Bound channel + log warning

Author: VirxEC

RLBotCS/Server/FlatBuffersServer.cs

@@ -20,7 +20,7 @@ ChannelWriter<IBridgeMessage> bridge
 
     private void AddSession(TcpClient client)
     {
-        Channel<SessionMessage> sessionChannel = Channel.CreateUnbounded<SessionMessage>();
+        Channel<SessionMessage> sessionChannel = Channel.CreateBounded<SessionMessage>(60);
         client.NoDelay = true;
 
         int clientId = client.Client.Handle.ToInt32();
@@ -96,7 +96,11 @@ private async Task HandleServer()
             while (true)
             {
                 TcpClient client = await _context.Server.AcceptTcpClientAsync();
-                AddSession(client);
+
+                lock (_context)
+                {
+                    AddSession(client);
+                }
             }
         }
         catch (Exception e)

RLBotCS/Server/ServerMessage/DistributeGamePacket.cs

@@ -1,4 +1,4 @@
-using RLBot.Flat;
+using RLBot.Flat;
 using RLBotCS.ManagerTools;
 
 namespace RLBotCS.Server.ServerMessage;
@@ -28,24 +28,15 @@ private static void DistributeBallPrediction(ServerContext context, GamePacketT
             lastTouch,
             packet.MatchInfo.WorldGravityZ
         );
-
-        foreach (var (writer, _) in context.Sessions.Values)
-        {
-            SessionMessage message = new SessionMessage.DistributeBallPrediction(prediction);
-            writer.TryWrite(message);
-        }
+        context.DistributeMessage(new SessionMessage.DistributeBallPrediction(prediction));
     }
 
     private static void DistributeState(ServerContext context, GamePacketT packet)
     {
         context.LastTickPacket = packet;
-        foreach (var (writer, _) in context.Sessions.Values)
-        {
-            SessionMessage message = new SessionMessage.DistributeGameState(
-                context.LastTickPacket
-            );
-            writer.TryWrite(message);
-        }
+        context.DistributeMessage(
+            new SessionMessage.DistributeGameState(context.LastTickPacket)
+        );
     }
 
     public ServerAction Execute(ServerContext context)

RLBotCS/Server/ServerMessage/SendMatchComm.cs

@@ -11,7 +11,7 @@ public ServerAction Execute(ServerContext context)
 
         if (context.LastTickPacket is null)
         {
-            context.Logger.LogWarning("Received MatchComm before receiving a GameTickPacket.");
+            context.Logger.LogWarning("Received MatchComm before receiving a GamePacket.");
             return ServerAction.Continue;
         }
 

RLBotCS/Server/ServerMessage/ServerContext.cs

@@ -46,4 +46,32 @@ public Dictionary<
     /// The BridgeHandler's config may contain updated names, e.g. "Nexto (2)",
     /// and updated loadouts.</summary>
     public MatchConfigurationT? MatchConfig { get; set; }
+
+    public readonly Dictionary<int, uint> MissedMessagesCount = new();
+
+    public void DistributeMessage(SessionMessage message)
+    {
+        foreach (var (id, (writer, _)) in Sessions)
+        {
+            if (!writer.TryWrite(message))
+            {
+                uint missedMessages = MissedMessagesCount.GetValueOrDefault(id);
+                missedMessages += 1;
+                MissedMessagesCount[id] = missedMessages;
+
+                // Log warning with exponential backoff,
+                // e.g. every 10, 100, 1000, etc. messages missed
+                // (including the first missed message)
+                uint powerOfTen = (uint)Math.Pow(10, Math.Ceiling(Math.Log10(missedMessages)));
+                if (missedMessages == powerOfTen)
+                {
+                    Logger.LogWarning(
+                        "Session {}'s outbound message queue is full ({} messages missed)",
+                        id,
+                        missedMessages
+                    );
+                }
+            }
+        }
+    }
 }

RLBotCS/Server/ServerMessage/SessionClosed.cs

@@ -8,6 +8,7 @@ public ServerAction Execute(ServerContext context)
     {
         context.Bridge.TryWrite(new RemoveClientRenders(ClientId));
         context.Sessions.Remove(ClientId);
+        context.MissedMessagesCount.Remove(ClientId);
 
         return ServerAction.Continue;
     }