juplo.de Git - demos/kafka/training/blob - src/main/java/de/juplo/kafka/EndlessConsumer.java

   1 package de.juplo.kafka;
   2
   3 import lombok.extern.slf4j.Slf4j;
   4 import org.apache.kafka.clients.consumer.ConsumerRebalanceListener;
   5 import org.apache.kafka.clients.consumer.ConsumerRecord;
   6 import org.apache.kafka.clients.consumer.ConsumerRecords;
   7 import org.apache.kafka.clients.consumer.KafkaConsumer;
   8 import org.apache.kafka.common.TopicPartition;
   9 import org.apache.kafka.common.errors.WakeupException;
  10 import org.apache.kafka.common.serialization.StringDeserializer;
  11
  12 import javax.annotation.PreDestroy;
  13 import java.time.Duration;
  14 import java.util.*;
  15 import java.util.concurrent.ExecutionException;
  16 import java.util.concurrent.ExecutorService;
  17 import java.util.concurrent.Future;
  18 import java.util.concurrent.atomic.AtomicBoolean;
  19
  20
  21 @Slf4j
  22 public class EndlessConsumer implements Runnable
  23 {
  24   private final ExecutorService executor;
  25   private final PartitionStatisticsRepository repository;
  26   private final String bootstrapServer;
  27   private final String groupId;
  28   private final String id;
  29   private final String topic;
  30   private final String autoOffsetReset;
  31
  32   private AtomicBoolean running = new AtomicBoolean();
  33   private long consumed = 0;
  34   private KafkaConsumer<String, String> consumer = null;
  35   private Future<?> future = null;
  36
  37   private final Map<TopicPartition, PartitionStatistics> seen = new HashMap<>();
  38
  39
  40   public EndlessConsumer(
  41       ExecutorService executor,
  42       PartitionStatisticsRepository repository,
  43       String bootstrapServer,
  44       String groupId,
  45       String clientId,
  46       String topic,
  47       String autoOffsetReset)
  48   {
  49     this.executor = executor;
  50     this.repository = repository;
  51     this.bootstrapServer = bootstrapServer;
  52     this.groupId = groupId;
  53     this.id = clientId;
  54     this.topic = topic;
  55     this.autoOffsetReset = autoOffsetReset;
  56   }
  57
  58   @Override
  59   public void run()
  60   {
  61     try
  62     {
  63       Properties props = new Properties();
  64       props.put("bootstrap.servers", bootstrapServer);
  65       props.put("group.id", groupId);
  66       props.put("client.id", id);
  67       props.put("enable.auto.commit", false);
  68       props.put("auto.offset.reset", autoOffsetReset);
  69       props.put("metadata.max.age.ms", "1000");
  70       props.put("key.deserializer", StringDeserializer.class.getName());
  71       props.put("value.deserializer", StringDeserializer.class.getName());
  72
  73       this.consumer = new KafkaConsumer<>(props);
  74
  75       log.info("{} - Subscribing to topic {}", id, topic);
  76       consumer.subscribe(Arrays.asList(topic), new ConsumerRebalanceListener()
  77       {
  78         @Override
  79         public void onPartitionsRevoked(Collection<TopicPartition> partitions)
  80         {
  81           partitions.forEach(tp ->
  82           {
  83             log.info("{} - removing partition: {}", id, tp);
  84             PartitionStatistics removed = seen.remove(tp);
  85             for (KeyCounter counter : removed.getStatistics())
  86             {
  87               log.info(
  88                   "{} - Seen {} messages for partition={}|key={}",
  89                   id,
  90                   counter.getResult(),
  91                   removed.getPartition(),
  92                   counter.getKey());
  93             }
  94             repository.save(new StatisticsDocument(removed, consumer.position(tp)));
  95           });
  96         }
  97
  98         @Override
  99         public void onPartitionsAssigned(Collection<TopicPartition> partitions)
 100         {
 101           partitions.forEach(tp ->
 102           {
 103             log.info("{} - adding partition: {}", id, tp);
 104             StatisticsDocument document =
 105                 repository
 106                     .findById(tp.toString())
 107                     .orElse(new StatisticsDocument(tp));
 108             consumer.seek(tp, document.offset);
 109             seen.put(tp, new PartitionStatistics(document));
 110           });
 111         }
 112       });
 113
 114       while (true)
 115       {
 116         ConsumerRecords<String, String> records =
 117             consumer.poll(Duration.ofSeconds(1));
 118
 119         // Do something with the data...
 120         log.info("{} - Received {} messages", id, records.count());
 121         for (ConsumerRecord<String, String> record : records)
 122         {
 123           consumed++;
 124           log.info(
 125               "{} - {}: {}/{} - {}={}",
 126               id,
 127               record.offset(),
 128               record.topic(),
 129               record.partition(),
 130               record.key(),
 131               record.value()
 132           );
 133
 134           TopicPartition partition = new TopicPartition(record.topic(), record.partition());
 135           String key = record.key() == null ? "NULL" : record.key();
 136           seen.get(partition).increment(key);
 137         }
 138
 139         seen.forEach((tp, statistics) -> repository.save(new StatisticsDocument(statistics, consumer.position(tp))));
 140       }
 141     }
 142     catch(WakeupException e)
 143     {
 144       log.info("{} - RIIING!", id);
 145     }
 146     catch(Exception e)
 147     {
 148       log.error("{} - Unexpected error: {}", id, e.toString(), e);
 149       running.set(false); // Mark the instance as not running
 150     }
 151     finally
 152     {
 153       log.info("{} - Closing the KafkaConsumer", id);
 154       consumer.close();
 155       log.info("{} - Consumer-Thread exiting", id);
 156     }
 157   }
 158
 159   public Map<TopicPartition, PartitionStatistics> getSeen()
 160   {
 161     return seen;
 162   }
 163
 164   public synchronized void start()
 165   {
 166     boolean stateChanged = running.compareAndSet(false, true);
 167     if (!stateChanged)
 168       throw new RuntimeException("Consumer instance " + id + " is already running!");
 169
 170     log.info("{} - Starting - consumed {} messages before", id, consumed);
 171     future = executor.submit(this);
 172   }
 173
 174   public synchronized void stop() throws ExecutionException, InterruptedException
 175   {
 176     boolean stateChanged = running.compareAndSet(true, false);
 177     if (!stateChanged)
 178       throw new RuntimeException("Consumer instance " + id + " is not running!");
 179
 180     log.info("{} - Stopping", id);
 181     consumer.wakeup();
 182     future.get();
 183     log.info("{} - Stopped - consumed {} messages so far", id, consumed);
 184   }
 185
 186   @PreDestroy
 187   public void destroy() throws ExecutionException, InterruptedException
 188   {
 189     log.info("{} - Destroy!", id);
 190     try
 191     {
 192       stop();
 193     }
 194     catch (IllegalStateException e)
 195     {
 196       log.info("{} - Was already stopped", id);
 197     }
 198     finally
 199     {
 200       log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
 201     }
 202   }
 203 }