I’m trying to parallelize logs with Queuehandler and Queuelistener in a fastapi application but the contextvars setted on the main thread does not propagate to “_monitor” thread of the QueueListener.

To contextualize, I set se contextVar on fastapi main file:

@app.middleware("http")
async def set_context_vars(request: Request, call_next: Callable) -> Any:

    ...
    log_extras.set(extra_logs)

    ...
    response = await call_next(request)

    ...

And use in it in a Formatter on a logger file.

class JsonFormatter(logging.Formatter):

    def format(self, record: logging.LogRecord) -> str:

        ...
        formatted = {
            ...
        }

        formatted.update(log_extras.get())
        return json.dumps(formatted)

Can anyone help me to understand how can I resolve this?