1 package de.juplo.kafka.wordcount.query;
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;
24 import javax.annotation.PostConstruct;
25 import javax.annotation.PreDestroy;
27 import java.util.Optional;
28 import java.util.Properties;
29 import java.util.concurrent.CompletableFuture;
31 import static org.apache.kafka.streams.errors.StreamsUncaughtExceptionHandler.StreamThreadExceptionResponse.SHUTDOWN_CLIENT;
36 public class QueryStreamProcessor
38 public final KafkaStreams streams;
39 public final HostInfo hostInfo;
40 public final String storeName = "rankingsByUsername";
41 public final StoreQueryParameters<ReadOnlyKeyValueStore<String, UserRanking>> storeParameters;
44 public QueryStreamProcessor(
45 QueryApplicationProperties properties,
47 ConfigurableApplicationContext context)
49 StreamsBuilder builder = new StreamsBuilder();
51 KTable<String, User> users = builder.table(properties.getUsersInputTopic());
52 KStream<String, Ranking> rankings = builder.stream(properties.getRankingInputTopic());
55 .join(users, (ranking, user) ->
58 .setFirstName(user.getFirstName())
59 .setLastName((user.getLastName()))
60 .setTop10(ranking.getEntries())
62 .toTable(Materialized.as(storeName));
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");
73 streams = new KafkaStreams(builder.build(), props);
74 streams.setUncaughtExceptionHandler((Throwable e) ->
76 log.error("Unexpected error!", e);
77 CompletableFuture.runAsync(() ->
79 log.info("Stopping application...");
80 SpringApplication.exit(context, () -> 1);
82 return SHUTDOWN_CLIENT;
85 hostInfo = HostInfo.buildFromEndpoint(properties.getApplicationServer());
86 storeParameters = StoreQueryParameters.fromNameAndType(storeName, QueryableStoreTypes.keyValueStore());;
89 public Optional<URI> getRedirect(String username)
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());
95 if (activeHost.equals(this.hostInfo) || activeHost.equals(HostInfo.unavailable()))
97 return Optional.empty();
100 URI location = URI.create("http://" + activeHost.host() + ":" + activeHost.port() + "/" + username);
101 log.debug("Redirecting to {}", location);
102 return Optional.of(location);
105 public Optional<UserRankingResponse> getUserRanking(String username)
109 .ofNullable(streams.store(storeParameters).get(username))
110 .map(userRanking -> UserRankingResponse.of(
111 userRanking.getFirstName(),
112 userRanking.getLastName(),
116 .map((Entry entry) -> UserRankingResponse.Entry.of(entry.getWord(), entry.getCount()))
117 .toArray(size -> new UserRankingResponse.Entry[size])));
123 log.info("Starting Stream-Processor");
130 log.info("Stopping Stream-Processor");