Unable to fetch the elements from stream source

Akka Libraries Akka Streams & Alpakka
,
1

Overview
I have two microservices called warehouse-microservice (server) & grocery-microservice (client). And I’m trying to implement a streaming request & streaming response between them using the akka-grpc library. But I’m facing a problem while fetching the streaming response in my grocery-microservice (client). Below is the client code description.

Problem Description:
I have a variable called responseStream of Source type onto which I’m accumulating a few elements. And then I want to return a future of the elements which are present inside this Source.

Below is the snippet of my function:

def streamingBroadcast(itemIds: List[Long]): Future[List[ItemStockAvailabilityDto]] = {
      logger.debug("Performing streaming requests")

      val itemIter = itemIds.toIterator
      val requestStream: Source[CheckStockRequest, NotUsed] =
        Source
          .fromIterator(() => itemIter)
          .map { itemId => CheckStockRequest(itemId, 1) }
          .mapMaterializedValue(_ => NotUsed)
      val responseStream: Source[CheckStockReply, NotUsed] = client.checkStockToAll(requestStream)
      responseStream.runFoldAsync(List.empty[ItemStockAvailabilityDto])((acc, item) => {
        logger.debug(s"got streaming reply for id: ${item.itemId} and qty: ${item.qtyAvailable}")
        Future.successful(acc :+ ItemStockAvailabilityDto(item.itemId, item.qtyAvailable))
      })
    }

And then I have another method called getQuote from where I call the streamingBroadcast method which looks something like this -

def getQuote(itemIds: List[Long], quantityRequested: Int): Future[List[GroceryItemAvailabilityDto]] = {
    streamingBroadcast(itemIds) map {
      case stockList: List[ItemStockAvailabilityDto] if stockList.nonEmpty =>
        logger.debug("we have some results for items " + stockList.map(_.itemId).mkString(","))
        stockList map { stock =>
          catalog.get(stock.itemId) match {
            case Some(item) =>
              val amt = if (stock.quantityAvailable < quantityRequested) stock.quantityAvailable else quantityRequested
              val msg = if (amt < quantityRequested) Some("We are unable to supply all you requested") else Some("We await your order")
              GroceryItemAvailabilityDto(stock.itemId, item.name, item.price, item.price * amt, quantityRequested, stock.quantityAvailable, msg)
            case None => throw new RuntimeException("item not found in warehouse: " + stock.itemId)
          }
        }
      case Nil => throw new RuntimeException("none of the items were found in warehouse: " + itemIds.mkString(","))
    }
  }

Problem
The problem I’m facing is that the code execution is not returning me any values from the getQuote method. And it is just hanging inside getQuote maybe & another waiting actor is timing out. Maybe because of the pattern matching inside that method? I also tried debugging the code to make sure that there are at least a few elements present inside the list.

Is there something that I’m doing wrong in creating a responseStream or accessing the elements in it? Please let me know if you need anymore information or the code snippet from the warehouse microservice (server).