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.scheduling.annotation.Async;
  10
  11 import java.time.Duration;
  12 import java.util.Arrays;
  13
  14
  15 @Slf4j
  16 @RequiredArgsConstructor
  17 public class SimpleConsumer
  18 {
  19   private final String id;
  20   private final String topic;
  21   private final Consumer<String, String> consumer;
  22
  23   private long consumed = 0;
  24
  25
  26   @Async
  27   public void run()
  28   {
  29     try
  30     {
  31       log.info("{} - Subscribing to topic test", id);
  32       consumer.subscribe(Arrays.asList(topic));
  33
  34       while (true)
  35       {
  36         ConsumerRecords<String, String> records =
  37             consumer.poll(Duration.ofSeconds(1));
  38
  39         log.info("{} - Received {} messages", id, records.count());
  40         for (ConsumerRecord<String, String> record : records)
  41         {
  42           consumed++;
  43           log.info(
  44               "{} - {}: {}/{} - {}={}",
  45               id,
  46               record.offset(),
  47               record.topic(),
  48               record.partition(),
  49               record.key(),
  50               record.value()
  51           );
  52         }
  53       }
  54     }
  55     catch(WakeupException e)
  56     {
  57       log.info("{} - Consumer was signaled to finish its work", id);
  58     }
  59     catch(Exception e)
  60     {
  61       log.error("{} - Unexpected error: {}, unsubscribing!", id, e.toString());
  62       consumer.unsubscribe();
  63     }
  64     finally
  65     {
  66       log.info("{} - Closing the KafkaConsumer", id);
  67       consumer.close();
  68       log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
  69     }
  70   }
  71 }