1 files changed, 40 insertions, 3 deletions
diff --git a/thallium-backend/src/settings.py b/thallium-backend/src/settings.py
index 2f9f6c1..931fc0d 100644
--- a/thallium-backend/src/settings.py
+++ b/thallium-backend/src/settings.py
@@ -1,9 +1,46 @@
-from pydantic_settings import BaseSettings
+import typing
+from collections.abc import AsyncGenerator
+from logging import getLogger
 
+import pydantic
+import pydantic_settings
+from fastapi import Depends
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+
+log = getLogger(__name__)
+
+
+class _Config(
+    pydantic_settings.BaseSettings,
+    env_prefix="backend_",
+    env_file=".env",
+    env_file_encoding="utf-8",
+    env_nested_delimiter="__",
+    extra="ignore",
+):
+    """General configuration settings for the service."""
 
-class _CONFIG(BaseSettings, env_file=".env", env_file_encoding="utf-8"):
     debug: bool = False
     git_sha: str = "development"
 
+    database_url: pydantic.SecretStr
+    token: pydantic.SecretStr
+
+
+CONFIG = _Config()
+
+
+class Connections:
+    """How to connect to other, internal services."""
+
+    DB_ENGINE = create_async_engine(CONFIG.database_url.get_secret_value(), echo=CONFIG.debug)
+    DB_SESSION_MAKER = async_sessionmaker(DB_ENGINE)
+
+
+async def _get_db_session() -> AsyncGenerator[AsyncSession, None]:
+    """Yield a database session, for use with a FastAPI dependency."""
+    async with Connections.DB_SESSION_MAKER() as session, session.begin():
+        yield session
+
 
-CONFIG = _CONFIG()
+DBSession = typing.Annotated[AsyncSession, Depends(_get_db_session)]