nixos: init moosefs module

nixos/modules/module-list.nix

···
   ./services/network-filesystems/litestream/default.nix
   ./services/network-filesystems/netatalk.nix
   ./services/network-filesystems/nfsd.nix
+  ./services/network-filesystems/moosefs.nix
   ./services/network-filesystems/openafs/client.nix
   ./services/network-filesystems/openafs/server.nix
   ./services/network-filesystems/orangefs/server.nix

nixos/modules/services/network-filesystems/moosefs.nix

···
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.moosefs;
+
+  mfsUser = if cfg.runAsUser then "moosefs" else "root";
+
+  settingsFormat = let
+
+    listSep = " ";
+    allowedTypes = with types; [ bool int float str ];
+    valueToString = val:
+        if isList val then concatStringsSep listSep (map (x: valueToString x) val)
+        else if isBool val then (if val then "1" else "0")
+        else toString val;
+
+    in {
+      type = with types; let
+        valueType = oneOf ([
+          (listOf valueType)
+        ] ++ allowedTypes) // {
+          description = "Flat key-value file";
+        };
+      in attrsOf valueType;
+
+      generate = name: value:
+        pkgs.writeText name ( lib.concatStringsSep "\n" (
+          lib.mapAttrsToList (key: val: "${key} = ${valueToString val}") value ));
+    };
+
+
+  initTool = pkgs.writeShellScriptBin "mfsmaster-init" ''
+    if [ ! -e ${cfg.master.settings.DATA_PATH}/metadata.mfs ]; then
+      cp ${pkgs.moosefs}/var/mfs/metadata.mfs.empty ${cfg.master.settings.DATA_PATH}
+      chmod +w ${cfg.master.settings.DATA_PATH}/metadata.mfs.empty
+      ${pkgs.moosefs}/bin/mfsmaster -a -c ${masterCfg} start
+      ${pkgs.moosefs}/bin/mfsmaster -c ${masterCfg} stop
+      rm ${cfg.master.settings.DATA_PATH}/metadata.mfs.empty
+    fi
+  '';
+
+  # master config file
+  masterCfg = settingsFormat.generate
+    "mfsmaster.cfg" cfg.master.settings;
+
+  # metalogger config file
+  metaloggerCfg = settingsFormat.generate
+    "mfsmetalogger.cfg" cfg.metalogger.settings;
+
+  # chunkserver config file
+  chunkserverCfg = settingsFormat.generate
+    "mfschunkserver.cfg" cfg.chunkserver.settings;
+
+  # generic template for all deamons
+  systemdService = name: extraConfig: configFile: {
+    wantedBy = [ "multi-user.target" ];
+    wants = [ "network-online.target" ];
+    after = [ "network.target" "network-online.target" ];
+
+    serviceConfig = {
+      Type = "forking";
+      ExecStart  = "${pkgs.moosefs}/bin/mfs${name} -c ${configFile} start";
+      ExecStop   = "${pkgs.moosefs}/bin/mfs${name} -c ${configFile} stop";
+      ExecReload = "${pkgs.moosefs}/bin/mfs${name} -c ${configFile} reload";
+      PIDFile = "${cfg."${name}".settings.DATA_PATH}/.mfs${name}.lock";
+    } // extraConfig;
+  };
+
+in {
+  ###### interface
+
+  options = {
+    services.moosefs = {
+      masterHost = mkOption {
+        type = types.str;
+        default = null;
+        description = "IP or DNS name of master host.";
+      };
+
+      runAsUser = mkOption {
+        type = types.bool;
+        default = true;
+        example = true;
+        description = "Run daemons as user moosefs instead of root.";
+      };
+
+      client.enable = mkEnableOption "Moosefs client.";
+
+      master = {
+        enable = mkOption {
+          type = types.bool;
+          description = ''
+            Enable Moosefs master daemon.
+
+            You need to run <literal>mfsmaster-init</literal> on a freshly installed master server to
+            initialize the <literal>DATA_PATH</literal> direcory.
+          '';
+          default = false;
+        };
+
+
+        exports = mkOption {
+          type = with types; listOf str;
+          default = null;
+          description = "Paths to export (see mfsexports.cfg).";
+          example = [
+            "* / rw,alldirs,admin,maproot=0:0"
+            "* . rw"
+          ];
+        };
+
+        openFirewall = mkOption {
+          type = types.bool;
+          description = "Whether to automatically open the necessary ports in the firewall.";
+          default = false;
+        };
+
+        settings = mkOption {
+          type = types.submodule {
+            freeformType = settingsFormat.type;
+
+            options.DATA_PATH = mkOption {
+              type = types.str;
+              default = "/var/lib/mfs";
+              description = "Data storage directory.";
+            };
+          };
+
+          description = "Contents of config file (mfsmaster.cfg).";
+        };
+      };
+
+      metalogger = {
+        enable = mkEnableOption "Moosefs metalogger daemon.";
+
+        settings = mkOption {
+          type = types.submodule {
+            freeformType = settingsFormat.type;
+
+            options.DATA_PATH = mkOption {
+              type = types.str;
+              default = "/var/lib/mfs";
+              description = "Data storage directory";
+            };
+          };
+
+          description = "Contents of metalogger config file (mfsmetalogger.cfg).";
+        };
+      };
+
+      chunkserver = {
+        enable = mkEnableOption "Moosefs chunkserver daemon.";
+
+        openFirewall = mkOption {
+          type = types.bool;
+          description = "Whether to automatically open the necessary ports in the firewall.";
+          default = false;
+        };
+
+        hdds = mkOption {
+          type = with types; listOf str;
+          default =  null;
+          description = "Mount points to be used by chunkserver for storage (see mfshdd.cfg).";
+          example = [ "/mnt/hdd1" ];
+        };
+
+        settings = mkOption {
+          type = types.submodule {
+            freeformType = settingsFormat.type;
+
+            options.DATA_PATH = mkOption {
+              type = types.str;
+              default = "/var/lib/mfs";
+              description = "Directory for lock file.";
+            };
+          };
+
+          description = "Contents of chunkserver config file (mfschunkserver.cfg).";
+        };
+      };
+    };
+  };
+
+  ###### implementation
+
+  config =  mkIf ( cfg.client.enable || cfg.master.enable || cfg.metalogger.enable || cfg.chunkserver.enable ) {
+
+    warnings = [ ( mkIf (!cfg.runAsUser) "Running moosefs services as root is not recommended.") ];
+
+    # Service settings
+    services.moosefs = {
+      master.settings = mkIf cfg.master.enable {
+        WORKING_USER = mfsUser;
+        EXPORTS_FILENAME = toString ( pkgs.writeText "mfsexports.cfg"
+          (concatStringsSep "\n" cfg.master.exports));
+      };
+
+      metalogger.settings = mkIf cfg.metalogger.enable {
+        WORKING_USER = mfsUser;
+        MASTER_HOST = cfg.masterHost;
+      };
+
+      chunkserver.settings = mkIf cfg.chunkserver.enable {
+        WORKING_USER = mfsUser;
+        MASTER_HOST = cfg.masterHost;
+        HDD_CONF_FILENAME = toString ( pkgs.writeText "mfshdd.cfg"
+          (concatStringsSep "\n" cfg.chunkserver.hdds));
+      };
+    };
+
+    # Create system user account for daemons
+    users = mkIf ( cfg.runAsUser && ( cfg.master.enable || cfg.metalogger.enable || cfg.chunkserver.enable ) ) {
+      users.moosefs = {
+        isSystemUser = true;
+        description = "moosefs daemon user";
+        group = "moosefs";
+      };
+      groups.moosefs = {};
+    };
+
+    environment.systemPackages =
+      (lib.optional cfg.client.enable pkgs.moosefs) ++
+      (lib.optional cfg.master.enable initTool);
+
+    networking.firewall.allowedTCPPorts =
+      (lib.optionals cfg.master.openFirewall [ 9419 9420 9421 ]) ++
+      (lib.optional cfg.chunkserver.openFirewall 9422);
+
+    # Ensure storage directories exist
+    systemd.tmpfiles.rules =
+         optional cfg.master.enable "d ${cfg.master.settings.DATA_PATH} 0700 ${mfsUser} ${mfsUser}"
+      ++ optional cfg.metalogger.enable "d ${cfg.metalogger.settings.DATA_PATH} 0700 ${mfsUser} ${mfsUser}"
+      ++ optional cfg.chunkserver.enable "d ${cfg.chunkserver.settings.DATA_PATH} 0700 ${mfsUser} ${mfsUser}";
+
+    # Service definitions
+    systemd.services.mfs-master = mkIf cfg.master.enable
+    ( systemdService "master" {
+      TimeoutStartSec = 1800;
+      TimeoutStopSec = 1800;
+      Restart = "no";
+    } masterCfg );
+
+    systemd.services.mfs-metalogger = mkIf cfg.metalogger.enable
+      ( systemdService "metalogger" { Restart = "on-abnormal"; } metaloggerCfg );
+
+    systemd.services.mfs-chunkserver = mkIf cfg.chunkserver.enable
+      ( systemdService "chunkserver" { Restart = "on-abnormal"; } chunkserverCfg );
+    };
+}
+