FastAPI

FastAPI already has its own dependency system, but diwire is still useful when you want:

• a single, typed object graph shared across your app

• request/job scopes with deterministic cleanup

• constructor injection for your domain/services

• handler signatures that stay friendly for FastAPI (only request parameters are visible)

Recommended pattern

1. Configure the container at startup and set it as current:

   from diwire import Container, container_context
   
   container = Container()
   container_context.set_current(container)
   

2. Use a request scope per request (created by the injected wrapper):

   from typing import Annotated
   from fastapi import FastAPI
   
   from diwire import Injected, container_context
   
   app = FastAPI()
   
   
   @app.get("/health")
   @container_context.resolve(scope="request")
   async def health(service: Annotated["Service", Injected()]) -> dict[str, str]:
       return {"status": service.ok()}
   

3. Register request-scoped services (Lifetime.SCOPED, scope="request") and any request-specific objects (like fastapi.Request) via factories/contextvars.

Runnable examples

See FastAPI for three progressively more advanced FastAPI examples:

• basic integration with explicit container calls

• decorator-based layering

• container_context + middleware-managed request context