package de.juplo.kafka;
import lombok.extern.slf4j.Slf4j;
+import org.apache.kafka.clients.consumer.ConsumerRebalanceListener;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
+import org.apache.kafka.common.TopicPartition;
import org.apache.kafka.common.errors.WakeupException;
import org.apache.kafka.common.serialization.StringDeserializer;
+import javax.annotation.PreDestroy;
import java.time.Duration;
-import java.util.Arrays;
-import java.util.Properties;
-import java.util.concurrent.locks.Condition;
-import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReentrantLock;
+import java.util.*;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Future;
+import java.util.concurrent.atomic.AtomicBoolean;
@Slf4j
-public class SimpleConsumer
+public class EndlessConsumer implements Runnable
{
+ private final ExecutorService executor;
+ private final PartitionStatisticsRepository repository;
+ private final String bootstrapServer;
+ private final String groupId;
+ private final String id;
+ private final String topic;
+ private final String autoOffsetReset;
+
+ private AtomicBoolean running = new AtomicBoolean();
private long consumed = 0;
- private KafkaConsumer<String, String> consumer;
- private Lock lock = new ReentrantLock();
- private Condition stopped = lock.newCondition();
+ private KafkaConsumer<String, String> consumer = null;
+ private Future<?> future = null;
+ private final Map<Integer, Map<String, Integer>> seen = new HashMap<>();
- public SimpleConsumer()
+
+ public EndlessConsumer(
+ ExecutorService executor,
+ PartitionStatisticsRepository repository,
+ String bootstrapServer,
+ String groupId,
+ String clientId,
+ String topic,
+ String autoOffsetReset)
{
- // tag::create[]
- Properties props = new Properties();
- props.put("bootstrap.servers", ":9092");
- props.put("group.id", "my-consumer"); // << Used for Offset-Commits
- // end::create[]
- props.put("auto.offset.reset", "earliest");
- // tag::create[]
- props.put("key.deserializer", StringDeserializer.class.getName());
- props.put("value.deserializer", StringDeserializer.class.getName());
-
- KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
- // end::create[]
- this.consumer = consumer;
+ this.executor = executor;
+ this.repository = repository;
+ this.bootstrapServer = bootstrapServer;
+ this.groupId = groupId;
+ this.id = clientId;
+ this.topic = topic;
+ this.autoOffsetReset = autoOffsetReset;
}
-
+ @Override
public void run()
{
- String id = "C";
-
try
{
- log.info("{} - Subscribing to topic test", id);
- consumer.subscribe(Arrays.asList("test"));
+ Properties props = new Properties();
+ props.put("bootstrap.servers", bootstrapServer);
+ props.put("group.id", groupId);
+ props.put("client.id", id);
+ props.put("auto.offset.reset", autoOffsetReset);
+ props.put("metadata.max.age.ms", "1000");
+ props.put("key.deserializer", StringDeserializer.class.getName());
+ props.put("value.deserializer", StringDeserializer.class.getName());
+
+ this.consumer = new KafkaConsumer<>(props);
+
+ log.info("{} - Subscribing to topic {}", id, topic);
+ consumer.subscribe(Arrays.asList(topic), new ConsumerRebalanceListener()
+ {
+ @Override
+ public void onPartitionsRevoked(Collection<TopicPartition> partitions)
+ {
+ partitions.forEach(tp ->
+ {
+ log.info("{} - removing partition: {}", id, tp);
+ Map<String, Integer> removed = seen.remove(tp.partition());
+ for (String key : removed.keySet())
+ {
+ log.info(
+ "{} - Seen {} messages for partition={}|key={}",
+ id,
+ removed.get(key),
+ tp.partition(),
+ key);
+ }
+ repository.save(new StatisticsDocument(tp.partition(), removed));
+ });
+ }
+
+ @Override
+ public void onPartitionsAssigned(Collection<TopicPartition> partitions)
+ {
+ partitions.forEach(tp ->
+ {
+ log.info("{} - adding partition: {}", id, tp);
+ seen.put(
+ tp.partition(),
+ repository
+ .findById(Integer.toString(tp.partition()))
+ .map(document -> document.statistics)
+ .orElse(new HashMap<>()));
+ });
+ }
+ });
- // tag::loop[]
while (true)
{
ConsumerRecords<String, String> records =
consumer.poll(Duration.ofSeconds(1));
// Do something with the data...
- // end::loop[]
log.info("{} - Received {} messages", id, records.count());
for (ConsumerRecord<String, String> record : records)
{
record.key(),
record.value()
);
+
+ Integer partition = record.partition();
+ String key = record.key() == null ? "NULL" : record.key();
+ Map<String, Integer> byKey = seen.get(partition);
+
+ if (!byKey.containsKey(key))
+ byKey.put(key, 0);
+
+ int seenByKey = byKey.get(key);
+ seenByKey++;
+ byKey.put(key, seenByKey);
}
- // tag::loop[]
}
- // end::loop[]
}
catch(WakeupException e)
{
}
catch(Exception e)
{
- log.error("{} - Unexpected error: {}", id, e.toString());
+ log.error("{} - Unexpected error: {}", id, e.toString(), e);
+ running.set(false); // Mark the instance as not running
}
finally
{
- this.lock.lock();
- try
- {
- log.info("{} - Closing the KafkaConsumer", id);
- consumer.close();
- log.info("C - DONE!");
- stopped.signal();
- }
- finally
- {
- this.lock.unlock();
- log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
- }
+ log.info("{} - Closing the KafkaConsumer", id);
+ consumer.close();
+ log.info("{} - Consumer-Thread exiting", id);
}
}
+ public Map<Integer, Map<String, Integer>> getSeen()
+ {
+ return seen;
+ }
- public static void main(String[] args) throws Exception
+ public synchronized void start()
{
- SimpleConsumer instance = new SimpleConsumer();
+ boolean stateChanged = running.compareAndSet(false, true);
+ if (!stateChanged)
+ throw new RuntimeException("Consumer instance " + id + " is already running!");
- Runtime.getRuntime().addShutdownHook(new Thread(() ->
- {
- instance.lock.lock();
- try
- {
- instance.consumer.wakeup();
- instance.stopped.await();
- }
- catch (InterruptedException e)
- {
- log.warn("Interrrupted while waiting for the consumer to stop!", e);
- }
- finally
- {
- instance.lock.unlock();
- }
- }));
+ log.info("{} - Starting - consumed {} messages before", id, consumed);
+ future = executor.submit(this);
+ }
+
+ public synchronized void stop() throws ExecutionException, InterruptedException
+ {
+ boolean stateChanged = running.compareAndSet(true, false);
+ if (!stateChanged)
+ throw new RuntimeException("Consumer instance " + id + " is not running!");
+
+ log.info("{} - Stopping", id);
+ consumer.wakeup();
+ future.get();
+ log.info("{} - Stopped - consumed {} messages so far", id, consumed);
+ }
- instance.run();
+ @PreDestroy
+ public void destroy() throws ExecutionException, InterruptedException
+ {
+ log.info("{} - Destroy!", id);
+ try
+ {
+ stop();
+ }
+ catch (IllegalStateException e)
+ {
+ log.info("{} - Was already stopped", id);
+ }
+ finally
+ {
+ log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
+ }
}
}
projects / demos / kafka / training / blobdiff