import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
+import jakarta.annotation.PostConstruct;
+import jakarta.annotation.PreDestroy;
import lombok.extern.slf4j.Slf4j;
-import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.common.serialization.Serdes;
import org.apache.kafka.streams.*;
+import org.apache.kafka.streams.kstream.KStream;
+import org.apache.kafka.streams.kstream.KTable;
import org.apache.kafka.streams.kstream.Materialized;
import org.apache.kafka.streams.state.HostInfo;
+import org.apache.kafka.streams.state.KeyValueBytesStoreSupplier;
import org.apache.kafka.streams.state.QueryableStoreTypes;
import org.apache.kafka.streams.state.ReadOnlyKeyValueStore;
-import org.springframework.boot.SpringApplication;
-import org.springframework.context.ConfigurableApplicationContext;
-import org.springframework.stereotype.Component;
-import javax.annotation.PostConstruct;
-import javax.annotation.PreDestroy;
import java.net.URI;
import java.util.Optional;
import java.util.Properties;
-import java.util.concurrent.CompletableFuture;
-
-import static org.apache.kafka.streams.errors.StreamsUncaughtExceptionHandler.StreamThreadExceptionResponse.SHUTDOWN_CLIENT;
@Slf4j
-@Component
public class QueryStreamProcessor
{
+ public static final String STORE_NAME = "rankings-by-username";
+
public final KafkaStreams streams;
public final HostInfo hostInfo;
- public final String storeName = "rankingsByUsername";
public final StoreQueryParameters<ReadOnlyKeyValueStore<String, String>> storeParameters;
public final ObjectMapper mapper;
public QueryStreamProcessor(
- QueryApplicationProperties properties,
- ObjectMapper mapper,
- ConfigurableApplicationContext context)
+ Properties props,
+ HostInfo applicationServer,
+ String usersInputTopic,
+ String rankingInputTopic,
+ KeyValueBytesStoreSupplier storeSupplier,
+ ObjectMapper mapper)
{
- StreamsBuilder builder = new StreamsBuilder();
+ Topology topology = buildTopology(
+ usersInputTopic,
+ rankingInputTopic,
+ storeSupplier,
+ mapper);
+ streams = new KafkaStreams(topology, props);
+ hostInfo = applicationServer;
+ storeParameters = StoreQueryParameters.fromNameAndType(STORE_NAME, QueryableStoreTypes.keyValueStore());;
+ this.mapper = mapper;
+ }
- builder.table(properties.getRankingInputTopic(), Materialized.as(storeName));
+ static Topology buildTopology(
+ String usersInputTopic,
+ String rankingInputTopic,
+ KeyValueBytesStoreSupplier storeSupplier,
+ ObjectMapper mapper)
+ {
+ StreamsBuilder builder = new StreamsBuilder();
- Properties props = new Properties();
- props.put(StreamsConfig.APPLICATION_ID_CONFIG, properties.getApplicationId());
- props.put(StreamsConfig.APPLICATION_SERVER_CONFIG, properties.getApplicationServer());
- props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, properties.getBootstrapServer());
- props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
- props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
- props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
+ KTable<String, String> users = builder.table(usersInputTopic);
+ KStream<String, String> rankings = builder.stream(rankingInputTopic);
+
+ rankings
+ .join(users, (rankingJson, userJson) ->
+ {
+ try
+ {
+ Ranking ranking = mapper.readValue(rankingJson, Ranking.class);
+ User user = mapper.readValue(userJson, User.class);
+
+ return mapper.writeValueAsString(
+ UserRanking.of(
+ user.getFirstName(),
+ user.getLastName(),
+ ranking.getEntries()));
+ }
+ catch (JsonProcessingException e)
+ {
+ throw new RuntimeException(e);
+ }
+ })
+ .toTable(Materialized.as(storeSupplier));
+
+ Topology topology = builder.build();
+ log.info("\n\n{}", topology.describe());
+
+ return topology;
+ }
- streams = new KafkaStreams(builder.build(), props);
- streams.setUncaughtExceptionHandler((Throwable e) ->
- {
- log.error("Unexpected error!", e);
- CompletableFuture.runAsync(() ->
- {
- log.info("Stopping application...");
- SpringApplication.exit(context, () -> 1);
- });
- return SHUTDOWN_CLIENT;
- });
-
- hostInfo = HostInfo.buildFromEndpoint(properties.getApplicationServer());
- storeParameters = StoreQueryParameters.fromNameAndType(storeName, QueryableStoreTypes.keyValueStore());;
- this.mapper = mapper;
+ ReadOnlyKeyValueStore<String, UserRanking> getStore()
+ {
+ return streams.store(storeParameters);
}
public Optional<URI> getRedirect(String username)
{
- KeyQueryMetadata metadata = streams.queryMetadataForKey(storeName, username, Serdes.String().serializer());
+ KeyQueryMetadata metadata = streams.queryMetadataForKey(STORE_NAME, username, Serdes.String().serializer());
HostInfo activeHost = metadata.activeHost();
log.debug("Local store for {}: {}, {}:{}", username, metadata.partition(), activeHost.host(), activeHost.port());
- if (activeHost.equals(this.hostInfo))
+ if (activeHost.equals(this.hostInfo) || activeHost.equals(HostInfo.unavailable()))
{
return Optional.empty();
}
return Optional.of(location);
}
- public Optional<Ranking> getRanking(String username)
+ public Optional<UserRanking> getUserRanking(String username)
{
return
Optional
- .ofNullable(streams.store(storeParameters).get(username))
+ .ofNullable(getStore().get(username))
.map(json ->
{
try
{
- return mapper.readValue(json, Ranking.class);
+ return mapper.readValue(json, UserRanking.class);
}
catch (JsonProcessingException e)
{
projects / demos / kafka / wordcount / blobdiff