juplo.de Git - demos/kafka/wordcount/blob - src/main/java/de/juplo/kafka/wordcount/query/QueryStreamProcessor.java

   1 package de.juplo.kafka.wordcount.query;
   2
   3 import com.fasterxml.jackson.core.JsonProcessingException;
   4 import com.fasterxml.jackson.databind.ObjectMapper;
   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.*;
  11 import org.apache.kafka.streams.kstream.KStream;
  12 import org.apache.kafka.streams.kstream.KTable;
  13 import org.apache.kafka.streams.kstream.Materialized;
  14 import org.apache.kafka.streams.state.HostInfo;
  15 import org.apache.kafka.streams.state.QueryableStoreTypes;
  16 import org.apache.kafka.streams.state.ReadOnlyKeyValueStore;
  17 import org.springframework.boot.SpringApplication;
  18 import org.springframework.context.ConfigurableApplicationContext;
  19 import org.springframework.stereotype.Component;
  20
  21 import javax.annotation.PostConstruct;
  22 import javax.annotation.PreDestroy;
  23 import java.net.URI;
  24 import java.util.Optional;
  25 import java.util.Properties;
  26 import java.util.concurrent.CompletableFuture;
  27
  28 import static org.apache.kafka.streams.errors.StreamsUncaughtExceptionHandler.StreamThreadExceptionResponse.SHUTDOWN_CLIENT;
  29
  30
  31 @Slf4j
  32 @Component
  33 public class QueryStreamProcessor
  34 {
  35         public final KafkaStreams streams;
  36         public final HostInfo hostInfo;
  37         public final String storeName = "rankingsByUsername";
  38         public final StoreQueryParameters<ReadOnlyKeyValueStore<String, UserRankingTO>> storeParameters;
  39
  40
  41         public QueryStreamProcessor(
  42                         QueryApplicationProperties properties,
  43                         ObjectMapper mapper,
  44                         ConfigurableApplicationContext context)
  45         {
  46                 StreamsBuilder builder = new StreamsBuilder();
  47
  48                 KTable<String, UserTO> users = builder.table(properties.getUsersInputTopic());
  49                 KStream<String, RankingTO> rankings = builder.stream(properties.getRankingInputTopic());
  50
  51                 rankings
  52                                 .join(users, (ranking, user) ->
  53                                                 UserRankingTO
  54                                                                 .newBuilder()
  55                                                                 .setFirstName(user.getFirstName())
  56                                                                 .setLastName((user.getLastName()))
  57                                                                 .setTop10(ranking.getEntries())
  58                                                                 .build())
  59                                 .toTable(Materialized.as(storeName));
  60
  61                 Properties props = new Properties();
  62                 props.put(StreamsConfig.APPLICATION_ID_CONFIG, properties.getApplicationId());
  63                 props.put(StreamsConfig.APPLICATION_SERVER_CONFIG, properties.getApplicationServer());
  64                 props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, properties.getBootstrapServer());
  65                 props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass());
  66                 props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, SpecificAvroSerde.class);
  67                 props.put(AbstractKafkaSchemaSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG, "https://schema-registry:9081/");
  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                 hostInfo = HostInfo.buildFromEndpoint(properties.getApplicationServer());
  83                 storeParameters = StoreQueryParameters.fromNameAndType(storeName, QueryableStoreTypes.keyValueStore());;
  84         }
  85
  86         public Optional<URI> getRedirect(String username)
  87         {
  88                 KeyQueryMetadata metadata = streams.queryMetadataForKey(storeName, username, Serdes.String().serializer());
  89                 HostInfo activeHost = metadata.activeHost();
  90                 log.debug("Local store for {}: {}, {}:{}", username, metadata.partition(), activeHost.host(), activeHost.port());
  91
  92                 if (activeHost.equals(this.hostInfo) || activeHost.equals(HostInfo.unavailable()))
  93                 {
  94                         return Optional.empty();
  95                 }
  96
  97                 URI location = URI.create("http://" + activeHost.host() + ":" + activeHost.port() + "/" + username);
  98                 log.debug("Redirecting to {}", location);
  99                 return Optional.of(location);
 100         }
 101
 102         public Optional<UserRanking> getUserRanking(String username)
 103         {
 104                 return
 105                                 Optional
 106                                                 .ofNullable(streams.store(storeParameters).get(username))
 107                                                 .map(userRankingTO -> UserRanking.of(
 108                                                                 userRankingTO.getFirstName().toString(),
 109                                                                 userRankingTO.getLastName().toString(),
 110                                                                 userRankingTO
 111                                                                                 .getTop10()
 112                                                                                 .stream()
 113                                                                                 .map(entryTO -> Entry.of(entryTO.getWord().toString(), entryTO.getCount()))
 114                                                                                 .toArray(size -> new Entry[size])));
 115         }
 116
 117         @PostConstruct
 118         public void start()
 119         {
 120                 log.info("Starting Stream-Processor");
 121                 streams.start();
 122         }
 123
 124         @PreDestroy
 125         public void stop()
 126         {
 127                 log.info("Stopping Stream-Processor");
 128                 streams.close();
 129         }
 130 }