panel/src/panel/configuration/to_module.py

@@ -0,0 +1,53 @@
+import json
+import textwrap
+
+# TODO(@fricklerhandwerk): mix this in as a method on the Pydantic Schema itself
+def generate_module(schema, service_name):
+    properties = schema.get("properties", {})
+    required = schema.get("required", [])
+
+    options = []
+    for name, prop in properties.items():
+        nix_type = {
+            "string": "types.str",
+            "integer": "types.int",
+            "boolean": "types.bool"
+        }[prop["type"]]
+
+        desc = prop.get("description")
+
+        default = None
+        if name not in required and "default" in prop:
+            to_nix_value = {
+                "string": lambda v: f'"{v}"',
+                "boolean": lambda v: str(v).lower(),
+                "integer": lambda v: str(v),
+                "number": lambda v: str(v)
+            }
+            default = to_nix_value[prop["type"]](prop["default"])
+
+        option = textwrap.dedent(f"""
+            {name} = mkOption {{{f'''
+              description = "{desc}";''' if desc else ''}
+              type = {nix_type};{f'''
+              default = {default};''' if default is not None else ''}
+            }};
+        """)
+
+        options.append(option.strip())
+
+    module = textwrap.dedent(f"""
+        {{ lib, ... }}:
+
+        let
+          cfg = config.services.{service_name};
+          inherit (lib) mkOption types;
+        in
+        {{
+          options.services.{service_name} = {{
+            {textwrap.indent("\n\n".join(options), '            ').strip()}
+          }};
+        }}
+    """)
+
+    return module

panel/src/panel/tests/test_to_module.py

@@ -0,0 +1,44 @@
+from django.test import TestCase
+from pydantic import BaseModel, Field
+import textwrap
+
+from panel.configuration import to_module
+
+
+class ConvertToModule(TestCase):
+    def test_minimal_module(self):
+        class Example(BaseModel):
+            name: str = Field(..., description="Service name")
+            port: int = Field(8080)
+            enable: bool = Field(True, description="Enable service")
+
+        expected = textwrap.dedent("""
+            { lib, ... }:
+
+            let
+              cfg = config.services.myservice;
+              inherit (lib) mkOption types;
+            in
+            {
+              options.services.myservice = {
+                name = mkOption {
+                  description = "Service name";
+                  type = types.str;
+                };
+
+                port = mkOption {
+                  type = types.int;
+                  default = 8080;
+                };
+
+                enable = mkOption {
+                  description = "Enable service";
+                  type = types.bool;
+                  default = true;
+                };
+              };
+            }
+        """)
+
+        actual = to_module.generate_module(Example.schema(), "myservice")
+        self.assertEqual(actual, expected)