ts2.scala

  
  case class PredictionResult(key: String, ts:Timestamp, 
  label: Float, prediction: Float, ratio: Float)


  def predict(appId:String, recordsIter:Iterator[FeaturesRecord]): 
  Seq[PredictionResult] = {
    val predDF = for {
      (trainSeq, actualValSeq) <- getForecastDataset(appId, recordsIter.toSeq)
      booster <- trainXGBBooster(trainSeq)
      forecastedVal <- predictXGBBooster(appId, booster, actualValSeq)
    } yield forecastedVal
    predDF match {
      case Success(predictionResults) => predictionResults
      case Failure(exc) => throw new RuntimeException(s"prediction failed due to $exc")
    }
  }