feat: new file structure

src/assistant/lib/clients/__init__.py

@@ -0,0 +1,3 @@
+from .postgres import AsyncPostgresClient
+
+__all__ = ["AsyncPostgresClient"]

src/assistant/lib/clients/postgres.py

@@ -0,0 +1,30 @@
+import sqlalchemy.ext.asyncio as sa_asyncio
+
+import lib.app.settings as app_settings
+
+
+class AsyncPostgresClient:
+    """Async Postgres Client that return sessionmaker."""
+
+    def __init__(self, settings: app_settings.Settings) -> None:
+        self.settings = settings.postgres
+        self.async_enging = sa_asyncio.create_async_engine(
+            url=self.settings.dsn,
+            pool_size=self.settings.pool_size,
+            pool_pre_ping=self.settings.pool_pre_ping,
+            echo=self.settings.echo,
+            future=True,
+        )
+
+    def get_async_session(self) -> sa_asyncio.async_sessionmaker[sa_asyncio.AsyncSession]:
+        async_session = sa_asyncio.async_sessionmaker(
+            bind=self.async_enging,
+            autocommit=self.settings.auto_commit,
+            autoflush=self.settings.auto_flush,
+            expire_on_commit=self.settings.expire_on_commit,
+        )
+
+        return async_session  # noqa: RET504
+
+    async def dispose_callback(self) -> None:
+        await self.async_enging.dispose()