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
  10 import java.time.Duration;
  11 import java.util.Arrays;
  12 import java.util.concurrent.ExecutorService;
  13
  14
  15 @Slf4j
  16 @RequiredArgsConstructor
  17 public class SimpleConsumer implements Runnable
  18 {
  19   private final ExecutorService executor;
  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   @Override
  28   public void run()
  29   {
  30     try
  31     {
  32       log.info("{} - Subscribing to topic test", id);
  33       consumer.subscribe(Arrays.asList(topic));
  34
  35       while (true)
  36       {
  37         ConsumerRecords<String, String> records =
  38             consumer.poll(Duration.ofSeconds(1));
  39
  40         log.info("{} - Received {} messages", id, records.count());
  41         for (ConsumerRecord<String, String> record : records)
  42         {
  43           consumed++;
  44           log.info(
  45               "{} - {}: {}/{} - {}={}",
  46               id,
  47               record.offset(),
  48               record.topic(),
  49               record.partition(),
  50               record.key(),
  51               record.value()
  52           );
  53         }
  54       }
  55     }
  56     catch(WakeupException e)
  57     {
  58       log.info("{} - Consumer was signaled to finish its work", id);
  59     }
  60     catch(Exception e)
  61     {
  62       log.error("{} - Unexpected error: {}, unsubscribing!", id, e.toString());
  63       consumer.unsubscribe();
  64     }
  65     finally
  66     {
  67       log.info("{} - Closing the KafkaConsumer", id);
  68       consumer.close();
  69       log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
  70     }
  71   }
  72 }