Merge pull request #583 from yeokyeong-yanolja/feature/get_variant_by…

…_name#571

feature : develop Endpoint to Fetch LLM Application Variant Parameters

agenta-backend/agenta_backend/routers/app_variant.py

@@ -61,6 +61,48 @@ async def list_app_variants(
         raise HTTPException(status_code=500, detail=str(e))
 
 
+@router.get("/get_variant_by_name/", response_model=AppVariant)
+async def get_variant_by_name(
+    app_name: str,
+    variant_name: str,
+    stoken_session: SessionContainer = Depends(verify_session()),
+):
+    """Fetches a specific app variant based on the given app_name and variant_name.
+
+    Arguments:
+        app_name (str): The name of the app to query.
+        variant_name (str): The name of the variant to query.
+
+    Raises:
+        HTTPException: Raises 404 if no matching variant is found,
+                       400 for ValueError, or 500 for any other exceptions.
+
+    Returns:
+        AppVariant: The fetched app variant.
+    """
+
+    try:
+        # Retrieve the user and organization ID based on the session token
+        kwargs = await get_user_and_org_id(stoken_session)
+
+        # Fetch the app variant using the provided app_name and variant_name
+        app_variant = await db_manager.get_app_variant_by_app_name_and_variant_name(
+            app_name=app_name, variant_name=variant_name, **kwargs
+        )
+        # Check if the fetched app variant is None and raise 404 if it is
+        if app_variant is None:
+            raise HTTPException(status_code=500, detail="App Variant not found")
+        return app_variant
+    except ValueError as e:
+        # Handle ValueErrors and return 400 status code
+        raise HTTPException(status_code=400, detail=str(e))
+    except HTTPException as e:
+        raise e
+    except Exception as e:
+        # Handle all other exceptions and return 500 status code
+        raise HTTPException(status_code=500, detail=str(e))
+
+
 @router.get("/list_apps/", response_model=List[App])
 async def list_apps(
     stoken_session: SessionContainer = Depends(verify_session()),

agenta-backend/agenta_backend/services/db_manager.py

@@ -237,6 +237,54 @@ async def list_app_variants(
     return app_variants
 
 
+async def get_app_variant_by_app_name_and_variant_name(
+    app_name: str, variant_name: str, show_soft_deleted: bool = False, **kwargs: dict
+) -> AppVariant:
+    """Fetches an app variant based on app_name and variant_name.
+
+    Args:
+        app_name (str): Name of the app.
+        variant_name (str): Name of the variant.
+        show_soft_deleted: if true, returns soft deleted variants as well
+        **kwargs (dict): Additional keyword arguments.
+
+    Returns:
+        AppVariant: The fetched app variant.
+    """
+
+    # Get the user object using the user ID
+    user = await get_user_object(kwargs["uid"])
+
+    # Construct the base query for the user
+    users_query = query.eq(AppVariantDB.user_id, user.id)
+
+    # Construct the query for soft-deleted items
+    soft_delete_query = query.eq(AppVariantDB.is_deleted, show_soft_deleted)
+
+    # Construct the final query filters
+    query_filters = (
+        query.eq(AppVariantDB.app_name, app_name)
+        & query.eq(AppVariantDB.variant_name, variant_name)
+        & users_query
+        & soft_delete_query
+    )
+
+    # Perform the database query
+    app_variants_db = await engine.find(
+        AppVariantDB,
+        query_filters,
+        sort=(AppVariantDB.app_name, AppVariantDB.variant_name),
+    )
+
+    # Convert the database object to AppVariant and return it
+    # Assuming that find will return a list, take the first element if it exists
+    app_variant: AppVariant = (
+        app_variant_db_to_pydantic(app_variants_db[0]) if app_variants_db else None
+    )
+
+    return app_variant
+
+
 async def list_apps(**kwargs: dict) -> List[App]:
     """
     Lists all the unique app names from the database

agenta-backend/tests/test_router_app_variant.py

@@ -82,6 +82,13 @@ def test_list_app_variant():
     assert response.json() == []
 
 
+def test_get_variant_by_name_with_invalid_names():
+    response = client.get(
+        "/app_variant/get_variant_by_name/?app_name=invalid&variant_name=invalid"
+    )
+    assert response.status_code == 500
+
+
 def test_list_app_variant_after_manual_add(app_variant, image):
     # This is the function from db_manager.py
     add_variant_based_on_image(app_variant, image)

agenta-cli/agenta/client/client.py

@@ -83,6 +83,29 @@ def list_variants(app_name: str, host: str) -> List[AppVariant]:
     return [AppVariant(**variant) for variant in app_variants]
 
 
+def get_variant_by_name(app_name: str, variant_name: str, host: str) -> AppVariant:
+    """Gets a variant by name
+
+    Arguments:
+        app_name -- the app name
+        variant_name -- the variant name
+
+    Returns:
+        the variant using the pydantic model
+    """
+    response = requests.get(
+        f"{host}/{BACKEND_URL_SUFFIX}/app_variant/get_variant_by_name/?app_name={app_name}&variant_name={variant_name}",
+        timeout=600,
+    )
+
+    # Check for successful request
+    if response.status_code != 200:
+        error_message = response.json()
+        raise APIRequestError(
+            f"Request to get_variant_by_name endpoint failed with status code {response.status_code} and error message: {error_message}."
+        )
+
+
 def remove_variant(app_name: str, variant_name: str, host: str):
     """Removes a variant from the backend