如何在函数中访问fastapi中间件中定义的request_id

Question

嗨，我的中间件是这样写的

@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

我希望中间件中定义的 request_id 可以在定义的其他函数中访问，我们该怎么做？

Answer 1

您可以使用不在异步任务之间共享的上下文变量来代替全局变量request_id

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()

Answer 2

另2个解决方案：

在你的中间件中存储request.state中的数据，然后在视图函数中访问request.state。 https://fastapi.tiangolo.com/tutorial/sql-databases/?h=request.#about-requeststate
或者使用starlette-context，就像flask中的g一样，这样就简单多了

from starlette_context import context
from starlette_context.middleware import RawContextMiddleware


app.add_middleware(RawContextMiddleware)


@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']

如何在函数中访问fastapi中间件中定义的request_id

How to access request_id defined in fastapi middleware in function

python

fastapi

loguru