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       @RequestParam(required = false) boolean error)
  34   {
  35     ResultRecorder result = new ResultRecorder(number+1);
  36
  37     for (int i = 1; i <= number; i++)
  38     {
  39       int next = error && i == (number+1)/2 ? i * -1 : i;
  40       send(key, new AddNumberMessage(number, next), correlationId, result);
  41     }
  42     send(key, new CalculateSumMessage(number), correlationId, result);
  43
  44     return result.getDeferredResult();
  45   }
  46
  47   private void send(
  48       String key,
  49       Object value,
  50       Long correlationId,
  51       ResultRecorder result)
  52   {
  53     final long time = System.currentTimeMillis();
  54
  55     final ProducerRecord<String, Object> record = new ProducerRecord<>(
  56         topic,  // Topic
  57         partition, // Partition
  58         key,    // Key
  59         value   // Value
  60     );
  61
  62     record.headers().add("source", id.getBytes());
  63     if (correlationId != null)
  64     {
  65       record.headers().add("id", BigInteger.valueOf(correlationId).toByteArray());
  66     }
  67
  68     producer.send(record, (metadata, e) ->
  69     {
  70       long now = System.currentTimeMillis();
  71       if (e == null)
  72       {
  73         // HANDLE SUCCESS
  74         result.addSuccess(metadata);
  75         produced++;
  76         log.debug(
  77             "{} - Sent key={} message={} partition={}/{} timestamp={} latency={}ms",
  78             id,
  79             record.key(),
  80             record.value(),
  81             metadata.partition(),
  82             metadata.offset(),
  83             metadata.timestamp(),
  84             now - time
  85         );
  86       }
  87       else
  88       {
  89         // HANDLE ERROR
  90         result.addFailure(e);
  91         log.error(
  92             "{} - ERROR key={} timestamp={} latency={}ms: {}",
  93             id,
  94             record.key(),
  95             metadata == null ? -1 : metadata.timestamp(),
  96             now - time,
  97             e.toString()
  98         );
  99       }
 100     });
 101
 102     long now = System.currentTimeMillis();
 103     log.trace(
 104         "{} - Queued message with key={} latency={}ms",
 105         id,
 106         record.key(),
 107         now - time
 108     );
 109   }
 110
 111   @ExceptionHandler
 112   @ResponseStatus(HttpStatus.BAD_REQUEST)
 113   public ErrorResponse illegalStateException(IllegalStateException e)
 114   {
 115     return new ErrorResponse(e.getMessage(), HttpStatus.BAD_REQUEST.value());
 116   }
 117 }