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;
14 @RequiredArgsConstructor
16 public class SumRebalanceListener implements PollIntervalAwareConsumerRebalanceListener
18 private final SumRecordHandler handler;
19 private final PartitionStatisticsRepository repository;
20 private final String id;
21 private final String topic;
22 private final Clock clock;
23 private final Duration commitInterval;
24 private final Consumer<String, String> consumer;
26 private Instant lastCommit = Instant.EPOCH;
29 public void onPartitionsAssigned(Collection<TopicPartition> partitions)
31 partitions.forEach(tp ->
33 Integer partition = tp.partition();
34 Long offset = consumer.position(tp);
35 log.info("{} - adding partition: {}, offset={}", id, partition, offset);
36 StateDocument document =
38 .findById(Integer.toString(partition))
39 .orElse(new StateDocument(partition));
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 handler.addPartition(partition, document.state);
51 public void onPartitionsRevoked(Collection<TopicPartition> partitions)
53 partitions.forEach(tp ->
55 Integer partition = tp.partition();
56 Long newOffset = consumer.position(tp);
58 "{} - removing partition: {}, offset of next message {})",
62 repository.save(new StateDocument(partition, handler.removePartition(partition), newOffset));
68 public void beforeNextPoll()
70 if (lastCommit.plus(commitInterval).isBefore(clock.instant()))
72 log.debug("Storing data and offsets, last commit: {}", lastCommit);
73 handler.getState().forEach((partiton, sumBusinessLogic) -> repository.save(
76 sumBusinessLogic.getState(),
77 consumer.position(new TopicPartition(topic, partiton)))));
78 lastCommit = clock.instant();