X-Git-Url: https://juplo.de/gitweb/?a=blobdiff_plain;f=src%2Fmain%2Fjava%2Fde%2Fjuplo%2Fkafka%2FApplicationRebalanceListener.java;fp=src%2Fmain%2Fjava%2Fde%2Fjuplo%2Fkafka%2FApplicationRebalanceListener.java;h=247b6f780667e85d676cb4f7f4f9d5e8c4f286a2;hb=706220a34eeecd09bd1d5dfa967be9e110b44a99;hp=0000000000000000000000000000000000000000;hpb=bf99986fe3daf527d93d444ce1ae7374a8faddcc;p=demos%2Fkafka%2Ftraining

diff --git a/src/main/java/de/juplo/kafka/ApplicationRebalanceListener.java b/src/main/java/de/juplo/kafka/ApplicationRebalanceListener.java
new file mode 100644
index 0000000..247b6f7
--- /dev/null
+++ b/src/main/java/de/juplo/kafka/ApplicationRebalanceListener.java
@@ -0,0 +1,76 @@
+package de.juplo.kafka;
+
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.kafka.common.TopicPartition;
+
+import java.time.Clock;
+import java.time.Duration;
+import java.time.Instant;
+import java.util.Collection;
+import java.util.Map;
+
+
+@RequiredArgsConstructor
+@Slf4j
+public class ApplicationRebalanceListener implements PollIntervalAwareConsumerRebalanceListener
+{
+  private final ApplicationRecordHandler recordHandler;
+  private final StateRepository stateRepository;
+  private final String id;
+  private final Clock clock;
+  private final Duration commitInterval;
+
+  private Instant lastCommit = Instant.EPOCH;
+
+  @Override
+  public void onPartitionsAssigned(Collection<TopicPartition> partitions)
+  {
+    partitions.forEach(tp ->
+    {
+      Integer partition = tp.partition();
+      log.info("{} - adding partition: {}", id, partition);
+      StateDocument document =
+          stateRepository
+              .findById(Integer.toString(partition))
+              .orElse(new StateDocument(partition));
+      recordHandler.addPartition(partition, document.state);
+    });
+  }
+
+  @Override
+  public void onPartitionsRevoked(Collection<TopicPartition> partitions)
+  {
+    partitions.forEach(tp ->
+    {
+      Integer partition = tp.partition();
+      log.info("{} - removing partition: {}", id, partition);
+      Map<String, Long> removed = recordHandler.removePartition(partition);
+      for (String key : removed.keySet())
+      {
+        log.info(
+            "{} - Seen {} messages for partition={}|key={}",
+            id,
+            removed.get(key),
+            partition,
+            key);
+      }
+      stateRepository.save(new StateDocument(partition, removed));
+    });
+  }
+
+
+  @Override
+  public void beforeNextPoll()
+  {
+    if (lastCommit.plus(commitInterval).isBefore(clock.instant()))
+    {
+      log.debug("Storing data, last commit: {}", lastCommit);
+      recordHandler.getState().forEach((partiton, statistics) -> stateRepository.save(
+          new StateDocument(
+              partiton,
+              statistics)));
+      lastCommit = clock.instant();
+    }
+  }
+}