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 Integer partition;
  21   private final KafkaProducer<String, Integer> producer;
  22
  23   private long produced = 0;
  24
  25   @PostMapping(path = "{key}")
  26   public DeferredResult<ProduceResult> send(
  27       @PathVariable String key,
  28       @RequestHeader(name = "X-id", required = false) Long correlationId,
  29       @RequestBody Integer value)
  30   {
  31     DeferredResult<ProduceResult> result = new DeferredResult<>();
  32
  33     final long time = System.currentTimeMillis();
  34
  35     final ProducerRecord<String, Integer> record = new ProducerRecord<>(
  36         topic,  // Topic
  37         partition, // Partition - Uses default-algorithm, if null
  38         key,    // Key
  39         value   // Value
  40     );
  41
  42     producer.send(record, (metadata, e) ->
  43     {
  44       long now = System.currentTimeMillis();
  45       if (e == null)
  46       {
  47         // HANDLE SUCCESS
  48         produced++;
  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       else
  62       {
  63         // HANDLE ERROR
  64         result.setErrorResult(new ProduceFailure(e));
  65         log.error(
  66             "{} - ERROR key={} timestamp={} latency={}ms: {}",
  67             id,
  68             record.key(),
  69             metadata == null ? -1 : metadata.timestamp(),
  70             now - time,
  71             e.toString()
  72         );
  73       }
  74     });
  75
  76     long now = System.currentTimeMillis();
  77     log.trace(
  78         "{} - Queued message with key={} latency={}ms",
  79         id,
  80         record.key(),
  81         now - time
  82     );
  83
  84     return result;
  85   }
  86
  87   @ExceptionHandler
  88   @ResponseStatus(HttpStatus.BAD_REQUEST)
  89   public ErrorResponse illegalStateException(IllegalStateException e)
  90   {
  91     return new ErrorResponse(e.getMessage(), HttpStatus.BAD_REQUEST.value());
  92   }
  93 }