just drop auto analysis requests silenty when queue is full

app/controllers/Ai.scala

@@ -35,8 +35,10 @@ object Ai extends LilaController {
         initialFen = get("initialFen", req),
         requestedByHuman = getBool("human", req),
         variant = requestVariant(req)
-      ).effectFold(
-          err => WS.url(s"$replyToUrl/err").post(err.toString),
+      ).effectFold({
+          case lila.ai.Queue.FullException => logwarn("Dropping analyse request, queue is full")
+          case err                         => WS.url(s"$replyToUrl/err").post(err.toString)
+        },
           infos => WS.url(replyToUrl).post(lila.analyse.Info encodeList infos)
         )
     }

modules/ai/src/main/Queue.scala

@@ -58,15 +58,15 @@ private[ai] final class Queue(config: Config) extends Actor {
         tasks += Task(req, sender, timeout)
       }
 
-    case FullAnalReq(moves, fen, requestedByHuman, variant) if (requestedByHuman || tasks.size < maxTasks) =>
+    case FullAnalReq(moves, fen, human, variant) if (human || tasks.size < maxTasks) =>
       val mrSender = sender
       val size = moves.size
       val startedAtPly = fen.flatMap(chess.format.Forsyth.getPly)
       implicit val timeout = makeTimeout {
-        if (requestedByHuman) 1.hour else 24.hours
+        if (human) 1.hour else 24.hours
       }
       val futures = (0 to size) map moves.take map { serie =>
-        self ? AnalReq(serie, fen, size, requestedByHuman, variant) mapTo manifest[Option[Evaluation]]
+        self ? AnalReq(serie, fen, size, human, variant) mapTo manifest[Option[Evaluation]]
       }
       Future.fold(futures)(Vector[Option[Evaluation]]())(_ :+ _) addFailureEffect {
         case e => mrSender ! Status.Failure(e)
@@ -74,7 +74,11 @@ private[ai] final class Queue(config: Config) extends Actor {
         mrSender ! Evaluation.toInfos(results.toList.map(_ | Evaluation.empty), moves, ~startedAtPly)
       }
 
-    case r: FullAnalReq =>
-      sender ! Status.Failure(new Exception("analysis queue is full"))
+    case r: FullAnalReq => sender ! Status.Failure(Queue.FullException)
   }
 }
+
+object Queue {
+
+  case object FullException extends Exception("Analysis queue is full")
+}

modules/ai/src/main/Server.scala

@@ -25,7 +25,7 @@ private[ai] final class Server(
     implicit val timeout = makeTimeout {
       if (requestedByHuman) 1.hour else 24.hours
     }
-    (queue ? FullAnalReq(uciMoves take config.analyseMaxPlies, initialFen map chess960Fen, requestedByHuman, variant)) mapTo manifest[List[Info]]
+    queue ? FullAnalReq(uciMoves take config.analyseMaxPlies, initialFen map chess960Fen, requestedByHuman, variant) mapTo manifest[List[Info]]
   }
 
   private def chess960Fen(fen: String) = (Forsyth << fen).fold(fen) { situation =>

modules/ai/src/main/package.scala

@@ -1,3 +1,3 @@
 package lila
 
-package object ai extends PackageObject with WithPlay 
+package object ai extends PackageObject with WithPlay