juplo.de Git - demos/kafka/wordcount/blob - src/main/java/de/juplo/kafka/wordcount/top10/Top10StreamProcessor.java

   1 package de.juplo.kafka.wordcount.top10;
   2
   3 import com.fasterxml.jackson.databind.ObjectMapper;
   4 import de.juplo.kafka.wordcount.avro.Entry;
   5 import de.juplo.kafka.wordcount.avro.Key;
   6 import de.juplo.kafka.wordcount.avro.Ranking;
   7 import io.confluent.kafka.serializers.AbstractKafkaSchemaSerDeConfig;
   8 import io.confluent.kafka.streams.serdes.avro.SpecificAvroSerde;
   9 import io.confluent.kafka.streams.serdes.avro.SpecificAvroSerializer;
  10 import lombok.extern.slf4j.Slf4j;
  11 import org.apache.kafka.clients.consumer.ConsumerConfig;
  12 import org.apache.kafka.common.serialization.Serdes;
  13 import org.apache.kafka.streams.*;
  14 import org.apache.kafka.streams.kstream.Consumed;
  15 import org.apache.kafka.streams.kstream.Grouped;
  16 import org.apache.kafka.streams.kstream.Materialized;
  17 import org.apache.kafka.streams.kstream.Produced;
  18 import org.springframework.boot.SpringApplication;
  19 import org.springframework.context.ConfigurableApplicationContext;
  20 import org.springframework.stereotype.Component;
  21
  22 import javax.annotation.PostConstruct;
  23 import javax.annotation.PreDestroy;
  24 import java.util.LinkedList;
  25 import java.util.Properties;
  26 import java.util.concurrent.CompletableFuture;
  27 import java.util.regex.Pattern;
  28
  29 import static org.apache.kafka.streams.errors.StreamsUncaughtExceptionHandler.StreamThreadExceptionResponse.SHUTDOWN_CLIENT;
  30
  31
  32 @Slf4j
  33 @Component
  34 public class Top10StreamProcessor
  35 {
  36         final static Pattern PATTERN = Pattern.compile("\\W+");
  37
  38         public final KafkaStreams streams;
  39
  40
  41         public Top10StreamProcessor(
  42                         Top10ApplicationProperties properties,
  43                         ObjectMapper mapper,
  44                         ConfigurableApplicationContext context)
  45         {
  46                 StreamsBuilder builder = new StreamsBuilder();
  47
  48                 builder
  49                                 .<Key, Long>stream(properties.getInputTopic(), Consumed.with(null, Serdes.Long()))
  50                                 .map((key, count) -> new KeyValue<>(
  51                                                 key.getUsername(),
  52                                                 Entry.newBuilder().setWord(key.getWord()).setCount(count).build()))
  53                                 .groupByKey(Grouped.keySerde(Serdes.String()))
  54                                 .aggregate(
  55                                                 () -> Ranking.newBuilder().setEntries(new LinkedList<Entry>()).build(),
  56                                                 (username, entry, ranking) -> {
  57                                                         ranking.getEntries().add(entry);
  58                                                         return ranking;
  59                                                 })
  60                                 .toStream()
  61                                 .to(properties.getOutputTopic(), Produced.keySerde(Serdes.String()));
  62
  63                 Properties props = new Properties();
  64                 props.put(StreamsConfig.APPLICATION_ID_CONFIG, properties.getApplicationId());
  65                 props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, properties.getBootstrapServer());
  66                 props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, SpecificAvroSerde.class);
  67                 props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, SpecificAvroSerde.class);
  68                 props.put(AbstractKafkaSchemaSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG, properties.getSchemaRegistry());
  69                 props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
  70
  71                 Topology topology = builder.build();
  72                 log.info("Topology:\n-----------------\n\n{}-----------------", topology.describe());
  73
  74                 streams = new KafkaStreams(topology, props);
  75                 streams.setUncaughtExceptionHandler((Throwable e) ->
  76                 {
  77                         log.error("Unexpected error!", e);
  78                         CompletableFuture.runAsync(() ->
  79                         {
  80                                 log.info("Stopping application...");
  81                                 SpringApplication.exit(context, () -> 1);
  82                         });
  83                         return SHUTDOWN_CLIENT;
  84                 });
  85         }
  86
  87         @PostConstruct
  88         public void start()
  89         {
  90                 log.info("Starting Stream-Processor");
  91                 streams.start();
  92         }
  93
  94         @PreDestroy
  95         public void stop()
  96         {
  97                 log.info("Stopping Stream-Processor");
  98                 streams.close();
  99         }
 100 }