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("auto.offset.reset", autoOffsetReset);
  68       props.put("metadata.max.age.ms", "1000");
  69       props.put("key.deserializer", StringDeserializer.class.getName());
  70       props.put("value.deserializer", StringDeserializer.class.getName());
  71
  72       this.consumer = new KafkaConsumer<>(props);
  73
  74       log.info("{} - Subscribing to topic {}", id, topic);
  75       consumer.subscribe(Arrays.asList(topic), new ConsumerRebalanceListener()
  76       {
  77         @Override
  78         public void onPartitionsRevoked(Collection<TopicPartition> partitions)
  79         {
  80           partitions.forEach(tp ->
  81           {
  82             log.info("{} - removing partition: {}", id, tp);
  83             Map<String, Integer> removed = seen.remove(tp.partition());
  84             for (String key : removed.keySet())
  85             {
  86               log.info(
  87                   "{} - Seen {} messages for partition={}|key={}",
  88                   id,
  89                   removed.get(key),
  90                   tp.partition(),
  91                   key);
  92             }
  93             repository.save(new StatisticsDocument(tp.partition(), removed));
  94           });
  95         }
  96
  97         @Override
  98         public void onPartitionsAssigned(Collection<TopicPartition> partitions)
  99         {
 100           partitions.forEach(tp ->
 101           {
 102             log.info("{} - adding partition: {}", id, tp);
 103             seen.put(
 104                 tp.partition(),
 105                 repository
 106                     .findById(Integer.toString(tp.partition()))
 107                     .map(document -> document.statistics)
 108                     .orElse(new HashMap<>()));
 109           });
 110         }
 111       });
 112
 113       while (true)
 114       {
 115         ConsumerRecords<String, String> records =
 116             consumer.poll(Duration.ofSeconds(1));
 117
 118         // Do something with the data...
 119         log.info("{} - Received {} messages", id, records.count());
 120         for (ConsumerRecord<String, String> record : records)
 121         {
 122           consumed++;
 123           log.info(
 124               "{} - {}: {}/{} - {}={}",
 125               id,
 126               record.offset(),
 127               record.topic(),
 128               record.partition(),
 129               record.key(),
 130               record.value()
 131           );
 132
 133           Integer partition = record.partition();
 134           String key = record.key() == null ? "NULL" : record.key();
 135           Map<String, Integer> byKey = seen.get(partition);
 136
 137           if (!byKey.containsKey(key))
 138             byKey.put(key, 0);
 139
 140           int seenByKey = byKey.get(key);
 141           seenByKey++;
 142           byKey.put(key, seenByKey);
 143         }
 144       }
 145     }
 146     catch(WakeupException e)
 147     {
 148       log.info("{} - RIIING!", id);
 149     }
 150     catch(Exception e)
 151     {
 152       log.error("{} - Unexpected error: {}", id, e.toString(), e);
 153       running.set(false); // Mark the instance as not running
 154     }
 155     finally
 156     {
 157       log.info("{} - Closing the KafkaConsumer", id);
 158       consumer.close();
 159       log.info("{} - Consumer-Thread exiting", id);
 160     }
 161   }
 162
 163   public Map<Integer, Map<String, Integer>> getSeen()
 164   {
 165     return seen;
 166   }
 167
 168   public synchronized void start()
 169   {
 170     boolean stateChanged = running.compareAndSet(false, true);
 171     if (!stateChanged)
 172       throw new RuntimeException("Consumer instance " + id + " is already running!");
 173
 174     log.info("{} - Starting - consumed {} messages before", id, consumed);
 175     future = executor.submit(this);
 176   }
 177
 178   public synchronized void stop() throws ExecutionException, InterruptedException
 179   {
 180     boolean stateChanged = running.compareAndSet(true, false);
 181     if (!stateChanged)
 182       throw new RuntimeException("Consumer instance " + id + " is not running!");
 183
 184     log.info("{} - Stopping", id);
 185     consumer.wakeup();
 186     future.get();
 187     log.info("{} - Stopped - consumed {} messages so far", id, consumed);
 188   }
 189
 190   @PreDestroy
 191   public void destroy() throws ExecutionException, InterruptedException
 192   {
 193     log.info("{} - Destroy!", id);
 194     try
 195     {
 196       stop();
 197     }
 198     catch (IllegalStateException e)
 199     {
 200       log.info("{} - Was already stopped", id);
 201     }
 202     finally
 203     {
 204       log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
 205     }
 206   }
 207 }