Specifying Future[Done] as materialized value when creating a source

Question

I'm trying to write some code as part of a larger integration test.

I have a function that creates a KinesisSource of type Source[KinesisRecord, Future[Done]:

protected def createKinesisSource(config: KinesisClientLibConfiguration): Source[KinesisRecord, Future[Done]]#Repr[MyFile.KinesisFlow] = {
  KinesisSource(config).mapAsync(1)(processRecord)
}

protected def processRecord(record: KinesisRecord): Future[KinesisFlow] = {
    Future { validateRecord(record) }
}

I want to create a fake source of the same type from a file. I have (pardon the code, I'm new to scala):

val records = scala.io.Source.fromFile("testFile.txt").getLines.toList
  .map(i => {
    new KinesisRecord( ByteString.fromString(i), "x", None, "x", None, Instant.now(), "x")
  })

Source(records).mapAsync(1)(processRecord)

That gives me a Source[KinesisRecord, NotUsed]. How can I change that to Source[KinesisRecord, Future[Done]]? I understand that the second parameter is the materialized value (see this post), but I'm not sure how to specify that value without actually applying a run function.

score 3 · Accepted Answer · answered Apr 08 '19 at 23:40

3

You could use mapMaterializedValue(_ => Future.successful(Done)) or Future.never

But if the materialized value has impact in your integration tests this will affect them because the Future will complete right after stream materialization or never.

answered Apr 08 '19 at 23:40

gabrielgiussi

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Specifying Future[Done] as materialized value when creating a source

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