feat: The position of the last seen messages is stored on a revoke

[demos/kafka/chat] / src / main / java / de / juplo / kafka / chat / backend / implementation / kafka / DataChannel.java

diff --git a/src/main/java/de/juplo/kafka/chat/backend/implementation/kafka/DataChannel.java b/src/main/java/de/juplo/kafka/chat/backend/implementation/kafka/DataChannel.java
index 2fa4998..2c3e60a 100644 (file)
--- a/src/main/java/de/juplo/kafka/chat/backend/implementation/kafka/DataChannel.java
+++ b/src/main/java/de/juplo/kafka/chat/backend/implementation/kafka/DataChannel.java
@@ -147,11 +147,16 @@ public class DataChannel implements Runnable, ConsumerRebalanceListener
       infoChannel.sendShardAssignedEvent(partition);
       shardingPublisherStrategy
           .publishOwnership(partition)
-          .doOnNext(instanceId -> log.info(
-              "Instance {} was published as owner of shard {}",
+          .doOnSuccess(instanceId -> log.info(
+              "Successfully published instance {} as owner of shard {}",
               instanceId,
               partition))
-          .subscribe();
+          .doOnError(throwable -> log.error(
+              "Could not publish instance {} as owner of shard {}: {}",
+              instanceId,
+              partition,
+              throwable))
+          .block();
     });
 
     consumer.resume(partitions);
@@ -164,6 +169,7 @@ public class DataChannel implements Runnable, ConsumerRebalanceListener
     {
       int partition = topicPartition.partition();
       isShardOwned[partition] = false;
+      nextOffset[partition] = consumer.position(topicPartition);
       log.info("Partition revoked: {} - next={}", partition, nextOffset[partition]);
       infoChannel.sendShardRevokedEvent(partition);
     });
@@ -266,6 +272,11 @@ public class DataChannel implements Runnable, ConsumerRebalanceListener
     KafkaChatMessageService kafkaChatRoomService =
         (KafkaChatMessageService) chatRoomData.getChatRoomService();
 
+    log.debug(
+        "Loaded message from partition={} at offset={}: {}",
+        partition,
+        offset,
+        message);
     kafkaChatRoomService.persistMessage(message);
   }
 
@@ -274,7 +285,12 @@ public class DataChannel implements Runnable, ConsumerRebalanceListener
     return IntStream
         .range(0, numShards)
         .filter(shard -> isShardOwned[shard])
-        .allMatch(shard -> nextOffset[shard] >= currentOffset[shard]);
+        .allMatch(shard ->
+        {
+          TopicPartition partition = new TopicPartition(topic, shard);
+          long position = consumer.position(partition);
+          return position >= currentOffset[shard];
+        });
   }
 
   private void pauseAllOwnedPartions()