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     List<PartitionInfo> partitions = consumer.listTopics().get(this.topic);
  69     Set<TopicPartition> assignment = new HashSet<>();
  70     for (PartitionInfo info : partitions)
  71     {
  72       LOG.debug("Found {}/{} (ISR: {})", info.topic(), info.partition(), info.inSyncReplicas());
  73       assignment.add(new TopicPartition(info.topic(), info.partition()));
  74     }
  75
  76     LOG.info("Using topic {} with {} partitions", topic, partitions);
  77
  78     KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
  79     consumer.assign(assignment);
  80
  81     this.watermarks = new Watermarks(partitions.size());
  82
  83     long[] currentOffsets = new long[partitions.size()];
  84     for (Map.Entry<TopicPartition, OffsetAndMetadata> entry : consumer.committed(assignment).entrySet())
  85     {
  86       LOG.info("Found current offset {} for partition {}", entry.getValue(), entry.getKey());
  87       currentOffsets[entry.getKey().partition()] = entry.getValue().offset() - 1l;
  88     }
  89     LOG.info("Current offsets: {}", currentOffsets);
  90
  91     long[] endOffsets = new long[partitions.size()];
  92     for (Map.Entry<TopicPartition, Long> entry : consumer.endOffsets(assignment).entrySet())
  93     {
  94       LOG.info("Found next offset {} for partition {}", entry.getValue(), entry.getKey());
  95       endOffsets[entry.getKey().partition()] = entry.getValue() - 1l;
  96     }
  97     LOG.info("End-offsets: {}", endOffsets);
  98
  99     while(!Arrays.equals(currentOffsets, endOffsets))
 100     {
 101       ConsumerRecords<String, String> records = consumer.poll(Duration.ofSeconds(1));
 102       LOG.debug("Fetched {} records", records.count());
 103       records.forEach(record ->
 104       {
 105         long recordSequenceNumber = Longs.fromByteArray(record.headers().lastHeader(HEADER).value());
 106         LOG.debug("Found watermark partition[{}]={}", record.partition(), recordSequenceNumber);
 107         watermarks.set(record.partition(), recordSequenceNumber);
 108         currentOffsets[record.partition()] = record.offset();
 109       });
 110       LOG.debug("Current offsets: {}", currentOffsets);
 111     }
 112
 113     LOG.info("Found watermarks: {}", watermarks);
 114
 115     sequenceNumber = watermarks.getLowest();
 116     LOG.info("Restored sequence-number: {}", sequenceNumber);
 117
 118     consumer.close();
 119
 120     this.clock = clock;
 121     this.cleanupInterval = properties.cleanupInterval;
 122     this.nextCleanup = LocalTime.now(clock);
 123   }
 124
 125   @Scheduled(fixedDelayString = "${de.juplo.kafka.outbox.interval}")
 126   public void poll()
 127   {
 128     List<OutboxItem> items;
 129     do
 130     {
 131       items = repository.fetch(sequenceNumber);
 132       LOG.debug("Polled {} new items", items.size());
 133       for (OutboxItem item : items)
 134         send(item);
 135       if (nextCleanup.isBefore(LocalTime.now(clock)))
 136       {
 137         int deleted = repository.delete(watermarks.getLowest());
 138         nextCleanup = LocalTime.now(clock).plus(cleanupInterval);
 139         LOG.info(
 140             "Cleaned up {} entries from outbox, next clean-up: {}",
 141             deleted,
 142             nextCleanup);
 143       }
 144     }
 145     while (items.size() > 0);
 146   }
 147
 148   void send(OutboxItem item)
 149   {
 150     final ProducerRecord<String, String> record =
 151         new ProducerRecord<>(topic, item.getKey(), item.getValue());
 152
 153     sequenceNumber = item.getSequenceNumber();
 154     record.headers().add(HEADER, Longs.toByteArray(sequenceNumber));
 155
 156     producer.send(record, (metadata, e) ->
 157     {
 158       if (metadata != null)
 159       {
 160         watermarks.set(metadata.partition(), item.getSequenceNumber());
 161         LOG.info(
 162             "{}/{}:{} - {}:{}={}",
 163             metadata.topic(),
 164             metadata.partition(),
 165             metadata.offset(),
 166             item.getSequenceNumber(),
 167             record.key(),
 168             record.value());
 169       }
 170       else
 171       {
 172         // HANDLE ERROR
 173         LOG.error(
 174             "{}/{} - {}:{}={} -> ",
 175             record.topic(),
 176             record.partition(),
 177             item.getSequenceNumber(),
 178             record.key(),
 179             record.value(),
 180             e);
 181       }
 182     });
 183   }
 184
 185
 186   @PreDestroy
 187   public void close()
 188   {
 189     producer.close(Duration.ofSeconds(5));
 190   }
 191 }