juplo.de Git - demos/kafka/training/blob - src/main/java/de/juplo/kafka/SimpleConsumer.java

   1 package de.juplo.kafka;
   2
   3 import lombok.RequiredArgsConstructor;
   4 import lombok.extern.slf4j.Slf4j;
   5 import org.apache.kafka.clients.consumer.Consumer;
   6 import org.apache.kafka.clients.consumer.ConsumerRecord;
   7 import org.apache.kafka.clients.consumer.ConsumerRecords;
   8 import org.apache.kafka.common.errors.WakeupException;
   9 import org.springframework.core.task.TaskExecutor;
  10
  11 import java.time.Duration;
  12 import java.util.Arrays;
  13
  14
  15 @Slf4j
  16 @RequiredArgsConstructor
  17 public class SimpleConsumer implements Runnable
  18 {
  19   private final TaskExecutor taskExecutor;
  20   private final String id;
  21   private final String topic;
  22   private final Consumer<String, String> consumer;
  23
  24   private long consumed = 0;
  25
  26
  27   public void start()
  28   {
  29     taskExecutor.execute(this);
  30   }
  31
  32   @Override
  33   public void run()
  34   {
  35     try
  36     {
  37       log.info("{} - Subscribing to topic test", id);
  38       consumer.subscribe(Arrays.asList(topic));
  39
  40       while (true)
  41       {
  42         ConsumerRecords<String, String> records =
  43             consumer.poll(Duration.ofSeconds(1));
  44
  45         log.info("{} - Received {} messages", id, records.count());
  46         for (ConsumerRecord<String, String> record : records)
  47         {
  48           consumed++;
  49           log.info(
  50               "{} - {}: {}/{} - {}={}",
  51               id,
  52               record.offset(),
  53               record.topic(),
  54               record.partition(),
  55               record.key(),
  56               record.value()
  57           );
  58         }
  59       }
  60     }
  61     catch(WakeupException e)
  62     {
  63       log.info("{} - Consumer was signaled to finish its work", id);
  64     }
  65     catch(Exception e)
  66     {
  67       log.error("{} - Unexpected error: {}, unsubscribing!", id, e.toString());
  68       consumer.unsubscribe();
  69     }
  70     finally
  71     {
  72       log.info("{} - Closing the KafkaConsumer", id);
  73       consumer.close();
  74       log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
  75     }
  76   }
  77 }