如何訪問function中fastapi中間件中定義的request_id

Question

嗨，我的中間件是這樣寫的

@app.middleware("http")
async def request_middleware(request, call_next):
    end_point = request.url.path
    global request_id
    request_id = get_request_id()
    with logger.contextualize(request_id=request_id, end_point=end_point):
        logger.info("----------Request started----------")
        try:
            response = await call_next(request)

        except Exception as ex:
            logger.error(f"Request failed: {ex}")
            response = JSONResponse()


        finally:
            response.headers["X-Request-Id"] = request_id
            logger.info("----------Request ended----------")
            return response

我希望中間件中定義的 request_id 可以在其他定義的 function 中訪問，我們該怎么做？

Answer 1

另外2個解決方案：

• 在中間件的request.state中存儲數據，然后在視圖函數中訪問request.state 。 更多信息https://fastapi.tiangolo.com/tutorial/sql-databases/?h=request.#about-requeststate
• 或者使用starlette-context ，這更容易

from starlette_context import context

@app.middleware("http")
async def request_middleware(request, call_next):
    request_id = get_request_id()
    context['request_id'] = request_id


@router.post('foobar')
async def foorbar():
    context['request_id']

Answer 2

您可以使用上下文變量代替全局 request_id，該變量不在異步任務之間共享

from contextvars import ContextVar

req_id: ContextVar[str] = ContextVar('req_id', default='')

# Inside your middleware
req_id.set(get_request_id())

# Inside other functions, even different files, you import that variable
req_id.get()