1 package de.juplo.kafka;
3 import lombok.RequiredArgsConstructor;
4 import lombok.extern.slf4j.Slf4j;
5 import org.apache.kafka.clients.consumer.Consumer;
6 import org.apache.kafka.common.TopicPartition;
8 import java.time.Clock;
9 import java.time.Duration;
10 import java.time.Instant;
11 import java.util.Collection;
15 @RequiredArgsConstructor
17 public class WordcountRebalanceListener implements PollIntervalAwareConsumerRebalanceListener
19 private final WordcountRecordHandler handler;
20 private final PartitionStatisticsRepository repository;
21 private final String id;
22 private final String topic;
23 private final Clock clock;
24 private final Duration commitInterval;
25 private final Consumer<String, String> consumer;
27 private Instant lastCommit = Instant.EPOCH;
30 public void onPartitionsAssigned(Collection<TopicPartition> partitions)
32 partitions.forEach(tp ->
34 Integer partition = tp.partition();
35 Long offset = consumer.position(tp);
36 log.info("{} - adding partition: {}, offset={}", id, partition, offset);
37 StatisticsDocument document =
39 .findById(Integer.toString(partition))
40 .orElse(new StatisticsDocument(partition));
41 if (document.offset >= 0)
43 // Only seek, if a stored offset was found
44 // Otherwise: Use initial offset, generated by Kafka
45 consumer.seek(tp, document.offset);
47 handler.addPartition(partition, document.statistics);
52 public void onPartitionsRevoked(Collection<TopicPartition> partitions)
54 partitions.forEach(tp ->
56 Integer partition = tp.partition();
57 Long newOffset = consumer.position(tp);
59 "{} - removing partition: {}, offset of next message {})",
63 Map<String, Map<String, Long>> removed = handler.removePartition(partition);
64 repository.save(new StatisticsDocument(partition, removed, consumer.position(tp)));
70 public void beforeNextPoll()
72 if (lastCommit.plus(commitInterval).isBefore(clock.instant()))
74 log.debug("Storing data and offsets, last commit: {}", lastCommit);
75 handler.getSeen().forEach((partiton, statistics) -> repository.save(
76 new StatisticsDocument(
79 consumer.position(new TopicPartition(topic, partiton)))));
80 lastCommit = clock.instant();