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.errors.WakeupException;
   8 import org.apache.kafka.common.serialization.LongDeserializer;
   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", LongDeserializer.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     finally
  85     {
  86       log.info("{} - Unsubscribing...", id);
  87       consumer.unsubscribe();
  88       running = false;
  89     }
  90   }
  91
  92   public synchronized void start()
  93   {
  94     if (running)
  95       throw new RuntimeException("Consumier instance " + id + " is already running!");
  96
  97     log.info("Running {}", id);
  98     future = executor.submit(this);
  99   }
 100
 101   public synchronized void stop() throws ExecutionException, InterruptedException
 102   {
 103     if (!running)
 104       throw new RuntimeException("Consumier instance " + id + " is not running!");
 105
 106     log.info("Stopping {}", id);
 107     running = false;
 108     consumer.wakeup();
 109     future.get();
 110   }
 111
 112   @PreDestroy
 113   public void destroy() throws ExecutionException, InterruptedException
 114   {
 115     stop();
 116     log.info("{} - Closing the KafkaConsumer", id);
 117     consumer.close(Duration.ofSeconds(3));
 118   }
 119 }