Akka gRPC + Slick应用程序导致"IllegalStateException:无法初始化ExecutionContext；AsyncExecutor已关闭“

Question

我尝试用Akka-gRPC和Slick开发gRPC服务器。我还将Airframe用于DI。

源代码是here

问题在于，如果它在作为gRPC服务器执行时收到请求，则会导致失败。如果它不是作为gRPC服务器启动，而只是从数据库中读取资源，则该过程成功。

有什么关系？

接下来，它使用slick从数据库中读取对象。...Component是机身对象。它将由主模块使用。

trait UserRepository {
  def getUser: Future[Seq[Tables.UsersRow]]
}

class UserRepositoryImpl(val profile: JdbcProfile, val db: JdbcProfile#Backend#Database) extends UserRepository {
  import profile.api._
  def getUser: Future[Seq[Tables.UsersRow]] = db.run(Tables.Users.result)
}

trait UserResolveService {
  private val repository = bind[UserRepository]
  def getAll: Future[Seq[Tables.UsersRow]] =
    repository.getUser
}


object userServiceComponent {
  val design = newDesign
    .bind[UserResolveService]
    .toSingleton
}

下面是gRPC服务器的源代码。

trait UserServiceImpl extends UserService {

  private val userResolveService            = bind[UserResolveService]
  private val system: ActorSystem           = bind[ActorSystem]
  implicit val ec: ExecutionContextExecutor = system.dispatcher

  override def getAll(in: GetUserListRequest): Future[GetUserListResponse] = {

    userResolveService.getAll.map(us =>
      GetUserListResponse(
        us.map(u =>
          myapp.proto.user.User(
            1,
            "t_horikoshi@example.com",
            "t_horikoshi",
            myapp.proto.user.User.UserRole.Admin
          )
        )
      )
    )
  }

}

trait GRPCServer {

  private val userServiceImpl      = bind[UserServiceImpl]
  implicit val system: ActorSystem = bind[ActorSystem]

  def run(): Future[Http.ServerBinding] = {

    implicit def ec: ExecutionContext = system.dispatcher
    val service: PartialFunction[HttpRequest, Future[HttpResponse]] =
      UserServiceHandler.partial(userServiceImpl)

    val reflection: PartialFunction[HttpRequest, Future[HttpResponse]] =
      ServerReflection.partial(List(UserService))

    // Akka HTTP 10.1 requires adapters to accept the new actors APIs
    val bound = Http().bindAndHandleAsync(
      ServiceHandler.concatOrNotFound(service, reflection),
      interface = "127.0.0.1",
      port = 8080,
      settings = ServerSettings(system)
    )

    bound.onComplete {
      case Success(binding) =>
        system.log.info(
          s"gRPC Server online at http://${binding.localAddress.getHostName}:${binding.localAddress.getPort}/"
        )
      case Failure(ex) =>
        system.log.error(ex, "occurred error")
    }

    bound
  }
}

object grpcComponent {
  val design = newDesign
    .bind[UserServiceImpl]
    .toSingleton
    .bind[GRPCServer]
    .toSingleton
}

下面是主模块。

object Main extends App {

  val conf = ConfigFactory
    .parseString("akka.http.server.preview.enable-http2 = on")
    .withFallback(ConfigFactory.defaultApplication())
  val system = ActorSystem("GRPCServer", conf)

  val dbConfig: DatabaseConfig[JdbcProfile] =
    DatabaseConfig.forConfig[JdbcProfile](path = "mydb")

  val design = newDesign
    .bind[JdbcProfile]
    .toInstance(dbConfig.profile)
    .bind[JdbcProfile#Backend#Database]
    .toInstance(dbConfig.db)
    .bind[UserRepository]
    .to[UserRepositoryImpl]
    .bind[ActorSystem]
    .toInstance(system)
    .add(userServiceComponent.design)
    .add(grpcComponent.design)

  design.withSession(s =>
    // Await.result(s.build[UserResolveService].getUser, Duration.Inf)) // success
    // Await.result(s.build[UserServiceImpl].getAll(GetUserListRequest()), Duration.Inf)) // success
    s.build[GRPCServer].run() // cause IllegalStateException when reciece request.

  )
}

当直接调用UserResolveService和UserServiceImpl时，从数据库加载对象的过程成功。

但是，当将应用程序作为gRPC服务器运行时，在收到请求时会发生错误。

​

​

虽然我想了一整天，但还是无法解决..。你能帮我解决一下吗。

Answer 1

它解决了。如果执行异步进程，则必须使用newSession启动gRPC服务器。我修得像that一样。