Contextvar-gestütztes Fehler-Tracking in asynchroner ASGI-Middleware

import contextvars
from django.core.exceptions import PermissionDenied
 
request_id_var = contextvars.ContextVar('request_id', default=None)
 
class AsyncExceptionContextMiddleware:
    def __init__(self, get_response):
        self.get_response = get_response
 
    async def __call__(self, request):
        token = request_id_var.set(request.headers.get('X-Request-ID', 'anon'))
        try:
            return await self.get_response(request)
        except PermissionDenied as exc:
            req_id = request_id_var.get()
            raise RuntimeError(f"[Req: {req_id}] Async Auth Failure: {exc}") from exc
        finally:
            request_id_var.reset(token)