feature: let an empty server hibernate and still take a match

apps/counterstrikesharp/Dockerfile

@@ -141,6 +141,7 @@ ENV DEFAULT_MAP="de_inferno"
 ENV STEAM_RELAY="false"
 
 ENV SERVER_TYPE="Ranked"
+ENV HIBERNATE_WHEN_EMPTY="false"
 
 ENV METAMOD_URL=https://github.com/alliedmodders/metamod-source/releases/download/2.0.0.1473/mmsource-2.0.0-git1473-linux.tar.gz
 ENV COUNTER_STRIKE_SHARP_URL=https://github.com/roflmuffin/CounterStrikeSharp/releases/download/v1.0.376/counterstrikesharp-with-runtime-linux-1.0.376.zip

apps/counterstrikesharp/scripts/setup.sh

@@ -45,6 +45,9 @@ echo "---Create Symbolic Links---"
 
 if [ "$SERVER_TYPE" = "Ranked" ]; then
   cp "/opt/server-cfg/ranked.server.cfg" "$INSTANCE_SERVER_DIR/game/csgo/cfg/server.cfg"
+  if [ "$HIBERNATE_WHEN_EMPTY" = "true" ]; then
+    sed -i 's/^sv_hibernate_when_empty.*/sv_hibernate_when_empty 1/' "$INSTANCE_SERVER_DIR/game/csgo/cfg/server.cfg"
+  fi
   cp "/opt/server-cfg/5stack.competitive.cfg" "$INSTANCE_SERVER_DIR/game/csgo/cfg"
   cp "/opt/server-cfg/5stack.duel.cfg" "$INSTANCE_SERVER_DIR/game/csgo/cfg"
   cp "/opt/server-cfg/5stack.knife.cfg" "$INSTANCE_SERVER_DIR/game/csgo/cfg"

apps/counterstrikesharp/src/FiveStack.Events/MapChange.cs

@@ -1,6 +1,7 @@
 using CounterStrikeSharp.API;
 using CounterStrikeSharp.API.Core;
 using FiveStack.Enums;
+using FiveStack.Utilities;
 using Microsoft.Extensions.Logging;
 
 namespace FiveStack;
@@ -19,7 +20,7 @@ public void ListenForMapChange()
 
                 // code smell: we have to wait till server exec's default cfgs
                 await Task.Delay(1000 * 5);
-                Server.NextFrame(() =>
+                HibernationUtility.NextFrame(() =>
                 {
                     MatchManager? match = _matchService.GetCurrentMatch();
                     match?.SyncActiveMapAfterMapStart();

apps/counterstrikesharp/src/FiveStack.Services/GameServer.cs

@@ -33,7 +33,7 @@ MatchService matchService
 
     public void SendCommands(string[] commands)
     {
-        Server.NextFrame(() => Server.ExecuteCommand(string.Join(";", commands)));
+        HibernationUtility.NextFrame(() => Server.ExecuteCommand(string.Join(";", commands)));
     }
 
     public void Message(
@@ -88,7 +88,7 @@ public void Ping(string pluginVersion)
         string? serverId = _environmentService.GetServerId();
         string? apiPassword = _environmentService.GetServerApiPassword();
 
-        Server.NextFrame(async () =>
+        Server.NextWorldUpdate(async () =>
         {
             if (serverId == null || apiPassword == null)
             {

apps/counterstrikesharp/src/FiveStack.Services/MatchManager.cs

@@ -613,7 +613,7 @@ public void SetupMatch(MatchData match)
             ApplyWorkshopBlockedCvars();
         }
 
-        Server.NextFrame(() =>
+        HibernationUtility.NextFrame(() =>
         {
             if (!wasAlreadySetup)
             {
@@ -866,7 +866,7 @@ private void StartWarmup()
             return;
         }
 
-        Server.NextFrame(() =>
+        HibernationUtility.NextFrame(() =>
         {
             bool isInWarmup = MatchUtility.Rules()?.WarmupPeriod ?? false;
 
@@ -1581,7 +1581,7 @@ public void SetupBroadcast()
                 .Find("tv_broadcast_origin_auth")
                 ?.SetValue($"{_matchData.id}:{_matchData.password}");
 
-            Server.NextFrame(() =>
+            HibernationUtility.NextFrame(() =>
             {
                 _gameServer.SendCommands(["tv_broadcast 1"]);
                 _logger.LogInformation("Sending TV Broadcast command");

apps/counterstrikesharp/src/FiveStack.Services/MatchService.cs

@@ -1,5 +1,6 @@
 using System.Text.Json;
 using CounterStrikeSharp.API;
+using CounterStrikeSharp.API.Modules.Cvars;
 using FiveStack.Entities;
 using FiveStack.Utilities;
 using Microsoft.Extensions.DependencyInjection;
@@ -89,7 +90,7 @@ public async void GetMatchFromApi()
         if (serverId == null || apiPassword == null)
         {
             await Task.Delay(1000 * 5);
-            Server.NextFrame(() =>
+            HibernationUtility.NextFrame(() =>
             {
                 GetMatchFromApi();
             });
@@ -113,7 +114,7 @@ public async void GetMatchFromApi()
                 httpResponse.EnsureSuccessStatusCode();
                 string? response = await httpResponse.Content.ReadAsStringAsync();
 
-                Server.NextFrame(() =>
+                HibernationUtility.NextFrame(() =>
                 {
                     Guid? previousMatchId = _currentMatch?.GetMatchData()?.id;
 
@@ -126,6 +127,8 @@ public async void GetMatchFromApi()
 
                         _currentMatch = null;
 
+                        StayAwake(false);
+
                         _logger.LogWarning(
                             $"No match assigned — clearing match {previousMatchId?.ToString() ?? "none"}"
                         );
@@ -139,6 +142,8 @@ public async void GetMatchFromApi()
                         return;
                     }
 
+                    StayAwake(true);
+
                     if (previousMatchId == matchData.id)
                     {
                         _logger.LogInformation(
@@ -178,6 +183,41 @@ public async void GetMatchFromApi()
         }
     }
 
+    private bool _heldAwake;
+
+    // A hibernating server runs no frames, so timers and the end-of-map work
+    // would stall once everyone left. It only hibernates while it has nothing
+    // to do: it is held awake from the moment it is given a match until that
+    // match is gone.
+    public void StayAwake(bool awake)
+    {
+        ConVar? hibernate = ConVar.Find("sv_hibernate_when_empty");
+
+        if (hibernate == null)
+        {
+            return;
+        }
+
+        if (awake)
+        {
+            if (hibernate.GetPrimitiveValue<bool>())
+            {
+                hibernate.SetValue(false);
+                _heldAwake = true;
+                _logger.LogInformation("holding the server awake for its match");
+            }
+
+            return;
+        }
+
+        if (_heldAwake)
+        {
+            hibernate.SetValue(true);
+            _heldAwake = false;
+            _logger.LogInformation("no match left, the server may hibernate again");
+        }
+    }
+
     public void GetMatchFromOffline()
     {
         string? offlineMatchData = _environmentService.GetOfflineMatchData();

apps/counterstrikesharp/src/FiveStack.Utilities/HibernationUtility.cs

@@ -0,0 +1,29 @@
+using CounterStrikeSharp.API;
+
+namespace FiveStack.Utilities;
+
+// A hibernating server stops running frames but keeps updating the world, and
+// it only wakes once somebody is let in. Whatever has to be in place before
+// that (the match, its password, the map) is queued through here: on the next
+// frame while the server is awake, exactly as before, and on the next world
+// update while it hibernates.
+public static class HibernationUtility
+{
+    private static volatile bool _hibernating;
+
+    public static void SetHibernating(bool hibernating)
+    {
+        _hibernating = hibernating;
+    }
+
+    public static void NextFrame(Action callback)
+    {
+        if (_hibernating)
+        {
+            Server.NextWorldUpdate(callback);
+            return;
+        }
+
+        Server.NextFrame(callback);
+    }
+}

apps/counterstrikesharp/src/FiveStackPlugin.cs

@@ -78,6 +78,7 @@ public override void Load(bool hotReload)
         );
 
         RegisterListener<Listeners.OnTick>(_rankSystem.OnTick);
+        RegisterListener<Listeners.OnServerHibernationUpdate>(HibernationUtility.SetHibernating);
 
         TimerUtility.AddTimer(
             RankSystem.RosterRefreshInterval,
@@ -140,6 +141,7 @@ public override void Unload(bool hotReload)
         );
 
         _matchService.GetCurrentMatch()?.Reset();
+        _matchService.StayAwake(false);
 
         _ = _matchEvents.Disconnect();
     }

apps/swiftly/Dockerfile

@@ -131,6 +131,7 @@ ENV DEFAULT_MAP="de_inferno"
 ENV STEAM_RELAY="false"
 
 ENV SERVER_TYPE="Ranked"
+ENV HIBERNATE_WHEN_EMPTY="false"
 
 ENV SWIFTLYS2_VERSION="v1.4.13"
 ENV SWIFTLYS2_URL=https://github.com/swiftly-solution/swiftlys2/releases/download/${SWIFTLYS2_VERSION}/swiftlys2-linux-${SWIFTLYS2_VERSION}-with-runtimes.zip

apps/swiftly/scripts/setup.sh

@@ -50,6 +50,9 @@ echo "---Create Symbolic Links---"
 
 if [ "$SERVER_TYPE" = "Ranked" ]; then
   cp "/opt/server-cfg/ranked.server.cfg" "$INSTANCE_SERVER_DIR/game/csgo/cfg/server.cfg"
+  if [ "$HIBERNATE_WHEN_EMPTY" = "true" ]; then
+    sed -i 's/^sv_hibernate_when_empty.*/sv_hibernate_when_empty 1/' "$INSTANCE_SERVER_DIR/game/csgo/cfg/server.cfg"
+  fi
   cp "/opt/server-cfg/5stack.base.cfg" "$INSTANCE_SERVER_DIR/game/csgo/cfg"
   cp "/opt/server-cfg/5stack.competitive.cfg" "$INSTANCE_SERVER_DIR/game/csgo/cfg"
   cp "/opt/server-cfg/5stack.duel.cfg" "$INSTANCE_SERVER_DIR/game/csgo/cfg"

apps/swiftly/src/FiveStack.Events/MapChange.cs

@@ -12,7 +12,7 @@ public async void OnMapLoad(IOnMapLoadEvent @event)
         _logger.LogInformation("map changed: precaching models");
 
         await Task.Delay(1000 * 5);
-        _core.Scheduler.NextTick(() =>
+        FiveStack.Utilities.HibernationUtility.NextTick(() =>
         {
             MatchManager? match = _matchService.GetCurrentMatch();
             match?.SyncActiveMapAfterMapStart();

apps/swiftly/src/FiveStack.Services/GameServer.cs

@@ -44,7 +44,7 @@ public void SendCommands(string[] commands)
             );
         }
 
-        _core.Scheduler.NextTick(() => _core.Engine.ExecuteCommand(string.Join(";", commands)));
+        HibernationUtility.NextTick(() => _core.Engine.ExecuteCommand(string.Join(";", commands)));
     }
 
     public void Message(
@@ -108,7 +108,7 @@ public void Ping(string pluginVersion)
         string? serverId = _environmentService.GetServerId();
         string? apiPassword = _environmentService.GetServerApiPassword();
 
-        _core.Scheduler.NextTick(() =>
+        _core.Scheduler.NextWorldUpdate(() =>
         {
             if (serverId == null || apiPassword == null)
             {

apps/swiftly/src/FiveStack.Services/MatchManager.cs

@@ -599,7 +599,7 @@ public void SetupMatch(MatchData match)
             ApplyWorkshopBlockedCvars();
         }
 
-        _core.Scheduler.NextTick(() =>
+        HibernationUtility.NextTick(() =>
         {
             if (!wasAlreadySetup)
             {
@@ -859,7 +859,7 @@ private void StartWarmup()
             return;
         }
 
-        _core.Scheduler.NextTick(() =>
+        HibernationUtility.NextTick(() =>
         {
             bool isInWarmup = MatchUtility.Rules()?.WarmupPeriod ?? false;
 
@@ -1572,7 +1572,7 @@ public void SetupBroadcast()
             SetConVar("tv_broadcast_url", $"{_environmentService.GetRelayUrl()}/{_matchData.id}");
             SetConVar("tv_broadcast_origin_auth", $"{_matchData.id}:{_matchData.password}");
 
-            _core.Scheduler.NextTick(() =>
+            HibernationUtility.NextTick(() =>
             {
                 _gameServer.SendCommands(["tv_broadcast 1"]);
                 _logger.LogInformation("Sending TV Broadcast command");

apps/swiftly/src/FiveStack.Services/MatchService.cs

@@ -89,7 +89,7 @@ public async void GetMatchFromApi()
         if (serverId == null || apiPassword == null)
         {
             await Task.Delay(1000 * 5);
-            _core.Scheduler.NextTick(() =>
+            HibernationUtility.NextTick(() =>
             {
                 GetMatchFromApi();
             });
@@ -113,7 +113,7 @@ public async void GetMatchFromApi()
                 httpResponse.EnsureSuccessStatusCode();
                 string? response = await httpResponse.Content.ReadAsStringAsync();
 
-                _core.Scheduler.NextTick(() =>
+                HibernationUtility.NextTick(() =>
                 {
                     Guid? previousMatchId = _currentMatch?.GetMatchData()?.id;
 
@@ -126,6 +126,8 @@ public async void GetMatchFromApi()
 
                         _currentMatch = null;
 
+                        StayAwake(false);
+
                         _logger.LogWarning(
                             $"No match assigned — clearing match {previousMatchId?.ToString() ?? "none"}"
                         );
@@ -139,6 +141,8 @@ public async void GetMatchFromApi()
                         return;
                     }
 
+                    StayAwake(true);
+
                     if (previousMatchId == matchData.id)
                     {
                         _logger.LogInformation(
@@ -178,6 +182,49 @@ public async void GetMatchFromApi()
         }
     }
 
+    private bool _heldAwake;
+
+    // A hibernating server runs no ticks, so timers and the end-of-map work
+    // would stall once everyone left. It only hibernates while it has nothing
+    // to do: it is held awake from the moment it is given a match until that
+    // match is gone.
+    public void StayAwake(bool awake)
+    {
+        try
+        {
+            var hibernate = _core.ConVar.Find<bool>("sv_hibernate_when_empty");
+
+            if (hibernate == null)
+            {
+                return;
+            }
+
+            if (awake)
+            {
+                if (hibernate.Value)
+                {
+                    // SetInternal applies now; a queued set waits for a tick
+                    hibernate.SetInternal(false);
+                    _heldAwake = true;
+                    _logger.LogInformation("holding the server awake for its match");
+                }
+
+                return;
+            }
+
+            if (_heldAwake)
+            {
+                hibernate.SetInternal(true);
+                _heldAwake = false;
+                _logger.LogInformation("no match left, the server may hibernate again");
+            }
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "unable to change sv_hibernate_when_empty");
+        }
+    }
+
     public void GetMatchFromOffline()
     {
         string? offlineMatchData = _environmentService.GetOfflineMatchData();