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   Future<?> future = null;
  30
  31
  32   public Consumer(
  33       ExecutorService executor,
  34       String bootstrapServer,
  35       String groupId,
  36       String clientId,
  37       String topic)
  38   {
  39     this.executor = executor;
  40
  41     this.id = clientId;
  42     this.topic = topic;
  43
  44     Properties props = new Properties();
  45     props.put("bootstrap.servers", bootstrapServer);
  46     props.put("group.id", groupId);
  47     props.put("client.id", clientId);
  48     props.put("key.deserializer", StringDeserializer.class.getName());
  49     props.put("value.deserializer", StringDeserializer.class.getName());
  50
  51     consumer = new KafkaConsumer<>(props);
  52   }
  53
  54
  55   @Override
  56   public void run()
  57   {
  58     log.info("{} - Subscribing to topic test", id);
  59     consumer.subscribe(Arrays.asList(topic));
  60
  61     try
  62     {
  63
  64       running = true;
  65
  66       while (running)
  67       {
  68         ConsumerRecords<Long, String> records = consumer.poll(Duration.ofSeconds(1));
  69         for (ConsumerRecord<Long, String> record : records)
  70           log.info(
  71               "{} - {}: {}/{} - {}",
  72               id,
  73               record.offset(),
  74               record.topic(),
  75               record.partition(),
  76               record.value()
  77           );
  78       }
  79     }
  80     catch(WakeupException e)
  81     {
  82       log.info("{} - RIIING!", id);
  83     }
  84     catch(Exception e)
  85     {
  86       log.error("{} - Unexpected error: {}", id, e.toString());
  87     }
  88     finally
  89     {
  90       log.info("{} - Unsubscribing...", id);
  91       consumer.unsubscribe();
  92       running = false;
  93     }
  94   }
  95
  96
  97   public void seek(long offset)
  98   {
  99     consumer
 100         .partitionsFor(topic)
 101         .forEach(partition ->
 102             consumer.seek(
 103                 new TopicPartition(topic, partition.partition()),
 104                 offset));
 105   }
 106
 107
 108   public synchronized void start()
 109   {
 110     if (running)
 111       throw new RuntimeException("Consumier instance " + id + " is already running!");
 112
 113     log.info("Running {}", id);
 114     future = executor.submit(this);
 115   }
 116
 117   public synchronized void stop() throws ExecutionException, InterruptedException
 118   {
 119     if (!running)
 120       throw new RuntimeException("Consumier instance " + id + " is not running!");
 121
 122     log.info("Stopping {}", id);
 123     running = false;
 124     consumer.wakeup();
 125     future.get();
 126   }
 127
 128
 129   @PreDestroy
 130   public void destroy() throws ExecutionException, InterruptedException
 131   {
 132     stop();
 133     log.info("{} - Closing the KafkaConsumer", id);
 134     consumer.close(Duration.ofSeconds(3));
 135   }
 136 }