/*
* Copyright © 2014 Cask Data, Inc.
*
* 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.
*/
package co.cask.cdap.metrics.runtime;
import co.cask.cdap.common.conf.CConfiguration;
import co.cask.cdap.metrics.MetricsConstants;
import co.cask.cdap.metrics.process.KafkaMetricsProcessorServiceFactory;
import co.cask.cdap.watchdog.election.MultiLeaderElection;
import co.cask.cdap.watchdog.election.PartitionChangeHandler;
import com.google.common.base.Throwables;
import com.google.common.util.concurrent.AbstractExecutionThreadService;
import com.google.common.util.concurrent.SettableFuture;
import com.google.inject.Inject;
import org.apache.twill.zookeeper.ZKClientService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Set;
import java.util.concurrent.Executor;
/**
* Metrics processor service that processes events from Kafka.
*/
public final class KafkaMetricsProcessorService extends AbstractExecutionThreadService {
private static final Logger LOG = LoggerFactory.getLogger(KafkaMetricsProcessorService.class);
private final MultiLeaderElection multiElection;
private final SettableFuture<?> completion;
@Inject
public KafkaMetricsProcessorService(CConfiguration conf,
ZKClientService zkClientService,
KafkaMetricsProcessorServiceFactory kafkaMetricsProcessorServiceFactory) {
int partitionSize = conf.getInt(MetricsConstants.ConfigKeys.KAFKA_PARTITION_SIZE,
MetricsConstants.DEFAULT_KAFKA_PARTITION_SIZE);
multiElection = new MultiLeaderElection(
zkClientService, "metrics-processor", partitionSize,
createPartitionChangeHandler(kafkaMetricsProcessorServiceFactory));
this.completion = SettableFuture.create();
}
@Override
protected Executor executor() {
return new Executor() {
@Override
public void execute(Runnable command) {
Thread t = new Thread(command, getServiceName());
t.setDaemon(true);
t.start();
}
};
}
@Override
protected void startUp() throws Exception {
LOG.info("Starting Metrics Processor ...");
multiElection.start();
}
@Override
protected void run() throws Exception {
completion.get();
}
@Override
protected void triggerShutdown() {
completion.set(null);
}
@Override
protected void shutDown() throws Exception {
LOG.info("Stopping Metrics Processor ...");
try {
multiElection.stop();
} catch (Exception e) {
LOG.error("Exception while shutting down.", e);
throw Throwables.propagate(e);
}
}
private PartitionChangeHandler createPartitionChangeHandler(final KafkaMetricsProcessorServiceFactory factory) {
return new PartitionChangeHandler() {
private co.cask.cdap.metrics.process.KafkaMetricsProcessorService service;
@Override
public void partitionsChanged(Set<Integer> partitions) {
LOG.info("Metrics Kafka partition changed {}", partitions);
try {
if (service != null) {
service.stopAndWait();
}
if (partitions.isEmpty() || !multiElection.isRunning()) {
service = null;
} else {
service = factory.create(partitions);
service.startAndWait();
}
} catch (Throwable t) {
LOG.error("Failed to change Kafka partition.", t);
completion.setException(t);
}
}
};
}
}