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 ApplicationRebalanceListener implements PollIntervalAwareConsumerRebalanceListener
19 private final ApplicationRecordHandler recordHandler;
20 private final StateRepository stateRepository;
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, Long> consumer;
27 private Instant lastCommit = Instant.EPOCH;
30 public void onPartitionsAssigned(Collection<TopicPartition> partitions)
32 partitions.forEach(tp ->
34 Integer partition = tp.partition();
35 StateDocument document =
37 .findById(Integer.toString(partition))
38 .orElse(new StateDocument(partition));
39 log.info("{} - adding partition: {}, offset={}", id, partition, document.offset);
40 if (document.offset >= 0)
42 // Only seek, if a stored offset was found
43 // Otherwise: Use initial offset, generated by Kafka
44 consumer.seek(tp, document.offset);
46 recordHandler.addPartition(partition, document.state);
51 public void onPartitionsRevoked(Collection<TopicPartition> partitions)
53 partitions.forEach(tp ->
55 Integer partition = tp.partition();
56 Long offset = consumer.position(tp);
58 "{} - removing partition: {}, offset of next message {})",
62 Map<String, Long> removed = recordHandler.removePartition(partition);
63 stateRepository.save(new StateDocument(partition, removed, offset));
69 public void beforeNextPoll()
71 if (lastCommit.plus(commitInterval).isBefore(clock.instant()))
73 log.debug("Storing data and offsets, last commit: {}", lastCommit);
74 recordHandler.getState().forEach((partiton, state) -> stateRepository.save(
78 consumer.position(new TopicPartition(topic, partiton)))));
79 lastCommit = clock.instant();