Expose

What it is

• An abstract base class (ABC) defining a contract for components that can be exposed:
  • as LangChain tools (for agent use)
  • as FastAPI routes (for HTTP access)

Public API

Class: Expose

Abstract interface; implement both methods in concrete subclasses.

• as_tools(self) -> list[BaseTool]

  • Purpose: Return a list of LangChain tools representing the component’s functionality.
  • Notes: BaseTool is only imported for typing under TYPE_CHECKING.

• as_api(self, router: APIRouter, route_name: str = "", name: str = "", description: str = "", description_stream: str = "", tags: list[str | Enum] | None = []) -> None

  • Purpose: Register FastAPI routes on the provided APIRouter to expose the component over HTTP.
  • Parameters:
    • router: FastAPI APIRouter to register routes on
    • route_name, name, description, description_stream: optional metadata strings
    • tags: optional list of tags (str or Enum) for FastAPI route tagging (default is [] in signature)

Configuration/Dependencies

• Depends on fastapi.APIRouter.
• Type hints refer to langchain_core.tools.BaseTool (imported only when type-checking).

Usage

from fastapi import APIRouter
from naas_abi_core.utils.Expose import Expose
 
class MyFeature(Expose):
    def as_tools(self):
        return []  # return a list of BaseTool instances
 
    def as_api(self, router: APIRouter, route_name: str = "", name: str = "",
               description: str = "", description_stream: str = "", tags=None):
        @router.get(f"/{route_name or 'my-feature'}", tags=tags or [])
        def endpoint():
            return {"ok": True}
 
router = APIRouter()
MyFeature().as_api(router, route_name="health")

Caveats

• Both methods are abstract; instantiating Expose directly is not possible.
• tags in the abstract method signature defaults to [] (a mutable default). Implementations may want to use None and normalize to a list internally.