juplo.de Git - demos/kafka/outbox/blob - delivery/src/main/java/de/juplo/kafka/outbox/delivery/OutboxProducer.java

   1 package de.juplo.kafka.outbox.delivery;
   2
   3 import com.google.common.primitives.Longs;
   4 import org.apache.kafka.clients.consumer.ConsumerRecords;
   5 import org.apache.kafka.clients.consumer.KafkaConsumer;
   6 import org.apache.kafka.clients.consumer.OffsetAndMetadata;
   7 import org.apache.kafka.common.PartitionInfo;
   8 import org.apache.kafka.common.TopicPartition;
   9 import org.apache.kafka.common.serialization.StringDeserializer;
  10 import org.apache.kafka.common.serialization.StringSerializer;
  11
  12 import java.time.Clock;
  13 import java.time.Duration;
  14 import java.time.LocalTime;
  15 import java.util.*;
  16
  17 import org.apache.kafka.clients.producer.KafkaProducer;
  18 import org.apache.kafka.clients.producer.ProducerRecord;
  19 import org.slf4j.Logger;
  20 import org.slf4j.LoggerFactory;
  21 import org.springframework.scheduling.annotation.Scheduled;
  22
  23 import javax.annotation.PreDestroy;
  24
  25 import static org.apache.kafka.clients.CommonClientConfigs.BOOTSTRAP_SERVERS_CONFIG;
  26 import static org.apache.kafka.clients.consumer.ConsumerConfig.*;
  27 import static org.apache.kafka.clients.producer.ProducerConfig.*;
  28
  29
  30 public class OutboxProducer
  31 {
  32   final static Logger LOG = LoggerFactory.getLogger(OutboxProducer.class);
  33
  34   public final static String HEADER = "#";
  35
  36   private final OutboxRepository repository;
  37   private final KafkaProducer<String, String> producer;
  38   private final String topic;
  39   private final Watermarks watermarks;
  40   private final Clock clock;
  41   private final Duration cleanupInterval;
  42
  43   private long sequenceNumber = 0l;
  44   private LocalTime nextCleanup;
  45
  46   public OutboxProducer(
  47       ApplicationProperties properties,
  48       OutboxRepository repository,
  49       Clock clock)
  50   {
  51     this.repository = repository;
  52
  53     Properties props = new Properties();
  54     props.put(BOOTSTRAP_SERVERS_CONFIG, properties.bootstrapServers);
  55     props.put(KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
  56     props.put(VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
  57     props.put(ENABLE_IDEMPOTENCE_CONFIG, true);
  58
  59     this.producer = new KafkaProducer<>(props);
  60     this.topic = properties.topic;
  61
  62     props = new Properties();
  63     props.put(BOOTSTRAP_SERVERS_CONFIG, properties.bootstrapServers);
  64     props.put(GROUP_ID_CONFIG, "outbox");
  65     props.put(KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
  66     props.put(VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
  67
  68     KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
  69     consumer.subscribe(Arrays.asList(this.topic));
  70     List<PartitionInfo> partitions = consumer.listTopics().get(this.topic);
  71     Set<TopicPartition> assignment = new HashSet<>();
  72     for (PartitionInfo info : partitions)
  73     {
  74       LOG.debug("Found {}/{} (ISR: {})", info.topic(), info.partition(), info.inSyncReplicas());
  75       assignment.add(new TopicPartition(info.topic(), info.partition()));
  76     }
  77
  78     LOG.info("Using topic {} with {} partitions", topic, partitions);
  79
  80     this.watermarks = new Watermarks(partitions.size());
  81
  82     long[] currentOffsets = new long[partitions.size()];
  83     for (Map.Entry<TopicPartition, OffsetAndMetadata> entry : consumer.committed(assignment).entrySet())
  84     {
  85       LOG.info("Found current offset {} for partition {}", entry.getValue(), entry.getKey());
  86       currentOffsets[entry.getKey().partition()] = entry.getValue().offset() - 1l;
  87     }
  88     LOG.info("Current offsets: {}", currentOffsets);
  89
  90     long[] endOffsets = new long[partitions.size()];
  91     for (Map.Entry<TopicPartition, Long> entry : consumer.endOffsets(assignment).entrySet())
  92     {
  93       LOG.info("Found next offset {} for partition {}", entry.getValue(), entry.getKey());
  94       endOffsets[entry.getKey().partition()] = entry.getValue() - 1l;
  95     }
  96     LOG.info("End-offsets: {}", endOffsets);
  97
  98     while(!Arrays.equals(currentOffsets, endOffsets))
  99     {
 100       ConsumerRecords<String, String> records = consumer.poll(Duration.ofSeconds(1));
 101       LOG.debug("Fetched {} records", records.count());
 102       records.forEach(record ->
 103       {
 104         long recordSequenceNumber = Longs.fromByteArray(record.headers().lastHeader(HEADER).value());
 105         LOG.debug("Found watermark partition[{}]={}", record.partition(), recordSequenceNumber);
 106         watermarks.set(record.partition(), recordSequenceNumber);
 107         currentOffsets[record.partition()] = record.offset();
 108       });
 109       LOG.debug("Current offsets: {}", currentOffsets);
 110     }
 111
 112     LOG.info("Found watermarks: {}", watermarks);
 113
 114     sequenceNumber = watermarks.getLowest();
 115     LOG.info("Restored sequence-number: {}", sequenceNumber);
 116
 117     consumer.close();
 118
 119     this.clock = clock;
 120     this.cleanupInterval = properties.cleanupInterval;
 121     this.nextCleanup = LocalTime.now(clock);
 122   }
 123
 124   @Scheduled(fixedDelayString = "${de.juplo.kafka.outbox.interval}")
 125   public void poll()
 126   {
 127     List<OutboxItem> items;
 128     do
 129     {
 130       items = repository.fetch(sequenceNumber);
 131       LOG.debug("Polled {} new items", items.size());
 132       for (OutboxItem item : items)
 133         send(item);
 134       if (nextCleanup.isBefore(LocalTime.now(clock)))
 135       {
 136         int deleted = repository.delete(watermarks.getLowest());
 137         nextCleanup = LocalTime.now(clock).plus(cleanupInterval);
 138         LOG.info(
 139             "Cleaned up {} entries from outbox, next clean-up: {}",
 140             deleted,
 141             nextCleanup);
 142       }
 143     }
 144     while (items.size() > 0);
 145   }
 146
 147   void send(OutboxItem item)
 148   {
 149     final ProducerRecord<String, String> record =
 150         new ProducerRecord<>(topic, item.getKey(), item.getValue());
 151
 152     sequenceNumber = item.getSequenceNumber();
 153     record.headers().add(HEADER, Longs.toByteArray(sequenceNumber));
 154
 155     producer.send(record, (metadata, e) ->
 156     {
 157       if (metadata != null)
 158       {
 159         watermarks.set(metadata.partition(), item.getSequenceNumber());
 160         LOG.info(
 161             "{}/{}:{} - {}:{}={}",
 162             metadata.topic(),
 163             metadata.partition(),
 164             metadata.offset(),
 165             item.getSequenceNumber(),
 166             record.key(),
 167             record.value());
 168       }
 169       else
 170       {
 171         // HANDLE ERROR
 172         LOG.error(
 173             "{}/{} - {}:{}={} -> ",
 174             record.topic(),
 175             record.partition(),
 176             item.getSequenceNumber(),
 177             record.key(),
 178             record.value(),
 179             e);
 180       }
 181     });
 182   }
 183
 184
 185   @PreDestroy
 186   public void close()
 187   {
 188     producer.close(Duration.ofSeconds(5));
 189   }
 190 }