juplo.de Git - demos/kafka/seek/blob - src/main/java/de/juplo/kafka/seek/Consumer.java

   1 package de.juplo.kafka.seek;
   2
   3 import lombok.extern.slf4j.Slf4j;
   4 import org.apache.kafka.clients.consumer.ConsumerRecord;
   5 import org.apache.kafka.clients.consumer.ConsumerRecords;
   6 import org.apache.kafka.clients.consumer.KafkaConsumer;
   7 import org.apache.kafka.common.TopicPartition;
   8 import org.apache.kafka.common.errors.WakeupException;
   9 import org.apache.kafka.common.serialization.StringDeserializer;
  10
  11 import javax.annotation.PreDestroy;
  12 import java.time.Duration;
  13 import java.util.Arrays;
  14 import java.util.Properties;
  15 import java.util.concurrent.ExecutionException;
  16 import java.util.concurrent.ExecutorService;
  17 import java.util.concurrent.Future;
  18
  19
  20 @Slf4j
  21 public class Consumer implements Runnable
  22 {
  23   private final ExecutorService executor;
  24   private final String id;
  25   private final String topic;
  26   private final KafkaConsumer<Long, String> consumer;
  27
  28   private boolean running = false;
  29   Long offset = null;
  30   Future<?> future = null;
  31
  32
  33   public Consumer(
  34       ExecutorService executor,
  35       String bootstrapServer,
  36       String groupId,
  37       String clientId,
  38       String topic)
  39   {
  40     this.executor = executor;
  41
  42     this.id = clientId;
  43     this.topic = topic;
  44
  45     Properties props = new Properties();
  46     props.put("bootstrap.servers", bootstrapServer);
  47     props.put("group.id", groupId);
  48     props.put("client.id", clientId);
  49     props.put("commit.interval.ms", 500);
  50     props.put("key.deserializer", StringDeserializer.class.getName());
  51     props.put("value.deserializer", StringDeserializer.class.getName());
  52
  53     consumer = new KafkaConsumer<>(props);
  54   }
  55
  56
  57   @Override
  58   public void run()
  59   {
  60     log.info("{} - Subscribing to topic test", id);
  61     consumer.subscribe(Arrays.asList(topic));
  62
  63     try
  64     {
  65
  66       running = true;
  67
  68       while (running)
  69       {
  70         if (offset != null)
  71         {
  72           log.info("{} - seeking to offset {}", id, offset);
  73           consumer
  74               .partitionsFor(topic)
  75               .forEach(partition ->
  76                   consumer.seek(
  77                       new TopicPartition(topic, partition.partition()),
  78                       offset));
  79           offset = null;
  80         }
  81
  82         ConsumerRecords<Long, String> records = consumer.poll(Duration.ofSeconds(1));
  83         for (ConsumerRecord<Long, String> record : records)
  84           log.info(
  85               "{} - {}: {}/{} - {}",
  86               id,
  87               record.offset(),
  88               record.topic(),
  89               record.partition(),
  90               record.value()
  91           );
  92       }
  93     }
  94     catch(WakeupException e)
  95     {
  96       log.info("{} - RIIING!", id);
  97     }
  98     catch(Exception e)
  99     {
 100       log.error("{} - Unexpected error: {}", id, e.toString());
 101     }
 102     finally
 103     {
 104       log.info("{} - Unsubscribing...", id);
 105       consumer.unsubscribe();
 106       running = false;
 107       offset = null;
 108     }
 109   }
 110
 111
 112   public void seek(long offset)
 113   {
 114     this.offset = offset;
 115   }
 116
 117
 118   public synchronized void start()
 119   {
 120     if (running)
 121       throw new RuntimeException("Consumier instance " + id + " is already running!");
 122
 123     log.info("Running {}", id);
 124     future = executor.submit(this);
 125   }
 126
 127   public synchronized void stop() throws ExecutionException, InterruptedException
 128   {
 129     if (!running)
 130       throw new RuntimeException("Consumier instance " + id + " is not running!");
 131
 132     log.info("Stopping {}", id);
 133     running = false;
 134     consumer.wakeup();
 135     future.get();
 136   }
 137
 138
 139   @PreDestroy
 140   public void destroy() throws ExecutionException, InterruptedException
 141   {
 142     stop();
 143     log.info("{} - Closing the KafkaConsumer", id);
 144     consumer.close(Duration.ofSeconds(3));
 145   }
 146 }