Verbesserte Tests und Korrekturen gemerged: sumup-adder -> stored-offsets stored-offsets
authorKai Moritz <kai@juplo.de>
Sun, 14 Aug 2022 18:52:49 +0000 (20:52 +0200)
committerKai Moritz <kai@juplo.de>
Sun, 14 Aug 2022 18:56:09 +0000 (20:56 +0200)
README.sh
pom.xml
src/main/java/de/juplo/kafka/ApplicationRebalanceListener.java
src/main/java/de/juplo/kafka/EndlessConsumer.java
src/main/java/de/juplo/kafka/PollIntervalAwareConsumerRebalanceListener.java
src/test/java/de/juplo/kafka/ApplicationTests.java
src/test/java/de/juplo/kafka/ErrorCannotBeGeneratedCondition.java [new file with mode: 0644]
src/test/java/de/juplo/kafka/GenericApplicationTests.java [new file with mode: 0644]
src/test/java/de/juplo/kafka/SkipWhenErrorCannotBeGenerated.java [new file with mode: 0644]

index b7bce99..133af42 100755 (executable)
--- a/README.sh
+++ b/README.sh
@@ -16,7 +16,8 @@ if [[
   "$1" = "build"
 ]]
 then
-  mvn install || exit
+  docker-compose rm -svf peter beate
+  mvn clean install || exit
 else
   echo "Using image existing images:"
   docker image ls $IMAGE
diff --git a/pom.xml b/pom.xml
index 701704d..fa78c70 100644 (file)
--- a/pom.xml
+++ b/pom.xml
   <version>1.0-SNAPSHOT</version>
   <name>Endless Consumer: a Simple Consumer-Group that reads and prints the topic and counts the received messages for each key by topic</name>
 
+  <properties>
+    <java.version>11</java.version>
+  </properties>
+
   <dependencies>
     <dependency>
       <groupId>org.springframework.boot</groupId>
index 59b420a..444b7b7 100644 (file)
@@ -25,6 +25,7 @@ public class ApplicationRebalanceListener implements PollIntervalAwareConsumerRe
   private final Consumer<String, Long> consumer;
 
   private Instant lastCommit = Instant.EPOCH;
+  private boolean commitsEnabled = true;
 
   @Override
   public void onPartitionsAssigned(Collection<TopicPartition> partitions)
@@ -59,8 +60,15 @@ public class ApplicationRebalanceListener implements PollIntervalAwareConsumerRe
           id,
           partition,
           offset);
-      Map<String, Long> removed = recordHandler.removePartition(partition);
-      stateRepository.save(new StateDocument(partition, removed, offset));
+      if (commitsEnabled)
+      {
+        Map<String, Long> removed = recordHandler.removePartition(partition);
+        stateRepository.save(new StateDocument(partition, removed, offset));
+      }
+      else
+      {
+        log.info("Offset commits are disabled! Last commit: {}", lastCommit);
+      }
     });
   }
 
@@ -68,6 +76,12 @@ public class ApplicationRebalanceListener implements PollIntervalAwareConsumerRe
   @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);
@@ -79,4 +93,16 @@ public class ApplicationRebalanceListener implements PollIntervalAwareConsumerRe
       lastCommit = clock.instant();
     }
   }
+
+  @Override
+  public void enableCommits()
+  {
+    commitsEnabled = true;
+  }
+
+  @Override
+  public void disableCommits()
+  {
+    commitsEnabled = false;
+  }
 }
index 17778be..58374f4 100644 (file)
@@ -42,6 +42,7 @@ 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)
@@ -91,7 +92,8 @@ public class EndlessConsumer<K, V> implements Runnable
     }
     catch(Exception e)
     {
-      log.error("{} - Unexpected error: {}", id, e.toString(), e);
+      log.error("{} - Unexpected error: {}, disabling commits", id, e.toString(), e);
+      rebalanceListener.disableCommits();
       shutdown(e);
     }
     finally
index 8abec12..c59418c 100644 (file)
@@ -6,4 +6,7 @@ import org.apache.kafka.clients.consumer.ConsumerRebalanceListener;
 public interface PollIntervalAwareConsumerRebalanceListener extends ConsumerRebalanceListener
 {
   default void beforeNextPoll() {}
+
+  default void enableCommits() {}
+  default void disableCommits() {}
 }
index 1f18e59..5166227 100644 (file)
 package de.juplo.kafka;
 
-import lombok.extern.slf4j.Slf4j;
 import org.apache.kafka.clients.consumer.ConsumerRecord;
-import org.apache.kafka.clients.consumer.KafkaConsumer;
-import org.apache.kafka.clients.producer.KafkaProducer;
 import org.apache.kafka.clients.producer.ProducerRecord;
-import org.apache.kafka.common.TopicPartition;
-import org.apache.kafka.common.errors.RecordDeserializationException;
-import org.apache.kafka.common.serialization.*;
+import org.apache.kafka.common.serialization.LongSerializer;
+import org.apache.kafka.common.serialization.StringSerializer;
 import org.apache.kafka.common.utils.Bytes;
-import org.junit.jupiter.api.*;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
-import org.springframework.boot.test.autoconfigure.data.mongo.AutoConfigureDataMongo;
-import org.springframework.boot.test.context.ConfigDataApplicationContextInitializer;
 import org.springframework.boot.test.context.TestConfiguration;
 import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Import;
-import org.springframework.kafka.test.context.EmbeddedKafka;
-import org.springframework.test.context.TestPropertySource;
-import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+import org.springframework.context.annotation.Primary;
+import org.springframework.test.context.ContextConfiguration;
 
-import java.time.Duration;
-import java.util.*;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.ExecutorService;
-import java.util.function.BiConsumer;
-import java.util.stream.Collectors;
-import java.util.stream.IntStream;
+import java.util.function.Consumer;
 
-import static de.juplo.kafka.ApplicationTests.PARTITIONS;
-import static de.juplo.kafka.ApplicationTests.TOPIC;
-import static org.assertj.core.api.Assertions.*;
-import static org.awaitility.Awaitility.*;
 
-
-@SpringJUnitConfig(initializers = ConfigDataApplicationContextInitializer.class)
-@TestMethodOrder(MethodOrderer.OrderAnnotation.class)
-@TestPropertySource(
-               properties = {
-                               "consumer.bootstrap-server=${spring.embedded.kafka.brokers}",
-                               "consumer.topic=" + TOPIC,
-                               "consumer.commit-interval=1s",
-                               "spring.mongodb.embedded.version=4.4.13" })
-@EmbeddedKafka(topics = TOPIC, partitions = PARTITIONS)
-@EnableAutoConfiguration
-@AutoConfigureDataMongo
-@Slf4j
-class ApplicationTests
+@ContextConfiguration(classes = ApplicationTests.Configuration.class)
+public class ApplicationTests extends GenericApplicationTests<String, Long>
 {
-       public static final String TOPIC = "FOO";
-       public static final int PARTITIONS = 10;
-
-
-       StringSerializer stringSerializer = new StringSerializer();
-
-       @Autowired
-       Serializer valueSerializer;
-       @Autowired
-       KafkaProducer<String, Bytes> kafkaProducer;
-       @Autowired
-       KafkaConsumer<String, Long> kafkaConsumer;
-       @Autowired
-       KafkaConsumer<Bytes, Bytes> offsetConsumer;
-       @Autowired
-       ApplicationProperties properties;
-       @Autowired
-       ExecutorService executor;
-       @Autowired
-  StateRepository stateRepository;
-       @Autowired
-  ApplicationRebalanceListener rebalanceListener;
-       @Autowired
-  ApplicationRecordHandler recordHandler;
-
-       EndlessConsumer<String, Long> endlessConsumer;
-       Map<TopicPartition, Long> oldOffsets;
-       Map<TopicPartition, Long> newOffsets;
-       Set<ConsumerRecord<String, Long>> receivedRecords;
-
-
-       /** Tests methods */
-
-       @Test
-       void commitsCurrentOffsetsOnSuccess() throws ExecutionException, InterruptedException
-       {
-               send100Messages((partition, key, counter) ->
-               {
-                       Bytes value = new Bytes(valueSerializer.serialize(TOPIC, counter));
-                       return new ProducerRecord<>(TOPIC, partition, key, value);
-               });
-
-               await("100 records received")
-                               .atMost(Duration.ofSeconds(30))
-                               .pollInterval(Duration.ofSeconds(1))
-                               .until(() -> receivedRecords.size() >= 100);
-
-               await("Offsets committed")
-                               .atMost(Duration.ofSeconds(10))
-                               .pollInterval(Duration.ofSeconds(1))
-                               .untilAsserted(() ->
-                               {
-                                       checkSeenOffsetsForProgress();
-                                       compareToCommitedOffsets(newOffsets);
-                               });
-
-               assertThatExceptionOfType(IllegalStateException.class)
-                               .isThrownBy(() -> endlessConsumer.exitStatus())
-                               .describedAs("Consumer should still be running");
-       }
-
-       @Test
-       void commitsOffsetOfErrorForReprocessingOnDeserializationError()
-       {
-               send100Messages((partition, key, counter) ->
-               {
-                       Bytes value = counter == 77
-                                       ? new Bytes(stringSerializer.serialize(TOPIC, "BOOM!"))
-                                       : new Bytes(valueSerializer.serialize(TOPIC, counter));
-                       return new ProducerRecord<>(TOPIC, partition, key, value);
-               });
-
-               await("Consumer failed")
-                               .atMost(Duration.ofSeconds(30))
-                               .pollInterval(Duration.ofSeconds(1))
-                               .until(() -> !endlessConsumer.running());
-
-               checkSeenOffsetsForProgress();
-               compareToCommitedOffsets(newOffsets);
-
-               endlessConsumer.start();
-               await("Consumer failed")
-                               .atMost(Duration.ofSeconds(30))
-                               .pollInterval(Duration.ofSeconds(1))
-                               .until(() -> !endlessConsumer.running());
-
-               checkSeenOffsetsForProgress();
-               compareToCommitedOffsets(newOffsets);
-               assertThat(receivedRecords.size())
-                               .describedAs("Received not all sent events")
-                               .isLessThan(100);
-
-               assertThatNoException()
-                               .describedAs("Consumer should not be running")
-                               .isThrownBy(() -> endlessConsumer.exitStatus());
-               assertThat(endlessConsumer.exitStatus())
-                               .describedAs("Consumer should have exited abnormally")
-                               .containsInstanceOf(RecordDeserializationException.class);
-       }
-
-
-       /** Helper methods for the verification of expectations */
-
-       void compareToCommitedOffsets(Map<TopicPartition, Long> offsetsToCheck)
-       {
-               doForCurrentOffsets((tp, offset) ->
-               {
-                       Long expected = offsetsToCheck.get(tp) + 1;
-                       log.debug("Checking, if the offset for {} is {}", tp, expected);
-                       assertThat(offset)
-                                       .describedAs("Committed offset corresponds to the offset of the consumer")
-                                       .isEqualTo(expected);
-               });
-       }
-
-       void checkSeenOffsetsForProgress()
-       {
-               // Be sure, that some messages were consumed...!
-               Set<TopicPartition> withProgress = new HashSet<>();
-               partitions().forEach(tp ->
-               {
-                       Long oldOffset = oldOffsets.get(tp) + 1;
-                       Long newOffset = newOffsets.get(tp) + 1;
-                       if (!oldOffset.equals(newOffset))
-                       {
-                               log.debug("Progress for {}: {} -> {}", tp, oldOffset, newOffset);
-                               withProgress.add(tp);
-                       }
-               });
-               assertThat(withProgress)
-                               .describedAs("Some offsets must have changed, compared to the old offset-positions")
-                               .isNotEmpty();
-       }
-
-
-       /** Helper methods for setting up and running the tests */
-
-       void seekToEnd()
-       {
-               offsetConsumer.assign(partitions());
-               partitions().forEach(tp ->
-               {
-                       Long offset = offsetConsumer.position(tp);
-                       log.info("New position for {}: {}", tp, offset);
-                       Integer partition = tp.partition();
-                       StateDocument document =
-                                       stateRepository
-                                                       .findById(partition.toString())
-                                                       .orElse(new StateDocument(partition));
-                       document.offset = offset;
-                       stateRepository.save(document);
-               });
-               offsetConsumer.unsubscribe();
-       }
-
-       void doForCurrentOffsets(BiConsumer<TopicPartition, Long> consumer)
-       {
-               partitions().forEach(tp ->
-               {
-                       String partition = Integer.toString(tp.partition());
-                       Optional<Long> offset = stateRepository.findById(partition).map(document -> document.offset);
-                       consumer.accept(tp, offset.orElse(0l));
-               });
-               }
-
-       List<TopicPartition> partitions()
-       {
-               return
-                               IntStream
-                                               .range(0, PARTITIONS)
-                                               .mapToObj(partition -> new TopicPartition(TOPIC, partition))
-                                               .collect(Collectors.toList());
-       }
-
-
-       public interface RecordGenerator<K, V>
-       {
-               public ProducerRecord<String, Bytes> generate(int partition, String key, long counter);
-       }
-
-       void send100Messages(RecordGenerator recordGenerator)
-       {
-               long i = 0;
-
-               for (int partition = 0; partition < 10; partition++)
-               {
-                       for (int key = 0; key < 10; key++)
-                       {
-                               ProducerRecord<String, Bytes> record =
-                                               recordGenerator.generate(partition, Integer.toString(partition*10+key%2), ++i);
-
-                               kafkaProducer.send(record, (metadata, e) ->
-                               {
-                                       if (metadata != null)
-                                       {
-                                               log.debug(
-                                                               "{}|{} - {}={}",
-                                                               metadata.partition(),
-                                                               metadata.offset(),
-                                                               record.key(),
-                                                               record.value());
-                                       }
-                                       else
-                                       {
-                                               log.warn(
-                                                               "Exception for {}={}: {}",
-                                                               record.key(),
-                                                               record.value(),
-                                                               e.toString());
-                                       }
-                               });
-                       }
-               }
-       }
-
-
-       @BeforeEach
-       public void init()
-       {
-               seekToEnd();
-
-               oldOffsets = new HashMap<>();
-               newOffsets = new HashMap<>();
-               receivedRecords = new HashSet<>();
-
-               doForCurrentOffsets((tp, offset) ->
-               {
-                       oldOffsets.put(tp, offset - 1);
-                       newOffsets.put(tp, offset - 1);
-               });
-
-               TestRecordHandler<String, Long> captureOffsetAndExecuteTestHandler =
-                               new TestRecordHandler<String, Long>(recordHandler) {
-                                       @Override
-                                       public void onNewRecord(ConsumerRecord<String, Long> record)
-                                       {
-                                               newOffsets.put(
-                                                               new TopicPartition(record.topic(), record.partition()),
-                                                               record.offset());
-                                               receivedRecords.add(record);
-                                       }
-                               };
-
-               endlessConsumer =
-                               new EndlessConsumer<>(
-                                               executor,
-                                               properties.getClientId(),
-                                               properties.getTopic(),
-                                               kafkaConsumer,
-            rebalanceListener,
-                                               captureOffsetAndExecuteTestHandler);
-
-               endlessConsumer.start();
-       }
-
-       @AfterEach
-       public void deinit()
-       {
-               try
-               {
-                       endlessConsumer.stop();
-               }
-               catch (Exception e)
-               {
-                       log.info("Exception while stopping the consumer: {}", e.toString());
-               }
-       }
-
-
-       @TestConfiguration
-       @Import(ApplicationConfiguration.class)
-       public static class Configuration
-       {
-               @Bean
-               Serializer<Long> serializer()
-               {
-                       return new LongSerializer();
-               }
-
-               @Bean
-               KafkaProducer<String, Bytes> kafkaProducer(ApplicationProperties properties)
-               {
-                       Properties props = new Properties();
-                       props.put("bootstrap.servers", properties.getBootstrapServer());
-                       props.put("linger.ms", 100);
-                       props.put("key.serializer", StringSerializer.class.getName());
-                       props.put("value.serializer", BytesSerializer.class.getName());
-
-                       return new KafkaProducer<>(props);
-               }
-
-               @Bean
-               KafkaConsumer<Bytes, Bytes> offsetConsumer(ApplicationProperties properties)
-               {
-                       Properties props = new Properties();
-                       props.put("bootstrap.servers", properties.getBootstrapServer());
-                       props.put("client.id", "OFFSET-CONSUMER");
-                       props.put("enable.auto.commit", false);
-                       props.put("auto.offset.reset", "latest");
-                       props.put("key.deserializer", BytesDeserializer.class.getName());
-                       props.put("value.deserializer", BytesDeserializer.class.getName());
-
-                       return new KafkaConsumer<>(props);
-               }
-       }
+  public ApplicationTests()
+  {
+    super(
+        new RecordGenerator()
+        {
+          final StringSerializer stringSerializer = new StringSerializer();
+          final LongSerializer longSerializer = new LongSerializer();
+
+
+          @Override
+          public int generate(
+              boolean poisonPills,
+              boolean logicErrors,
+              Consumer<ProducerRecord<Bytes, Bytes>> messageSender)
+          {
+            int i = 0;
+
+            for (int partition = 0; partition < 10; partition++)
+            {
+              for (int key = 0; key < 10; key++)
+              {
+                i++;
+
+                Bytes value = new Bytes(longSerializer.serialize(TOPIC, (long)i));
+                if (i == 77)
+                {
+                  if (logicErrors)
+                  {
+                    value = new Bytes(longSerializer.serialize(TOPIC, Long.MIN_VALUE));
+                  }
+                  if (poisonPills)
+                  {
+                    value = new Bytes(stringSerializer.serialize(TOPIC, "BOOM (Poison-Pill)!"));
+                  }
+                }
+
+                ProducerRecord<Bytes, Bytes> record =
+                    new ProducerRecord<>(
+                        TOPIC,
+                        partition,
+                        new Bytes(stringSerializer.serialize(TOPIC,Integer.toString(partition*10+key%2))),
+                        value);
+
+                messageSender.accept(record);
+              }
+            }
+
+            return i;
+          }
+        });
+  }
+
+
+  @TestConfiguration
+  public static class Configuration
+  {
+    @Primary
+    @Bean
+    public ApplicationRecordHandler recordHandler()
+    {
+      ApplicationRecordHandler recordHandler = new ApplicationRecordHandler();
+      return new ApplicationRecordHandler()
+      {
+        @Override
+        public void accept(ConsumerRecord<String, Long> record)
+        {
+          if (record.value() == Long.MIN_VALUE)
+            throw new RuntimeException("BOOM (Logic-Error)!");
+          super.accept(record);
+        }
+      };
+    }
+  }
 }
diff --git a/src/test/java/de/juplo/kafka/ErrorCannotBeGeneratedCondition.java b/src/test/java/de/juplo/kafka/ErrorCannotBeGeneratedCondition.java
new file mode 100644 (file)
index 0000000..606218f
--- /dev/null
@@ -0,0 +1,60 @@
+package de.juplo.kafka;
+
+import org.junit.jupiter.api.extension.ConditionEvaluationResult;
+import org.junit.jupiter.api.extension.ExecutionCondition;
+import org.junit.jupiter.api.extension.ExtensionContext;
+import org.junit.platform.commons.util.AnnotationUtils;
+
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+
+public class ErrorCannotBeGeneratedCondition implements ExecutionCondition
+{
+  @Override
+  public ConditionEvaluationResult evaluateExecutionCondition(ExtensionContext context)
+  {
+    final Optional<SkipWhenErrorCannotBeGenerated> optional =
+        AnnotationUtils.findAnnotation(
+            context.getElement(),
+            SkipWhenErrorCannotBeGenerated.class);
+
+    if (context.getTestInstance().isEmpty())
+      return ConditionEvaluationResult.enabled("Test-instance ist not available");
+
+    if (optional.isPresent())
+    {
+      SkipWhenErrorCannotBeGenerated skipWhenErrorCannotBeGenerated = optional.get();
+      GenericApplicationTests instance = (GenericApplicationTests)context.getTestInstance().get();
+      List<String> missingRequiredErrors = new LinkedList<>();
+
+      if (skipWhenErrorCannotBeGenerated.poisonPill() && !instance.recordGenerator.canGeneratePoisonPill())
+        missingRequiredErrors.add("Poison-Pill");
+
+      if (skipWhenErrorCannotBeGenerated.logicError() && !instance.recordGenerator.canGenerateLogicError())
+        missingRequiredErrors.add("Logic-Error");
+
+      StringBuilder builder = new StringBuilder();
+      builder.append(context.getTestClass().get().getSimpleName());
+
+      if (missingRequiredErrors.isEmpty())
+      {
+        builder.append(" can generate all required types of errors");
+        return ConditionEvaluationResult.enabled(builder.toString());
+      }
+
+      builder.append(" cannot generate the required error(s): ");
+      builder.append(
+          missingRequiredErrors
+              .stream()
+              .collect(Collectors.joining(", ")));
+
+      return ConditionEvaluationResult.disabled(builder.toString());
+    }
+
+    return ConditionEvaluationResult.enabled(
+        "Not annotated with " + SkipWhenErrorCannotBeGenerated.class.getSimpleName());
+  }
+}
diff --git a/src/test/java/de/juplo/kafka/GenericApplicationTests.java b/src/test/java/de/juplo/kafka/GenericApplicationTests.java
new file mode 100644 (file)
index 0000000..fa3d911
--- /dev/null
@@ -0,0 +1,390 @@
+package de.juplo.kafka;
+
+import lombok.extern.slf4j.Slf4j;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.apache.kafka.clients.consumer.KafkaConsumer;
+import org.apache.kafka.clients.producer.KafkaProducer;
+import org.apache.kafka.clients.producer.ProducerRecord;
+import org.apache.kafka.common.TopicPartition;
+import org.apache.kafka.common.errors.RecordDeserializationException;
+import org.apache.kafka.common.serialization.*;
+import org.apache.kafka.common.utils.Bytes;
+import org.junit.jupiter.api.*;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.autoconfigure.data.mongo.AutoConfigureDataMongo;
+import org.springframework.boot.test.context.ConfigDataApplicationContextInitializer;
+import org.springframework.boot.test.context.TestConfiguration;
+import org.springframework.context.annotation.Import;
+import org.springframework.kafka.test.context.EmbeddedKafka;
+import org.springframework.test.context.TestPropertySource;
+import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+
+import java.time.Duration;
+import java.util.*;
+import java.util.concurrent.ExecutorService;
+import java.util.function.BiConsumer;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+import static de.juplo.kafka.GenericApplicationTests.PARTITIONS;
+import static de.juplo.kafka.GenericApplicationTests.TOPIC;
+import static org.assertj.core.api.Assertions.*;
+import static org.awaitility.Awaitility.*;
+
+
+@SpringJUnitConfig(initializers = ConfigDataApplicationContextInitializer.class)
+@TestPropertySource(
+               properties = {
+                               "consumer.bootstrap-server=${spring.embedded.kafka.brokers}",
+                               "consumer.topic=" + TOPIC,
+                               "consumer.commit-interval=1s",
+                               "spring.mongodb.embedded.version=4.4.13" })
+@EmbeddedKafka(topics = TOPIC, partitions = PARTITIONS)
+@EnableAutoConfiguration
+@AutoConfigureDataMongo
+@Slf4j
+abstract class GenericApplicationTests<K, V>
+{
+       public static final String TOPIC = "FOO";
+       public static final int PARTITIONS = 10;
+
+
+       @Autowired
+       KafkaConsumer<K, V> kafkaConsumer;
+       @Autowired
+       Consumer<ConsumerRecord<K, V>> consumer;
+       @Autowired
+       ApplicationProperties properties;
+       @Autowired
+       ExecutorService executor;
+       @Autowired
+       StateRepository stateRepository;
+       @Autowired
+       PollIntervalAwareConsumerRebalanceListener rebalanceListener;
+       @Autowired
+       RecordHandler<K, V> recordHandler;
+
+       KafkaProducer<Bytes, Bytes> testRecordProducer;
+       KafkaConsumer<Bytes, Bytes> offsetConsumer;
+       EndlessConsumer<K, V> endlessConsumer;
+       Map<TopicPartition, Long> oldOffsets;
+       Map<TopicPartition, Long> newOffsets;
+       Set<ConsumerRecord<K, V>> receivedRecords;
+
+
+       final RecordGenerator recordGenerator;
+       final Consumer<ProducerRecord<Bytes, Bytes>> messageSender;
+
+       public GenericApplicationTests(RecordGenerator recordGenerator)
+       {
+               this.recordGenerator = recordGenerator;
+               this.messageSender = (record) -> sendMessage(record);
+       }
+
+
+       /** Tests methods */
+
+       @Test
+       void commitsCurrentOffsetsOnSuccess()
+       {
+               int numberOfGeneratedMessages =
+                               recordGenerator.generate(false, false, messageSender);
+
+               await(numberOfGeneratedMessages + " records received")
+                               .atMost(Duration.ofSeconds(30))
+                               .pollInterval(Duration.ofSeconds(1))
+                               .until(() -> receivedRecords.size() >= numberOfGeneratedMessages);
+
+               await("Offsets committed")
+                               .atMost(Duration.ofSeconds(10))
+                               .pollInterval(Duration.ofSeconds(1))
+                               .untilAsserted(() ->
+                               {
+                                       checkSeenOffsetsForProgress();
+                                       compareToCommitedOffsets(newOffsets);
+                               });
+
+               assertThatExceptionOfType(IllegalStateException.class)
+                               .isThrownBy(() -> endlessConsumer.exitStatus())
+                               .describedAs("Consumer should still be running");
+
+               recordGenerator.assertBusinessLogic();
+       }
+
+       @Test
+       @SkipWhenErrorCannotBeGenerated(poisonPill = true)
+       void commitsOffsetOfErrorForReprocessingOnDeserializationError()
+       {
+               int numberOfGeneratedMessages =
+                               recordGenerator.generate(true, false, messageSender);
+
+               await("Consumer failed")
+                               .atMost(Duration.ofSeconds(30))
+                               .pollInterval(Duration.ofSeconds(1))
+                               .until(() -> !endlessConsumer.running());
+
+               checkSeenOffsetsForProgress();
+               compareToCommitedOffsets(newOffsets);
+
+               endlessConsumer.start();
+               await("Consumer failed")
+                               .atMost(Duration.ofSeconds(30))
+                               .pollInterval(Duration.ofSeconds(1))
+                               .until(() -> !endlessConsumer.running());
+
+               checkSeenOffsetsForProgress();
+               compareToCommitedOffsets(newOffsets);
+               assertThat(receivedRecords.size())
+                               .describedAs("Received not all sent events")
+                               .isLessThan(numberOfGeneratedMessages);
+
+               assertThatNoException()
+                               .describedAs("Consumer should not be running")
+                               .isThrownBy(() -> endlessConsumer.exitStatus());
+               assertThat(endlessConsumer.exitStatus())
+                               .describedAs("Consumer should have exited abnormally")
+                               .containsInstanceOf(RecordDeserializationException.class);
+
+               recordGenerator.assertBusinessLogic();
+       }
+
+       @Test
+       @SkipWhenErrorCannotBeGenerated(logicError = true)
+       void doesNotCommitOffsetsOnLogicError()
+       {
+               int numberOfGeneratedMessages =
+                               recordGenerator.generate(false, true, messageSender);
+
+               await("Consumer failed")
+                               .atMost(Duration.ofSeconds(30))
+                               .pollInterval(Duration.ofSeconds(1))
+                               .until(() -> !endlessConsumer.running());
+
+               checkSeenOffsetsForProgress();
+               compareToCommitedOffsets(oldOffsets);
+
+               endlessConsumer.start();
+               await("Consumer failed")
+                               .atMost(Duration.ofSeconds(30))
+                               .pollInterval(Duration.ofSeconds(1))
+                               .until(() -> !endlessConsumer.running());
+
+               checkSeenOffsetsForProgress();
+               compareToCommitedOffsets(oldOffsets);
+               assertThat(receivedRecords.size())
+                               .describedAs("Received not all sent events")
+                               .isLessThan(numberOfGeneratedMessages);
+
+               assertThatNoException()
+                               .describedAs("Consumer should not be running")
+                               .isThrownBy(() -> endlessConsumer.exitStatus());
+               assertThat(endlessConsumer.exitStatus())
+                               .describedAs("Consumer should have exited abnormally")
+                               .containsInstanceOf(RuntimeException.class);
+
+               recordGenerator.assertBusinessLogic();
+       }
+
+
+       /** Helper methods for the verification of expectations */
+
+       void compareToCommitedOffsets(Map<TopicPartition, Long> offsetsToCheck)
+       {
+               doForCurrentOffsets((tp, offset) ->
+               {
+                       Long expected = offsetsToCheck.get(tp) + 1;
+                       log.debug("Checking, if the offset for {} is {}", tp, expected);
+                       assertThat(offset)
+                                       .describedAs("Committed offset corresponds to the offset of the consumer")
+                                       .isEqualTo(expected);
+               });
+       }
+
+       void checkSeenOffsetsForProgress()
+       {
+               // Be sure, that some messages were consumed...!
+               Set<TopicPartition> withProgress = new HashSet<>();
+               partitions().forEach(tp ->
+               {
+                       Long oldOffset = oldOffsets.get(tp) + 1;
+                       Long newOffset = newOffsets.get(tp) + 1;
+                       if (!oldOffset.equals(newOffset))
+                       {
+                               log.debug("Progress for {}: {} -> {}", tp, oldOffset, newOffset);
+                               withProgress.add(tp);
+                       }
+               });
+               assertThat(withProgress)
+                               .describedAs("Some offsets must have changed, compared to the old offset-positions")
+                               .isNotEmpty();
+       }
+
+
+       /** Helper methods for setting up and running the tests */
+
+       void seekToEnd()
+       {
+               offsetConsumer.assign(partitions());
+               partitions().forEach(tp ->
+               {
+                       Long offset = offsetConsumer.position(tp);
+                       log.info("New position for {}: {}", tp, offset);
+                       Integer partition = tp.partition();
+                       StateDocument document =
+                                       stateRepository
+                                                       .findById(partition.toString())
+                                                       .orElse(new StateDocument(partition));
+                       document.offset = offset;
+                       stateRepository.save(document);
+               });
+               offsetConsumer.unsubscribe();
+       }
+
+       void doForCurrentOffsets(BiConsumer<TopicPartition, Long> consumer)
+       {
+               partitions().forEach(tp ->
+               {
+                       String partition = Integer.toString(tp.partition());
+                       Optional<Long> offset = stateRepository.findById(partition).map(document -> document.offset);
+                       consumer.accept(tp, offset.orElse(0l));
+               });
+       }
+
+       List<TopicPartition> partitions()
+       {
+               return
+                               IntStream
+                                               .range(0, PARTITIONS)
+                                               .mapToObj(partition -> new TopicPartition(TOPIC, partition))
+                                               .collect(Collectors.toList());
+       }
+
+
+       public interface RecordGenerator
+       {
+               int generate(
+                               boolean poisonPills,
+                               boolean logicErrors,
+                               Consumer<ProducerRecord<Bytes, Bytes>> messageSender);
+
+               default boolean canGeneratePoisonPill()
+               {
+                       return true;
+               }
+
+               default boolean canGenerateLogicError()
+               {
+                       return true;
+               }
+
+               default void assertBusinessLogic()
+               {
+                       log.debug("No business-logic to assert");
+               }
+       }
+
+       void sendMessage(ProducerRecord<Bytes, Bytes> record)
+       {
+               testRecordProducer.send(record, (metadata, e) ->
+               {
+                       if (metadata != null)
+                       {
+                               log.debug(
+                                               "{}|{} - {}={}",
+                                               metadata.partition(),
+                                               metadata.offset(),
+                                               record.key(),
+                                               record.value());
+                       }
+                       else
+                       {
+                               log.warn(
+                                               "Exception for {}={}: {}",
+                                               record.key(),
+                                               record.value(),
+                                               e.toString());
+                       }
+               });
+       }
+
+
+       @BeforeEach
+       public void init()
+       {
+               Properties props;
+               props = new Properties();
+               props.put("bootstrap.servers", properties.getBootstrapServer());
+               props.put("linger.ms", 100);
+               props.put("key.serializer", BytesSerializer.class.getName());
+               props.put("value.serializer", BytesSerializer.class.getName());
+               testRecordProducer = new KafkaProducer<>(props);
+
+               props = new Properties();
+               props.put("bootstrap.servers", properties.getBootstrapServer());
+               props.put("client.id", "OFFSET-CONSUMER");
+               props.put("group.id", properties.getGroupId());
+               props.put("key.deserializer", BytesDeserializer.class.getName());
+               props.put("value.deserializer", BytesDeserializer.class.getName());
+               offsetConsumer = new KafkaConsumer<>(props);
+
+               seekToEnd();
+
+               oldOffsets = new HashMap<>();
+               newOffsets = new HashMap<>();
+               receivedRecords = new HashSet<>();
+
+               doForCurrentOffsets((tp, offset) ->
+               {
+                       oldOffsets.put(tp, offset - 1);
+                       newOffsets.put(tp, offset - 1);
+               });
+
+               TestRecordHandler<K, V> captureOffsetAndExecuteTestHandler =
+                               new TestRecordHandler<K, V>(recordHandler)
+                               {
+                                       @Override
+                                       public void onNewRecord(ConsumerRecord<K, V> record)
+                                       {
+                                               newOffsets.put(
+                                                               new TopicPartition(record.topic(), record.partition()),
+                                                               record.offset());
+                                               receivedRecords.add(record);
+                                       }
+                               };
+
+               endlessConsumer =
+                               new EndlessConsumer<>(
+                                               executor,
+                                               properties.getClientId(),
+                                               properties.getTopic(),
+                                               kafkaConsumer,
+                                               rebalanceListener,
+                                               captureOffsetAndExecuteTestHandler);
+
+               endlessConsumer.start();
+       }
+
+       @AfterEach
+       public void deinit()
+       {
+               try
+               {
+                       endlessConsumer.stop();
+                       testRecordProducer.close();
+                       offsetConsumer.close();
+               }
+               catch (Exception e)
+               {
+                       log.info("Exception while stopping the consumer: {}", e.toString());
+               }
+       }
+
+
+       @TestConfiguration
+       @Import(ApplicationConfiguration.class)
+       public static class Configuration
+       {
+       }
+}
diff --git a/src/test/java/de/juplo/kafka/SkipWhenErrorCannotBeGenerated.java b/src/test/java/de/juplo/kafka/SkipWhenErrorCannotBeGenerated.java
new file mode 100644 (file)
index 0000000..6d15e9e
--- /dev/null
@@ -0,0 +1,15 @@
+package de.juplo.kafka;
+
+import org.junit.jupiter.api.extension.ExtendWith;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+
+@Retention(RetentionPolicy.RUNTIME)
+@ExtendWith(ErrorCannotBeGeneratedCondition.class)
+public @interface SkipWhenErrorCannotBeGenerated
+{
+  boolean poisonPill() default false;
+  boolean logicError() default false;
+}