juplo.de Git - demos/kafka/training/blob - src/main/java/de/juplo/kafka/RestGateway.java

   1 package de.juplo.kafka;
   2
   3 import lombok.RequiredArgsConstructor;
   4 import lombok.extern.slf4j.Slf4j;
   5 import org.apache.kafka.clients.producer.ProducerRecord;
   6 import org.apache.kafka.clients.producer.RecordMetadata;
   7 import org.springframework.http.HttpStatus;
   8 import org.springframework.kafka.core.KafkaTemplate;
   9 import org.springframework.kafka.support.SendResult;
  10 import org.springframework.util.concurrent.ListenableFuture;
  11 import org.springframework.web.bind.annotation.*;
  12 import org.springframework.web.context.request.async.DeferredResult;
  13
  14
  15 @Slf4j
  16 @RequestMapping
  17 @ResponseBody
  18 @RequiredArgsConstructor
  19 public class RestGateway
  20 {
  21   private final String id;
  22   private final Integer partition;
  23   private final KafkaTemplate<String, Integer> kafkaTemplate;
  24
  25   private long produced = 0;
  26
  27   @PostMapping(path = "{key}")
  28   public DeferredResult<ProduceResult> send(
  29       @PathVariable String key,
  30       @RequestHeader(name = "X-id", required = false) Long correlationId,
  31       @RequestBody Integer value)
  32   {
  33     DeferredResult<ProduceResult> result = new DeferredResult<>();
  34
  35     final long time = System.currentTimeMillis();
  36
  37     ListenableFuture<SendResult<String, Integer>> future =
  38         kafkaTemplate.send(null, partition, key, value);
  39
  40     long now = System.currentTimeMillis();
  41
  42     future.addCallback(
  43         sendResult ->
  44         {
  45           // HANDLE SUCCESS
  46           produced++;
  47           RecordMetadata metadata = sendResult.getRecordMetadata();
  48           ProducerRecord<String, Integer> record = sendResult.getProducerRecord();
  49           result.setResult(new ProduceSuccess(metadata.partition(), metadata.offset()));
  50           log.debug(
  51               "{} - Sent key={} message={} partition={}/{} timestamp={} latency={}ms",
  52               id,
  53               record.key(),
  54               record.value(),
  55               metadata.partition(),
  56               metadata.offset(),
  57               metadata.timestamp(),
  58               now - time
  59           );
  60         },
  61         e->
  62         {
  63           // HANDLE ERROR
  64           result.setErrorResult(new ProduceFailure(e));
  65           log.error(
  66               "{} - ERROR key={} latency={}ms: {}",
  67               id,
  68               key,
  69               now - time,
  70               e.toString()
  71           );
  72         });
  73
  74     log.trace(
  75         "{} - Queued message with key={} latency={}ms",
  76         id,
  77         key,
  78         now - time
  79     );
  80
  81     return result;
  82   }
  83
  84   @ExceptionHandler
  85   @ResponseStatus(HttpStatus.BAD_REQUEST)
  86   public ErrorResponse illegalStateException(IllegalStateException e)
  87   {
  88     return new ErrorResponse(e.getMessage(), HttpStatus.BAD_REQUEST.value());
  89   }
  90 }