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