Scala 为什么失败案例从未达到?
我有一个websocket客户端,如下所示:Scala 为什么失败案例从未达到?,scala,akka,akka-stream,Scala,Akka,Akka Stream,我有一个websocket客户端,如下所示: object Main extends App { private val sapServer = "127.0.0.1:8080" implicit val system = ActorSystem("WsSystem") implicit val materializer = ActorMaterializer() implicit val dispatcher = system.dispatcher RestartSo
object Main extends App {
private val sapServer = "127.0.0.1:8080"
implicit val system = ActorSystem("WsSystem")
implicit val materializer = ActorMaterializer()
implicit val dispatcher = system.dispatcher
RestartSource.withBackoff(
minBackoff = 3.seconds,
maxBackoff = 30.seconds,
randomFactor = 0.2
) { () =>
// Consider if the server supports websocket or not
val (supported, source) = Source.tick(1.seconds, 15.seconds, TextMessage.Strict(Monoid.empty[String]))
.viaMat(Http().webSocketClientFlow(WebSocketRequest(s"ws://$sapServer")))(Keep.right)
.preMaterialize()
supported.flatMap { upgrade =>
//Switching from HTTP to WS protocol
if (upgrade.response.status == StatusCodes.SwitchingProtocols)
Future.successful(Done)
else
throw new RuntimeException(s"Connection failed: ${upgrade.response.status}")
}
source
}.runWith(Sink.foreach(println))
.onComplete {
case Success(_) =>
//Do nothing
Unit
case Failure(_) =>
println("Probably server is down.")
}
}
我还没有启动websocket服务器,但是,我希望它显示服务器可能已关闭。
在控制台上。但我得到的是:
[WARN] [06/09/2019 15:06:25.823] [WsSystem-akka.actor.default-dispatcher-14] [RestartWithBackoffSource(akka://WsSystem)] Restarting graph due to failure. stack_trace: (akka.stream.StreamTcpException: Tcp command [Connect(127.0.0.1:8080,None,List(),Some(10 seconds),true)] failed because of java.net.ConnectException: Connection refused)
[WARN] [06/09/2019 15:06:32.674] [WsSystem-akka.actor.default-dispatcher-13] [RestartWithBackoffSource(akka://WsSystem)] Restarting graph due to failure. stack_trace: (akka.stream.StreamTcpException: Tcp command [Connect(127.0.0.1:8080,None,List(),Some(10 seconds),true)] failed because of java.net.ConnectException: Connection refused)
[WARN] [06/09/2019 15:06:45.367] [WsSystem-akka.actor.default-dispatcher-3] [RestartWithBackoffSource(akka://WsSystem)] Restarting graph due to failure. stack_trace: (akka.stream.StreamTcpException: Tcp command [Connect(127.0.0.1:8080,None,List(),Some(10 seconds),true)] failed because of java.net.ConnectException: Connection refused)
[WARN] [06/09/2019 15:07:09.828] [WsSystem-akka.actor.default-dispatcher-13] [RestartWithBackoffSource(akka://WsSystem)] Restarting graph due to failure. stack_trace: (akka.stream.StreamTcpException: Tcp command [Connect(127.0.0.1:8080,None,List(),Some(10 seconds),true)] failed because of java.net.ConnectException: Connection refused)
问题是,如何捕获
StreamTcpException
异常?支持的未来是连接异常失败的未来,而不是重新启动源代码的未来。withBackoff
正在创建的未来。做一些类似于:
supported.flatMap {...}.onComplete {
case Failure(_) =>
println("Probably server is down.")
}
将打印您期望的消息