juplo.de Git - demos/microservices/blob - validation-results/src/main/java/de/trion/microservices/validationresults/ValidationResultsService.java

   1 package de.trion.microservices.validationresults;
   2
   3
   4 import de.trion.microservices.avro.Order;
   5 import de.trion.microservices.avro.OrderState;
   6 import static de.trion.microservices.avro.OrderState.APPROVED;
   7 import static de.trion.microservices.avro.OrderState.DECLINED;
   8 import de.trion.microservices.avro.OrderValidation;
   9 import static de.trion.microservices.avro.OrderValidationResult.PASS;
  10 import io.confluent.kafka.streams.serdes.avro.SpecificAvroSerde;
  11 import java.time.Duration;
  12 import java.util.Properties;
  13 import javax.annotation.PostConstruct;
  14 import javax.annotation.PreDestroy;
  15 import org.apache.kafka.common.serialization.Serdes;
  16 import org.apache.kafka.streams.KafkaStreams;
  17 import org.apache.kafka.streams.StreamsBuilder;
  18 import org.apache.kafka.streams.Topology;
  19 import org.apache.kafka.streams.kstream.JoinWindows;
  20 import org.slf4j.Logger;
  21 import org.slf4j.LoggerFactory;
  22 import org.springframework.stereotype.Component;
  23
  24
  25 @Component
  26 public class ValidationResultsService
  27 {
  28   final static Logger LOG = LoggerFactory.getLogger(ValidationResultsService.class);
  29
  30   private final String orders;
  31   private final String validation;
  32   private final KafkaStreams streams;
  33
  34
  35   public ValidationResultsService(ApplicationProperties config)
  36   {
  37     orders = config.ordersTopic;
  38     validation = config.validationTopic;
  39
  40     Properties properties = new Properties();
  41     properties.put("bootstrap.servers", config.bootstrapServers);
  42     properties.put("application.id", "validation-results");
  43     properties.put("schema.registry.url", config.schemaRegistryUrl);
  44     properties.put("default.key.serde", Serdes.String().getClass());
  45     properties.put("default.value.serde", SpecificAvroSerde.class);
  46
  47     StreamsBuilder builder = new StreamsBuilder();
  48     builder
  49         .<String,Order>stream(orders)
  50         .filter((id, order) -> order.getState() == OrderState.CREATED)
  51         .join(
  52             builder.<String,OrderValidation>stream(validation),
  53             (order, outcome) ->
  54             {
  55               return
  56                   Order
  57                       .newBuilder(order)
  58                       .setState(outcome.getValidationResult() == PASS ? APPROVED : DECLINED)
  59                       .build();
  60             },
  61             JoinWindows.of(Duration.ofHours(1)))
  62         .to(orders);
  63
  64     Topology topology = builder.build();
  65     streams = new KafkaStreams(topology, properties);
  66     streams.setUncaughtExceptionHandler((Thread t, Throwable e) ->
  67     {
  68       LOG.error("Unexpected error in thread {}: {}", t, e.toString());
  69       try
  70       {
  71         streams.close();
  72       }
  73       catch (Exception ex)
  74       {
  75         LOG.error("Could not close KafkaStreams!", ex);
  76       }
  77     });
  78   }
  79
  80
  81   @PostConstruct
  82   public void start()
  83   {
  84     streams.start();
  85   }
  86
  87   @PreDestroy
  88   public void stop()
  89   {
  90     streams.close();
  91   }
  92 }