HealthIndicator implementiert

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

diff --git a/src/main/java/de/juplo/kafka/EndlessConsumer.java b/src/main/java/de/juplo/kafka/EndlessConsumer.java
index da2f8f0..adebff1 100644 (file)
--- a/src/main/java/de/juplo/kafka/EndlessConsumer.java
+++ b/src/main/java/de/juplo/kafka/EndlessConsumer.java
@@ -10,11 +10,13 @@ import org.apache.kafka.common.serialization.StringDeserializer;
 import javax.annotation.PreDestroy;
 import java.time.Duration;
 import java.util.Arrays;
+import java.util.Optional;
 import java.util.Properties;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Future;
-import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 
 
 @Slf4j
@@ -25,24 +27,30 @@ public class EndlessConsumer implements Runnable
   private final String groupId;
   private final String id;
   private final String topic;
+  private final String autoOffsetReset;
 
-  private AtomicBoolean running = new AtomicBoolean();
+  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;
-  private Future<?> future = null;
+
 
   public EndlessConsumer(
       ExecutorService executor,
       String bootstrapServer,
       String groupId,
       String clientId,
-      String topic)
+      String topic,
+      String autoOffsetReset)
   {
     this.executor = executor;
     this.bootstrapServer = bootstrapServer;
     this.groupId = groupId;
     this.id = clientId;
     this.topic = topic;
+    this.autoOffsetReset = autoOffsetReset;
   }
 
   @Override
@@ -54,7 +62,7 @@ public class EndlessConsumer implements Runnable
       props.put("bootstrap.servers", bootstrapServer);
       props.put("group.id", groupId);
       props.put("client.id", id);
-      props.put("auto.offset.reset", "earliest");
+      props.put("auto.offset.reset", autoOffsetReset);
       props.put("key.deserializer", StringDeserializer.class.getName());
       props.put("value.deserializer", StringDeserializer.class.getName());
 
@@ -88,11 +96,12 @@ public class EndlessConsumer implements Runnable
     catch(WakeupException e)
     {
       log.info("{} - RIIING!", id);
+      shutdown();
     }
     catch(Exception e)
     {
       log.error("{} - Unexpected error: {}", id, e.toString(), e);
-      running.set(false); // Mark the instance as not running
+      shutdown(e);
     }
     finally
     {
@@ -102,27 +111,62 @@ public class EndlessConsumer implements Runnable
     }
   }
 
+  private void shutdown()
+  {
+    shutdown(null);
+  }
 
-  public synchronized void start()
+  private void shutdown(Exception e)
   {
-    boolean stateChanged = running.compareAndSet(false, true);
-    if (!stateChanged)
-      throw new RuntimeException("Consumer instance " + id + " is already running!");
+    lock.lock();
+    try
+    {
+      running = false;
+      exception = e;
+      condition.signal();
+    }
+    finally
+    {
+      lock.unlock();
+    }
+  }
 
-    log.info("{} - Starting - consumed {} messages before", id, consumed);
-    future = executor.submit(this);
+  public void start()
+  {
+    lock.lock();
+    try
+    {
+      if (running)
+        throw new IllegalStateException("Consumer instance " + id + " is already running!");
+
+      log.info("{} - Starting - consumed {} messages before", id, consumed);
+      running = true;
+      exception = null;
+      executor.submit(this);
+    }
+    finally
+    {
+      lock.unlock();
+    }
   }
 
   public synchronized void stop() throws ExecutionException, InterruptedException
   {
-    boolean stateChanged = running.compareAndSet(true, false);
-    if (!stateChanged)
-      throw new RuntimeException("Consumer instance " + id + " is not running!");
-
-    log.info("{} - Stopping", id);
-    consumer.wakeup();
-    future.get();
-    log.info("{} - Stopped - consumed {} messages so far", id, consumed);
+    lock.lock();
+    try
+    {
+      if (!running)
+        throw new IllegalStateException("Consumer instance " + id + " is not running!");
+
+      log.info("{} - Stopping", id);
+      consumer.wakeup();
+      condition.await();
+      log.info("{} - Stopped - consumed {} messages so far", id, consumed);
+    }
+    finally
+    {
+      lock.unlock();
+    }
   }
 
   @PreDestroy
@@ -137,9 +181,42 @@ public class EndlessConsumer implements Runnable
     {
       log.info("{} - Was already stopped", id);
     }
+    catch (Exception e)
+    {
+      log.error("{} - Unexpected exception while trying to stop the consumer", id, e);
+    }
     finally
     {
       log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
     }
   }
+
+  public boolean running()
+  {
+    lock.lock();
+    try
+    {
+      return running;
+    }
+    finally
+    {
+      lock.unlock();
+    }
+  }
+
+  public Optional<Exception> exitStatus()
+  {
+    lock.lock();
+    try
+    {
+      if (running)
+        throw new IllegalStateException("No exit-status available: Consumer instance " + id + " is running!");
+
+      return Optional.ofNullable(exception);
+    }
+    finally
+    {
+      lock.unlock();
+    }
+  }
 }