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 String topic;
  23   private final Integer partition;
  24   private final KafkaTemplate<String, Integer> kafkaTemplate;
  25
  26   private long produced = 0;
  27
  28   @PostMapping(path = "{key}")
  29   public DeferredResult<ProduceResult> send(
  30       @PathVariable String key,
  31       @RequestHeader(name = "X-id", required = false) Long correlationId,
  32       @RequestBody Integer value)
  33   {
  34     DeferredResult<ProduceResult> result = new DeferredResult<>();
  35
  36     final long time = System.currentTimeMillis();
  37
  38     ListenableFuture<SendResult<String, Integer>> future =
  39         kafkaTemplate.send(topic, partition, key, value);
  40
  41     long now = System.currentTimeMillis();
  42
  43     future.addCallback(
  44         sendResult ->
  45         {
  46           // HANDLE SUCCESS
  47           produced++;
  48           RecordMetadata metadata = sendResult.getRecordMetadata();
  49           ProducerRecord<String, Integer> record = sendResult.getProducerRecord();
  50           result.setResult(new ProduceSuccess(metadata.partition(), metadata.offset()));
  51           log.debug(
  52               "{} - Sent key={} message={} partition={}/{} timestamp={} latency={}ms",
  53               id,
  54               record.key(),
  55               record.value(),
  56               metadata.partition(),
  57               metadata.offset(),
  58               metadata.timestamp(),
  59               now - time
  60           );
  61         },
  62         e->
  63         {
  64           // HANDLE ERROR
  65           result.setErrorResult(new ProduceFailure(e));
  66           log.error(
  67               "{} - ERROR key={} latency={}ms: {}",
  68               id,
  69               key,
  70               now - time,
  71               e.toString()
  72           );
  73         });
  74
  75     log.trace(
  76         "{} - Queued message with key={} latency={}ms",
  77         id,
  78         key,
  79         now - time
  80     );
  81
  82     return result;
  83   }
  84
  85   @ExceptionHandler
  86   @ResponseStatus(HttpStatus.BAD_REQUEST)
  87   public ErrorResponse illegalStateException(IllegalStateException e)
  88   {
  89     return new ErrorResponse(e.getMessage(), HttpStatus.BAD_REQUEST.value());
  90   }
  91 }