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.KafkaProducer;
   6 import org.apache.kafka.clients.producer.ProducerRecord;
   7 import org.springframework.http.HttpStatus;
   8 import org.springframework.web.bind.annotation.*;
   9 import org.springframework.web.context.request.async.DeferredResult;
  10
  11
  12 @Slf4j
  13 @RequestMapping
  14 @ResponseBody
  15 @RequiredArgsConstructor
  16 public class RestGateway
  17 {
  18   private final String id;
  19   private final String topic;
  20   private final KafkaProducer<String, Integer> producer;
  21
  22   private long produced = 0;
  23
  24   @PostMapping(path = "{key}")
  25   public DeferredResult<ProduceResult> send(
  26       @PathVariable String key,
  27       @RequestHeader(name = "X-id", required = false) Long correlationId,
  28       @RequestBody Integer value)
  29   {
  30     DeferredResult<ProduceResult> result = new DeferredResult<>();
  31
  32     final long time = System.currentTimeMillis();
  33
  34     final ProducerRecord<String, Integer> record = new ProducerRecord<>(
  35         topic,  // Topic
  36         key,    // Key
  37         value   // Value
  38     );
  39
  40     producer.send(record, (metadata, e) ->
  41     {
  42       long now = System.currentTimeMillis();
  43       if (e == null)
  44       {
  45         // HANDLE SUCCESS
  46         produced++;
  47         result.setResult(new ProduceSuccess(metadata.partition(), metadata.offset()));
  48         log.debug(
  49             "{} - Sent key={} message={} partition={}/{} timestamp={} latency={}ms",
  50             id,
  51             record.key(),
  52             record.value(),
  53             metadata.partition(),
  54             metadata.offset(),
  55             metadata.timestamp(),
  56             now - time
  57         );
  58       }
  59       else
  60       {
  61         // HANDLE ERROR
  62         result.setErrorResult(new ProduceFailure(e));
  63         log.error(
  64             "{} - ERROR key={} timestamp={} latency={}ms: {}",
  65             id,
  66             record.key(),
  67             metadata == null ? -1 : metadata.timestamp(),
  68             now - time,
  69             e.toString()
  70         );
  71       }
  72     });
  73
  74     long now = System.currentTimeMillis();
  75     log.trace(
  76         "{} - Queued message with key={} latency={}ms",
  77         id,
  78         record.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 }