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.databind.ObjectMapper;
   4 import de.juplo.kafka.wordcount.avro.Entry;
   5 import de.juplo.kafka.wordcount.avro.Ranking;
   6 import de.juplo.kafka.wordcount.avro.User;
   7 import de.juplo.kafka.wordcount.avro.UserRanking;
   8 import io.confluent.kafka.serializers.AbstractKafkaSchemaSerDeConfig;
   9 import io.confluent.kafka.streams.serdes.avro.SpecificAvroSerde;
  10 import lombok.extern.slf4j.Slf4j;
  11 import org.apache.kafka.clients.consumer.ConsumerConfig;
  12 import org.apache.kafka.common.serialization.Serdes;
  13 import org.apache.kafka.streams.*;
  14 import org.apache.kafka.streams.kstream.KStream;
  15 import org.apache.kafka.streams.kstream.KTable;
  16 import org.apache.kafka.streams.kstream.Materialized;
  17 import org.apache.kafka.streams.state.HostInfo;
  18 import org.apache.kafka.streams.state.QueryableStoreTypes;
  19 import org.apache.kafka.streams.state.ReadOnlyKeyValueStore;
  20 import org.springframework.boot.SpringApplication;
  21 import org.springframework.context.ConfigurableApplicationContext;
  22 import org.springframework.stereotype.Component;
  23
  24 import javax.annotation.PostConstruct;
  25 import javax.annotation.PreDestroy;
  26 import java.net.URI;
  27 import java.util.Optional;
  28 import java.util.Properties;
  29 import java.util.concurrent.CompletableFuture;
  30
  31 import static org.apache.kafka.streams.errors.StreamsUncaughtExceptionHandler.StreamThreadExceptionResponse.SHUTDOWN_CLIENT;
  32
  33
  34 @Slf4j
  35 @Component
  36 public class QueryStreamProcessor
  37 {
  38         public final KafkaStreams streams;
  39         public final HostInfo hostInfo;
  40         public final String storeName = "rankingsByUsername";
  41         public final StoreQueryParameters<ReadOnlyKeyValueStore<String, UserRanking>> storeParameters;
  42
  43
  44         public QueryStreamProcessor(
  45                         QueryApplicationProperties properties,
  46                         ObjectMapper mapper,
  47                         ConfigurableApplicationContext context)
  48         {
  49                 StreamsBuilder builder = new StreamsBuilder();
  50
  51                 KTable<String, User> users = builder.table(properties.getUsersInputTopic());
  52                 KStream<String, Ranking> rankings = builder.stream(properties.getRankingInputTopic());
  53
  54                 rankings
  55                                 .join(users, (ranking, user) ->
  56                                                 UserRanking
  57                                                                 .newBuilder()
  58                                                                 .setFirstName(user.getFirstName())
  59                                                                 .setLastName((user.getLastName()))
  60                                                                 .setTop10(ranking.getEntries())
  61                                                                 .build())
  62                                 .toTable(Materialized.as(storeName));
  63
  64                 Properties props = new Properties();
  65                 props.put(StreamsConfig.APPLICATION_ID_CONFIG, properties.getApplicationId());
  66                 props.put(StreamsConfig.APPLICATION_SERVER_CONFIG, properties.getApplicationServer());
  67                 props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, properties.getBootstrapServer());
  68                 props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass());
  69                 props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, SpecificAvroSerde.class);
  70                 props.put(AbstractKafkaSchemaSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG, "https://schema-registry:9081/");
  71                 props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
  72
  73                 streams = new KafkaStreams(builder.build(), props);
  74                 streams.setUncaughtExceptionHandler((Throwable e) ->
  75                 {
  76                         log.error("Unexpected error!", e);
  77                         CompletableFuture.runAsync(() ->
  78                         {
  79                                 log.info("Stopping application...");
  80                                 SpringApplication.exit(context, () -> 1);
  81                         });
  82                         return SHUTDOWN_CLIENT;
  83                 });
  84
  85                 hostInfo = HostInfo.buildFromEndpoint(properties.getApplicationServer());
  86                 storeParameters = StoreQueryParameters.fromNameAndType(storeName, QueryableStoreTypes.keyValueStore());;
  87         }
  88
  89         public Optional<URI> getRedirect(String username)
  90         {
  91                 KeyQueryMetadata metadata = streams.queryMetadataForKey(storeName, username, Serdes.String().serializer());
  92                 HostInfo activeHost = metadata.activeHost();
  93                 log.debug("Local store for {}: {}, {}:{}", username, metadata.partition(), activeHost.host(), activeHost.port());
  94
  95                 if (activeHost.equals(this.hostInfo) || activeHost.equals(HostInfo.unavailable()))
  96                 {
  97                         return Optional.empty();
  98                 }
  99
 100                 URI location = URI.create("http://" + activeHost.host() + ":" + activeHost.port() + "/" + username);
 101                 log.debug("Redirecting to {}", location);
 102                 return Optional.of(location);
 103         }
 104
 105         public Optional<UserRankingResponse> getUserRanking(String username)
 106         {
 107                 return
 108                                 Optional
 109                                                 .ofNullable(streams.store(storeParameters).get(username))
 110                                                 .map(userRanking -> UserRankingResponse.of(
 111                                                                 userRanking.getFirstName(),
 112                                                                 userRanking.getLastName(),
 113                                                                 userRanking
 114                                                                                 .getTop10()
 115                                                                                 .stream()
 116                                                                                 .map((Entry entry) -> UserRankingResponse.Entry.of(entry.getWord(), entry.getCount()))
 117                                                                                 .toArray(size -> new UserRankingResponse.Entry[size])));
 118         }
 119
 120         @PostConstruct
 121         public void start()
 122         {
 123                 log.info("Starting Stream-Processor");
 124                 streams.start();
 125         }
 126
 127         @PreDestroy
 128         public void stop()
 129         {
 130                 log.info("Stopping Stream-Processor");
 131                 streams.close();
 132         }
 133 }