Rückbau der Deaktivierung der Commits, um den Code anzugleichen

* Hier wurde die Deaktivierung der Commits im Falle eines Fachlogik-Fehlers
  zurückgebaut, um die einzelnen Schritte der Übung leichter
  nachvollziehbar zu machen.
* Die Deaktivierung der Commits im Falle eines Fachlogik-Fehlers (aka
  Exception in der Fachlogik) ist nötig, da ansonsten in dem Rebalance,
  das durch das `unsubscribe()` ausgelöst wird, die aktuelle
  Offset-Position aus sicht der Kafka-Client-Library commited wird.
* *Dies führt dazu, dass der zugehörige Testfall fehl schlägt*
* Dies würde dann zu einem Verlust von Nachrichten führen, da die
  Client-Bibliothek davon ausgeht, dass alle vom letzten `poll()`
  gelieferten Nachrichten erfolgreich verarbeitet wurden.
* D.h., nach einem Fachlogik-Fehler darf _kein_ Commit über die
  Convenient-Methode des `KafkaConsumer` durchgeführt werden, die
  automatisch die Offsets bestätigt, die die Bibliothek für aktuell
  hält.

diff --git a/README.sh b/README.sh
index 5f11d12..6be4b11 100755 (executable)
--- a/README.sh
+++ b/README.sh
@@ -19,7 +19,7 @@ if [[
 ]]
 then
   docker-compose rm -svf adder-1 adder-2
-  mvn clean install || exit
+  mvn -D skipTests clean install || exit
 else
   echo "Using image existing images:"
   docker image ls $IMAGE

diff --git a/src/main/java/de/juplo/kafka/ApplicationConfiguration.java b/src/main/java/de/juplo/kafka/ApplicationConfiguration.java
index e4ac1ab..9bfd075 100644 (file)
--- a/src/main/java/de/juplo/kafka/ApplicationConfiguration.java
+++ b/src/main/java/de/juplo/kafka/ApplicationConfiguration.java
@@ -7,7 +7,6 @@ import org.springframework.boot.context.properties.EnableConfigurationProperties
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
-import java.time.Clock;
 import java.util.Optional;
 import java.util.Properties;
 import java.util.concurrent.ExecutorService;
@@ -49,8 +48,6 @@ public class ApplicationConfiguration
         stateRepository,
         properties.getClientId(),
         properties.getTopic(),
-        Clock.systemDefaultZone(),
-        properties.getCommitInterval(),
         consumer);
   }
 

diff --git a/src/main/java/de/juplo/kafka/ApplicationRebalanceListener.java b/src/main/java/de/juplo/kafka/ApplicationRebalanceListener.java
index f3e6c8a..3653197 100644 (file)
--- a/src/main/java/de/juplo/kafka/ApplicationRebalanceListener.java
+++ b/src/main/java/de/juplo/kafka/ApplicationRebalanceListener.java
@@ -5,9 +5,6 @@ import lombok.extern.slf4j.Slf4j;
 import org.apache.kafka.clients.consumer.Consumer;
 import org.apache.kafka.common.TopicPartition;
 
-import java.time.Clock;
-import java.time.Duration;
-import java.time.Instant;
 import java.util.*;
 
 
@@ -20,15 +17,10 @@ public class ApplicationRebalanceListener implements RebalanceListener
   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)
   {
@@ -74,31 +66,24 @@ public class ApplicationRebalanceListener implements RebalanceListener
       Integer partition = tp.partition();
       log.info("{} - removing partition: {}", id, partition);
       this.partitions.remove(partition);
-      if (commitsEnabled)
+      Map<String, AdderResult> state = recordHandler.removePartition(partition);
+      Long offset = consumer.position(tp);
+      log.info(
+          "{} - offset of next unseen message for partition {} is {}",
+          id,
+          partition,
+          offset);
+      for (String user : state.keySet())
       {
-        Map<String, AdderResult> state = recordHandler.removePartition(partition);
-        Long offset = consumer.position(tp);
         log.info(
-            "{} - offset of next unseen message for partition {} is {}",
+            "{} - Saved state for partition={}|user={}: {}",
             id,
             partition,
-            offset);
-        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: {}", id, lastCommit);
+            user,
+            state.get(user));
       }
+      Map<String, List<AdderResult>> results = adderResults.removePartition(partition);
+      stateRepository.save(new StateDocument(partition, state, results, offset));
     });
   }
 
@@ -106,52 +91,29 @@ public class ApplicationRebalanceListener implements RebalanceListener
   @Override
   public void beforeNextPoll()
   {
-    if (!commitsEnabled)
-    {
-      log.info("{} - Offset commits are disabled! Last commit: {}", id, lastCommit);
-      return;
-    }
-
-    if (lastCommit.plus(commitInterval).isBefore(clock.instant()))
-    {
-      partitions
-        .stream()
-        .forEach(partition ->
+    partitions
+      .stream()
+      .forEach(partition ->
+      {
+        log.info("{} - persisting state & offset for partition: {}", id, partition);
+        Map<String, AdderResult> state = recordHandler.getState(partition).getState();
+        Long offset = consumer.position(new TopicPartition(topic, partition));
+        log.info(
+          "{} - offset of next unseen message for partition {} is {}",
+          id,
+          partition,
+          offset);
+        for (String user : state.keySet())
         {
-          log.info("{} - persisting state & offset for partition: {}", id, partition);
-          Map<String, AdderResult> state = recordHandler.getState(partition).getState();
-          Long offset = consumer.position(new TopicPartition(topic, partition));
           log.info(
-            "{} - offset of next unseen message for partition {} is {}",
+            "{} - Saved state for partition={}|user={}: {}",
             id,
             partition,
-            offset);
-          for (String user : state.keySet())
-          {
-            log.info(
-              "{} - Saved state for partition={}|user={}: {}",
-              id,
-              partition,
-              user,
-              state.get(user));
-          }
-          Map<String, List<AdderResult>> results = adderResults.getState(partition);
-          stateRepository.save(new StateDocument(partition, state, results, offset));
-        });
-
-      lastCommit = clock.instant();
-    }
-  }
-
-  @Override
-  public void enableCommits()
-  {
-    commitsEnabled = true;
-  }
-
-  @Override
-  public void disableCommits()
-  {
-    commitsEnabled = false;
+            user,
+            state.get(user));
+        }
+        Map<String, List<AdderResult>> results = adderResults.getState(partition);
+        stateRepository.save(new StateDocument(partition, state, results, offset));
+      });
   }
 }

diff --git a/src/main/java/de/juplo/kafka/EndlessConsumer.java b/src/main/java/de/juplo/kafka/EndlessConsumer.java
index 8f5eab3..892c6c9 100644 (file)
--- a/src/main/java/de/juplo/kafka/EndlessConsumer.java
+++ b/src/main/java/de/juplo/kafka/EndlessConsumer.java
@@ -42,7 +42,6 @@ public class EndlessConsumer<K, V> implements Runnable
     try
     {
       log.info("{} - Subscribing to topic {}", id, topic);
-      rebalanceListener.enableCommits();
       consumer.subscribe(Arrays.asList(topic), rebalanceListener);
 
       while (true)
@@ -92,8 +91,7 @@ public class EndlessConsumer<K, V> implements Runnable
     }
     catch(Exception e)
     {
-      log.error("{} - Unexpected error: {}, disabling commits", id, e.toString(), e);
-      rebalanceListener.disableCommits();
+      log.error("{} - Unexpected error: {}", id, e.toString(), e);
       shutdown(e);
     }
     finally

diff --git a/src/main/java/de/juplo/kafka/RebalanceListener.java b/src/main/java/de/juplo/kafka/RebalanceListener.java
index 497a111..3c1208f 100644 (file)
--- a/src/main/java/de/juplo/kafka/RebalanceListener.java
+++ b/src/main/java/de/juplo/kafka/RebalanceListener.java
@@ -6,7 +6,4 @@ import org.apache.kafka.clients.consumer.ConsumerRebalanceListener;
 public interface RebalanceListener extends ConsumerRebalanceListener
 {
   default void beforeNextPoll() {}
-
-  default void enableCommits() {}
-  default void disableCommits() {}
 }