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     try
  61     {
  62       log.info("{} - Subscribing to topic test", id);
  63       consumer.subscribe(Arrays.asList(topic));
  64
  65       while (running)
  66       {
  67         if (offset != null)
  68         {
  69           log.info("{} - seeking to offset {}", id, offset);
  70           consumer
  71               .partitionsFor(topic)
  72               .forEach(partition ->
  73                   consumer.seek(
  74                       new TopicPartition(topic, partition.partition()),
  75                       offset));
  76           offset = null;
  77         }
  78
  79         ConsumerRecords<Long, String> records = consumer.poll(Duration.ofSeconds(1));
  80         for (ConsumerRecord<Long, String> record : records)
  81           log.info(
  82               "{} - {}: {}/{} - {}",
  83               id,
  84               record.offset(),
  85               record.topic(),
  86               record.partition(),
  87               record.value()
  88           );
  89       }
  90     }
  91     catch(WakeupException e)
  92     {
  93       log.info("{} - RIIING!", id);
  94     }
  95     catch(Exception e)
  96     {
  97       log.error("{} - Unexpected error: {}", id, e.toString());
  98     }
  99     finally
 100     {
 101       log.info("{} - Unsubscribing...", id);
 102       running = false;
 103       consumer.unsubscribe();
 104       offset = null;
 105     }
 106   }
 107
 108
 109   public void seek(long offset)
 110   {
 111     this.offset = offset;
 112   }
 113
 114
 115   public synchronized void start()
 116   {
 117     if (running)
 118       throw new RuntimeException("Consumier instance " + id + " is already running!");
 119
 120     log.info("Running {}", id);
 121     running = true;
 122     future = executor.submit(this);
 123   }
 124
 125   public synchronized void stop() throws ExecutionException, InterruptedException
 126   {
 127     if (!running)
 128       throw new RuntimeException("Consumier instance " + id + " is not running!");
 129
 130     log.info("Stopping {}", id);
 131     running = false;
 132     consumer.wakeup();
 133     future.get();
 134   }
 135
 136   @PreDestroy
 137   public void destroy() throws ExecutionException, InterruptedException
 138   {
 139     stop();
 140     log.info("{} - Closing the KafkaConsumer", id);
 141     consumer.close(Duration.ofSeconds(3));
 142   }
 143 }