1 package de.juplo.kafka.wordcount.users;
3 import com.fasterxml.jackson.core.JsonProcessingException;
4 import com.fasterxml.jackson.databind.ObjectMapper;
5 import lombok.extern.slf4j.Slf4j;
6 import org.apache.kafka.clients.consumer.ConsumerConfig;
7 import org.apache.kafka.common.serialization.Serdes;
8 import org.apache.kafka.streams.*;
9 import org.apache.kafka.streams.kstream.Materialized;
10 import org.apache.kafka.streams.state.HostInfo;
11 import org.apache.kafka.streams.state.QueryableStoreTypes;
12 import org.apache.kafka.streams.state.ReadOnlyKeyValueStore;
13 import org.springframework.boot.SpringApplication;
14 import org.springframework.context.ConfigurableApplicationContext;
15 import org.springframework.stereotype.Component;
17 import javax.annotation.PostConstruct;
18 import javax.annotation.PreDestroy;
20 import java.util.Optional;
21 import java.util.Properties;
22 import java.util.concurrent.CompletableFuture;
24 import static org.apache.kafka.streams.errors.StreamsUncaughtExceptionHandler.StreamThreadExceptionResponse.SHUTDOWN_CLIENT;
29 public class UsersStreamProcessor
31 public final KafkaStreams streams;
32 public final HostInfo hostInfo;
33 public final String storeName = "rankingsByUsername";
34 public final StoreQueryParameters<ReadOnlyKeyValueStore<String, String>> storeParameters;
35 public final ObjectMapper mapper;
38 public UsersStreamProcessor(
39 UsersApplicationProperties properties,
41 ConfigurableApplicationContext context)
43 StreamsBuilder builder = new StreamsBuilder();
44 builder.table(properties.getTopic(), Materialized.as(storeName));
46 Properties props = new Properties();
47 props.put(StreamsConfig.APPLICATION_ID_CONFIG, properties.getApplicationId());
48 props.put(StreamsConfig.APPLICATION_SERVER_CONFIG, properties.getApplicationServer());
49 props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, properties.getBootstrapServer());
50 props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
51 props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
52 props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
54 streams = new KafkaStreams(builder.build(), props);
55 streams.setUncaughtExceptionHandler((Throwable e) ->
57 log.error("Unexpected error!", e);
58 CompletableFuture.runAsync(() ->
60 log.info("Stopping application...");
61 SpringApplication.exit(context, () -> 1);
63 return SHUTDOWN_CLIENT;
66 hostInfo = HostInfo.buildFromEndpoint(properties.getApplicationServer());
67 storeParameters = StoreQueryParameters.fromNameAndType(storeName, QueryableStoreTypes.keyValueStore());;
71 public Optional<URI> getRedirect(String username)
73 KeyQueryMetadata metadata = streams.queryMetadataForKey(storeName, username, Serdes.String().serializer());
74 HostInfo activeHost = metadata.activeHost();
75 log.debug("Local store for {}: {}, {}:{}", username, metadata.partition(), activeHost.host(), activeHost.port());
77 if (activeHost.equals(this.hostInfo) || activeHost.equals(HostInfo.unavailable()))
79 return Optional.empty();
82 URI location = URI.create("http://" + activeHost.host() + ":" + activeHost.port() + "/" + username);
83 log.debug("Redirecting to {}", location);
84 return Optional.of(location);
87 public Optional<User> getUser(String username)
91 .ofNullable(streams.store(storeParameters).get(username))
96 return mapper.readValue(json, User.class);
98 catch (JsonProcessingException e)
100 throw new RuntimeException(e);
108 log.info("Starting Stream-Processor");
115 log.info("Stopping Stream-Processor");