fix Config source priority and add tests (#200)

ragna/core/_config.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from pathlib import Path
-from typing import Union
+from typing import Type, Union
 
 import tomlkit
 from pydantic import Field, ImportString, field_validator
@@ -17,12 +17,14 @@
 from ._utils import RagnaException
 
 
-class ConfigBase:
+class ConfigBase(BaseSettings):
     @classmethod
-    def customise_sources(
+    def settings_customise_sources(
         cls,
+        settings_cls: Type[BaseSettings],
         init_settings: PydanticBaseSettingsSource,
         env_settings: PydanticBaseSettingsSource,
+        dotenv_settings: PydanticBaseSettingsSource,
         file_secret_settings: PydanticBaseSettingsSource,
     ) -> tuple[PydanticBaseSettingsSource, ...]:
         # This order is needed to prioritize values from environment variables over
@@ -32,15 +34,15 @@ def customise_sources(
         # explicitly passed to the constructor. For example, if the environment variable
         # 'RAGNA_RAG_DATABASE_URL' is set, any values passed to
         # `RagnaConfig(rag=RagConfig(database_url=...))` is ignored.
-        # TODO: Find a way to achieve the following priorities:
+        # FIXME: Find a way to achieve the following priorities:
         #  1. Explicitly passed to Python object
         #  2. Environment variable
         #  3. Configuration file
         #  4. Default
         return env_settings, init_settings
 
 
-class CoreConfig(BaseSettings):
+class CoreConfig(ConfigBase):
     model_config = SettingsConfigDict(env_prefix="ragna_core_")
 
     queue_url: str = "memory"
@@ -54,7 +56,7 @@ class CoreConfig(BaseSettings):
     ]
 
 
-class ApiConfig(BaseSettings):
+class ApiConfig(ConfigBase):
     model_config = SettingsConfigDict(env_prefix="ragna_api_")
 
     url: str = "http://127.0.0.1:31476"
@@ -67,15 +69,15 @@ class ApiConfig(BaseSettings):
     ] = "ragna.core.RagnaDemoAuthentication"  # type: ignore[assignment]
 
 
-class UiConfig(BaseSettings):
+class UiConfig(ConfigBase):
     model_config = SettingsConfigDict(env_prefix="ragna_ui_")
 
     url: str = "http://127.0.0.1:31477"
     # FIXME: this needs to be dynamic for the url
     origins: list[str] = ["http://127.0.0.1:31477"]
 
 
-class Config(BaseSettings):
+class Config(ConfigBase):
     """Ragna configuration"""
 
     model_config = SettingsConfigDict(env_prefix="ragna_")

tests/core/test_config.py

@@ -0,0 +1,33 @@
+import os
+
+import pytest
+
+from ragna import Config
+
+
+@pytest.mark.xfail()
+def test_explicit_gt_env_var(mocker, tmp_path):
+    explicit = tmp_path / "explicit"
+
+    env_var = tmp_path / "env_var"
+    mocker.patch.dict(os.environ, values={"RAGNA_LOCAL_CACHE_ROOT": str(env_var)})
+
+    config = Config(local_cache_root=explicit)
+
+    assert config.local_cache_root == explicit
+
+
+def test_env_var_gt_config_file(mocker, tmp_path):
+    config_file = tmp_path / "config_file"
+    config = Config(local_cache_root=config_file)
+    assert config.local_cache_root == config_file
+
+    config_path = tmp_path / "ragna.toml"
+    config.to_file(config_path)
+
+    env_var = tmp_path / "env_var"
+    mocker.patch.dict(os.environ, values={"RAGNA_LOCAL_CACHE_ROOT": str(env_var)})
+
+    config = Config.from_file(config_path)
+
+    assert config.local_cache_root == env_var