</parent>
<groupId>de.juplo.kafka</groupId>
- <artifactId>endless-consumer</artifactId>
+ <artifactId>wordcount</artifactId>
<version>1.0-SNAPSHOT</version>
- <name>Endless Consumer: a Simple Consumer-Group that reads and prints the topic and counts the received messages for each key by topic</name>
+ <name>Wordcount</name>
+ <description>Splits the incomming sentences into words and counts the words per user.</description>
<dependencies>
<dependency>
public class Application implements ApplicationRunner
{
@Autowired
- EndlessConsumer endlessConsumer;
+ Wordcount wordcount;
@Autowired
ExecutorService executor;
public void run(ApplicationArguments args) throws Exception
{
log.info("Starting EndlessConsumer");
- endlessConsumer.start();
+ wordcount.start();
}
@PreDestroy
try
{
log.info("Stopping EndlessConsumer");
- endlessConsumer.stop();
+ wordcount.stop();
}
catch (IllegalStateException e)
{
}
@Bean
- public EndlessConsumer<String, String> endlessConsumer(
+ public Wordcount<String, String> endlessConsumer(
KafkaConsumer<String, String> kafkaConsumer,
ExecutorService executor,
Consumer<ConsumerRecord<String, String>> handler,
ApplicationProperties properties)
{
return
- new EndlessConsumer<>(
+ new Wordcount<>(
executor,
repository,
properties.getClientId(),
@RequiredArgsConstructor
public class ApplicationHealthIndicator implements HealthIndicator
{
- private final EndlessConsumer<String, String> consumer;
+ private final Wordcount<?,?> wordcount;
@Override
{
try
{
- return consumer
+ return wordcount
.exitStatus()
.map(Health::down)
.orElse(Health.outOfService())
@RequiredArgsConstructor
public class DriverController
{
- private final EndlessConsumer consumer;
+ private final Wordcount consumer;
@PostMapping("start")
+++ /dev/null
-package de.juplo.kafka;
-
-import lombok.RequiredArgsConstructor;
-import lombok.extern.slf4j.Slf4j;
-import org.apache.kafka.clients.consumer.*;
-import org.apache.kafka.common.TopicPartition;
-import org.apache.kafka.common.errors.RecordDeserializationException;
-import org.apache.kafka.common.errors.WakeupException;
-
-import javax.annotation.PreDestroy;
-import java.time.Clock;
-import java.time.Duration;
-import java.time.Instant;
-import java.util.*;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.locks.Condition;
-import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReentrantLock;
-
-
-@Slf4j
-@RequiredArgsConstructor
-public class EndlessConsumer<K, V> implements ConsumerRebalanceListener, Runnable
-{
- private final ExecutorService executor;
- private final PartitionStatisticsRepository repository;
- private final String id;
- private final String topic;
- private final Clock clock;
- private final Duration commitInterval;
- private final Consumer<K, V> consumer;
- private final java.util.function.Consumer<ConsumerRecord<K, V>> handler;
-
- private final Lock lock = new ReentrantLock();
- private final Condition condition = lock.newCondition();
- private boolean running = false;
- private Exception exception;
- private long consumed = 0;
-
- private final Map<Integer, Map<String, Long>> seen = new HashMap<>();
-
-
- @Override
- public void onPartitionsRevoked(Collection<TopicPartition> partitions)
- {
- partitions.forEach(tp ->
- {
- Integer partition = tp.partition();
- Long newOffset = consumer.position(tp);
- log.info(
- "{} - removing partition: {}, offset of next message {})",
- id,
- partition,
- newOffset);
- Map<String, Long> removed = seen.remove(partition);
- for (String key : removed.keySet())
- {
- log.info(
- "{} - Seen {} messages for partition={}|key={}",
- id,
- removed.get(key),
- partition,
- key);
- }
- repository.save(new StatisticsDocument(partition, removed, consumer.position(tp)));
- });
- }
-
- @Override
- public void onPartitionsAssigned(Collection<TopicPartition> partitions)
- {
- partitions.forEach(tp ->
- {
- Integer partition = tp.partition();
- Long offset = consumer.position(tp);
- log.info("{} - adding partition: {}, offset={}", id, partition, offset);
- StatisticsDocument document =
- repository
- .findById(Integer.toString(partition))
- .orElse(new StatisticsDocument(partition));
- if (document.offset >= 0)
- {
- // Only seek, if a stored offset was found
- // Otherwise: Use initial offset, generated by Kafka
- consumer.seek(tp, document.offset);
- }
- seen.put(partition, document.statistics);
- });
- }
-
-
- @Override
- public void run()
- {
- try
- {
- log.info("{} - Subscribing to topic {}", id, topic);
- consumer.subscribe(Arrays.asList(topic), this);
-
- Instant lastCommit = clock.instant();
-
- while (true)
- {
- ConsumerRecords<K, V> records =
- consumer.poll(Duration.ofSeconds(1));
-
- // Do something with the data...
- log.info("{} - Received {} messages", id, records.count());
- for (ConsumerRecord<K, V> record : records)
- {
- log.info(
- "{} - {}: {}/{} - {}={}",
- id,
- record.offset(),
- record.topic(),
- record.partition(),
- record.key(),
- record.value()
- );
-
- handler.accept(record);
-
- consumed++;
-
- Integer partition = record.partition();
- String key = record.key() == null ? "NULL" : record.key().toString();
- Map<String, Long> byKey = seen.get(partition);
-
- if (!byKey.containsKey(key))
- byKey.put(key, 0l);
-
- long seenByKey = byKey.get(key);
- seenByKey++;
- byKey.put(key, seenByKey);
- }
-
- if (lastCommit.plus(commitInterval).isBefore(clock.instant()))
- {
- log.debug("Storing data and offsets, last commit: {}", lastCommit);
- seen.forEach((partiton, statistics) -> repository.save(
- new StatisticsDocument(
- partiton,
- statistics,
- consumer.position(new TopicPartition(topic, partiton)))));
- lastCommit = clock.instant();
- }
- }
- }
- catch(WakeupException e)
- {
- log.info("{} - RIIING! Request to stop consumption - commiting current offsets!", id);
- shutdown();
- }
- catch(RecordDeserializationException e)
- {
- TopicPartition tp = e.topicPartition();
- long offset = e.offset();
- log.error(
- "{} - Could not deserialize message on topic {} with offset={}: {}",
- id,
- tp,
- offset,
- e.getCause().toString());
-
- shutdown(e);
- }
- catch(Exception e)
- {
- log.error("{} - Unexpected error: {}", id, e.toString(), e);
- shutdown(e);
- }
- finally
- {
- log.info("{} - Consumer-Thread exiting", id);
- }
- }
-
- private void shutdown()
- {
- shutdown(null);
- }
-
- private void shutdown(Exception e)
- {
- lock.lock();
- try
- {
- try
- {
- log.info("{} - Unsubscribing from topic {}", id, topic);
- consumer.unsubscribe();
- }
- catch (Exception ue)
- {
- log.error(
- "{} - Error while unsubscribing from topic {}: {}",
- id,
- topic,
- ue.toString());
- }
- finally
- {
- running = false;
- exception = e;
- condition.signal();
- }
- }
- finally
- {
- lock.unlock();
- }
- }
-
- public Map<Integer, Map<String, Long>> getSeen()
- {
- return seen;
- }
-
- public void start()
- {
- lock.lock();
- try
- {
- if (running)
- throw new IllegalStateException("Consumer instance " + id + " is already running!");
-
- log.info("{} - Starting - consumed {} messages before", id, consumed);
- running = true;
- exception = null;
- executor.submit(this);
- }
- finally
- {
- lock.unlock();
- }
- }
-
- public synchronized void stop() throws InterruptedException
- {
- lock.lock();
- try
- {
- if (!running)
- throw new IllegalStateException("Consumer instance " + id + " is not running!");
-
- log.info("{} - Stopping", id);
- consumer.wakeup();
- condition.await();
- log.info("{} - Stopped - consumed {} messages so far", id, consumed);
- }
- finally
- {
- lock.unlock();
- }
- }
-
- @PreDestroy
- public void destroy() throws ExecutionException, InterruptedException
- {
- log.info("{} - Destroy!", id);
- log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
- }
-
- public boolean running()
- {
- lock.lock();
- try
- {
- return running;
- }
- finally
- {
- lock.unlock();
- }
- }
-
- public Optional<Exception> exitStatus()
- {
- lock.lock();
- try
- {
- if (running)
- throw new IllegalStateException("No exit-status available: Consumer instance " + id + " is running!");
-
- return Optional.ofNullable(exception);
- }
- finally
- {
- lock.unlock();
- }
- }
-}
--- /dev/null
+package de.juplo.kafka;
+
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.kafka.clients.consumer.*;
+import org.apache.kafka.common.TopicPartition;
+import org.apache.kafka.common.errors.RecordDeserializationException;
+import org.apache.kafka.common.errors.WakeupException;
+
+import javax.annotation.PreDestroy;
+import java.time.Clock;
+import java.time.Duration;
+import java.time.Instant;
+import java.util.*;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+
+@Slf4j
+@RequiredArgsConstructor
+public class Wordcount<K, V> implements ConsumerRebalanceListener, Runnable
+{
+ private final ExecutorService executor;
+ private final PartitionStatisticsRepository repository;
+ private final String id;
+ private final String topic;
+ private final Clock clock;
+ private final Duration commitInterval;
+ private final Consumer<K, V> consumer;
+ private final java.util.function.Consumer<ConsumerRecord<K, V>> handler;
+
+ private final Lock lock = new ReentrantLock();
+ private final Condition condition = lock.newCondition();
+ private boolean running = false;
+ private Exception exception;
+ private long consumed = 0;
+
+ private final Map<Integer, Map<String, Long>> seen = new HashMap<>();
+
+
+ @Override
+ public void onPartitionsRevoked(Collection<TopicPartition> partitions)
+ {
+ partitions.forEach(tp ->
+ {
+ Integer partition = tp.partition();
+ Long newOffset = consumer.position(tp);
+ log.info(
+ "{} - removing partition: {}, offset of next message {})",
+ id,
+ partition,
+ newOffset);
+ Map<String, Long> removed = seen.remove(partition);
+ for (String key : removed.keySet())
+ {
+ log.info(
+ "{} - Seen {} messages for partition={}|key={}",
+ id,
+ removed.get(key),
+ partition,
+ key);
+ }
+ repository.save(new StatisticsDocument(partition, removed, consumer.position(tp)));
+ });
+ }
+
+ @Override
+ public void onPartitionsAssigned(Collection<TopicPartition> partitions)
+ {
+ partitions.forEach(tp ->
+ {
+ Integer partition = tp.partition();
+ Long offset = consumer.position(tp);
+ log.info("{} - adding partition: {}, offset={}", id, partition, offset);
+ StatisticsDocument document =
+ repository
+ .findById(Integer.toString(partition))
+ .orElse(new StatisticsDocument(partition));
+ if (document.offset >= 0)
+ {
+ // Only seek, if a stored offset was found
+ // Otherwise: Use initial offset, generated by Kafka
+ consumer.seek(tp, document.offset);
+ }
+ seen.put(partition, document.statistics);
+ });
+ }
+
+
+ @Override
+ public void run()
+ {
+ try
+ {
+ log.info("{} - Subscribing to topic {}", id, topic);
+ consumer.subscribe(Arrays.asList(topic), this);
+
+ Instant lastCommit = clock.instant();
+
+ while (true)
+ {
+ ConsumerRecords<K, V> records =
+ consumer.poll(Duration.ofSeconds(1));
+
+ // Do something with the data...
+ log.info("{} - Received {} messages", id, records.count());
+ for (ConsumerRecord<K, V> record : records)
+ {
+ log.info(
+ "{} - {}: {}/{} - {}={}",
+ id,
+ record.offset(),
+ record.topic(),
+ record.partition(),
+ record.key(),
+ record.value()
+ );
+
+ handler.accept(record);
+
+ consumed++;
+
+ Integer partition = record.partition();
+ String key = record.key() == null ? "NULL" : record.key().toString();
+ Map<String, Long> byKey = seen.get(partition);
+
+ if (!byKey.containsKey(key))
+ byKey.put(key, 0l);
+
+ long seenByKey = byKey.get(key);
+ seenByKey++;
+ byKey.put(key, seenByKey);
+ }
+
+ if (lastCommit.plus(commitInterval).isBefore(clock.instant()))
+ {
+ log.debug("Storing data and offsets, last commit: {}", lastCommit);
+ seen.forEach((partiton, statistics) -> repository.save(
+ new StatisticsDocument(
+ partiton,
+ statistics,
+ consumer.position(new TopicPartition(topic, partiton)))));
+ lastCommit = clock.instant();
+ }
+ }
+ }
+ catch(WakeupException e)
+ {
+ log.info("{} - RIIING! Request to stop consumption - commiting current offsets!", id);
+ shutdown();
+ }
+ catch(RecordDeserializationException e)
+ {
+ TopicPartition tp = e.topicPartition();
+ long offset = e.offset();
+ log.error(
+ "{} - Could not deserialize message on topic {} with offset={}: {}",
+ id,
+ tp,
+ offset,
+ e.getCause().toString());
+
+ shutdown(e);
+ }
+ catch(Exception e)
+ {
+ log.error("{} - Unexpected error: {}", id, e.toString(), e);
+ shutdown(e);
+ }
+ finally
+ {
+ log.info("{} - Consumer-Thread exiting", id);
+ }
+ }
+
+ private void shutdown()
+ {
+ shutdown(null);
+ }
+
+ private void shutdown(Exception e)
+ {
+ lock.lock();
+ try
+ {
+ try
+ {
+ log.info("{} - Unsubscribing from topic {}", id, topic);
+ consumer.unsubscribe();
+ }
+ catch (Exception ue)
+ {
+ log.error(
+ "{} - Error while unsubscribing from topic {}: {}",
+ id,
+ topic,
+ ue.toString());
+ }
+ finally
+ {
+ running = false;
+ exception = e;
+ condition.signal();
+ }
+ }
+ finally
+ {
+ lock.unlock();
+ }
+ }
+
+ public Map<Integer, Map<String, Long>> getSeen()
+ {
+ return seen;
+ }
+
+ public void start()
+ {
+ lock.lock();
+ try
+ {
+ if (running)
+ throw new IllegalStateException("Consumer instance " + id + " is already running!");
+
+ log.info("{} - Starting - consumed {} messages before", id, consumed);
+ running = true;
+ exception = null;
+ executor.submit(this);
+ }
+ finally
+ {
+ lock.unlock();
+ }
+ }
+
+ public synchronized void stop() throws InterruptedException
+ {
+ lock.lock();
+ try
+ {
+ if (!running)
+ throw new IllegalStateException("Consumer instance " + id + " is not running!");
+
+ log.info("{} - Stopping", id);
+ consumer.wakeup();
+ condition.await();
+ log.info("{} - Stopped - consumed {} messages so far", id, consumed);
+ }
+ finally
+ {
+ lock.unlock();
+ }
+ }
+
+ @PreDestroy
+ public void destroy() throws ExecutionException, InterruptedException
+ {
+ log.info("{} - Destroy!", id);
+ log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
+ }
+
+ public boolean running()
+ {
+ lock.lock();
+ try
+ {
+ return running;
+ }
+ finally
+ {
+ lock.unlock();
+ }
+ }
+
+ public Optional<Exception> exitStatus()
+ {
+ lock.lock();
+ try
+ {
+ if (running)
+ throw new IllegalStateException("No exit-status available: Consumer instance " + id + " is running!");
+
+ return Optional.ofNullable(exception);
+ }
+ finally
+ {
+ lock.unlock();
+ }
+ }
+}
projects / demos / kafka / training / commitdiff