X-Git-Url: http://juplo.de/gitweb/?a=blobdiff_plain;f=src%2Fmain%2Fjava%2Fde%2Fjuplo%2Fkafka%2FEndlessConsumer.java;h=a5a5ce6b76dc9ad4c60cdfcc0aadec3fd3a720a7;hb=0224b257a2b0ef295765d1b3bfed7c4479c280e7;hp=e4d969748e896ff18863cd465b6e8ab9ee91c2be;hpb=95b1d2d6fd83c68aa0db3e426f173921600e44a6;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 e4d9697..a5a5ce6 100644
--- a/src/main/java/de/juplo/kafka/EndlessConsumer.java
+++ b/src/main/java/de/juplo/kafka/EndlessConsumer.java
@@ -1,131 +1,100 @@
 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.common.errors.WakeupException;
-import org.apache.kafka.common.serialization.StringDeserializer;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.kafka.annotation.KafkaListener;
+import org.springframework.kafka.config.KafkaListenerEndpointRegistry;
+import org.springframework.stereotype.Component;
 
-import java.time.Duration;
-import java.util.Arrays;
-import java.util.Properties;
-import java.util.concurrent.locks.Condition;
-import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReentrantLock;
+import javax.annotation.PreDestroy;
+import java.util.List;
+import java.util.function.Consumer;
 
 
+@Component
 @Slf4j
-public class SimpleConsumer
+@RequiredArgsConstructor
+public class EndlessConsumer<K, V>
 {
+  @Autowired
+  private KafkaListenerEndpointRegistry registry;
+  @Value("${consumer.client-id}")
+  String id;
+  @Autowired
+  Consumer<ConsumerRecord<K, V>> handler;
+
   private long consumed = 0;
-  private KafkaConsumer<String, String> consumer;
-  private Lock lock = new ReentrantLock();
-  private Condition stopped = lock.newCondition();
+
+  @KafkaListener(
+      id = "${consumer.client-id}",
+      idIsGroup = false,
+      topics = "${consumer.topic}",
+      containerFactory = "batchFactory",
+      autoStartup = "false")
+  public void receive(List<ConsumerRecord<K, V>> records)
+  {
+    // Do something with the data...
+    log.info("{} - Received {} messages", id, records.size());
+    for (ConsumerRecord<K, V> record : records)
+    {
+      log.info(
+          "{} - {}: {}/{} - {}={}",
+          id,
+          record.offset(),
+          record.topic(),
+          record.partition(),
+          record.key(),
+          record.value()
+      );
+
+      handler.accept(record);
+
+      consumed++;
+    }
+  }
 
 
-  public SimpleConsumer()
+  public synchronized void start()
   {
-    // tag::create[]
-    Properties props = new Properties();
-    props.put("bootstrap.servers", ":9092");
-    props.put("group.id", "my-consumer"); // << Used for Offset-Commits
-    // end::create[]
-    props.put("auto.offset.reset", "earliest");
-    // tag::create[]
-    props.put("key.deserializer", StringDeserializer.class.getName());
-    props.put("value.deserializer", StringDeserializer.class.getName());
+    if (registry.getListenerContainer(id).isChildRunning())
+      throw new IllegalStateException("Consumer instance " + id + " is already running!");
 
-    KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
-    // end::create[]
-    this.consumer = consumer;
+    log.info("{} - Starting - consumed {} messages before", id, consumed);
+    registry.getListenerContainer(id).start();
   }
 
-
-  public void run()
+  public synchronized void stop()
   {
-    String id = "C";
+    if (!registry.getListenerContainer(id).isChildRunning())
+      throw new IllegalStateException("Consumer instance " + id + " is not running!");
 
+    log.info("{} - Stopping", id);
+    registry.getListenerContainer(id).stop();
+    log.info("{} - Stopped - consumed {} messages so far", id, consumed);
+  }
+
+  @PreDestroy
+  public void destroy()
+  {
+    log.info("{} - Destroy!", id);
     try
     {
-      log.info("{} - Subscribing to topic test", id);
-      consumer.subscribe(Arrays.asList("test"));
-
-      // tag::loop[]
-      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)
-        {
-          consumed++;
-          log.info(
-              "{} - {}: {}/{} - {}={}",
-              id,
-              record.offset(),
-              record.topic(),
-              record.partition(),
-              record.key(),
-              record.value()
-          );
-        }
-        // tag::loop[]
-      }
-      // end::loop[]
+      stop();
     }
-    catch(WakeupException e)
+    catch (IllegalStateException e)
     {
-      log.info("{} - RIIING!", id);
+      log.info("{} - Was already stopped", id);
     }
-    catch(Exception e)
+    catch (Exception e)
     {
-      log.error("{} - Unexpected error: {}", id, e.toString());
+      log.error("{} - Unexpected exception while trying to stop the consumer", id, e);
     }
     finally
     {
-      this.lock.lock();
-      try
-      {
-        log.info("{} - Closing the KafkaConsumer", id);
-        consumer.close();
-        log.info("C - DONE!");
-        stopped.signal();
-      }
-      finally
-      {
-        this.lock.unlock();
-        log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
-      }
+      log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
     }
   }
-
-
-  public static void main(String[] args) throws Exception
-  {
-    SimpleConsumer instance = new SimpleConsumer();
-
-    Runtime.getRuntime().addShutdownHook(new Thread(() ->
-    {
-      instance.lock.lock();
-      try
-      {
-        instance.consumer.wakeup();
-        instance.stopped.await();
-      }
-      catch (InterruptedException e)
-      {
-        log.warn("Interrrupted while waiting for the consumer to stop!", e);
-      }
-      finally
-      {
-        instance.lock.unlock();
-      }
-    }));
-
-    instance.run();
-  }
 }