cambria.constants.CambriaConstants;
import com.att.nsa.cambria.utils.ConfigurationReader;
import com.att.nsa.drumlin.till.nv.rrNvReadable;
/**
* @NotThreadSafe but expected to be used within KafkaConsumerFactory, which
* must be
* @author author
*
*/
@NotThreadSafe
public class KafkaConsumerCache {
private static final String kSetting_ConsumerHandoverWaitMs = "cambria.consumer.cache.handoverWaitMs";
private static final int kDefault_ConsumerHandoverWaitMs = 500;
private static final String kSetting_SweepEverySeconds = "cambria.consumer.cache.sweepFreqSeconds";
private static final String kSetting_TouchEveryMs = "cambria.consumer.cache.touchFreqMs";
private static final String kSetting_ZkBasePath = "cambria.consumer.cache.zkBasePath";
private static final String kDefault_ZkBasePath = CambriaConstants.kDefault_ZkRoot + "/consumerCache";
// kafka defaults to timing out a client after 6 seconds of inactivity, but
// it heartbeats even when the client isn't fetching. Here, we don't
// want to prematurely rebalance the consumer group. Assuming clients are
// hitting
// the server at least every 30 seconds, timing out after 2 minutes should
// be okay.
// FIXME: consider allowing the client to specify its expected call rate?
private static final long kDefault_MustTouchEveryMs = (long)1000 * 60 * 2;
// check for expirations pretty regularly
private static final long kDefault_SweepEverySeconds = 15;
private enum Status {
NOT_STARTED, CONNECTED, DISCONNECTED, SUSPENDED
}
/**
* User defined exception class for kafka consumer cache
*
* @author author
*
*/
public class KafkaConsumerCacheException extends Exception {
/**
* To throw the exception
*
* @param t
*/
KafkaConsumerCacheException(Throwable t) {
super(t);
}
/**
*
* @param s
*/
public KafkaConsumerCacheException(String s) {
super(s);
}
private static final long serialVersionUID = 1L;
}
/**
* Creates a KafkaConsumerCache object. Before it is used, you must call
* startCache()
*
* @param apiId
* @param s
* @param metrics
*/
public KafkaConsumerCache(String apiId, MetricsSet metrics) {
if (apiId == null) {
throw new IllegalArgumentException("API Node ID must be specified.");
}
fApiId = apiId;
// fSettings = s;
fMetrics = metrics;
String strkSetting_ZkBasePath= AJSCPropertiesMap.getProperty(CambriaConstants.msgRtr_prop,kSetting_ZkBasePath);
if(null==strkSetting_ZkBasePath)strkSetting_ZkBasePath = kDefault_ZkBasePath;
fBaseZkPath = strkSetting_ZkBasePath;
fConsumers = new ConcurrentHashMap<String, KafkaConsumer>();
fSweepScheduler = Executors.newScheduledThreadPool(1);
curatorConsumerCache = null;
status = Status.NOT_STARTED;
listener = new ConnectionStateListener() {
public void stateChanged(CuratorFramework client, ConnectionState newState) {
if (newState == ConnectionState.LOST) {
log.info("ZooKeeper connection expired");
handleConnectionLoss();
} else if (newState == ConnectionState.READ_ONLY) {
log.warn("ZooKeeper connection set to read only mode.");
} else if (newState == ConnectionState.RECONNECTED) {
log.info("ZooKeeper connection re-established");
handleReconnection();
} else if (newState == ConnectionState.SUSPENDED) {
log.warn("ZooKeeper connection has been suspended.");
handleConnectionSuspended();
}
}
};
}
/**
* Start the cache service. This must be called before any get/put
* operations.
*
* @param mode
* DMAAP or cambria
* @param curator
* @throws IOException
* @throws KafkaConsumerCacheException
*/
public void startCache(String mode, CuratorFramework curator) throws KafkaConsumerCacheException {
try {
// CuratorFramework curator = null;
// Changed the class from where we are initializing the curator
// framework
if (mode != null && mode.equals(CambriaConstants.CAMBRIA)) {
curator = ConfigurationReader.getCurator();
} else if (mode != null && mode.equals(CambriaConstants.DMAAP)) {
curator = getCuratorFramework(curator);
}
curator.getConnectionStateListenable().addListener(listener);
setStatus(Status.CONNECTED);
curatorConsumerCache = new PathChildrenCache(curator, fBaseZkPath, true);
curatorConsumerCache.start();
curatorConsumerCache.getListenable().addListener(new PathChildrenCacheListener() {
public void childEvent(CuratorFramework client, PathChildrenCacheEvent event) throws Exception {
switch (event.getType()) {
case CHILD_ADDED: {
final String apiId = new String(event.getData().getData());
final String consumer = ZKPaths.getNodeFromPath(event.getData().getPath());
log.info(apiId + " started consumer " + consumer);
break;
}
case CHILD_UPDATED: {
final String apiId = new String(event.getData().getData());
final String consumer = ZKPaths.getNodeFromPath(event.getData().getPath());
if (fConsumers.containsKey(consumer)) {
log.info(apiId + " claimed consumer " + consumer + " from " + fApiId);
dropClaimedConsumer(consumer);
}
break;
}
case CHILD_REMOVED: {
final String consumer = ZKPaths.getNodeFromPath(event.getData().getPath());
if (fConsumers.containsKey(consumer)) {
log.info("Someone wanted consumer " + consumer + " gone; removing it from the cache");
dropConsumer(consumer, false);
}
break;
}
default:
break;
}
}
});
// initialize the ZK path
EnsurePath ensurePath = new EnsurePath(fBaseZkPath);
ensurePath.ensure(curator.getZookeeperClient());
//final long freq = fSettings.getLong(kSetting_SweepEverySeconds, kDefault_SweepEverySeconds);
long freq = kDefault_SweepEverySeconds;
String strkSetting_SweepEverySeconds = AJSCPropertiesMap.getProperty(CambriaConstants.msgRtr_prop,kSetting_SweepEverySeconds);
if(null==strkSetting_SweepEverySeconds) strkSetting_SweepEverySeconds = kDefault_SweepEverySeconds+"";
freq = Long.parseLong(strkSetting_SweepEverySeconds);
fSweepScheduler.scheduleAtFixedRate(new sweeper(), freq, freq, TimeUnit.SECONDS);
log.info("KafkaConsumerCache started");
log.info("sweeping cached clients every " + freq + " seconds");
} catch (ZkException e) {
throw new KafkaConsumerCacheException(e);
} catch (Exception e) {
throw new KafkaConsumerCacheException(e);
}
}
/**
* Getting the curator oject to start the zookeeper connection estabished
*
* @param curator
* @return curator object
*/
public static CuratorFramework getCuratorFramework(CuratorFramework curator) {
if (curator.getState() == CuratorFrameworkState.LATENT) {
curator.start();
try {
curator.blockUntilConnected();
} catch (InterruptedException e) {
// Ignore
log.error("error while setting curator framework :" + e.getMessage());
Thread.currentThread().interrupt();
}
}
return curator;
}
/**
* Stop the cache service.
*/
public void stopCache() {
setStatus(Status.DISCONNECTED);
final CuratorFramework curator = ConfigurationReader.getCurator();
if (curator != null) {
try {
curator.getConnectionStateListenable().removeListener(listener);
curatorConsumerCache.close();
log.info("Curator client closed");
} catch (ZkInterruptedException e) {
log.error("Curator client close interrupted: " + e);
} catch (IOException e) {
log.error("Error while closing curator PathChildrenCache for KafkaConsumerCache" + e);
}
curatorConsumerCache = null;
}
if (fSweepScheduler != null) {
fSweepScheduler.shutdownNow();
log.info("cache sweeper stopped");
}
if (fConsumers != null) {
fConsumers.clear();
fConsumers = null;
}
setStatus(Status.NOT_STARTED);
log.info("Consumer cache service stopped");
}
/**
* Get a cached consumer by topic, group, and id, if it exists (and remains
* valid) In addition, this method waits for all other consumer caches in
* the cluster to release their ownership and delete their version of this
* consumer.
*
* @param topic
* @param consumerGroupId
* @param clientId
* @return a consumer, or null
*/
public KafkaConsumer getConsumerFor(String topic, String consumerGroupId, String clientId)
throws KafkaConsumerCacheException {
if (getStatus() != KafkaConsumerCache.Status.CONNECTED)
throw new KafkaConsumerCacheException("The cache service is unavailable.");
final String consumerKey = makeConsumerKey(topic, consumerGroupId, clientId);
final KafkaConsumer kc = fConsumers.get(consumerKey);
if (kc != null) {
log.debug("Consumer cache hit for [" + consumerKey + "], last was at " + kc.getLastTouch());
kc.touch();
fMetrics.onKafkaConsumerCacheHit();
} else {
log.debug("Consumer cache miss for [" + consumerKey + "]");
fMetrics.onKafkaConsumerCacheMiss();
}
return kc;
}
/**
* Put a consumer into the cache by topic, group and ID
*
* @param topic
* @param consumerGroupId
* @param consumerId
* @param consumer
* @throws KafkaConsumerCacheException
*/
public void putConsumerFor(String topic, String consumerGroupId, String consumerId, KafkaConsumer consumer)
throws KafkaConsumerCacheException {
if (getStatus() != KafkaConsumerCache.Status.CONNECTED)
throw new KafkaConsumerCacheException("The cache service is unavailable.");
final String consumerKey = makeConsumerKey(topic, consumerGroupId, consumerId);
fConsumers.put(consumerKey, consumer);
}
public Collection<? extends Consumer> getConsumers() {
return new LinkedList<KafkaConsumer>(fConsumers.values());
}
/**
* This method is to drop all the consumer
*/
public void dropAllConsumers() {
for (Entry<String, KafkaConsumer> entry : fConsumers.entrySet()) {
dropConsumer(entry.getKey(), true);
}
// consumers should be empty here
if (fConsumers.size() > 0) {
log.warn("During dropAllConsumers, the consumer map is not empty.");
fConsumers.clear();
}
}
/**
* Drop a consumer from our cache due to a timeout
*
* @param key
*/
private void dropTimedOutConsumer(String key) {
fMetrics.onKafkaConsumerTimeout();
if (!fConsumers.containsKey(key)) {
log.warn("Attempted to drop a timed out consumer which was not in our cache: " + key);
return;
}
// First, drop this consumer from our cache
dropConsumer(key, true);
final CuratorFramework curator = ConfigurationReader.getCurator();
try {
curator.delete().guaranteed().forPath(fBaseZkPath + "/" + key);
} catch (NoNodeException e) {
log.error("Exception at : " + e);
} catch (Exception e) {
log.error("Unexpected exception while deleting consumer: " + e);
}
log.info("Dropped " + key + " consumer due to timeout");
}
/**
* Drop a consumer from our cache due to another API node claiming it as
* their own.
*
* @param key
*/
private void dropClaimedConsumer(String key) {
// if the consumer is still in our cache, it implies a claim.
if (fConsumers.containsKey(key)) {
fMetrics.onKafkaConsumerClaimed();
log.info("Consumer [" + key + "] claimed by another node.");
}
dropConsumer(key, false);
}
/**
* Removes the consumer from the cache and closes its connection to the
* kafka broker(s).
*
* @param key
* @param dueToTimeout
*/
private void dropConsumer(String key, boolean dueToTimeout) {
final KafkaConsumer kc = fConsumers.remove(key);
if (kc != null) {
log.info("closing Kafka consumer " + key);
kc.close();
}
}
// private final rrNvReadable fSettings;
private final MetricsSet fMetrics;
private final String fBaseZkPath;
private final ScheduledExecutorService fSweepScheduler;
private final String fApiId;
private final ConnectionStateListener listener;
private ConcurrentHashMap<String, KafkaConsumer> fConsumers;
private PathChildrenCache curatorConsumerCache;
private volatile Status status;
private void handleReconnection() {
log.info("Reading current cache data from ZK and synchronizing local cache");
final List<ChildData> cacheData = curatorConsumerCache.getCurrentData();
// Remove all the consumers in this API nodes cache that now belong to
// other API nodes.
for (ChildData cachedConsumer : cacheData) {
final String consumerId = ZKPaths.getNodeFromPath(cachedConsumer.getPath());
final String owningApiId = (cachedConsumer.getData() != null) ? new String(cachedConsumer.getData())
: "undefined";
if (!fApiId.equals(owningApiId)) {
fConsumers.remove(consumerId);
}
}
setStatus(Status.CONNECTED);
}
private void handleConnectionSuspended() {
log.info("Suspending cache until ZK connection is re-established");
setStatus(Status.SUSPENDED);
}
private void handleConnectionLoss() {
log.info("Clearing consumer cache (shutting down all Kafka consumers on this node)");
setStatus(Status.DISCONNECTED);
closeAllCachedConsumers();
fConsumers.clear();
}
private void closeAllCachedConsumers() {
for (Entry<String, KafkaConsumer> entry : fConsumers.entrySet()) {
entry.getValue().close();
}
}
private static String makeConsumerKey(String topic, String consumerGroupId, String clientId) {
return topic + "::" + consumerGroupId + "::" + clientId;
}
/**
* This method is to get a lock
*
* @param topic
* @param consumerGroupId
* @param consumerId
* @throws KafkaConsumerCacheException
*/
public void signalOwnership(final String topic, final String consumerGroupId, final String consumerId)
throws KafkaConsumerCacheException {
// get a lock at <base>/<topic>::<consumerGroupId>::<consumerId>
final String consumerKey = makeConsumerKey(topic, consumerGroupId, consumerId);
try {
final String consumerPath = fBaseZkPath + "/" + consumerKey;
log.debug(fApiId + " attempting to claim ownership of consumer " + consumerKey);
final CuratorFramework curator = ConfigurationReader.getCurator();
try {
curator.setData().forPath(consumerPath, fApiId.getBytes());
} catch (KeeperException.NoNodeException e) {
log.error(e.toString());
curator.create().creatingParentsIfNeeded().forPath(consumerPath, fApiId.getBytes());
}
log.info(fApiId + " successfully claimed ownership of consumer " + consumerKey);
} catch (Exception e) {
log.error(fApiId + " failed to claim ownership of consumer " + consumerKey);
throw new KafkaConsumerCacheException(e);
}
log.info("Backing off to give the Kafka broker time to clean up the ZK data for this consumer");
try {
int kSetting_ConsumerHandoverWaitMs = kDefault_ConsumerHandoverWaitMs;
String strkSetting_ConsumerHandoverWaitMs= AJSCPropertiesMap.getProperty(CambriaConstants.msgRtr_prop,kSetting_ConsumerHandoverWaitMs+"");
if(strkSetting_ConsumerHandoverWaitMs!=null) kSetting_ConsumerHandoverWaitMs = Integer.parseInt(strkSetting_ConsumerHandoverWaitMs);
Thread.sleep(kSetting_ConsumerHandoverWaitMs);
//Thread.sleep(fSettings.getInt(kSetting_ConsumerHandoverWaitMs, kDefault_ConsumerHandoverWaitMs));
} catch (InterruptedException e) {
log.error(e.toString());
Thread.currentThread().interrupt();
}
}
private void sweep() {
final LinkedList<String> removals = new LinkedList<String>();
long mustTouchEveryMs = kDefault_MustTouchEveryMs;
String strkSetting_TouchEveryMs = AJSCPropertiesMap.getProperty(CambriaConstants.msgRtr_prop,kSetting_TouchEveryMs);
//if(null!=strkSetting_TouchEveryMs) strkSetting_TouchEveryMs = kDefault_MustTouchEveryMs+"";
if(null!=strkSetting_TouchEveryMs)
{
mustTouchEveryMs = Long.parseLong(strkSetting_TouchEveryMs);
}
//final long mustTouchEveryMs = fSettings.getLong(kSetting_TouchEveryMs, kDefault_MustTouchEveryMs);
final long oldestAllowedTouchMs = System.currentTimeMillis() - mustTouchEveryMs;
for (Entry<String, KafkaConsumer> e : fConsumers.entrySet()) {
final long lastTouchMs = e.getValue().getLastTouch();
log.debug("consumer " + e.getKey() + " last touched at " + lastTouchMs);
if (lastTouchMs < oldestAllowedTouchMs) {
log.info("consumer " + e.getKey() + " has expired");
removals.add(e.getKey());
}
}
for (String key : removals) {
dropTimedOutConsumer(key);
}
}
/**
* Creating a thread to run the sweep method
*
* @author author
*
*/
private class sweeper implements Runnable {
/**
* run method
*/
public void run() {
sweep();
}
}
/**
* This method is to drop consumer
*
* @param topic
* @param consumerGroup
* @param clientId
*/
public void dropConsumer(String topic, String consumerGroup, String clientId) {
dropConsumer(makeConsumerKey(topic, consumerGroup, clientId), false);
}
private Status getStatus() {
return this.status;
}
private void setStatus(Status status) {
this.status = status;
}
private static final EELFLogger log = EELFManager.getInstance().getLogger(KafkaConsumerCache.class);
//private static final Logger log = LoggerFactory.getLogger(KafkaConsumerCache.class);
}
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