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.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 import java.math.BigInteger;
  12
  13
  14 @Slf4j
  15 @RequestMapping
  16 @ResponseBody
  17 @RequiredArgsConstructor
  18 public class RestProducer
  19 {
  20   private final String id;
  21   private final String topic;
  22   private final Integer partition;
  23   private final KafkaProducer<String, Object> producer;
  24
  25   private long produced = 0;
  26
  27   @PostMapping(path = "{key}")
  28   public DeferredResult<ProduceResult> send(
  29       @PathVariable String key,
  30       @RequestHeader(name = "X-id", required = false) Long correlationId,
  31       @RequestBody Integer number)
  32   {
  33     ResultRecorder result = new ResultRecorder(number+1);
  34
  35     for (int i = 1; i <= number; i++)
  36     {
  37       send(key, new AddNumberMessage(number, i), correlationId, result);
  38     }
  39     send(key, new CalculateSumMessage(number), correlationId, result);
  40
  41     return result.getDeferredResult();
  42   }
  43
  44   private void send(
  45       String key,
  46       Object value,
  47       Long correlationId,
  48       ResultRecorder result)
  49   {
  50     final long time = System.currentTimeMillis();
  51
  52     final ProducerRecord<String, Object> record = new ProducerRecord<>(
  53         topic,  // Topic
  54         partition, // Partition
  55         key,    // Key
  56         value   // Value
  57     );
  58
  59     record.headers().add("source", id.getBytes());
  60     if (correlationId != null)
  61     {
  62       record.headers().add("id", BigInteger.valueOf(correlationId).toByteArray());
  63     }
  64
  65     producer.send(record, (metadata, e) ->
  66     {
  67       long now = System.currentTimeMillis();
  68       if (e == null)
  69       {
  70         // HANDLE SUCCESS
  71         result.addSuccess(metadata);
  72         produced++;
  73         log.debug(
  74             "{} - Sent key={} message={} partition={}/{} timestamp={} latency={}ms",
  75             id,
  76             record.key(),
  77             record.value(),
  78             metadata.partition(),
  79             metadata.offset(),
  80             metadata.timestamp(),
  81             now - time
  82         );
  83       }
  84       else
  85       {
  86         // HANDLE ERROR
  87         result.addFailure(e);
  88         log.error(
  89             "{} - ERROR key={} timestamp={} latency={}ms: {}",
  90             id,
  91             record.key(),
  92             metadata == null ? -1 : metadata.timestamp(),
  93             now - time,
  94             e.toString()
  95         );
  96       }
  97     });
  98
  99     long now = System.currentTimeMillis();
 100     log.trace(
 101         "{} - Queued message with key={} latency={}ms",
 102         id,
 103         record.key(),
 104         now - time
 105     );
 106   }
 107
 108   @ExceptionHandler
 109   @ResponseStatus(HttpStatus.BAD_REQUEST)
 110   public ErrorResponse illegalStateException(IllegalStateException e)
 111   {
 112     return new ErrorResponse(e.getMessage(), HttpStatus.BAD_REQUEST.value());
 113   }
 114 }