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 jakarta.annotation.PostConstruct;
   4 import jakarta.annotation.PreDestroy;
   5 import lombok.extern.slf4j.Slf4j;
   6 import org.apache.kafka.common.serialization.Serdes;
   7 import org.apache.kafka.streams.*;
   8 import org.apache.kafka.streams.kstream.*;
   9 import org.apache.kafka.streams.state.HostInfo;
  10 import org.apache.kafka.streams.state.KeyValueBytesStoreSupplier;
  11 import org.apache.kafka.streams.state.QueryableStoreTypes;
  12 import org.apache.kafka.streams.state.ReadOnlyKeyValueStore;
  13 import org.springframework.kafka.support.serializer.JsonSerde;
  14
  15 import java.net.URI;
  16 import java.util.Optional;
  17 import java.util.Properties;
  18
  19
  20 @Slf4j
  21 public class QueryStreamProcessor
  22 {
  23         public static final String STATS_TYPE = "COUNTER";
  24         public static final String USER_STORE_NAME = "users";
  25         public static final String RANKING_STORE_NAME = "rankings";
  26
  27         public final KafkaStreams streams;
  28         public final HostInfo hostInfo;
  29         public final StoreQueryParameters<ReadOnlyKeyValueStore<String, UserRanking>> storeParameters;
  30
  31
  32         public QueryStreamProcessor(
  33                         Properties props,
  34                         HostInfo applicationServer,
  35                         String usersInputTopic,
  36                         String rankingInputTopic,
  37                         KeyValueBytesStoreSupplier userStoreSupplier,
  38                         KeyValueBytesStoreSupplier rankingStoreSupplier)
  39         {
  40                 Topology topology = buildTopology(
  41                                 usersInputTopic,
  42                                 rankingInputTopic,
  43                                 userStoreSupplier,
  44                                 rankingStoreSupplier);
  45                 streams = new KafkaStreams(topology, props);
  46                 hostInfo = applicationServer;
  47                 storeParameters = StoreQueryParameters.fromNameAndType(RANKING_STORE_NAME, QueryableStoreTypes.keyValueStore());;
  48         }
  49
  50         static Topology buildTopology(
  51                         String usersInputTopic,
  52                         String rankingInputTopic,
  53                         KeyValueBytesStoreSupplier userStoreSupplier,
  54                         KeyValueBytesStoreSupplier rankingStoreSupplier)
  55         {
  56                 StreamsBuilder builder = new StreamsBuilder();
  57
  58                 KTable<String, User> users = builder
  59                                 .stream(
  60                                                 usersInputTopic,
  61                                                 Consumed.with(Serdes.String(), new JsonSerde().copyWithType(User.class)))
  62                                 .toTable(
  63                                                 Materialized
  64                                                                 .<String, User>as(userStoreSupplier)
  65                                                                 .withKeySerde(Serdes.String())
  66                                                                 .withValueSerde(new JsonSerde().copyWithType(User.class)));
  67                 KStream<String, Ranking> rankings = builder
  68                                 .<Key, Ranking>stream(rankingInputTopic)
  69                                 .filter((key, value) -> STATS_TYPE.equals(key.getType()))
  70                                 .map((key, value) -> new KeyValue<>(key.getChannel(), value));
  71
  72                 rankings
  73                                 .join(users, (ranking, user) -> UserRanking.of(
  74                                                 user.getFirstName(),
  75                                                 user.getLastName(),
  76                                                 ranking.getEntries()),
  77                                                 Joined.keySerde(Serdes.String()))
  78                                 .toTable(
  79                                                 Materialized
  80                                                                 .<String, UserRanking>as(rankingStoreSupplier)
  81                                                                 .withKeySerde(Serdes.String())
  82                                                                 .withValueSerde(new JsonSerde().copyWithType(UserRanking.class)));
  83
  84                 Topology topology = builder.build();
  85                 log.info("\n\n{}", topology.describe());
  86
  87                 return topology;
  88         }
  89
  90         ReadOnlyKeyValueStore<String, UserRanking> getStore()
  91         {
  92                 return streams.store(storeParameters);
  93         }
  94
  95         public Optional<URI> getRedirect(String username)
  96         {
  97                 KeyQueryMetadata metadata = streams.queryMetadataForKey(RANKING_STORE_NAME, username, Serdes.String().serializer());
  98                 HostInfo activeHost = metadata.activeHost();
  99                 log.debug("Local store for {}: {}, {}:{}", username, metadata.partition(), activeHost.host(), activeHost.port());
 100
 101                 if (activeHost.equals(this.hostInfo) || activeHost.equals(HostInfo.unavailable()))
 102                 {
 103                         return Optional.empty();
 104                 }
 105
 106                 URI location = URI.create("http://" + activeHost.host() + ":" + activeHost.port() + "/" + username);
 107                 log.debug("Redirecting to {}", location);
 108                 return Optional.of(location);
 109         }
 110
 111         public Optional<UserRanking> getUserRanking(String username)
 112         {
 113                 return Optional.ofNullable(getStore().get(username));
 114         }
 115
 116         @PostConstruct
 117         public void start()
 118         {
 119                 log.info("Starting Stream-Processor");
 120                 streams.start();
 121         }
 122
 123         @PreDestroy
 124         public void stop()
 125         {
 126                 log.info("Stopping Stream-Processor");
 127                 streams.close();
 128         }
 129 }