feat: Kafka producer config, ability to set batch.size

feat: handling producer events

README.md

@@ -42,6 +42,7 @@ Prometheus-kafka-adapter listens for metrics coming from Prometheus and sends th
 - `KAFKA_TOPIC`: defines kafka topic to be used, defaults to `metrics`. Could use go template, labels are passed (as a map) to the template: e.g: `metrics.{{ index . "__name__" }}` to use per-metric topic. Two template functions are available: replace (`{{ index . "__name__" | replace "message" "msg" }}`) and substring (`{{ index . "__name__" | substring 0 5 }}`)
 - `KAFKA_COMPRESSION`: defines the compression type to be used, defaults to `none`.
 - `KAFKA_BATCH_NUM_MESSAGES`: defines the number of messages to batch write, defaults to `10000`.
+- `KAFKA_BATCH_SIZE`: Maximum size (in bytes) of all messages batched in one MessageSet, including protocol framing overhead, defaults to `1000000`.
 - `KAFKA_LINGER_MS`:  Delay in milliseconds to wait for messages in the producer queue to accumulate before constructing message batches, defaults to `5`.
 - `SERIALIZATION_FORMAT`: defines the serialization format, can be `json`, `avro-json`, defaults to `json`.
 - `PORT`: defines http port to listen, defaults to `8080`, used directly by [gin](https://github.com/gin-gonic/gin).

config.go

@@ -37,6 +37,7 @@ var (
 	basicauthPassword      = ""
 	kafkaCompression       = "none"
 	kafkaBatchNumMessages  = "10000"
+	kafkaBatchSize         = "1000000"
 	kafkaLingerMs          = "5"
 	kafkaSslClientCertFile = ""
 	kafkaSslClientKeyFile  = ""
@@ -83,6 +84,10 @@ func init() {
 		kafkaBatchNumMessages = value
 	}
 
+	if value := os.Getenv("KAFKA_BATCH_SIZE"); value != "" {
+		kafkaBatchSize = value
+	}
+
 	if value := os.Getenv("KAFKA_LINGER_MS"); value != "" {
 		kafkaLingerMs = value
 	}

handlers.go

@@ -76,13 +76,34 @@ func receiveHandler(producer *kafka.Producer, serializer Serializer) func(c *gin
 					Value:          metric,
 				}, nil)
 
+				go func() {
+					for event := range producer.Events() {
+						switch ev := event.(type) {
+						case *kafka.Message:
+							message := ev
+							if message.TopicPartition.Error != nil {
+								logrus.WithError(message.TopicPartition.Error).Errorf("failed to deliver message: %v",
+									message.TopicPartition)
+							} else {
+								logrus.Debugf("delivered to topic %s [%d] at offset %v",
+									*message.TopicPartition.Topic,
+									message.TopicPartition.Partition,
+									message.TopicPartition.Offset)
+							}
+						case kafka.Error:
+							logrus.WithError(err).Errorf("Error: %v", ev)
+						default:
+							logrus.Infof("Ignored event: %s", ev)
+						}
+					}
+				}()
+
 				if err != nil {
 					if err.(kafka.Error).Code() == kafka.ErrQueueFull {
-						// Producer queue is full, wait 1s for messages
-						// to be delivered then try again.
-						logrus.Info("producer queue is full, waiting 1s")
+						// Producer queue is full, wait 1s for messages to delivered
+						// Maybe we should fail fast? As we are losing data...
+						logrus.Warning("producer queue is full, waiting 1s")
 						time.Sleep(time.Second)
-						continue
 					}
 
 					objectsFailed.Add(float64(1))

main.go

@@ -28,15 +28,15 @@ func main() {
 	logrus.Info("creating kafka producer")
 
 	kafkaConfig := kafka.ConfigMap{
-		"bootstrap.servers":            kafkaBrokerList,
-		"compression.codec":            kafkaCompression,
-		"batch.num.messages":           kafkaBatchNumMessages,
-		"queue.buffering.max.messages": kafkaBatchNumMessages,
-		"enable.idempotence":           true,
-		"linger.ms":                    kafkaLingerMs,
-		"go.batch.producer":            true,  // Enable batch producer (for increased performance).
-		"go.delivery.reports":          false, // per-message delivery reports to the Events() channel
-		"acks":                         kafkaAcks,
+		"bootstrap.servers":      kafkaBrokerList,
+		"compression.codec":      kafkaCompression,
+		"batch.num.messages":     kafkaBatchNumMessages,
+		"batch.size":             kafkaBatchSize,
+		"linger.ms":              kafkaLingerMs,
+		"go.batch.producer":      true, // Enable batch producer (for increased performance).
+		"go.delivery.reports":    true, // per-message delivery reports to the Events() channel
+		"go.logs.channel.enable": true,
+		"acks":                   kafkaAcks,
 	}
 
 	if kafkaSslClientCertFile != "" && kafkaSslClientKeyFile != "" && kafkaSslCACertFile != "" {