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       @RequestParam(required = false) boolean error)
  33   {
  34     ResultRecorder result = new ResultRecorder(number+1);
  35
  36     for (int i = 1; i <= number; i++)
  37     {
  38       int next = error && i == (number+1)/2 ? i * -1 : i;
  39       send(key, new AddNumberMessage(number, next), correlationId, result);
  40     }
  41     send(key, new CalculateSumMessage(number), correlationId, result);
  42
  43     return result.getDeferredResult();
  44   }
  45
  46   private void send(
  47       String key,
  48       Object value,
  49       Long correlationId,
  50       ResultRecorder result)
  51   {
  52     final long time = System.currentTimeMillis();
  53
  54     final ProducerRecord<String, Object> record = new ProducerRecord<>(
  55         topic,  // Topic
  56         partition, // Partition
  57         key,    // Key
  58         value   // Value
  59     );
  60
  61     record.headers().add("source", id.getBytes());
  62     if (correlationId != null)
  63     {
  64       record.headers().add("id", BigInteger.valueOf(correlationId).toByteArray());
  65     }
  66
  67     producer.send(record, (metadata, e) ->
  68     {
  69       long now = System.currentTimeMillis();
  70       if (e == null)
  71       {
  72         // HANDLE SUCCESS
  73         result.addSuccess(metadata);
  74         produced++;
  75         log.debug(
  76             "{} - Sent key={} message={} partition={}/{} timestamp={} latency={}ms",
  77             id,
  78             record.key(),
  79             record.value(),
  80             metadata.partition(),
  81             metadata.offset(),
  82             metadata.timestamp(),
  83             now - time
  84         );
  85       }
  86       else
  87       {
  88         // HANDLE ERROR
  89         result.addFailure(e);
  90         log.error(
  91             "{} - ERROR key={} timestamp={} latency={}ms: {}",
  92             id,
  93             record.key(),
  94             metadata == null ? -1 : metadata.timestamp(),
  95             now - time,
  96             e.toString()
  97         );
  98       }
  99     });
 100
 101     long now = System.currentTimeMillis();
 102     log.trace(
 103         "{} - Queued message with key={} latency={}ms",
 104         id,
 105         record.key(),
 106         now - time
 107     );
 108   }
 109
 110   @ExceptionHandler
 111   @ResponseStatus(HttpStatus.BAD_REQUEST)
 112   public ErrorResponse illegalStateException(IllegalStateException e)
 113   {
 114     return new ErrorResponse(e.getMessage(), HttpStatus.BAD_REQUEST.value());
 115   }
 116 }