README.sh an geändertes Compose-Setup angepasst

[demos/kafka/training] / src / main / java / de / juplo / kafka / SimpleConsumer.java

diff --git a/src/main/java/de/juplo/kafka/SimpleConsumer.java b/src/main/java/de/juplo/kafka/SimpleConsumer.java
index 03a9e6a..cab2fb8 100644 (file)
--- a/src/main/java/de/juplo/kafka/SimpleConsumer.java
+++ b/src/main/java/de/juplo/kafka/SimpleConsumer.java
@@ -4,6 +4,7 @@ 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.common.errors.WakeupException;
 import org.apache.kafka.common.serialization.StringDeserializer;
 
 import java.time.Duration;
@@ -18,9 +19,8 @@ public class SimpleConsumer
   private final String topic;
   private final KafkaConsumer<String, String> consumer;
 
+  private volatile boolean running = false;
   private long consumed = 0;
-  private volatile boolean running = true;
-  private volatile boolean done = false;
 
   public SimpleConsumer(String broker, String topic, String groupId, String clientId)
   {
@@ -28,6 +28,7 @@ public class SimpleConsumer
     props.put("bootstrap.servers", broker);
     props.put("group.id", groupId); // ID für die Offset-Commits
     props.put("client.id", clientId); // Nur zur Wiedererkennung
+    props.put("auto.offset.reset", "earliest"); // Von Beginn an lesen
     props.put("partition.assignment.strategy", "org.apache.kafka.clients.consumer.CooperativeStickyAssignor");
     props.put("key.deserializer", StringDeserializer.class.getName());
     props.put("value.deserializer", StringDeserializer.class.getName());
@@ -45,15 +46,13 @@ public class SimpleConsumer
     {
       log.info("{} - Subscribing to topic test", id);
       consumer.subscribe(Arrays.asList("test"));
+      running = true;
 
-      // tag::loop[]
-      while (running)
+      while (true)
       {
         ConsumerRecords<String, String> records =
             consumer.poll(Duration.ofSeconds(1));
 
-        // Do something with the data...
-        // end::loop[]
         log.info("{} - Received {} messages", id, records.count());
         for (ConsumerRecord<String, String> record : records)
         {
@@ -68,9 +67,11 @@ public class SimpleConsumer
               record.value()
           );
         }
-        // tag::loop[]
       }
-      // end::loop[]
+    }
+    catch(WakeupException e)
+    {
+      log.info("{} - Consumer was signaled to finish its work", id);
     }
     catch(Exception e)
     {
@@ -78,10 +79,10 @@ public class SimpleConsumer
     }
     finally
     {
+      running = false;
       log.info("{} - Closing the KafkaConsumer", id);
       consumer.close();
       log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
-      done = true;
     }
   }
 
@@ -110,8 +111,9 @@ public class SimpleConsumer
 
     Runtime.getRuntime().addShutdownHook(new Thread(() ->
     {
-      instance.running = false;
-      while (!instance.done)
+      instance.consumer.wakeup();
+
+      while (instance.running)
       {
         log.info("Waiting for main-thread...");
         try