raftify 0.1.82

Experimental High level Raft framework
Documentation
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use bincode::serialize;
use std::{
    net::{SocketAddr, ToSocketAddrs},
    sync::Arc,
    time::Duration,
};
use tokio::{
    sync::{
        mpsc,
        oneshot::{self, Receiver},
    },
    time::timeout,
};
use tonic::{transport::Server, Request, Response, Status};

#[cfg(feature = "tls")]
use tonic::transport::{Certificate, Identity, ServerTlsConfig};

use super::{
    macro_utils::function_name,
    raft_service::{
        self,
        raft_service_server::{RaftService, RaftServiceServer},
    },
    Config, Error,
};
use crate::{
    create_client,
    raft::{eraftpb::Message as RaftMessage, logger::Logger},
    raft_service::ProposeArgs,
    request::{
        common::confchange_request::ConfChangeRequest, server_request_message::ServerRequestMsg,
    },
    response::server_response_message::{
        ConfChangeResponseResult, RequestIdResponseResult, ResponseResult, ServerResponseMsg,
    },
    AbstractLogEntry, AbstractStateMachine, StableStorage,
};

#[derive(Clone)]
pub struct RaftServer<
    LogEntry: AbstractLogEntry,
    LogStorage: StableStorage + 'static,
    FSM: AbstractStateMachine,
> {
    tx: mpsc::Sender<ServerRequestMsg<LogEntry, LogStorage, FSM>>,
    raft_addr: SocketAddr,
    config: Config,
    logger: Arc<dyn Logger>,
}

impl<
        LogEntry: AbstractLogEntry + 'static,
        LogStorage: StableStorage + Send + Sync + 'static,
        FSM: AbstractStateMachine + 'static,
    > RaftServer<LogEntry, LogStorage, FSM>
{
    pub fn new<A: ToSocketAddrs>(
        tx: mpsc::Sender<ServerRequestMsg<LogEntry, LogStorage, FSM>>,
        raft_addr: A,
        config: Config,
        logger: Arc<dyn Logger>,
    ) -> Self {
        let raft_addr = raft_addr.to_socket_addrs().unwrap().next().unwrap();
        RaftServer {
            tx,
            raft_addr,
            config,
            logger,
        }
    }

    pub(crate) async fn run(self, rx_quit_signal: Receiver<()>) -> Result<(), Error> {
        let raft_addr = self.raft_addr;
        let logger = self.logger.clone();
        logger.debug(&format!(
            "RaftServer starts to listen gRPC requests on \"{}\"...",
            raft_addr
        ));

        let quit_signal = async {
            rx_quit_signal.await.ok();
        };

        let mut server_builder = Server::builder();

        #[cfg(feature = "tls")]
        if let Some(tls_cfg) = &self.config.server_tls_config {
            logger.debug("TLS enabled.");
            let cert_path = tls_cfg
                .cert_path
                .as_ref()
                .expect("Server requires cert_path");
            let cert = tokio::fs::read(cert_path).await?;
            let key_path = tls_cfg.key_path.as_ref().expect("Server requires key_path");
            let key = tokio::fs::read(key_path).await?;
            let identity = Identity::from_pem(cert, key);

            let mut tls_config = ServerTlsConfig::new().identity(identity);

            // mTLS
            if let Some(ca_cert_path) = &tls_cfg.ca_cert_path {
                let ca_cert = tokio::fs::read(ca_cert_path).await?;
                let ca_cert = Certificate::from_pem(ca_cert);
                tls_config = tls_config.client_ca_root(ca_cert);
            }

            server_builder = server_builder.tls_config(tls_config)?;
        }

        server_builder
            .add_service(RaftServiceServer::new(self))
            .serve_with_shutdown(raft_addr, quit_signal)
            .await?;

        Ok(())
    }
}

impl<
        LogEntry: AbstractLogEntry + 'static,
        LogStorage: StableStorage + 'static,
        FSM: AbstractStateMachine + 'static,
    > RaftServer<LogEntry, LogStorage, FSM>
{
    fn print_send_error(&self, function_name: &str) {
        self.logger.error(&format!(
            "Error occurred in sending message ('RaftServer --> RaftNode'). Function: '{}'",
            function_name
        ));
    }
}

#[tonic::async_trait]
impl<
        LogEntry: AbstractLogEntry + 'static,
        LogStorage: StableStorage + Sync + Send + 'static,
        FSM: AbstractStateMachine + 'static,
    > RaftService for RaftServer<LogEntry, LogStorage, FSM>
{
    async fn request_id(
        &self,
        request: Request<raft_service::RequestIdArgs>,
    ) -> Result<Response<raft_service::RequestIdResponse>, Status> {
        let request_args = request.into_inner();
        let sender = self.tx.clone();
        let (tx_msg, rx_msg) = oneshot::channel();
        sender
            .send(ServerRequestMsg::RequestId {
                raft_addr: request_args.raft_addr.clone(),
                tx_msg,
            })
            .await
            .unwrap();
        let response = rx_msg.await.unwrap();

        match response {
            ServerResponseMsg::RequestId { result } => match result {
                RequestIdResponseResult::Success {
                    reserved_id,
                    leader_id,
                    peers,
                } => Ok(Response::new(raft_service::RequestIdResponse {
                    code: raft_service::ResultCode::Ok as i32,
                    leader_id,
                    reserved_id,
                    leader_addr: self.raft_addr.to_string(),
                    peers: serialize(&peers).unwrap(),
                    ..Default::default()
                })),
                RequestIdResponseResult::Error(e) => {
                    Ok(Response::new(raft_service::RequestIdResponse {
                        code: raft_service::ResultCode::Error as i32,
                        error: e.to_string().as_bytes().to_vec(),
                        ..Default::default()
                    }))
                }
                RequestIdResponseResult::WrongLeader { leader_addr, .. } => {
                    let mut client =
                        create_client(leader_addr, self.config.client_tls_config.clone())
                            .await
                            .unwrap();
                    let reply = client.request_id(request_args).await?.into_inner();

                    Ok(Response::new(reply))
                }
            },
            _ => unreachable!(),
        }
    }

    async fn change_config(
        &self,
        request: Request<raft_service::ChangeConfigArgs>,
    ) -> Result<Response<raft_service::ChangeConfigResponse>, Status> {
        let request_args = request.into_inner();
        let sender = self.tx.clone();
        let (tx_msg, rx_msg) = oneshot::channel();

        let conf_change_request: ConfChangeRequest = request_args.clone().into();

        let message = ServerRequestMsg::ChangeConfig {
            conf_change: conf_change_request,
            tx_msg,
        };

        // TODO: Handle this kind of errors
        match sender.send(message).await {
            Ok(_) => {}
            Err(_) => {
                self.print_send_error(function_name!());
            }
        }

        let mut reply = raft_service::ChangeConfigResponse::default();

        match timeout(
            Duration::from_secs_f32(self.config.conf_change_request_timeout),
            rx_msg,
        )
        .await
        {
            Ok(Ok(raft_response)) => {
                match raft_response {
                    ServerResponseMsg::ConfigChange { result } => match result {
                        ConfChangeResponseResult::JoinSuccess {
                            assigned_ids,
                            peers,
                        } => {
                            reply.result_type =
                                raft_service::ChangeConfigResultType::ChangeConfigSuccess as i32;
                            reply.assigned_ids = assigned_ids;
                            reply.peers = serialize(&peers).unwrap();
                        }
                        ConfChangeResponseResult::RemoveSuccess {} => {
                            reply.result_type =
                                raft_service::ChangeConfigResultType::ChangeConfigSuccess as i32;
                        }
                        ConfChangeResponseResult::Error(e) => {
                            reply.result_type =
                                raft_service::ChangeConfigResultType::ChangeConfigUnknownError
                                    as i32;
                            reply.error = e.to_string().as_bytes().to_vec();
                        }
                        ConfChangeResponseResult::WrongLeader { leader_addr, .. } => {
                            reply.result_type =
                                raft_service::ChangeConfigResultType::ChangeConfigWrongLeader
                                    as i32;

                            let mut client =
                                create_client(leader_addr, self.config.client_tls_config.clone())
                                    .await
                                    .unwrap();
                            reply = client.change_config(request_args).await?.into_inner();
                        }
                    },
                    _ => unreachable!(),
                }
                reply.result_type =
                    raft_service::ChangeConfigResultType::ChangeConfigSuccess as i32;
            }
            Ok(Err(e)) => {
                reply.result_type =
                    raft_service::ChangeConfigResultType::ChangeConfigUnknownError as i32;
                reply.error = e.to_string().as_bytes().to_vec();
            }
            Err(e) => {
                reply.result_type =
                    raft_service::ChangeConfigResultType::ChangeConfigTimeoutError as i32;
                reply.error = e.to_string().as_bytes().to_vec();
                self.logger.error(&format!(
                    "Confchange request timeout! (\"conf_change_request_timeout\" = {})",
                    self.config.conf_change_request_timeout
                ));
            }
        }

        Ok(Response::new(reply))
    }

    async fn send_message(
        &self,
        request: Request<RaftMessage>,
    ) -> Result<Response<raft_service::Empty>, Status> {
        let request_args = request.into_inner();
        let sender = self.tx.clone();
        match sender
            .send(ServerRequestMsg::SendMessage {
                message: Box::new(request_args),
            })
            .await
        {
            Ok(_) => (),
            Err(_) => self.print_send_error(function_name!()),
        }

        Ok(Response::new(raft_service::Empty {}))
    }

    async fn propose(
        &self,
        request: Request<raft_service::ProposeArgs>,
    ) -> Result<Response<raft_service::ProposeResponse>, Status> {
        let request_args = request.into_inner();
        let sender = self.tx.clone();

        let (tx_msg, rx_msg) = oneshot::channel();
        match sender
            .send(ServerRequestMsg::Propose {
                proposal: request_args.msg.clone(),
                tx_msg,
            })
            .await
        {
            Ok(_) => (),
            Err(_) => self.print_send_error(function_name!()),
        }

        let response = rx_msg.await.unwrap();
        match response {
            ServerResponseMsg::Propose { result } => {
                match result {
                    ResponseResult::Success => Ok(Response::new(raft_service::ProposeResponse {
                        ..Default::default()
                    })),
                    ResponseResult::Error(error) => {
                        Ok(Response::new(raft_service::ProposeResponse {
                            error: error.to_string().as_bytes().to_vec(),
                        }))
                    }
                    ResponseResult::WrongLeader { leader_addr, .. } => {
                        // TODO: Handle this kind of errors
                        let mut client =
                            create_client(leader_addr, self.config.client_tls_config.clone())
                                .await
                                .unwrap();
                        let _ = client
                            .propose(ProposeArgs {
                                msg: request_args.msg,
                            })
                            .await?;

                        Ok(Response::new(raft_service::ProposeResponse {
                            ..Default::default()
                        }))
                    }
                }
            }
            _ => unreachable!(),
        }
    }

    async fn debug_node(
        &self,
        request: Request<raft_service::Empty>,
    ) -> Result<Response<raft_service::DebugNodeResponse>, Status> {
        let _request_args = request.into_inner();
        let sender = self.tx.clone();
        let (tx_msg, rx_msg) = oneshot::channel();

        match sender.send(ServerRequestMsg::DebugNode { tx_msg }).await {
            Ok(_) => (),
            Err(_) => self.print_send_error(function_name!()),
        }

        let response = rx_msg.await.unwrap();
        match response {
            ServerResponseMsg::DebugNode { result_json } => {
                Ok(Response::new(raft_service::DebugNodeResponse {
                    result_json,
                }))
            }
            _ => unreachable!(),
        }
    }

    async fn get_peers(
        &self,
        request: Request<raft_service::Empty>,
    ) -> Result<Response<raft_service::GetPeersResponse>, Status> {
        let _request_args = request.into_inner();
        let (tx_msg, rx_msg) = oneshot::channel();
        let sender = self.tx.clone();
        match sender.send(ServerRequestMsg::GetPeers { tx_msg }).await {
            Ok(_) => (),
            Err(_) => self.print_send_error(function_name!()),
        }
        let response = rx_msg.await.unwrap();

        match response {
            ServerResponseMsg::GetPeers { peers } => {
                Ok(Response::new(raft_service::GetPeersResponse {
                    peers_json: peers.to_json(),
                }))
            }
            _ => unreachable!(),
        }
    }

    async fn leave_joint(
        &self,
        request: Request<raft_service::Empty>,
    ) -> Result<Response<raft_service::Empty>, Status> {
        let _request_args = request.into_inner();
        let (tx_msg, rx_msg) = oneshot::channel();
        let sender = self.tx.clone();
        match sender.send(ServerRequestMsg::LeaveJoint { tx_msg }).await {
            Ok(_) => (),
            Err(_) => self.print_send_error(function_name!()),
        }
        let response = rx_msg.await.unwrap();

        match response {
            ServerResponseMsg::LeaveJoint {} => Ok(Response::new(raft_service::Empty {})),
            _ => unreachable!(),
        }
    }

    async fn set_peers(
        &self,
        request: Request<raft_service::Peers>,
    ) -> Result<Response<raft_service::Empty>, Status> {
        let request_args = request.into_inner();
        let peers = request_args.into();

        let (tx_msg, rx_msg) = oneshot::channel();
        let sender = self.tx.clone();
        match sender
            .send(ServerRequestMsg::SetPeers { peers, tx_msg })
            .await
        {
            Ok(_) => (),
            Err(_) => self.print_send_error(function_name!()),
        }
        let response = rx_msg.await.unwrap();

        match response {
            ServerResponseMsg::SetPeers {} => Ok(Response::new(raft_service::Empty {})),
            _ => unreachable!(),
        }
    }

    async fn create_snapshot(
        &self,
        request: Request<raft_service::Empty>,
    ) -> Result<Response<raft_service::Empty>, Status> {
        let _request_args = request.into_inner();
        let (tx_msg, rx_msg) = oneshot::channel();
        let sender = self.tx.clone();
        match sender
            .send(ServerRequestMsg::CreateSnapshot { tx_msg })
            .await
        {
            Ok(_) => (),
            Err(_) => self.print_send_error(function_name!()),
        }
        let response = rx_msg.await.unwrap();

        match response {
            ServerResponseMsg::CreateSnapshot {} => Ok(Response::new(raft_service::Empty {})),
            _ => unreachable!(),
        }
    }
}