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