feat: initial implementation of minecraft-servers

hosts/Infini-DESKTOP/default.nix

@@ -18,4 +18,25 @@
     eth0.useDHCP = true;
     wlp41s0.useDHCP = true;
   };
+
+  # services.minecraft-servers = {
+  #   enable = true;
+  #   openFirewall = true;
+
+  #   servers = {
+  #     test = {
+  #       enable = true;
+  #       eula = true;
+  #       # declarative = true;
+  #       # serverProperties.server-port = 25565;
+  #     };
+
+  #     # test2 = {
+  #     #   enable = true;
+  #     #   eula = true;
+  #     #   declarative = true;
+  #     #   serverProperties.server-port = 25566;
+  #     # };
+  #   };
+  # };
 }

modules/minecraft-servers.nix

@@ -0,0 +1,211 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.minecraft-servers;
+
+  eulaFile = builtins.toFile "eula.txt" ''
+    # eula.txt managed by NixOS Configuration
+    eula=true
+  '';
+
+  whitelistFile = server:
+    pkgs.writeText "whitelist.json" (builtins.toJSON (mapAttrsToList (n: v: {
+      name = n;
+      uuid = v;
+    }) server.whitelist));
+
+  cfgToString = v: if builtins.isBool v then boolToString v else toString v;
+
+  serverPropertiesFile = server:
+    pkgs.writeText "server.properties" (''
+      # server.properties managed by NixOS configuration
+    '' + concatStringsSep "\n"
+      (mapAttrsToList (n: v: "${n}=${cfgToString v}") server.serverProperties));
+
+  tmux = "${getBin pkgs.tmux}/bin/tmux";
+
+  stopScript = name:
+    pkgs.writeScript "minecraft-stop" ''
+      #!${pkgs.runtimeShell}
+
+      if ! [ -d "/proc/$1" ]; then
+        exit 0
+      fi
+
+      ${tmux} -S ${cfgdataDir}/${name}.sock send-keys Enter stop Enter
+      ${getBin pkgs.coreutils}/bin/tail --pid-"$1" -f /dev/null
+    '';
+
+  cfgdataDir = "/var/lib/minecraft";
+
+  mkService = name: inst:
+    builtins.trace "${name} building" {
+      name = "minecraft-server-${name}";
+      value = builtins.trace "${name}: value: build" {
+        description = "Minecraft Server Service: ${name}";
+        wantedBy = [ "multi-user.target" ];
+        after = [ "network.target" ];
+
+        serviceConfig =
+          builtins.trace "${name}: value: serviceConfig: building" {
+            ExecStart = ''
+                    ${tmux} -S ${cfgdataDir}/${name}.sock new \
+                      -d ${inst.package}/bin/minecraft-server ${inst.jvmOpts}
+              #     '';
+            ExecStop = "${stopScript name} $MAINPID";
+            Restart = "always";
+            Type = "forking";
+            GuessMainPIP = true;
+            User = "minecraft";
+            WorkingDirectory = "${cfgdataDir}/${name}";
+          };
+
+        preStart = ''
+          ln -sf ${eulaFile} eula.txt
+        '' + (if inst.declarative then ''
+          if [ -e .declarative ]; then
+            # Was declarative before, no need to back up anything
+            ln -sf ${whitelistFile inst} whitelist.json
+            cp -f ${serverPropertiesFile inst} server.properties
+          else
+            # Declarative for the first time, backup stateful files
+            ln -sb --suffix=.stateful ${whitelistFile inst} whitelist.json
+            cp -b --suffix=.stateful ${
+              serverPropertiesFile inst
+            } server.properties
+            # server.properties must have write permissions, because every time
+            # the server starts it first parses the file and then regenerates it..
+            chmod +w server.properties
+            echo "Autogenerated file that signifies that this server configuration is managed declaratively by NixOS" \
+              > .declarative
+          fi
+        '' else ''
+          if [ -e .declarative ]; then
+            rm .declarative
+          fi
+        '');
+
+        postStart = ''
+          ${pkgs.coreutils}/bin/chmod 660 ${cfgdataDir}/${name}.sock
+          ${pkgs.coreutils}/bin/chgrp minecraft ${cfgdataDir}/${name}.sock
+        '';
+      };
+    };
+
+  generatedServices = mapAttrs' mkService cfg.servers;
+
+in {
+  options = {
+    services.minecraft-servers = {
+      enable = mkEnableOption "minecraft servers";
+      # TODO: verbose minecraft-servers enable option
+
+      openFirewall =
+        mkEnableOption "opening the firewall for each server by default";
+      # TODO: verbose outer openFirewall option
+
+      dataDir = mkOption {
+        type = types.path;
+        default = "/var/lib/minecraft";
+        # TODO: verbose dataDir option
+      };
+
+      servers = mkOption {
+        type = types.attrsOf (types.submodule {
+          enable = mkEnableOption "this minecraft server";
+          # TODO: verbose server enable option
+
+          declarative = mkEnableOption "declarative server management";
+          # TODO: verbose declarative option
+
+          eula = mkEnableOption "accepting the eula";
+          # TODO: verbose eula option
+
+          openFirewall = mkOption {
+            type = types.bool;
+            default = true; # cfg.openFirewall;
+            # TODO: openFirewall description
+          };
+
+          jvmOpts = mkOption {
+            type = types.separatedString " ";
+            default = "-Xmx2048M -Xms2048M";
+            # TODO: verbose jvmOpts option
+          };
+
+          package = mkOption {
+            type = types.package;
+            default = pkgs.minecraft-server;
+            # TODO: verbose package option
+          };
+
+          whitelist = mkOption {
+            type = let
+              minecraftUUID = types.strMatching
+                "[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}"
+                // {
+                  description = "Minecraft UUID";
+                };
+            in types.attrsOf minecraftUUID;
+            default = { };
+            # TODO: verbose whitelist option
+          };
+
+          serverProperties = mkOption {
+            type = with types; attrsOf (oneOf [ bool int str ]);
+            default = { server-port = 25565; };
+            # TODO: verbose serverProperties option
+          };
+        });
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    users.users.minecraft = {
+      description = "Minecraft server service user";
+      home = cfg.dataDir;
+      createHome = true;
+      isSystemUser = true;
+      group = "minecraft";
+    };
+
+    users.groups.minecraft = { };
+
+    systemd.services =
+      mkIf (cfg.enable && cfg.servers != { }) generatedServices;
+
+  };
+
+  # networking.firewall = let
+
+  #   propertyFunc = attrsets.mapAttrsToList (name: value:
+  #     let props = value.serverProperties;
+  #     in (if value.declarative then [
+  #       (props.server-port or 25565)
+  #       (if props.enable-rcon or false then
+  #         props."rcon.port" or 25575
+  #       else
+  #         null)
+  #       (if props.enable-query or false then
+  #         props "query.port" or 25565
+  #       else
+  #         null)
+  #     ] else
+  #       null)) cfg.servers;
+
+  #   openedPorts = lists.flatten [ serverPorts queryPorts rconPorts ];
+  # in {
+  #   allowedUDPPorts = openedPorts;
+  #   allowedTCPPorts = openedPorts;
+  # };
+
+  # assertions = [{
+  #   assertion = all (i: i.eula == true) (attrValues cfg.servers);
+  #   message = "You must agree to Mojangs EULA to run minecraft-server."
+  #     + " Read https://account.mojang.com/documents/minecraft_eula and"
+  #     + " set `services.minecraft-servers.servers.<name>.eula` to `true` for all servers if you agree.";
+  # }];
+}

users/infinidoge/default.nix

@@ -103,7 +103,7 @@
       "PASSWORD SET IN THE FUTURE";
     description = "Infinidoge";
     isNormalUser = true;
-    extraGroups = [ "wheel" ];
+    extraGroups = [ "wheel" "minecraft" ];
     shell = pkgs.zsh;
   };
 }