How to change mutable state on Server?

[Cosmoflips]

I have a mutable state on Server and i want it change according to the request from Client.But i find it can't refer self as &mut self in fn,neither add a node:Arc<Mutex<Node>> parameter in request fn.

#[derive(Clone,Debug, Default)]
pub struct ServerBuffer {
    node:Arc<Mutex<Node>>,
    message:String
}
#[tonic::async_trait]
impl AppendEntries for ServerBuffer {
    async fn request(
        &self,
        request: Request<AppendEntriesRequest>,
    ) -> Result<Response<AppendEntriesReply>, Status> {
        let message = request.metadata().get("message");
        match message{
            Some(message)=>{
                println!("AppendEntriesRequest: {:?}", message.to_str());
                self.message = message.to_str().unwrap().to_string();
                self.node.lock().await.read(self.message.clone());
            }
            None=>{println!("No message in Metadata!");}
        }

        let reply = raft_rpc::AppendEntriesReply {
            term: request.into_inner().term.into(),
            success: true
        };

        Ok(Response::new(reply))
    }
}

Is there any way to achieve such result?
Thanks very much

[davidpdrsn]

lock gives you a mutable reference even through a &self

let mut node = self.node.lock().await;

[Cosmoflips]

Thank for your answer.
Is there only RefCell or Mutex can change it now and no other way?

[davidpdrsn]

There are other types that can do this but you want Mutex. RefCell is only for single threaded stuff, which doesn't work with tonic.