Merge der überarbeiteten Compose-Konfiguration ('stored-state')

[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 7cb77aa..c79b1e0 100644 (file)
--- a/src/main/java/de/juplo/kafka/EndlessConsumer.java
+++ b/src/main/java/de/juplo/kafka/EndlessConsumer.java
@@ -14,8 +14,9 @@ import java.time.Duration;
 import java.util.*;
 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
@@ -29,10 +30,13 @@ public class EndlessConsumer implements Runnable
   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;
+
 
   private final Map<Integer, Map<String, Integer>> seen = new HashMap<>();
 
@@ -64,6 +68,7 @@ public class EndlessConsumer implements Runnable
       props.put("bootstrap.servers", bootstrapServer);
       props.put("group.id", groupId);
       props.put("client.id", id);
+      props.put("enable.auto.commit", false);
       props.put("auto.offset.reset", autoOffsetReset);
       props.put("metadata.max.age.ms", "1000");
       props.put("key.deserializer", StringDeserializer.class.getName());
@@ -90,7 +95,7 @@ public class EndlessConsumer implements Runnable
                   tp.partition(),
                   key);
             }
-            repository.save(new StatisticsDocument(tp.partition(), removed));
+            repository.save(new StatisticsDocument(tp.partition(), removed, consumer.position(tp)));
           });
         }
 
@@ -100,12 +105,12 @@ public class EndlessConsumer implements Runnable
           partitions.forEach(tp ->
           {
             log.info("{} - adding partition: {}", id, tp);
-            seen.put(
-                tp.partition(),
+            StatisticsDocument document =
                 repository
                     .findById(Integer.toString(tp.partition()))
-                    .map(document -> document.statistics)
-                    .orElse(new HashMap<>()));
+                    .orElse(new StatisticsDocument(tp.partition()));
+            consumer.seek(tp, document.offset);
+            seen.put(tp.partition(), document.statistics);
           });
         }
       });
@@ -141,16 +146,23 @@ public class EndlessConsumer implements Runnable
           seenByKey++;
           byKey.put(key, seenByKey);
         }
+
+        seen.forEach((partiton, statistics) -> repository.save(
+            new StatisticsDocument(
+                partiton,
+                statistics,
+                consumer.position(new TopicPartition(topic, partiton)))));
       }
     }
     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
     {
@@ -160,31 +172,67 @@ public class EndlessConsumer implements Runnable
     }
   }
 
+  private void shutdown()
+  {
+    shutdown(null);
+  }
+
+  private void shutdown(Exception e)
+  {
+    lock.lock();
+    try
+    {
+      running = false;
+      exception = e;
+      condition.signal();
+    }
+    finally
+    {
+      lock.unlock();
+    }
+  }
+
   public Map<Integer, Map<String, Integer>> getSeen()
   {
     return seen;
   }
 
-  public synchronized void start()
+  public void start()
   {
-    boolean stateChanged = running.compareAndSet(false, true);
-    if (!stateChanged)
-      throw new RuntimeException("Consumer instance " + id + " is already running!");
+    lock.lock();
+    try
+    {
+      if (running)
+        throw new IllegalStateException("Consumer instance " + id + " is already running!");
 
-    log.info("{} - Starting - consumed {} messages before", id, consumed);
-    future = executor.submit(this);
+      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
@@ -199,9 +247,42 @@ 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();
+    }
+  }
 }