juplo.de Git - demos/kafka/wordcount/blob - src/main/java/de/juplo/kafka/wordcount/splitter/SplitterStreamProcessor.java

   1 package de.juplo.kafka.wordcount.splitter;
   2
   3 import lombok.extern.slf4j.Slf4j;
   4 import org.apache.kafka.clients.consumer.ConsumerConfig;
   5 import org.apache.kafka.common.serialization.Serdes;
   6 import org.apache.kafka.streams.KafkaStreams;
   7 import org.apache.kafka.streams.StreamsBuilder;
   8 import org.apache.kafka.streams.StreamsConfig;
   9 import org.apache.kafka.streams.kstream.Consumed;
  10 import org.apache.kafka.streams.kstream.KStream;
  11 import org.apache.kafka.streams.kstream.Produced;
  12 import org.springframework.boot.SpringApplication;
  13 import org.springframework.context.ConfigurableApplicationContext;
  14 import org.springframework.kafka.support.serializer.JsonSerde;
  15 import org.springframework.stereotype.Component;
  16
  17 import jakarta.annotation.PostConstruct;
  18 import jakarta.annotation.PreDestroy;
  19 import java.util.Arrays;
  20 import java.util.Properties;
  21 import java.util.concurrent.CompletableFuture;
  22 import java.util.regex.Pattern;
  23
  24 import static org.apache.kafka.streams.errors.StreamsUncaughtExceptionHandler.StreamThreadExceptionResponse.SHUTDOWN_CLIENT;
  25
  26
  27 @Slf4j
  28 @Component
  29 public class SplitterStreamProcessor
  30 {
  31         final static Pattern PATTERN = Pattern.compile("\\W+");
  32
  33         public final KafkaStreams streams;
  34
  35
  36         public SplitterStreamProcessor(
  37                         SplitterApplicationProperties properties,
  38                         ConfigurableApplicationContext context)
  39         {
  40                 StreamsBuilder builder = new StreamsBuilder();
  41
  42                 JsonSerde<Recording> recordSerde =
  43                                 new JsonSerde<>(Recording.class).ignoreTypeHeaders();
  44
  45                 KStream<String, Recording> source = builder.stream(
  46                                 properties.getInputTopic(),
  47                                 Consumed.with(Serdes.String(), recordSerde));
  48
  49                 source
  50                                 .flatMapValues(recording -> Arrays
  51                                                         .stream(PATTERN.split(recording.getSentence()))
  52                                                         .map(word -> Word.of(recording.getUser(), word))
  53                                                         .toList())
  54                                 .to(properties.getOutputTopic());
  55
  56                 Properties props = new Properties();
  57                 props.put(StreamsConfig.APPLICATION_ID_CONFIG, properties.getApplicationId());
  58                 props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, properties.getBootstrapServer());
  59                 props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
  60                 props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, JsonSerde.class.getName());
  61                 props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
  62
  63                 streams = new KafkaStreams(builder.build(), props);
  64                 streams.setUncaughtExceptionHandler((Throwable e) ->
  65                 {
  66                         log.error("Unexpected error!", e);
  67                         CompletableFuture.runAsync(() ->
  68                         {
  69                                 log.info("Stopping application...");
  70                                 SpringApplication.exit(context, () -> 1);
  71                         });
  72                         return SHUTDOWN_CLIENT;
  73                 });
  74         }
  75
  76         @PostConstruct
  77         public void start()
  78         {
  79                 log.info("Starting Stream-Processor");
  80                 streams.start();
  81         }
  82
  83         @PreDestroy
  84         public void stop()
  85         {
  86                 log.info("Stopping Stream-Processor");
  87                 streams.close();
  88         }
  89 }