X-Git-Url: https://juplo.de/gitweb/?a=blobdiff_plain;f=src%2Fmain%2Fjava%2Fde%2Fjuplo%2Fkafka%2FEndlessConsumer.java;h=92802b981f5bcf465758c9b257949ad6b104f8b6;hb=1c97cf9d1a93d5cfb6f1123cb45f644238798608;hp=18cef23c16b96c723559f8bd79f6ad2106a41e16;hpb=014de600554a5f9ba620fdadb8581b5882bc4d20;p=demos%2Fkafka%2Ftraining

diff --git a/src/main/java/de/juplo/kafka/EndlessConsumer.java b/src/main/java/de/juplo/kafka/EndlessConsumer.java
index 18cef23..92802b9 100644
--- a/src/main/java/de/juplo/kafka/EndlessConsumer.java
+++ b/src/main/java/de/juplo/kafka/EndlessConsumer.java
@@ -1,16 +1,15 @@
 package de.juplo.kafka;
 
+import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
-import org.apache.kafka.clients.consumer.ConsumerRecord;
-import org.apache.kafka.clients.consumer.ConsumerRecords;
-import org.apache.kafka.clients.consumer.KafkaConsumer;
+import org.apache.kafka.clients.consumer.*;
+import org.apache.kafka.common.TopicPartition;
+import org.apache.kafka.common.errors.RecordDeserializationException;
 import org.apache.kafka.common.errors.WakeupException;
-import org.apache.kafka.common.serialization.StringDeserializer;
 
 import javax.annotation.PreDestroy;
 import java.time.Duration;
-import java.util.Arrays;
-import java.util.Properties;
+import java.util.*;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.locks.Condition;
@@ -19,66 +18,41 @@ import java.util.concurrent.locks.ReentrantLock;
 
 
 @Slf4j
-public class EndlessConsumer implements Runnable
+@RequiredArgsConstructor
+public class EndlessConsumer<K, V> implements Runnable
 {
   private final ExecutorService executor;
-  private final String bootstrapServer;
-  private final String groupId;
   private final String id;
   private final String topic;
-  private final String autoOffsetReset;
+  private final Consumer<K, V> consumer;
+  private final RebalanceListener rebalanceListener;
+  private final RecordHandler<K, V> recordHandler;
 
   private final Lock lock = new ReentrantLock();
   private final Condition condition = lock.newCondition();
   private boolean running = false;
+  private Exception exception;
   private long consumed = 0;
-  private KafkaConsumer<String, String> consumer = null;
 
 
-  public EndlessConsumer(
-      ExecutorService executor,
-      String bootstrapServer,
-      String groupId,
-      String clientId,
-      String topic,
-      String autoOffsetReset)
-  {
-    this.executor = executor;
-    this.bootstrapServer = bootstrapServer;
-    this.groupId = groupId;
-    this.id = clientId;
-    this.topic = topic;
-    this.autoOffsetReset = autoOffsetReset;
-  }
 
   @Override
   public void run()
   {
     try
     {
-      Properties props = new Properties();
-      props.put("bootstrap.servers", bootstrapServer);
-      props.put("group.id", groupId);
-      props.put("client.id", id);
-      props.put("auto.offset.reset", autoOffsetReset);
-      props.put("key.deserializer", StringDeserializer.class.getName());
-      props.put("value.deserializer", StringDeserializer.class.getName());
-
-      this.consumer = new KafkaConsumer<>(props);
-
       log.info("{} - Subscribing to topic {}", id, topic);
-      consumer.subscribe(Arrays.asList(topic));
+      consumer.subscribe(Arrays.asList(topic), rebalanceListener);
 
       while (true)
       {
-        ConsumerRecords<String, String> records =
+        ConsumerRecords<K, V> records =
             consumer.poll(Duration.ofSeconds(1));
 
         // Do something with the data...
         log.info("{} - Received {} messages", id, records.count());
-        for (ConsumerRecord<String, String> record : records)
+        for (ConsumerRecord<K, V> record : records)
         {
-          consumed++;
           log.info(
               "{} - {}: {}/{} - {}={}",
               id,
@@ -88,34 +62,75 @@ public class EndlessConsumer implements Runnable
               record.key(),
               record.value()
           );
+
+          recordHandler.accept(record);
+
+          consumed++;
         }
+
+        rebalanceListener.beforeNextPoll();
       }
     }
     catch(WakeupException e)
     {
-      log.info("{} - RIIING!", id);
+      log.info("{} - RIIING! Request to stop consumption - commiting current offsets!", id);
+      consumer.commitSync();
       shutdown();
     }
+    catch(RecordDeserializationException e)
+    {
+      TopicPartition tp = e.topicPartition();
+      long offset = e.offset();
+      log.error(
+          "{} - Could not deserialize  message on topic {} with offset={}: {}",
+          id,
+          tp,
+          offset,
+          e.getCause().toString());
+
+      consumer.commitSync();
+      shutdown(e);
+    }
     catch(Exception e)
     {
       log.error("{} - Unexpected error: {}", id, e.toString(), e);
-      shutdown();
+      shutdown(e);
     }
     finally
     {
-      log.info("{} - Closing the KafkaConsumer", id);
-      consumer.close();
       log.info("{} - Consumer-Thread exiting", id);
     }
   }
 
   private void shutdown()
+  {
+    shutdown(null);
+  }
+
+  private void shutdown(Exception e)
   {
     lock.lock();
     try
     {
-      running = false;
-      condition.signal();
+      try
+      {
+        log.info("{} - Unsubscribing from topic {}", id, topic);
+        consumer.unsubscribe();
+      }
+      catch (Exception ue)
+      {
+        log.error(
+            "{} - Error while unsubscribing from topic {}: {}",
+            id,
+            topic,
+            ue.toString());
+      }
+      finally
+      {
+        running = false;
+        exception = e;
+        condition.signal();
+      }
     }
     finally
     {
@@ -133,6 +148,7 @@ public class EndlessConsumer implements Runnable
 
       log.info("{} - Starting - consumed {} messages before", id, consumed);
       running = true;
+      exception = null;
       executor.submit(this);
     }
     finally
@@ -141,7 +157,7 @@ public class EndlessConsumer implements Runnable
     }
   }
 
-  public synchronized void stop() throws ExecutionException, InterruptedException
+  public synchronized void stop() throws InterruptedException
   {
     lock.lock();
     try
@@ -164,21 +180,35 @@ public class EndlessConsumer implements Runnable
   public void destroy() throws ExecutionException, InterruptedException
   {
     log.info("{} - Destroy!", id);
+    log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
+  }
+
+  public boolean running()
+  {
+    lock.lock();
     try
     {
-      stop();
+      return running;
     }
-    catch (IllegalStateException e)
+    finally
     {
-      log.info("{} - Was already stopped", id);
+      lock.unlock();
     }
-    catch (Exception e)
+  }
+
+  public Optional<Exception> exitStatus()
+  {
+    lock.lock();
+    try
     {
-      log.error("{} - Unexpected exception while trying to stop the consumer", id, e);
+      if (running)
+        throw new IllegalStateException("No exit-status available: Consumer instance " + id + " is running!");
+
+      return Optional.ofNullable(exception);
     }
     finally
     {
-      log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
+      lock.unlock();
     }
   }
 }