From 76ff79019cceb00d966d5cb1a6d26f195b2e2607 Mon Sep 17 00:00:00 2001
From: wo2wz <189177184+wo2wz@users.noreply.github.com>
Date: Thu, 11 Dec 2025 11:43:39 -0500
Subject: [PATCH] minecraft-server: adjust for velocity, use template unit,
 ditch screen and use fifo systemd socket for input

it actually works now, don't know why terminal multiplexers give an error even with pty access but this setup is better overall anyway
---
 .../services/gameserver/minecraft-server.nix  | 313 +++++++++---------
 1 file changed, 165 insertions(+), 148 deletions(-)

diff --git a/modules/nixos/services/gameserver/minecraft-server.nix b/modules/nixos/services/gameserver/minecraft-server.nix
index 2b06991..251a5fa 100644
--- a/modules/nixos/services/gameserver/minecraft-server.nix
+++ b/modules/nixos/services/gameserver/minecraft-server.nix
@@ -2,11 +2,6 @@
 
 
 {
-  networking.firewall = {
-    allowedTCPPorts = [ 10000 ];
-    allowedUDPPorts = [ 10000 ];
-  };
-
   users = {
     users.minecraft = {
       group = "minecraft";
@@ -18,155 +13,177 @@
     groups.minecraft = {};
   };
 
-  environment.systemPackages = [
-    # to control the interactive server console
-    pkgs.screen
+  environment.etc."minecraft/java21_args".text = ''
+    --add-modules=jdk.incubator.vector
+    -XX:+UseG1GC
+    -XX:MaxGCPauseMillis=200
+    -XX:+UnlockExperimentalVMOptions
+    -XX:+UnlockDiagnosticVMOptions
+    -XX:+DisableExplicitGC
+    -XX:+AlwaysPreTouch
+    -XX:G1NewSizePercent=28
+    -XX:G1MaxNewSizePercent=50
+    -XX:G1HeapRegionSize=16M
+    -XX:G1ReservePercent=15
+    -XX:G1MixedGCCountTarget=3
+    -XX:InitiatingHeapOccupancyPercent=20
+    -XX:G1MixedGCLiveThresholdPercent=90
+    -XX:SurvivorRatio=32
+    -XX:G1HeapWastePercent=5
+    -XX:MaxTenuringThreshold=1
+    -XX:+PerfDisableSharedMem
+    -XX:G1SATBBufferEnqueueingThresholdPercent=30
+    -XX:G1ConcMarkStepDurationMillis=5
+    -XX:G1RSetUpdatingPauseTimePercent=0
+    -XX:+UseNUMA
+    -XX:-DontCompileHugeMethods
+    -XX:MaxNodeLimit=240000
+    -XX:NodeLimitFudgeFactor=8000
+    -XX:ReservedCodeCacheSize=400M
+    -XX:NonNMethodCodeHeapSize=12M
+    -XX:ProfiledCodeHeapSize=194M
+    -XX:NonProfiledCodeHeapSize=194M
+    -XX:NmethodSweepActivity=1
+    -XX:+UseFastUnorderedTimeStamps
+    -XX:+UseCriticalJavaThreadPriority
+    -XX:AllocatePrefetchStyle=3
+    -XX:+AlwaysActAsServerClassMachine
+    -XX:+UseTransparentHugePages
+    -XX:LargePageSizeInBytes=2M
+    -XX:+UseLargePages
+    -XX:+EagerJVMCI
+    -XX:+UseStringDeduplication
+    -XX:+UseAES
+    -XX:+UseAESIntrinsics
+    -XX:+UseFMA
+    -XX:+UseLoopPredicate
+    -XX:+RangeCheckElimination
+    -XX:+OptimizeStringConcat
+    -XX:+UseCompressedOops
+    -XX:+UseThreadPriorities
+    -XX:+OmitStackTraceInFastThrow
+    -XX:+RewriteBytecodes
+    -XX:+RewriteFrequentPairs
+    -XX:+UseFPUForSpilling
+    -XX:+UseFastStosb
+    -XX:+UseNewLongLShift
+    -XX:+UseVectorCmov
+    -XX:+UseXMMForArrayCopy
+    -XX:+UseXmmI2D
+    -XX:+UseXmmI2F
+    -XX:+UseXmmLoadAndClearUpper
+    -XX:+UseXmmRegToRegMoveAll
+    -XX:+EliminateLocks
+    -XX:+DoEscapeAnalysis
+    -XX:+AlignVector
+    -XX:+OptimizeFill
+    -XX:+EnableVectorSupport
+    -XX:+UseCharacterCompareIntrinsics
+    -XX:+UseCopySignIntrinsic
+    -XX:+UseVectorStubs
+    -XX:UseAVX=2
+    -XX:UseSSE=4
+    -XX:+UseFastJNIAccessors
+    -XX:+UseInlineCaches
+    -XX:+SegmentedCodeCache
+    -Djdk.nio.maxCachedBufferSize=262144
+    -Djdk.graal.UsePriorityInlining=true
+    -Djdk.graal.Vectorization=true
+    -Djdk.graal.OptDuplication=true
+    -Djdk.graal.DetectInvertedLoopsAsCounted=true
+    -Djdk.graal.LoopInversion=true
+    -Djdk.graal.VectorizeHashes=true
+    -Djdk.graal.EnterprisePartialUnroll=true
+    -Djdk.graal.VectorizeSIMD=true
+    -Djdk.graal.StripMineNonCountedLoops=true
+    -Djdk.graal.SpeculativeGuardMovement=true
+    -Djdk.graal.TuneInlinerExploration=1
+    -Djdk.graal.LoopRotation=true
+    -Djdk.graal.CompilerConfiguration=enterprise
+  '';
 
-    pkgs.graalvmPackages.graalvm-oracle_17
-    inputs.nixpkgs-pin.legacyPackages.${pkgs.stdenv.hostPlatform.system}.graalvm-ce
-  ];
+  systemd = {
+    targets.multi-user.wants = [
+      "minecraft@countries.service"
+      "minecraft@monifactory.service"
+    ];
 
-  environment.etc = {
-    "minecraft/java21_args".text = ''
-      -Xmx8G
-      -Xms8G
-      --add-modules=jdk.incubator.vector
-      -XX:+UseG1GC
-      -XX:MaxGCPauseMillis=200
-      -XX:+UnlockExperimentalVMOptions
-      -XX:+UnlockDiagnosticVMOptions
-      -XX:+DisableExplicitGC
-      -XX:+AlwaysPreTouch
-      -XX:G1NewSizePercent=28
-      -XX:G1MaxNewSizePercent=50
-      -XX:G1HeapRegionSize=16M
-      -XX:G1ReservePercent=15
-      -XX:G1MixedGCCountTarget=3
-      -XX:InitiatingHeapOccupancyPercent=20
-      -XX:G1MixedGCLiveThresholdPercent=90
-      -XX:SurvivorRatio=32
-      -XX:G1HeapWastePercent=5
-      -XX:MaxTenuringThreshold=1
-      -XX:+PerfDisableSharedMem
-      -XX:G1SATBBufferEnqueueingThresholdPercent=30
-      -XX:G1ConcMarkStepDurationMillis=5
-      -XX:G1RSetUpdatingPauseTimePercent=0
-      -XX:+UseNUMA
-      -XX:-DontCompileHugeMethods
-      -XX:MaxNodeLimit=240000
-      -XX:NodeLimitFudgeFactor=8000
-      -XX:ReservedCodeCacheSize=400M
-      -XX:NonNMethodCodeHeapSize=12M
-      -XX:ProfiledCodeHeapSize=194M
-      -XX:NonProfiledCodeHeapSize=194M
-      -XX:NmethodSweepActivity=1
-      -XX:+UseFastUnorderedTimeStamps
-      -XX:+UseCriticalJavaThreadPriority
-      -XX:AllocatePrefetchStyle=3
-      -XX:+AlwaysActAsServerClassMachine
-      -XX:+UseTransparentHugePages
-      -XX:LargePageSizeInBytes=2M
-      -XX:+UseLargePages
-      -XX:+EagerJVMCI
-      -XX:+UseStringDeduplication
-      -XX:+UseAES
-      -XX:+UseAESIntrinsics
-      -XX:+UseFMA
-      -XX:+UseLoopPredicate
-      -XX:+RangeCheckElimination
-      -XX:+OptimizeStringConcat
-      -XX:+UseCompressedOops
-      -XX:+UseThreadPriorities
-      -XX:+OmitStackTraceInFastThrow
-      -XX:+RewriteBytecodes
-      -XX:+RewriteFrequentPairs
-      -XX:+UseFPUForSpilling
-      -XX:+UseFastStosb
-      -XX:+UseNewLongLShift
-      -XX:+UseVectorCmov
-      -XX:+UseXMMForArrayCopy
-      -XX:+UseXmmI2D
-      -XX:+UseXmmI2F
-      -XX:+UseXmmLoadAndClearUpper
-      -XX:+UseXmmRegToRegMoveAll
-      -XX:+EliminateLocks
-      -XX:+DoEscapeAnalysis
-      -XX:+AlignVector
-      -XX:+OptimizeFill
-      -XX:+EnableVectorSupport
-      -XX:+UseCharacterCompareIntrinsics
-      -XX:+UseCopySignIntrinsic
-      -XX:+UseVectorStubs
-      -XX:UseAVX=2
-      -XX:UseSSE=4
-      -XX:+UseFastJNIAccessors
-      -XX:+UseInlineCaches
-      -XX:+SegmentedCodeCache
-      -Djdk.nio.maxCachedBufferSize=262144
-      -Djdk.graal.UsePriorityInlining=true
-      -Djdk.graal.Vectorization=true
-      -Djdk.graal.OptDuplication=true
-      -Djdk.graal.DetectInvertedLoopsAsCounted=true
-      -Djdk.graal.LoopInversion=true
-      -Djdk.graal.VectorizeHashes=true
-      -Djdk.graal.EnterprisePartialUnroll=true
-      -Djdk.graal.VectorizeSIMD=true
-      -Djdk.graal.StripMineNonCountedLoops=true
-      -Djdk.graal.SpeculativeGuardMovement=true
-      -Djdk.graal.TuneInlinerExploration=1
-      -Djdk.graal.LoopRotation=true
-      -Djdk.graal.CompilerConfiguration=enterprise
-    '';
-  };
+    sockets."minecraft@" = {
+      partOf = [ "minecraft@%i.service" ];
+      socketConfig = {
+        SocketUser = "minecraft";
+        SocketGroup = "minecraft";
+        SocketMode = "0600";
 
-  systemd.services.minecraft = {
-    description = "Minecraft Java Edition server";
-    wants = [ "network-online.target" ];
-    after = [ "network-online.target" ];
+        ListenFIFO = "%t/minecraft-%i.stdin";
+        RemoveOnStop = true;
+      };
+    };
 
-    path = [ pkgs.screen ];
-    script = "screen -dmS minecraft -- ${lib.getExe inputs.nixpkgs-pin.legacyPackages.${pkgs.stdenv.hostPlatform.system}.graalvm-ce} @/etc/minecraft/java21_args -jar server.jar nogui";
+    services."minecraft@" = {
+      description = "Minecraft Java Edition server for %i";
+      wants = [ "network-online.target" "velocity.service" ];
+      after = [ "network-online.target" "velocity.service" ];
 
-    serviceConfig = {
-      User = "minecraft";
-      Group = "minecraft";
-      WorkingDirectory = "/var/lib/minecraft/vanilla";
-      Type = "forking";
-      Restart = "on-failure";
-      TimerSlackNSec = "5ms";
+      environment = {
+        JAVA_17_PATH = lib.getExe pkgs.graalvmPackages.graalvm-oracle_17;
+        JAVA_21_PATH = lib.getExe inputs.nixpkgs-pin.legacyPackages.${pkgs.stdenv.hostPlatform.system}.graalvm-ce;
+      };
 
-      # very necessary and sane hardening for a private minecraft server
-      CapabilityBoundingSet = [ "" ];
-      DeviceAllow = [ "" ];
-      DevicePolicy = "strict";
-      LockPersonality = true;
-      MemoryDenyWriteExecute = true;
-      NoNewPrivileges = true;
-      PrivateDevices = true;
-      PrivateTmp = true;
-      PrivateUsers = true;
-      ProcSubset = "pid";
-      ProtectClock = true;
-      ProtectControlGroups = true;
-      ProtectHome = true;
-      ProtectHostname = true;
-      ProtectKernelLogs = true;
-      ProtectKernelModules = true;
-      ProtectKernelTunables = true;
-      ProtectProc = "invisible";
-      ProtectSystem = "strict";
-      RemoveIPC = true;
-      RestrictAddressFamilies = [
-        "AF_INET"
-        "AF_INET6"
-        "AF_UNIX"
-      ];
-      RestrictNamespaces = true;
-      RestrictRealtime = true;
-      RestrictSUIDSGID = true;
-      SystemCallArchitectures = "native";
-      SystemCallFilter = [ "@system-service" ];
-      UMask = "0027";
+      serviceConfig = {
+        User = "minecraft";
+        Group = "minecraft";
+        StateDirectory = "minecraft/%i";
+        StateDirectoryMode = "0700";
+        WorkingDirectory = "%S/minecraft/%i";
+
+        ExecStart = "${lib.getExe pkgs.bash} run.sh";
+
+        Type = "exec";
+        Restart = "always";
+        # minecraft responds to SIGINT to stop the server
+        KillSignal = "SIGINT";
+        # minecraft sends exit code 130 when stopped
+        SuccessExitStatus = 130;
+
+        # use socket for stdin to send commands
+        Sockets = "minecraft@%i.socket";
+        StandardInput = "socket";
+        StandardOutput = "journal";
+        StandardError = "journal";
+
+        # hardening
+        CapabilityBoundingSet = [ "" ];
+        DeviceAllow = [ "" ];
+        DevicePolicy = "strict";
+        LockPersonality = true;
+        NoNewPrivileges = true;
+        PrivateDevices = true;
+        PrivateTmp = true;
+        PrivateUsers = true;
+        ProcSubset = "pid";
+        ProtectClock = true;
+        ProtectControlGroups = true;
+        ProtectHome = true;
+        ProtectHostname = true;
+        ProtectKernelLogs = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        ProtectProc = "invisible";
+        ProtectSystem = "strict";
+        RemoveIPC = true;
+        RestrictAddressFamilies = [
+          "AF_INET"
+          "AF_INET6"
+          "AF_UNIX"
+        ];
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+        SystemCallArchitectures = "native";
+        SystemCallFilter = [ "@system-service" ];
+        UMask = "0077";
+      };
     };
   };
 }