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<Integer, Map<String, Integer>> 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             Map<String, Integer> removed = seen.remove(tp.partition());
  85             for (String key : removed.keySet())
  86             {
  87               log.info(
  88                   "{} - Seen {} messages for partition={}|key={}",
  89                   id,
  90                   removed.get(key),
  91                   tp.partition(),
  92                   key);
  93             }
  94             repository.save(new StatisticsDocument(tp.partition(), 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(Integer.toString(tp.partition()))
 107                     .orElse(new StatisticsDocument(tp.partition()));
 108             consumer.seek(tp, document.offset);
 109             seen.put(tp.partition(), document.statistics);
 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           Integer partition = record.partition();
 135           String key = record.key() == null ? "NULL" : record.key();
 136           Map<String, Integer> byKey = seen.get(partition);
 137
 138           if (!byKey.containsKey(key))
 139             byKey.put(key, 0);
 140
 141           int seenByKey = byKey.get(key);
 142           seenByKey++;
 143           byKey.put(key, seenByKey);
 144         }
 145
 146         seen.forEach((partiton, statistics) -> repository.save(
 147             new StatisticsDocument(
 148                 partiton,
 149                 statistics,
 150                 consumer.position(new TopicPartition(topic, partiton)))));
 151       }
 152     }
 153     catch(WakeupException e)
 154     {
 155       log.info("{} - RIIING!", id);
 156     }
 157     catch(Exception e)
 158     {
 159       log.error("{} - Unexpected error: {}", id, e.toString(), e);
 160       running.set(false); // Mark the instance as not running
 161     }
 162     finally
 163     {
 164       log.info("{} - Closing the KafkaConsumer", id);
 165       consumer.close();
 166       log.info("{} - Consumer-Thread exiting", id);
 167     }
 168   }
 169
 170   public Map<Integer, Map<String, Integer>> getSeen()
 171   {
 172     return seen;
 173   }
 174
 175   public synchronized void start()
 176   {
 177     boolean stateChanged = running.compareAndSet(false, true);
 178     if (!stateChanged)
 179       throw new RuntimeException("Consumer instance " + id + " is already running!");
 180
 181     log.info("{} - Starting - consumed {} messages before", id, consumed);
 182     future = executor.submit(this);
 183   }
 184
 185   public synchronized void stop() throws ExecutionException, InterruptedException
 186   {
 187     boolean stateChanged = running.compareAndSet(true, false);
 188     if (!stateChanged)
 189       throw new RuntimeException("Consumer instance " + id + " is not running!");
 190
 191     log.info("{} - Stopping", id);
 192     consumer.wakeup();
 193     future.get();
 194     log.info("{} - Stopped - consumed {} messages so far", id, consumed);
 195   }
 196
 197   @PreDestroy
 198   public void destroy() throws ExecutionException, InterruptedException
 199   {
 200     log.info("{} - Destroy!", id);
 201     try
 202     {
 203       stop();
 204     }
 205     catch (IllegalStateException e)
 206     {
 207       log.info("{} - Was already stopped", id);
 208     }
 209     finally
 210     {
 211       log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
 212     }
 213   }
 214 }