stages/wsl-distribution: stage to write wsl config

This is a new stage to be able to write a (subset) of relevant keys into
the `wsl-distribution` configuration file.

The file, and these options, are necessary for the enablement of fancy
logos and experiences in WSL2.

Signed-off-by: Simon de Vlieger <supakeen@redhat.com>

stages/org.osbuild.wsl-distribution.conf

@@ -0,0 +1,60 @@
+#!/usr/bin/python3
+import sys
+
+import iniparse
+
+import osbuild.api
+
+
+def main(tree, options):
+    oobe = options.get("oobe", {})
+    shortcut = options.get("shortcut", {})
+
+    # Don't write an empty file
+    if not oobe and not shortcut:
+        return 0
+
+    wsl_conf_path = f"{tree}/etc/wsl-distribution.conf"
+    wsl_config = iniparse.SafeConfigParser()
+
+    try:
+        with open(wsl_conf_path, "r", encoding="utf8") as f:
+            wsl_config.readfp(f)
+    except FileNotFoundError:
+        print(
+            f"WSL distribution configuration file '{wsl_conf_path}' does not exist, will be created."
+        )
+
+    if oobe:
+        if not wsl_config.has_section("oobe"):
+            wsl_config.add_section("oobe")
+
+        if "default_uid" in oobe:
+            wsl_config.set("oobe", "defaultUid", str(oobe["default_uid"]))
+
+        if "default_name" in oobe:
+            wsl_config.set("oobe", "defaultName", oobe["default_name"])
+
+    if shortcut:
+        if not wsl_config.has_section("shortcut"):
+            wsl_config.add_section("shortcut")
+
+        if "enabled" in shortcut:
+            # this turns the boolean `True` into `true` (or `False`)
+            wsl_config.set(
+                "shortcut", "enabled", str(shortcut["enabled"]).lower()
+            )
+
+        if "icon" in shortcut:
+            wsl_config.set("shortcut", "icon", shortcut["icon"])
+
+    with open(wsl_conf_path, mode="w", encoding="utf8") as f:
+        wsl_config.write(f)
+
+    return 0
+
+
+if __name__ == "__main__":
+    args = osbuild.api.arguments()
+    r = main(args["tree"], args["options"])
+    sys.exit(r)

stages/org.osbuild.wsl-distribution.conf.meta.json

@@ -0,0 +1,46 @@
+{
+  "summary": "Configure distribution settings in Windows Subsystem for Linux.",
+  "description": [
+    "The stage configures the WSL distribution settings on the system."
+  ],
+  "schema_2": {
+    "options": {
+      "additionalProperties": false,
+      "description": "WSL distribution configuration.",
+      "properties": {
+        "oobe": {
+          "type": "object",
+          "description": "Configures the [oobe] section.",
+          "additionalProperties": false,
+          "minProperties": 1,
+          "properties": {
+            "default_uid": {
+              "type": "integer",
+              "default": 1000,
+              "description": "Default login UID."
+            },
+            "default_name": {
+              "type": "string",
+              "description": "Name of the distribution."
+            }
+          }
+        },
+        "shortcut": {
+          "type": "object",
+          "description": "Configures the [shortcut] section.",
+          "additionalProperties": false,
+          "properties": {
+            "enabled": {
+              "type": "boolean",
+              "description": "Enable a shortcut icon."
+            },
+            "icon": {
+              "type": "string",
+              "description": "Path of the shortcut icon."
+            }
+          }
+        }
+      }
+    }
+  }
+}

stages/test/test_wsl_distribution_conf.py

@@ -0,0 +1,80 @@
+#!/usr/bin/python3
+
+import pytest
+
+from osbuild import testutil
+
+STAGE_NAME = "org.osbuild.wsl-distribution.conf"
+
+
+@pytest.mark.parametrize("test_data,expected_err", [
+    # bad
+    ({"oobe": "must-be-object"}, "'must-be-object' is not of type 'object'"),
+    ({"shortcut": "must-be-object"}, "'must-be-object' is not of type 'object'"),
+    ({"shortcut": {"enabled": 1}}, "1 is not of type 'boolean'"),
+    ({"oobe": {"default_uid": True}}, "True is not of type 'integer'"),
+    # good
+    ({
+        "oobe":
+        {
+            "default_uid": 1000,
+            "default_name": "RedHatEnterpriseLinux-10.0",
+        },
+        "shortcut":
+        {
+            "enabled": True,
+            "icon": "/usr/share/pixmaps/fedora-logo.ico",
+        }
+    }, "")
+])
+def test_wsl_distribution_conf_schema_validation(stage_schema, test_data, expected_err):
+    test_input = {
+        "type": STAGE_NAME,
+        "options": {
+        }
+    }
+    test_input["options"].update(test_data)
+    res = stage_schema.validate(test_input)
+
+    if expected_err == "":
+        assert res.valid is True, f"err: {[e.as_dict() for e in res.errors]}"
+    else:
+        assert res.valid is False
+        testutil.assert_jsonschema_error_contains(res, expected_err, expected_num_errs=1)
+
+
+def test_wsl_distribution_conf_writes_file(tmp_path, stage_module):
+    treepath = tmp_path / "tree"
+
+    etcpath = treepath / "etc"
+    etcpath.mkdir(parents=True, exist_ok=True)
+
+    confpath = "wsl-distribution.conf"
+
+    fullpath = etcpath / confpath
+
+    options = {
+        "oobe": {
+            "default_name": "RedHatEnterpriseLinux-10.0",
+            "default_uid": 1000,
+        },
+        "shortcut": {
+            "enabled": True,
+            "icon": "/usr/share/pixmaps/fedora-logo.ico",
+        }
+    }
+
+    stage_module.main(treepath, options)
+
+    assert fullpath.exists()
+
+    confdata = fullpath.read_text()
+
+    assert confdata == """\
+[oobe]
+defaultUid = 1000
+defaultName = RedHatEnterpriseLinux-10.0
+
+[shortcut]
+enabled = true
+icon = /usr/share/pixmaps/fedora-logo.ico"""