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