nixos/btrbk: inherit lib functions to simplify use-sites

nixos/modules/services/backup/btrbk.nix

@@ -1,18 +1,36 @@
 { config, pkgs, lib, ... }:
 let
+  inherit (lib)
+    concatMapStringsSep
+    concatStringsSep
+    filterAttrs
+    flatten
+    isAttrs
+    isString
+    literalExpression
+    mapAttrs'
+    mapAttrsToList
+    mkIf
+    mkOption
+    optionalString
+    partition
+    typeOf
+    types
+    ;
+
   cfg = config.services.btrbk;
   sshEnabled = cfg.sshAccess != [ ];
   serviceEnabled = cfg.instances != { };
   attr2Lines = attr:
     let
-      pairs = lib.attrsets.mapAttrsToList (name: value: { inherit name value; }) attr;
+      pairs = mapAttrsToList (name: value: { inherit name value; }) attr;
       isSubsection = value:
-        if builtins.isAttrs value then true
-        else if builtins.isString value then false
-        else throw "invalid type in btrbk config ${builtins.typeOf value}";
-      sortedPairs = lib.lists.partition (x: isSubsection x.value) pairs;
+        if isAttrs value then true
+        else if isString value then false
+        else throw "invalid type in btrbk config ${typeOf value}";
+      sortedPairs = partition (x: isSubsection x.value) pairs;
     in
-    lib.flatten (
+    flatten (
       # non subsections go first
       (
         map (pair: [ "${pair.name} ${pair.value}" ]) sortedPairs.wrong
@@ -22,7 +40,7 @@ let
         map
           (
             pair:
-            lib.mapAttrsToList
+            mapAttrsToList
               (
                 childname: value:
                   [ "${pair.name} ${childname}" ] ++ (map (x: " " + x) (attr2Lines value))
@@ -34,7 +52,7 @@ let
     )
   ;
   addDefaults = settings: { backend = "btrfs-progs-sudo"; } // settings;
-  mkConfigFile = settings: lib.concatStringsSep "\n" (attr2Lines (addDefaults settings));
+  mkConfigFile = settings: concatStringsSep "\n" (attr2Lines (addDefaults settings));
   mkTestedConfigFile = name: settings:
     let
       configFile = pkgs.writeText "btrbk-${name}.conf" (mkConfigFile settings);
@@ -55,38 +73,38 @@ in
 
   options = {
     services.btrbk = {
-      extraPackages = lib.mkOption {
+      extraPackages = mkOption {
         description = "Extra packages for btrbk, like compression utilities for <literal>stream_compress</literal>";
-        type = lib.types.listOf lib.types.package;
+        type = types.listOf types.package;
         default = [ ];
-        example = lib.literalExpression "[ pkgs.xz ]";
+        example = literalExpression "[ pkgs.xz ]";
       };
-      niceness = lib.mkOption {
+      niceness = mkOption {
         description = "Niceness for local instances of btrbk. Also applies to remote ones connecting via ssh when positive.";
-        type = lib.types.ints.between (-20) 19;
+        type = types.ints.between (-20) 19;
         default = 10;
       };
-      ioSchedulingClass = lib.mkOption {
+      ioSchedulingClass = mkOption {
         description = "IO scheduling class for btrbk (see ionice(1) for a quick description). Applies to local instances, and remote ones connecting by ssh if set to idle.";
-        type = lib.types.enum [ "idle" "best-effort" "realtime" ];
+        type = types.enum [ "idle" "best-effort" "realtime" ];
         default = "best-effort";
       };
-      instances = lib.mkOption {
+      instances = mkOption {
         description = "Set of btrbk instances. The instance named <literal>btrbk</literal> is the default one.";
-        type = with lib.types;
+        type = with types;
           attrsOf (
             submodule {
               options = {
-                onCalendar = lib.mkOption {
-                  type = lib.types.nullOr lib.types.str;
+                onCalendar = mkOption {
+                  type = types.nullOr types.str;
                   default = "daily";
                   description = ''
                     How often this btrbk instance is started. See systemd.time(7) for more information about the format.
                     Setting it to null disables the timer, thus this instance can only be started manually.
                   '';
                 };
-                settings = lib.mkOption {
-                  type = let t = lib.types.attrsOf (lib.types.either lib.types.str (t // { description = "instances of this type recursively"; })); in t;
+                settings = mkOption {
+                  type = let t = types.attrsOf (types.either types.str (t // { description = "instances of this type recursively"; })); in t;
                   default = { };
                   example = {
                     snapshot_preserve_min = "2d";
@@ -108,16 +126,16 @@ in
           );
         default = { };
       };
-      sshAccess = lib.mkOption {
+      sshAccess = mkOption {
         description = "SSH keys that should be able to make or push snapshots on this system remotely with btrbk";
-        type = with lib.types; listOf (
+        type = with types; listOf (
           submodule {
             options = {
-              key = lib.mkOption {
+              key = mkOption {
                 type = str;
                 description = "SSH public key allowed to login as user <literal>btrbk</literal> to run remote backups.";
               };
-              roles = lib.mkOption {
+              roles = mkOption {
                 type = listOf (enum [ "info" "source" "target" "delete" "snapshot" "send" "receive" ]);
                 example = [ "source" "info" "send" ];
                 description = "What actions can be performed with this SSH key. See ssh_filter_btrbk(1) for details";
@@ -130,7 +148,7 @@ in
     };
 
   };
-  config = lib.mkIf (sshEnabled || serviceEnabled) {
+  config = mkIf (sshEnabled || serviceEnabled) {
     environment.systemPackages = [ pkgs.btrbk ] ++ cfg.extraPackages;
     security.sudo.extraRules = [
       {
@@ -157,14 +175,14 @@ in
         (
           v:
           let
-            options = lib.concatMapStringsSep " " (x: "--" + x) v.roles;
+            options = concatMapStringsSep " " (x: "--" + x) v.roles;
             ioniceClass = {
               "idle" = 3;
               "best-effort" = 2;
               "realtime" = 1;
             }.${cfg.ioSchedulingClass};
           in
-          ''command="${pkgs.util-linux}/bin/ionice -t -c ${toString ioniceClass} ${lib.optionalString (cfg.niceness >= 1) "${pkgs.coreutils}/bin/nice -n ${toString cfg.niceness}"} ${pkgs.btrbk}/share/btrbk/scripts/ssh_filter_btrbk.sh --sudo ${options}" ${v.key}''
+          ''command="${pkgs.util-linux}/bin/ionice -t -c ${toString ioniceClass} ${optionalString (cfg.niceness >= 1) "${pkgs.coreutils}/bin/nice -n ${toString cfg.niceness}"} ${pkgs.btrbk}/share/btrbk/scripts/ssh_filter_btrbk.sh --sudo ${options}" ${v.key}''
         )
         cfg.sshAccess;
     };
@@ -174,7 +192,7 @@ in
       "d /var/lib/btrbk/.ssh 0700 btrbk btrbk"
       "f /var/lib/btrbk/.ssh/config 0700 btrbk btrbk - StrictHostKeyChecking=accept-new"
     ];
-    environment.etc = lib.mapAttrs'
+    environment.etc = mapAttrs'
       (
         name: instance: {
           name = "btrbk/${name}.conf";
@@ -182,7 +200,7 @@ in
         }
       )
       cfg.instances;
-    systemd.services = lib.mapAttrs'
+    systemd.services = mapAttrs'
       (
         name: _: {
           name = "btrbk-${name}";
@@ -204,7 +222,7 @@ in
       )
       cfg.instances;
 
-    systemd.timers = lib.mapAttrs'
+    systemd.timers = mapAttrs'
       (
         name: instance: {
           name = "btrbk-${name}";
@@ -219,7 +237,7 @@ in
           };
         }
       )
-      (lib.filterAttrs (name: instance: instance.onCalendar != null)
+      (filterAttrs (name: instance: instance.onCalendar != null)
         cfg.instances);
   };