X-Git-Url: https://juplo.de/gitweb/?a=blobdiff_plain;f=src%2Fmain%2Fjava%2Fde%2Fjuplo%2Fkafka%2FApplicationRebalanceListener.java;h=b517d3574efc3b2c4b0c022c9f78a60e7084fe44;hb=a4bbf334910cb37fabadb720cd0ee7f2a21ecaa7;hp=6d3850f677b33e8ad71695527ac9386e3e42c1fd;hpb=2d25525ef70a90709edc48bd9542d1b08a2888a2;p=demos%2Fkafka%2Ftraining

diff --git a/src/main/java/de/juplo/kafka/ApplicationRebalanceListener.java b/src/main/java/de/juplo/kafka/ApplicationRebalanceListener.java
index 6d3850f..b517d35 100644
--- a/src/main/java/de/juplo/kafka/ApplicationRebalanceListener.java
+++ b/src/main/java/de/juplo/kafka/ApplicationRebalanceListener.java
@@ -2,7 +2,7 @@ package de.juplo.kafka;
 
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
-import org.apache.kafka.clients.consumer.ConsumerRebalanceListener;
+import org.apache.kafka.clients.consumer.Consumer;
 import org.apache.kafka.common.TopicPartition;
 
 import java.time.Clock;
@@ -13,15 +13,22 @@ import java.util.*;
 
 @RequiredArgsConstructor
 @Slf4j
-public class ApplicationRebalanceListener implements ConsumerRebalanceListener
+public class ApplicationRebalanceListener implements PollIntervalAwareConsumerRebalanceListener
 {
   private final ApplicationRecordHandler recordHandler;
   private final AdderResults adderResults;
   private final StateRepository stateRepository;
   private final String id;
+  private final String topic;
+  private final Clock clock;
+  private final Duration commitInterval;
+  private final Consumer consumer;
 
   private final Set<Integer> partitions = new HashSet<>();
 
+  private Instant lastCommit = Instant.EPOCH;
+  private boolean commitsEnabled = true;
+
   @Override
   public void onPartitionsAssigned(Collection<TopicPartition> partitions)
   {
@@ -34,6 +41,17 @@ public class ApplicationRebalanceListener implements ConsumerRebalanceListener
           stateRepository
               .findById(Integer.toString(partition))
               .orElse(new StateDocument(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);
+        log.info(
+            "{} - Seeking to offset {} for partition {}",
+            id,
+            document.offset,
+            partition);
+      }
       recordHandler.addPartition(partition, document.state);
       for (String user : document.state.keySet())
       {
@@ -56,18 +74,66 @@ public class ApplicationRebalanceListener implements ConsumerRebalanceListener
       Integer partition = tp.partition();
       log.info("{} - removing partition: {}", id, partition);
       this.partitions.remove(partition);
-      Map<String, AdderResult> state = recordHandler.removePartition(partition);
-      for (String user : state.keySet())
+      Long offset = consumer.position(tp);
+      if (commitsEnabled)
       {
         log.info(
-            "{} - Saved state for partition={}|user={}: {}",
+            "{} - Storing {} as offset of next message for partition {}",
             id,
-            partition,
-            user,
-            state.get(user));
+            offset,
+            partition);
+        Map<String, AdderResult> state = recordHandler.removePartition(partition);
+        for (String user : state.keySet())
+        {
+          log.info(
+              "{} - Saved state for partition={}|user={}: {}",
+              id,
+              partition,
+              user,
+              state.get(user));
+        }
+        Map<String, List<AdderResult>> results = adderResults.removePartition(partition);
+        stateRepository.save(new StateDocument(partition, state, results, offset));
+      }
+      else
+      {
+        log.info("Offset commits are disabled! Last commit: {}", lastCommit);
       }
-      Map<String, List<AdderResult>> results = adderResults.removePartition(partition);
-      stateRepository.save(new StateDocument(partition, state, results));
     });
   }
+
+
+  @Override
+  public void beforeNextPoll()
+  {
+    if (!commitsEnabled)
+    {
+      log.info("Offset commits are disabled! Last commit: {}", lastCommit);
+      return;
+    }
+
+    if (lastCommit.plus(commitInterval).isBefore(clock.instant()))
+    {
+      log.debug("Storing data and offsets, last commit: {}", lastCommit);
+      partitions.forEach(partition -> stateRepository.save(
+          new StateDocument(
+              partition,
+              recordHandler.getState(partition).getState(),
+              adderResults.getState(partition),
+              consumer.position(new TopicPartition(topic, partition)))));
+      lastCommit = clock.instant();
+    }
+  }
+
+  @Override
+  public void enableCommits()
+  {
+    commitsEnabled = true;
+  }
+
+  @Override
+  public void disableCommits()
+  {
+    commitsEnabled = false;
+  }
 }