use std::collections::HashMap; use std::net::SocketAddr; use std::pin::Pin; use std::sync::atomic::{self, AtomicU32}; use std::sync::{Arc, Mutex}; use std::task::Poll; use arc_swap::ArcSwapOption; use async_trait::async_trait; use bytes::Bytes; use log::{debug, error, trace}; use futures::io::AsyncReadExt; use futures::Stream; use kuska_handshake::async_std::{handshake_client, BoxStream}; use tokio::net::TcpStream; use tokio::select; use tokio::sync::{mpsc, oneshot, watch}; use tokio_util::compat::*; #[cfg(feature = "telemetry")] use opentelemetry::{ trace::{FutureExt, Span, SpanKind, TraceContextExt, Tracer}, Context, KeyValue, }; #[cfg(feature = "telemetry")] use opentelemetry_contrib::trace::propagator::binary::*; use crate::error::*; use crate::message::*; use crate::netapp::*; use crate::recv::*; use crate::send::*; use crate::stream::*; use crate::util::*; pub(crate) struct ClientConn { pub(crate) remote_addr: SocketAddr, pub(crate) peer_id: NodeID, query_send: ArcSwapOption>, next_query_number: AtomicU32, inflight: Mutex>>, } impl ClientConn { pub(crate) async fn init( netapp: Arc, socket: TcpStream, peer_id: NodeID, ) -> Result<(), Error> { let remote_addr = socket.peer_addr()?; let mut socket = socket.compat(); // Do handshake to authenticate and prove our identity to server let handshake = handshake_client( &mut socket, netapp.netid.clone(), netapp.id, netapp.privkey.clone(), peer_id, ) .await?; debug!( "Handshake complete (client) with {}@{}", hex::encode(&peer_id), remote_addr ); // Create BoxStream layer that encodes content let (read, write) = socket.split(); let (mut read, write) = BoxStream::from_handshake(read, write, handshake, 0x8000).split_read_write(); // Before doing anything, receive version tag and // check they are running the same version as us let mut their_version_tag = VersionTag::default(); read.read_exact(&mut their_version_tag[..]).await?; if their_version_tag != netapp.version_tag { let msg = format!( "different version tags: {} (theirs) vs. {} (ours)", hex::encode(their_version_tag), hex::encode(netapp.version_tag) ); error!("Cannot connect to {}: {}", hex::encode(&peer_id[..8]), msg); return Err(Error::VersionMismatch(msg)); } // Build and launch stuff that manages sending requests client-side let (query_send, query_recv) = mpsc::unbounded_channel(); let (stop_recv_loop, stop_recv_loop_recv) = watch::channel(false); let conn = Arc::new(ClientConn { remote_addr, peer_id, next_query_number: AtomicU32::from(RequestID::default()), query_send: ArcSwapOption::new(Some(Arc::new(query_send))), inflight: Mutex::new(HashMap::new()), }); netapp.connected_as_client(peer_id, conn.clone()); let debug_name = format!("CLI {}", hex::encode(&peer_id[..8])); tokio::spawn(async move { let debug_name_2 = debug_name.clone(); let send_future = tokio::spawn(conn.clone().send_loop(query_recv, write, debug_name_2)); let conn2 = conn.clone(); let recv_future = tokio::spawn(async move { select! { r = conn2.recv_loop(read, debug_name) => r, _ = await_exit(stop_recv_loop_recv) => Ok(()) } }); send_future.await.log_err("ClientConn send_loop"); // FIXME: should do here: wait for inflight requests to all have their response stop_recv_loop .send(true) .log_err("ClientConn send true to stop_recv_loop"); recv_future.await.log_err("ClientConn recv_loop"); // Make sure we don't wait on any more requests that won't // have a response conn.inflight.lock().unwrap().clear(); netapp.disconnected_as_client(&peer_id, conn); }); Ok(()) } pub fn close(&self) { self.query_send.store(None); } pub(crate) async fn call( self: Arc, req: Req, path: &str, prio: RequestPriority, ) -> Result, Error> where T: Message, { let query_send = self.query_send.load_full().ok_or(Error::ConnectionClosed)?; let id = self .next_query_number .fetch_add(1, atomic::Ordering::Relaxed); cfg_if::cfg_if! { if #[cfg(feature = "telemetry")] { let tracer = opentelemetry::global::tracer("netapp"); let mut span = tracer.span_builder(format!("RPC >> {}", path)) .with_kind(SpanKind::Client) .start(&tracer); let propagator = BinaryPropagator::new(); let telemetry_id: Bytes = propagator.to_bytes(span.span_context()).to_vec().into(); } else { let telemetry_id: Bytes = Bytes::new(); } }; // Encode request let req_enc = req.into_enc(prio, path.as_bytes().to_vec().into(), telemetry_id); let req_msg_len = req_enc.msg.len(); let (req_stream, req_order) = req_enc.encode(); // Send request through let (resp_send, resp_recv) = oneshot::channel(); let old = self.inflight.lock().unwrap().insert(id, resp_send); if let Some(old_ch) = old { error!( "Too many inflight requests! RequestID collision. Interrupting previous request." ); let _ = old_ch.send(Box::pin(futures::stream::once(async move { Err(std::io::Error::new( std::io::ErrorKind::Other, "RequestID collision, too many inflight requests", )) }))); } debug!( "request: query_send {}, path {}, prio {} (serialized message: {} bytes)", id, path, prio, req_msg_len ); #[cfg(feature = "telemetry")] span.set_attribute(KeyValue::new("len_query_msg", req_msg_len as i64)); query_send.send(SendItem::Stream(id, prio, req_order, req_stream))?; let canceller = CancelOnDrop::new(id, query_send.as_ref().clone()); cfg_if::cfg_if! { if #[cfg(feature = "telemetry")] { let stream = resp_recv .with_context(Context::current_with_span(span)) .await?; } else { let stream = resp_recv.await?; } } let stream = Box::pin(canceller.for_stream(stream)); let resp_enc = RespEnc::decode(stream).await?; debug!("client: got response to request {} (path {})", id, path); Resp::from_enc(resp_enc) } } impl SendLoop for ClientConn {} #[async_trait] impl RecvLoop for ClientConn { fn recv_handler(self: &Arc, id: RequestID, stream: ByteStream) { trace!("ClientConn recv_handler {}", id); let mut inflight = self.inflight.lock().unwrap(); if let Some(ch) = inflight.remove(&id) { if ch.send(stream).is_err() { debug!("Could not send request response, probably because request was interrupted. Dropping response."); } } else { debug!("Got unexpected response to request {}, dropping it", id); } } } // ---- struct CancelOnDrop { id: RequestID, query_send: mpsc::UnboundedSender, } impl CancelOnDrop { fn new(id: RequestID, query_send: mpsc::UnboundedSender) -> Self { Self { id, query_send } } fn for_stream(self, stream: ByteStream) -> CancelOnDropStream { CancelOnDropStream { cancel: Some(self), stream: stream, } } } impl Drop for CancelOnDrop { fn drop(&mut self) { trace!("cancelling request {}", self.id); let _ = self.query_send.send(SendItem::Cancel(self.id)); } } #[pin_project::pin_project] struct CancelOnDropStream { cancel: Option, #[pin] stream: ByteStream, } impl Stream for CancelOnDropStream { type Item = Packet; fn poll_next( self: Pin<&mut Self>, cx: &mut std::task::Context<'_>, ) -> Poll> { let this = self.project(); let res = this.stream.poll_next(cx); if matches!(res, Poll::Ready(None)) { if let Some(c) = this.cancel.take() { trace!("defusing cancel request {}", c.id); std::mem::forget(c) } } res } fn size_hint(&self) -> (usize, Option) { self.stream.size_hint() } }