Add pydantic to docs/metadata.py

Author: rod7760

docs/metadata.py

@@ -1,12 +1,14 @@
 """
-Support parsing pyinfra plugins and parsing
-their metadata to docs generator.
+Support parsing pyinfra-metadata.toml
+
+Currently just parses plugins their metadata.
 """
 
 import tomllib
-from dataclasses import dataclass
 from typing import Literal
 
+from pydantic import BaseModel, TypeAdapter, field_validator
+
 AllowedTagType = Literal[
     "boot",
     "containers",
@@ -25,16 +27,17 @@
 ]
 
 
-@dataclass(frozen=True)
-class Tag:
+class Tag(BaseModel):
     """Representation of a plugin tag."""
 
     value: AllowedTagType
 
-    def __post_init__(self):
+    @field_validator("value", mode="before")
+    def _validate_value(cls, v) -> AllowedTagType:
         allowed_tags = set(AllowedTagType.__args__)
-        if self.value not in allowed_tags:
+        if v not in allowed_tags:
             raise ValueError(f"Invalid tag: {self.value}. Allowed: {allowed_tags}")
+        return v
 
     @property
     def title_case(self) -> str:
@@ -48,11 +51,10 @@ def __eq__(self, other):
         return NotImplemented
 
 
-ALLOWED_TAGS = [Tag(tag) for tag in set(AllowedTagType.__args__)]
+ALLOWED_TAGS = [Tag(value=tag) for tag in set(AllowedTagType.__args__)]
 
 
-@dataclass
-class Plugin:
+class Plugin(BaseModel):
     """Representation of a pyinfra plugin."""
 
     name: str
@@ -61,18 +63,16 @@ class Plugin:
     type: Literal["operation", "fact", "connector", "deploy"]
     tags: list[Tag]
 
+    @field_validator("tags", mode="before")
+    def _wrap_tags(cls, v):
+        return [Tag(value=tag) if not isinstance(tag, Tag) else tag for tag in v]
+
 
 def parse_plugins(metadata_text: str) -> list[Plugin]:
     """Given the contents of a pyinfra-metadata.toml parse out the plugins."""
     pyinfra_metadata = tomllib.loads(metadata_text).get("pyinfra", None)
     if not pyinfra_metadata:
         raise ValueError("Missing [pyinfra.plugins] section in pyinfra-metadata.toml")
-
-    plugins = []
-    for p in pyinfra_metadata["plugins"]:
-        data = pyinfra_metadata["plugins"][p]
-        # ensure Tag types and not strings
-        data["tags"] = [Tag(t) for t in data["tags"]]
-        plugin = Plugin(**data)
-        plugins.append(plugin)
-    return plugins
+    return TypeAdapter(list[Plugin]).validate_python(
+        pyinfra_metadata["plugins"].values()
+    )

pyproject.toml

@@ -20,6 +20,7 @@ dependencies = [
     "typeguard>=4,<5",
     "distro>=1.6,<2",
     "packaging>=16.1",
+    "pydantic>=2.11,<3",
     "typing-extensions; python_version < '3.11'", # Backport of typing for Unpack (added 3.11)
 ]
 classifiers = [