using Guice with akka Props - Appropriate actor constructor not found

Question

I have kafkaProducer actor:

class KafkaProducerActor @Inject()(
  avroProducer: MyKafkaProducerAvro,
  jsonProducer: MyKafkaProducerJson,
  metrics: PrometheusMetricsService
)
  extends Actor
{
  def handleErrs(block: => Unit): Unit = {
    try {
      block
    } catch {
      case e: Exception =>
        Logger.error(s"failed to produce kafka message, error: ${e.getMessage}, cause: ${ExceptionUtils.getRootCause(e)}, stacktrace: ${ExceptionUtils.getStackTrace(e)}")
        metrics.incKafkaErrorCounter(e.getClass.getName)
    }
  }

  override def receive: Receive = {
    case rec: ProducerRecord[GenericRecord, GenericRecord] =>
      handleErrs(avroProducer.produce(rec))

    case ProducerRecordJson(topic, key, content) =>
      handleErrs(jsonProducer.produce(new ProducerRecord[String, String](topic, key, content)))
  }
}

Also, i'm trying to use actorSystem to get the actorRef:

  val kafka: ActorRef = actorSystem.actorOf(KafkaProducerActor.props, name = "kafkaProducerActor")

For that i defined in KafkaProducerActor:

object KafkaProducerActor {
  def props: Props = Props(classOf[KafkaProducerActor])
}

which Warns the following:

Appropriate actor constructor not found Dynamic invocation could be replaced with a constructor invocation

when replacing dynamic invocation with a constructor invocation (as compiler suggest) i.e:

object KafkaProducerActor {
  def props: Props = Props(new KafkaProducerActor())
}

I get compilation error:

Unspecified value parameters: avroProducer: MyKafkaProducerAvro, jsonProducer: MyKafkaProducerJson, metrics: PrometheusMetricsService

what is the right way to initiate the Props in this situation?

Does this post help? abhsrivastava.github.io/2017/11/03/Actors-With-Guice — Yik San Chan

Artem Sokolov Artem Sokolov · Accepted Answer · 2020-08-26T22:44:30

You should inject your services in the context where you call KafkaProducerActor.props and just pass it as parameters.

Or just inject it manually into the constructor but you will need a static global injection for that. You can achieve it with helpers like that:

object InjectHelper {
    lazy val injector: Injector = {
        val moduleInstance: com.google.inject.Module = ??? // somehow get  your guice module
        Guice.createInjector(moduleInstance)
    }

    def inject[T](implicit mf: Manifest[T]): T =
        InjectHelper.injector.getInstance(mf.runtimeClass).asInstanceOf[T]
}

object KafkaProducerActor {
  def props: Props = Props(
    new KafkaProducerActor(
      InjectHelper.inject[MyKafkaProducerAvro],
      InjectHelper.inject[MyKafkaProducerJson],
      InjectHelper.inject[PrometheusMetricsService]
    )
  )
}

using Guice with akka Props - Appropriate actor constructor not found

1 Answers