如何在失败的情况下使用多个期货

Question

我有一个有两条消息的参与者，第一个负责在mongoDB中插入数据，第二个参与者负责在elasticsearch、InserInMongo和Inserins中插入数据。也就是说，当mongoDB插入操作失败或ES插入操作因某些异常而失败时，会出现这种情况，我正在做类似的事情

try {
        val mongoFuture: Future[Boolean] = ask(artGroupPersistenceActor, PersistArtGroupInMongo(artGroup)).mapTo[Boolean]
        val esFuture: Future[Boolean] = ask(artGroupPersistenceActor, PersistArtGroupInES(artGroup)).mapTo[Boolean]
        val resultMongo = Await.result(mongoFuture, timeout.duration)
        log.debug("store: Record Inserted inserted in mongoDB  {}", resultMongo)
        val resultES = Await.result(esFuture, timeout.duration)
        log.debug("store: Record Inserted in ES  {}", resultES)
}
catch {
        case e: Exception =>
          log.error("store:While inserting an artgroup Exception in artGroupPersistenceActor  actor", e)
          throw e
      }

在这里，我想如果mongoFuture失败，那么我抓住它的异常，它应该继续与esFuture

或者如果两个未来都失败了，我得到了两个例外，我如何存档这个场景？

Answer 1

如果您只想记录异常，只需对每个异常执行以下操作：

mongoFuture.failed.foreach {ex => logger.error("Mongo error", ex)}

Answer 2

您可以使用recovery，它将处理原始Future包含的任何匹配的可抛出物：

    val mongoFuture = ask(artGroupPersistenceActor, PersistArtGroupInMongo(artGroup))
        .mapTo[Boolean]
        .recover {
          case e =>
            println("error in mongo: " + e)
            false
        }

      val esFuture = ask(artGroupPersistenceActor, PersistArtGroupInES(artGroup))
        .mapTo[Boolean]
        .recover {
          case e =>
            println("error in ES: " + e)
            false
        }

      val f = Future.sequence(List(mongoFuture, esFuture))
      val result: Seq[Boolean] = Await.result(f, Duration.Inf)

      println(result)

Answer 3

你可以这样试试。

    for {
        x <- Future.successful {
            try {
                code here...
            } catch {
                case _: Exception => 
                    println("Error Inserting In Mongo ")
                    false
            }
        }
        y <- Future.successful {
            try {
                code here...
                    // throw new IllegalStateException("Exception thrown")
            } catch {
                case _: IllegalStateException => 
                    println("Error Inserting In ES ")
                    false
            }
        }

    } yield(x, y)

现在，如果在执行过程中发生错误，您可以进行操作..祝您好运。