pkgs.formats.configobj: init

Co-authored-by: Matt Sturgeon <matt@sturgeon.me.uk>

nixos/doc/manual/development/settings-options.section.md

@@ -322,6 +322,14 @@ have a predefined type and string generator already declared under
 
     The attribute `lib.type.atom` contains the used INI atom.
 
+`pkgs.formats.configobj` { }
+
+:   A function taking an attribute set with values
+
+    It returns a set with [ConfigObj](https://pypi.org/project/configobj/)-specific attributes `type` and `generate` as specified [below](#pkgs-formats-result).
+    The type of the input is an attribute mapping supporting both atoms and nested attribute sets (sections/subsections), as supported by ConfigObj.
+    The renderer is based on Python's `configobj` module.
+
 `pkgs.formats.iniWithGlobalSection` { *`listsAsDuplicateKeys`* ? false, *`listToValue`* ? null, \.\.\. }
 
 :   A function taking an attribute set with values

pkgs/pkgs-lib/formats.nix

@@ -131,6 +131,8 @@ optionalAttrs allowAliases aliases
 
   php = (import ./formats/php/default.nix { inherit lib pkgs; }).format;
 
+  configobj = (import ./formats/configobj/default.nix { inherit lib pkgs; }).format;
+
   json =
     { }:
     {

pkgs/pkgs-lib/formats/configobj/default.nix

@@ -0,0 +1,36 @@
+{
+  lib,
+  pkgs,
+}:
+let
+  inherit (lib)
+    toJSON
+    ;
+
+  inherit (lib.types)
+    serializableValueWith
+    ;
+in
+{
+  format =
+    { }:
+    {
+      type = serializableValueWith { typeName = "ConfigObj mapping"; };
+
+      generate =
+        name: value:
+        pkgs.runCommandLocal name
+          {
+            nativeBuildInputs = [
+              (pkgs.python3.withPackages (ps: [ ps.configobj ]))
+            ];
+
+            valuesJSON = toJSON value;
+            __structuredAttrs = true;
+            strictDeps = true;
+          }
+          ''
+            printf "%s" "$valuesJSON" | python3 ${./generate.py} > "$out"
+          '';
+    };
+}

pkgs/pkgs-lib/formats/configobj/generate.py

@@ -0,0 +1,7 @@
+import json
+import sys
+from configobj import ConfigObj
+
+config = ConfigObj(interpolation=False, encoding="UTF8")
+config.update(json.load(sys.stdin))
+config.write(sys.stdout.buffer)

pkgs/pkgs-lib/tests/formats.nix

@@ -229,6 +229,110 @@ runBuildTests {
     '';
   };
 
+  configobjAtoms = shouldPass {
+    format = formats.configobj { };
+    input = {
+      bool = true;
+      int = 10;
+      float = 3.141;
+      str = "string";
+    };
+    expected = ''
+      bool = True
+      float = 3.141
+      int = 10
+      str = string
+    '';
+  };
+
+  configobjListWithoutListToValue = shouldPass {
+    format = formats.configobj { };
+    input = {
+      items = [
+        1
+        true
+        "x"
+      ];
+    };
+    expected = ''
+      items = 1, True, x
+    '';
+  };
+
+  configobjNestedAttrsets = shouldPass {
+    format = formats.configobj { };
+    input = {
+      server = {
+        host = "127.0.0.1";
+        port = 8080;
+        enabled = true;
+        tags = [
+          "web"
+          "nix"
+          42
+        ];
+      };
+
+      logging = {
+        level = "info";
+        rotate = true;
+      };
+
+      interfaces = {
+        local = {
+          address = "123";
+          coin = {
+            foo = "bar";
+          };
+        };
+        remote = {
+          address = "456";
+        };
+      };
+    };
+    expected = ''
+      [interfaces]
+      [[local]]
+      address = 123
+      [[[coin]]]
+      foo = bar
+      [[remote]]
+      address = 456
+      [logging]
+      level = info
+      rotate = True
+      [server]
+      enabled = True
+      host = 127.0.0.1
+      port = 8080
+      tags = web, nix, 42
+    '';
+  };
+
+  configobjNullableValues = shouldPass {
+    format = formats.configobj { };
+    input = {
+      nullable = null;
+      nested = {
+        keep = "ok";
+        missing = null;
+      };
+    };
+    expected = ''
+      nullable = None
+      [nested]
+      keep = ok
+      missing = None
+    '';
+  };
+
+  configobjInvalidAtom = shouldFail {
+    format = formats.configobj { };
+    input = {
+      function = _: 1;
+    };
+  };
+
   iniInvalidAtom = shouldFail {
     format = formats.ini { };
     input = {