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.core.JsonProcessingException;
   4 import com.fasterxml.jackson.databind.ObjectMapper;
   5 import jakarta.annotation.PostConstruct;
   6 import jakarta.annotation.PreDestroy;
   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.springframework.boot.SpringApplication;
  15 import org.springframework.context.ConfigurableApplicationContext;
  16 import org.springframework.kafka.support.serializer.JsonDeserializer;
  17 import org.springframework.kafka.support.serializer.JsonSerde;
  18 import org.springframework.kafka.support.serializer.JsonSerializer;
  19 import org.springframework.stereotype.Component;
  20
  21 import java.util.Properties;
  22 import java.util.concurrent.CompletableFuture;
  23 import java.util.regex.Pattern;
  24
  25 import static org.apache.kafka.streams.errors.StreamsUncaughtExceptionHandler.StreamThreadExceptionResponse.SHUTDOWN_CLIENT;
  26
  27
  28 @Slf4j
  29 @Component
  30 public class Top10StreamProcessor
  31 {
  32         final static Pattern PATTERN = Pattern.compile("\\W+");
  33
  34         public final KafkaStreams streams;
  35
  36
  37         public Top10StreamProcessor(
  38                         Top10ApplicationProperties properties,
  39                         ObjectMapper mapper,
  40                         ConfigurableApplicationContext context)
  41         {
  42                 StreamsBuilder builder = new StreamsBuilder();
  43
  44                 builder
  45                                 .<String, String>stream(properties.getInputTopic())
  46                                 .map((keyJson, countStr) ->
  47                                 {
  48                                         try
  49                                         {
  50                                                 Key key = mapper.readValue(keyJson, Key.class);
  51                                                 Long count = Long.parseLong(countStr);
  52                                                 Entry entry = Entry.of(key.getWord(), count);
  53                                                 String entryJson = mapper.writeValueAsString(entry);
  54                                                 return new KeyValue<>(key.getUsername(), entryJson);
  55                                         }
  56                                         catch (JsonProcessingException e)
  57                                         {
  58                                                 throw new RuntimeException(e);
  59                                         }
  60                                 })
  61                                 .groupByKey()
  62                                 .aggregate(
  63                                                 () -> "{\"entries\"     : []}",
  64                                                 (username, entryJson, rankingJson) ->
  65                                                 {
  66                                                         try
  67                                                         {
  68                                                                 Ranking ranking = mapper.readValue(rankingJson, Ranking.class);
  69                                                                 ranking.add(mapper.readValue(entryJson, Entry.class));
  70                                                                 return mapper.writeValueAsString(ranking);
  71                                                         }
  72                                                         catch (JsonProcessingException e)
  73                                                         {
  74                                                                 throw new RuntimeException(e);
  75                                                         }
  76                                                 }
  77                                 )
  78                                 .toStream()
  79                                 .to(properties.getOutputTopic());
  80
  81                 Properties props = new Properties();
  82                 props.put(StreamsConfig.APPLICATION_ID_CONFIG, properties.getApplicationId());
  83                 props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, properties.getBootstrapServer());
  84                 props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, JsonSerde.class.getName());
  85                 props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, JsonSerde.class.getName());
  86                 props.put(JsonSerializer.ADD_TYPE_INFO_HEADERS, false);
  87                 props.put(JsonDeserializer.TRUSTED_PACKAGES, Word.class.getPackageName());
  88                 props.put(JsonDeserializer.KEY_DEFAULT_TYPE, Word.class.getName());
  89                 props.put(JsonDeserializer.VALUE_DEFAULT_TYPE, WordCount.class.getName());
  90                 props.put(JsonDeserializer.USE_TYPE_INFO_HEADERS, false);
  91                 props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
  92
  93                 streams = new KafkaStreams(builder.build(), props);
  94                 streams.setUncaughtExceptionHandler((Throwable e) ->
  95                 {
  96                         log.error("Unexpected error!", e);
  97                         CompletableFuture.runAsync(() ->
  98                         {
  99                                 log.info("Stopping application...");
 100                                 SpringApplication.exit(context, () -> 1);
 101                         });
 102                         return SHUTDOWN_CLIENT;
 103                 });
 104         }
 105
 106         @PostConstruct
 107         public void start()
 108         {
 109                 log.info("Starting Stream-Processor");
 110                 streams.start();
 111         }
 112
 113         @PreDestroy
 114         public void stop()
 115         {
 116                 log.info("Stopping Stream-Processor");
 117                 streams.close();
 118         }
 119 }