Console crashes when a client connects after graph.shutdown has been called for non-interactive executions.

[pstutz]

Exception in proxy method getLogMessages(: akka.pattern.AskTimeoutException: Recipient[Actor[akka://SignalCollect/user/Coordinator]] had already been terminated. from Actorakka://SignalCollect/user/Coordinator
akka.pattern.AskTimeoutException: Recipient[Actor[akka://SignalCollect/user/Coordinator]] had already been terminated.
at akka.pattern.AskSupport$class.ask(AskSupport.scala:79)
at akka.pattern.package$.ask(package.scala:41)
at akka.pattern.AskSupport$AskableActorRef.$qmark(AskSupport.scala:154)
at com.signalcollect.messaging.AkkaProxy.invoke(AkkaProxy.scala:108)
at $Proxy5.getLogMessages(Unknown Source)
at com.signalcollect.console.LogDataProvider.fetch(DataProvider.scala:174)
at com.signalcollect.console.WebSocketConsoleServer.onMessage(ConsoleServer.scala:427)
at org.java_websocket.server.WebSocketServer.onWebsocketMessage(WebSocketServer.java:469)
at org.java_websocket.WebSocketImpl.decodeFrames(WebSocketImpl.java:368)
at org.java_websocket.WebSocketImpl.decode(WebSocketImpl.java:157)
at org.java_websocket.server.WebSocketServer$WebSocketWorker.run(WebSocketServer.java:657)
WebSocket - client connected: 0:0:0:0:0:0:0:1
WebSocket - client connected: 0:0:0:0:0:0:0:1

[pstutz]

Problem happened with the WebCrawler example, did not try with other examples.

[cshapeshifter]

We're now catching this exception, but for some reason, it still is getting printed. In https://github.com/uzh/signal-collect/blob/master/src/main/scala/com/signalcollect/messaging/AkkaProxy.scala#L108 the exception is thrown, but it's supposed to be caught in https://github.com/uzh/signal-collect/blob/master/src/main/scala/com/signalcollect/messaging/AkkaProxy.scala#L115 so I don't know why the stack is being printed. It's only supposed to print a short error message.

So now we print an error message in case something goes majorly wrong due to coordinator or graph shutdown. I have no idea though why the other exception is still printed.

I'm removing the console tag because it is catching the exception now. If you can figure out why the exception is printed in AkkaProxy, the issue can be closed.