| /* |
| * 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. |
| */ |
| package org.apache.twill.internal.kafka.client; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.common.util.concurrent.AbstractIdleService; |
| import org.apache.twill.common.Cancellable; |
| import org.apache.twill.common.Threads; |
| import org.apache.twill.kafka.client.BrokerService; |
| import org.apache.twill.kafka.client.Compression; |
| import org.apache.twill.kafka.client.KafkaClientService; |
| import org.apache.twill.kafka.client.KafkaConsumer; |
| import org.apache.twill.kafka.client.KafkaPublisher; |
| import org.apache.twill.zookeeper.ZKClient; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.lang.ref.Reference; |
| import java.lang.ref.ReferenceQueue; |
| import java.lang.ref.WeakReference; |
| import java.util.Collections; |
| import java.util.IdentityHashMap; |
| import java.util.Map; |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.ScheduledExecutorService; |
| import java.util.concurrent.TimeUnit; |
| |
| /** |
| * A KafkaClientService that uses ZooKeeper for broker discovery. |
| */ |
| public class ZKKafkaClientService extends AbstractIdleService implements KafkaClientService, Runnable { |
| |
| private static final Logger LOG = LoggerFactory.getLogger(ZKKafkaClientService.class); |
| private static final long PUBLISHER_CLEANUP_SECONDS = 1; |
| |
| private final BrokerService brokerService; |
| |
| // Maintains a weak reference key map for calling publisher.shutdown when garbage collected. |
| private final Map<WeakReference<KafkaPublisher>, Cancellable> publishers; |
| private final ReferenceQueue<KafkaPublisher> referenceQueue; |
| |
| private final SimpleKafkaConsumer consumer; |
| |
| // For running cleanup job |
| private ScheduledExecutorService scheduler; |
| |
| public ZKKafkaClientService(ZKClient zkClient) { |
| this.brokerService = new ZKBrokerService(zkClient); |
| this.publishers = Collections.synchronizedMap(new IdentityHashMap<WeakReference<KafkaPublisher>, Cancellable>()); |
| this.referenceQueue = new ReferenceQueue<KafkaPublisher>(); |
| this.consumer = new SimpleKafkaConsumer(brokerService); |
| } |
| |
| @Override |
| public KafkaPublisher getPublisher(KafkaPublisher.Ack ack, Compression compression) { |
| Preconditions.checkState(isRunning(), "Service is not running."); |
| |
| // Wrap the publisher with a weak reference and save the cancellable for closing the publisher. |
| SimpleKafkaPublisher publisher = new SimpleKafkaPublisher(brokerService, ack, compression); |
| publishers.put(new WeakReference<KafkaPublisher>(publisher, referenceQueue), publisher.start()); |
| return publisher; |
| } |
| |
| @Override |
| public KafkaConsumer getConsumer() { |
| Preconditions.checkState(isRunning(), "Service is not running."); |
| return consumer; |
| } |
| |
| @Override |
| public void run() { |
| // For calling publisher.producer.close() on garbage collected |
| Reference<? extends KafkaPublisher> ref = referenceQueue.poll(); |
| while (ref != null && isRunning()) { |
| publishers.remove(ref).cancel(); |
| ref = referenceQueue.poll(); |
| } |
| } |
| |
| @Override |
| protected void startUp() throws Exception { |
| scheduler = Executors.newSingleThreadScheduledExecutor(Threads.createDaemonThreadFactory("kafka-client-cleanup")); |
| scheduler.scheduleAtFixedRate(this, PUBLISHER_CLEANUP_SECONDS, PUBLISHER_CLEANUP_SECONDS, TimeUnit.SECONDS); |
| |
| // Start broker service to get auto-updated brokers information. |
| brokerService.startAndWait(); |
| } |
| |
| @Override |
| protected void shutDown() throws Exception { |
| LOG.info("Stopping KafkaClientService"); |
| scheduler.shutdownNow(); |
| for (Cancellable cancellable : publishers.values()) { |
| cancellable.cancel(); |
| } |
| consumer.stop(); |
| |
| brokerService.stopAndWait(); |
| LOG.info("KafkaClientService stopped"); |
| } |
| } |