nixos xfs_quota: add new module for managing xfs_quota projects

nixos/modules/module-list.nix

@@ -74,6 +74,7 @@
   ./programs/venus.nix
   ./programs/wvdial.nix
   ./programs/freetds.nix
+  ./programs/xfs_quota.nix
   ./programs/zsh/zsh.nix
   ./rename.nix
   ./security/apparmor.nix

nixos/modules/programs/xfs_quota.nix

@@ -0,0 +1,109 @@
+# Configuration for the xfs_quota command
+
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.programs.xfs_quota;
+
+  limitOptions = opts: concatStringsSep " " [
+    (optionalString (opts.sizeSoftLimit != null) "bsoft=${opts.sizeSoftLimit}")
+    (optionalString (opts.sizeHardLimit != null) "bhard=${opts.sizeHardLimit}")
+  ];
+
+in
+
+{
+
+  ###### interface
+
+  options = {
+
+    programs.xfs_quota = {
+      projects = mkOption {
+        type = types.attrsOf (types.submodule {
+          options = {
+            id = mkOption {
+              type = types.int;
+              description = "Project ID.";
+            };
+
+            fileSystem = mkOption {
+              type = types.string;
+              description = "XFS filesystem hosting the xfs_quota project.";
+              default = "/";
+            };
+
+            path = mkOption {
+              type = types.string;
+              description = "Project directory.";
+            };
+
+            sizeSoftLimit = mkOption {
+              type = types.nullOr types.string;
+              default = null;
+              example = "30g";
+              description = "Soft limit of the project size";
+            };
+
+            sizeHardLimit = mkOption {
+              type = types.nullOr types.string;
+              default = null;
+              example = "50g";
+              description = "Hard limit of the project size.";
+            };
+          };
+        });
+
+        description = "Setup of xfs_quota projects. Make sure the filesystem is mounted with the pquota option.";
+
+        example = {
+          "projname" = {
+            id = 50;
+            path = "/xfsprojects/projname";
+            sizeHardLimit = "50g";
+          };
+        };
+      };
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkIf (cfg.projects != {}) {
+
+    environment.etc.projects.source = pkgs.writeText "etc-project"
+      (concatStringsSep "\n" (mapAttrsToList
+        (name: opts: "${toString opts.id}:${opts.path}") cfg.projects));
+
+    environment.etc.projid.source = pkgs.writeText "etc-projid"
+      (concatStringsSep "\n" (mapAttrsToList
+        (name: opts: "${name}:${toString opts.id}") cfg.projects));
+
+    systemd.services = mapAttrs' (name: opts:
+      nameValuePair "xfs_quota-${name}" {
+        description = "Setup xfs_quota for project ${name}";
+        script = ''
+          ${pkgs.xfsprogs}/bin/xfs_quota -x -c 'project -s ${name}' ${opts.fileSystem}
+          ${pkgs.xfsprogs}/bin/xfs_quota -x -c 'limit -p ${limitOptions opts} ${name}' ${opts.fileSystem}
+        '';
+
+        wantedBy = [ "multi-user.target" ];
+        after = [ ((replaceChars [ "/" ] [ "-" ] opts.fileSystem) + ".mount") ];
+
+        restartTriggers = [ (pkgs.writeText "xfs_quota-project-trigger-${name}" (builtins.toJSON opts)) ];
+
+        serviceConfig = {
+          Type = "oneshot";
+          RemainAfterExit = true;
+        };
+      }
+    ) cfg.projects;
+
+  };
+
+}