Akka-grpc server stops immediately after running

[9claudiu]

I've created a simple GRPC server as in the documentation.

val registerService: HttpRequest => Future[HttpResponse] =
     RegisterServiceHandler(new RegisterImpl())

     val binding = Http().newServerAt(interface = "127.0.0.1", port = port).bind(registerService)

     binding.foreach { binding => println(s"gRPC server bound to: ${binding.localAddress}") }
     binding

I have the following protobuf which makes akka generate the interfaces

syntax = "proto3";

option java_multiple_files = true;
option java_package = "cityfeed.application.grpc";
option java_outer_classname = "AuthenticationProto";

package auth;

service RegisterService {
  rpc RegisterUser (RegisterRequest) returns (RegisterResponse) {}
}

message RegisterRequest {
  string email_address = 1;
  string username = 2;
  string full_name = 3;
  string password = 4;
  string address = 5;
  string city = 6;
  string neighborhood = 7;
}

message RegisterResponse {
  bool registerSuccess = 1;
}

And as for my implementation, it looks like this:

class RegisterImpl(implicit mat: Materializer) extends RegisterService with LazyLogging {
  override def registerUser(request: RegisterRequest): Future[RegisterResponse] = {
    val credentials = UserCredentials(UUID.randomUUID(), request.username, request.emailAddress, request.password)
    val user = User(None, request.fullName, request.city, request.address, request.neighborhood, credentials)

    val responseIO = for {
      insertedRows <- userRepository.insertUser(user)
    } yield insertedRows

    responseIO.attempt.map {
      case Right(rows) =>
        logger.info(s"Inserted $rows rows")
        new RegisterResponse(true)
      case Left(e) =>
        logger.error(s"User registration failed because of error: ${e.getMessage}")
        new RegisterResponse(false)
    }.unsafeToFuture()
  }
}

When I'm running the server everything goes well, but the server stops immediately, it doesn't listen for calls. I'm not sure if it's an akka related issue, it could be sbt related, but I'm trying my luck here.

[9claudiu]

It seems it was indeed a sbt related issue, I've downgraded sbt version from 1.6.1 to 1.5.2

[raboof]

Thanks for the report! If you don't mind I'd like to keep this issue open, since indeed I see the same issue with https://github.com/akka/akka-grpc-quickstart-scala.g8 , and we do want that to work :)

[raboof]

Looks like this is indeed a change in behavior in sbt that might go away again in the future, tracked in sbt/sbt#6767 .

[raboof]

As an alternative to downgrading sbt, I can recommend using https://github.com/spray/sbt-revolver/ and starting your application from the sbt console. Perhaps we should consider recommending this in our docs as well?

[raboof]

Ah, or you could set fork := true, no further changes necessary

[9claudiu]

nice, thank you for your suggestions @raboof
it would be nice to find it also in the docs

[kkurt]

I have same issue with akka-grp-server... Is there any progress?

[raboof]

I have same issue with akka-grp-server... Is there any progress?

The status is still that you can fix it by setting fork := true and that it'd be nice to add this to the docs.