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

   1 package de.juplo.kafka;
   2
   3 import lombok.RequiredArgsConstructor;
   4 import lombok.extern.slf4j.Slf4j;
   5 import org.apache.kafka.clients.producer.Producer;
   6 import org.apache.kafka.clients.producer.KafkaProducer;
   7 import org.apache.kafka.clients.producer.ProducerRecord;
   8 import org.springframework.http.HttpStatus;
   9 import org.springframework.web.bind.annotation.*;
  10 import org.springframework.web.context.request.async.DeferredResult;
  11
  12 import java.math.BigInteger;
  13
  14
  15 @Slf4j
  16 @RequestMapping
  17 @ResponseBody
  18 @RequiredArgsConstructor
  19 public class RestProducer
  20 {
  21   private final String id;
  22   private final String topic;
  23   private final Integer partition;
  24   private final Producer<String, Object> producer;
  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 number)
  33   {
  34     ResultRecorder result = new ResultRecorder(number+1);
  35
  36     for (int i = 1; i <= number; i++)
  37     {
  38       send(key, new AddNumberMessage(number, i), correlationId, result);
  39     }
  40     send(key, new CalculateSumMessage(number), correlationId, result);
  41
  42     return result.getDeferredResult();
  43   }
  44
  45   private void send(
  46       String key,
  47       Object value,
  48       Long correlationId,
  49       ResultRecorder result)
  50   {
  51     final long time = System.currentTimeMillis();
  52
  53     final ProducerRecord<String, Object> record = new ProducerRecord<>(
  54         topic,  // Topic
  55         partition, // Partition
  56         key,    // Key
  57         value   // Value
  58     );
  59
  60     record.headers().add("source", id.getBytes());
  61     if (correlationId != null)
  62     {
  63       record.headers().add("id", BigInteger.valueOf(correlationId).toByteArray());
  64     }
  65
  66     producer.send(record, (metadata, e) ->
  67     {
  68       long now = System.currentTimeMillis();
  69       if (e == null)
  70       {
  71         // HANDLE SUCCESS
  72         result.addSuccess(metadata);
  73         produced++;
  74         log.debug(
  75             "{} - Sent key={} message={} partition={}/{} timestamp={} latency={}ms",
  76             id,
  77             record.key(),
  78             record.value(),
  79             metadata.partition(),
  80             metadata.offset(),
  81             metadata.timestamp(),
  82             now - time
  83         );
  84       }
  85       else
  86       {
  87         // HANDLE ERROR
  88         result.addFailure(e);
  89         log.error(
  90             "{} - ERROR key={} timestamp={} latency={}ms: {}",
  91             id,
  92             record.key(),
  93             metadata == null ? -1 : metadata.timestamp(),
  94             now - time,
  95             e.toString()
  96         );
  97       }
  98     });
  99
 100     long now = System.currentTimeMillis();
 101     log.trace(
 102         "{} - Queued message with key={} latency={}ms",
 103         id,
 104         record.key(),
 105         now - time
 106     );
 107   }
 108
 109   @ExceptionHandler
 110   @ResponseStatus(HttpStatus.BAD_REQUEST)
 111   public ErrorResponse illegalStateException(IllegalStateException e)
 112   {
 113     return new ErrorResponse(e.getMessage(), HttpStatus.BAD_REQUEST.value());
 114   }
 115 }