juplo.de Git - demos/kafka/wordcount/blob - src/main/java/de/juplo/kafka/wordcount/counter/CounterStreamProcessor.java

   1 package de.juplo.kafka.wordcount.counter;
   2
   3 import com.fasterxml.jackson.databind.ObjectMapper;
   4 import de.juplo.kafka.wordcount.avro.Key;
   5 import io.confluent.kafka.serializers.AbstractKafkaSchemaSerDeConfig;
   6 import io.confluent.kafka.streams.serdes.avro.SpecificAvroSerde;
   7 import lombok.extern.slf4j.Slf4j;
   8 import org.apache.kafka.clients.consumer.ConsumerConfig;
   9 import org.apache.kafka.common.serialization.Serdes;
  10 import org.apache.kafka.streams.KafkaStreams;
  11 import org.apache.kafka.streams.KeyValue;
  12 import org.apache.kafka.streams.StreamsBuilder;
  13 import org.apache.kafka.streams.StreamsConfig;
  14 import org.apache.kafka.streams.kstream.Consumed;
  15 import org.apache.kafka.streams.kstream.KStream;
  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.Arrays;
  23 import java.util.Properties;
  24 import java.util.concurrent.CompletableFuture;
  25 import java.util.regex.Pattern;
  26
  27 import static org.apache.kafka.streams.errors.StreamsUncaughtExceptionHandler.StreamThreadExceptionResponse.SHUTDOWN_CLIENT;
  28
  29
  30 @Slf4j
  31 @Component
  32 public class CounterStreamProcessor
  33 {
  34         final static Pattern PATTERN = Pattern.compile("\\W+");
  35
  36         public final KafkaStreams streams;
  37
  38
  39         public CounterStreamProcessor(
  40                         CounterApplicationProperties properties,
  41                         ObjectMapper mapper,
  42                         ConfigurableApplicationContext context)
  43         {
  44                 StreamsBuilder builder = new StreamsBuilder();
  45
  46                 KStream<String, String> source =
  47                                 builder.stream(
  48                                                 properties.getInputTopic(),
  49                                                 Consumed.with(Serdes.String(), Serdes.String()));
  50
  51                 source
  52                                 .flatMapValues(sentence -> Arrays.asList(PATTERN.split(sentence)))
  53                                 .map((username, word) ->
  54                                                 new KeyValue<>(
  55                                                                 Key.newBuilder().setUsername(username).setWord(word).build(),
  56                                                                 0l))
  57                                 .groupByKey()
  58                                 .count()
  59                                 .toStream()
  60                                 .to(properties.getOutputTopic());
  61
  62                 Properties props = new Properties();
  63                 props.put(StreamsConfig.APPLICATION_ID_CONFIG, properties.getApplicationId());
  64                 props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, properties.getBootstrapServer());
  65                 props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, SpecificAvroSerde.class);
  66                 props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.Long().getClass().getName());
  67                 props.put(AbstractKafkaSchemaSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG, properties.getSchemaRegistry());
  68                 props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
  69
  70                 streams = new KafkaStreams(builder.build(), props);
  71                 streams.setUncaughtExceptionHandler((Throwable e) ->
  72                 {
  73                         log.error("Unexpected error!", e);
  74                         CompletableFuture.runAsync(() ->
  75                         {
  76                                 log.info("Stopping application...");
  77                                 SpringApplication.exit(context, () -> 1);
  78                         });
  79                         return SHUTDOWN_CLIENT;
  80                 });
  81         }
  82
  83         @PostConstruct
  84         public void start()
  85         {
  86                 log.info("Starting Stream-Processor");
  87                 streams.start();
  88         }
  89
  90         @PreDestroy
  91         public void stop()
  92         {
  93                 log.info("Stopping Stream-Processor");
  94                 streams.close();
  95         }
  96 }