import uuid

from starlette.middleware.base import BaseHTTPMiddleware

class RequestIdMiddleware(BaseHTTPMiddleware):
    async def dispatch(self, request, call_next):
        rid = request.headers.get("x-request-id") or str(uuid.uuid4())
        request.state.request_id = rid
        response = await call_next(request)
        response.headers["X-Request-Id"] = rid
        return response

app.add_middleware(RequestIdMiddleware)