hacker-challenge-sgx-general/rewrite/src/grpc/server.rs

#![allow(dead_code)]

use super::challenge::update_server::UpdateServer;
use super::challenge::{Empty, Keys, NodeUpdate};
use crate::datastore::Store;
use crate::grpc::challenge::update_server::Update;
use std::pin::Pin;
use std::sync::Arc;
use tokio::sync::broadcast::Sender;
use tokio_stream::{Stream, StreamExt};
use tonic::{transport::Server, Request, Response, Status, Streaming};

pub struct MyServer {
    ds: Arc<Store>,
    tx: Sender<NodeUpdate>,
}

impl MyServer {
    pub fn init(ds: Arc<Store>, tx: Sender<NodeUpdate>) -> Self {
        Self { ds, tx }
    }

    pub async fn start(self) {
        let addr = "0.0.0.0:31373".parse().unwrap();
        if let Err(e) = Server::builder()
            .add_service(UpdateServer::new(self))
            .serve(addr)
            .await
        {
            println!("gRPC server failed: {e:?}");
        };
    }
}

#[tonic::async_trait]
impl Update for MyServer {
    type GetUpdatesStream = Pin<Box<dyn Stream<Item = Result<NodeUpdate, Status>> + Send>>;

    async fn get_updates(
        &self,
        req: Request<Streaming<NodeUpdate>>,
    ) -> Result<Response<Self::GetUpdatesStream>, Status> {
        let remote_ip = req.remote_addr().unwrap().ip().to_string();
        let tx = self.tx.clone();
        let mut rx = self.tx.subscribe();
        let mut inbound = req.into_inner();
        let ds = self.ds.clone();

        let stream = async_stream::stream! {
            let full_update_list: Vec<NodeUpdate> = ds.get_node_list().into_iter().map(Into::<NodeUpdate>::into).collect();
            for update in full_update_list {
                yield Ok(update);
            }

            loop {
                tokio::select! {
                    Some(msg) = inbound.next() => {
                        match msg {
                            Ok(mut update) => {
                                if update.ip == "localhost" {
                                    update.ip = remote_ip.clone();
                                    // note that we don't set this node online,
                                    // as it can be behind NAT
                                }
                                if update.ip != "127.0.0.1" && ds.process_node_update(update.clone().into()).await {
                                    if let Err(_) = tx.send(update.clone()) {
                                        println!("tokio broadcast receivers had an issue consuming the channel");
                                    }
                                };
                            }
                            Err(e) => {
                                yield Err(Status::internal(format!("Error receiving client stream: {}", e)));
                                break;
                            }
                        }
                    }
                    Ok(update) = rx.recv() => {
                        yield Ok(update);
                        // disconnect client if too many connections are active
                        if tx.receiver_count() > 9 {
                            yield Err(Status::internal("Already have too many clients. Connect to another server."));
                            return;
                        }
                    }

                }
            }
        };

        Ok(Response::new(Box::pin(stream) as Self::GetUpdatesStream))
    }

    async fn get_keys(&self, _request: Request<Empty>) -> Result<Response<Keys>, Status> {
        let reply = Keys {
            keypair: self.ds.get_keypair_base58(),
            token_address: self.ds.get_token_address(),
        };
        Ok(Response::new(reply))
    }
}