peer.rs

   1use crate::{ErrorCode, ErrorCodeExt, ErrorExt, RpcError};
   2
   3use super::{
   4    proto::{self, AnyTypedEnvelope, EnvelopedMessage, MessageStream, PeerId, RequestMessage},
   5    Connection,
   6};
   7use anyhow::{anyhow, Context, Result};
   8use collections::HashMap;
   9use futures::{
  10    channel::{mpsc, oneshot},
  11    stream::BoxStream,
  12    FutureExt, SinkExt, Stream, StreamExt, TryFutureExt,
  13};
  14use parking_lot::{Mutex, RwLock};
  15use serde::{ser::SerializeStruct, Serialize};
  16use std::{
  17    fmt, future,
  18    future::Future,
  19    marker::PhantomData,
  20    sync::atomic::Ordering::SeqCst,
  21    sync::{
  22        atomic::{self, AtomicU32},
  23        Arc,
  24    },
  25    time::Duration,
  26    time::Instant,
  27};
  28use tracing::instrument;
  29
  30#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Serialize)]
  31pub struct ConnectionId {
  32    pub owner_id: u32,
  33    pub id: u32,
  34}
  35
  36impl Into<PeerId> for ConnectionId {
  37    fn into(self) -> PeerId {
  38        PeerId {
  39            owner_id: self.owner_id,
  40            id: self.id,
  41        }
  42    }
  43}
  44
  45impl From<PeerId> for ConnectionId {
  46    fn from(peer_id: PeerId) -> Self {
  47        Self {
  48            owner_id: peer_id.owner_id,
  49            id: peer_id.id,
  50        }
  51    }
  52}
  53
  54impl fmt::Display for ConnectionId {
  55    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  56        write!(f, "{}/{}", self.owner_id, self.id)
  57    }
  58}
  59
  60pub struct Receipt<T> {
  61    pub sender_id: ConnectionId,
  62    pub message_id: u32,
  63    payload_type: PhantomData<T>,
  64}
  65
  66impl<T> Clone for Receipt<T> {
  67    fn clone(&self) -> Self {
  68        *self
  69    }
  70}
  71
  72impl<T> Copy for Receipt<T> {}
  73
  74#[derive(Clone, Debug)]
  75pub struct TypedEnvelope<T> {
  76    pub sender_id: ConnectionId,
  77    pub original_sender_id: Option<PeerId>,
  78    pub message_id: u32,
  79    pub payload: T,
  80    pub received_at: Instant,
  81}
  82
  83impl<T> TypedEnvelope<T> {
  84    pub fn original_sender_id(&self) -> Result<PeerId> {
  85        self.original_sender_id
  86            .ok_or_else(|| anyhow!("missing original_sender_id"))
  87    }
  88}
  89
  90impl<T: RequestMessage> TypedEnvelope<T> {
  91    pub fn receipt(&self) -> Receipt<T> {
  92        Receipt {
  93            sender_id: self.sender_id,
  94            message_id: self.message_id,
  95            payload_type: PhantomData,
  96        }
  97    }
  98}
  99
 100pub struct Peer {
 101    epoch: AtomicU32,
 102    pub connections: RwLock<HashMap<ConnectionId, ConnectionState>>,
 103    next_connection_id: AtomicU32,
 104}
 105
 106#[derive(Clone, Serialize)]
 107pub struct ConnectionState {
 108    #[serde(skip)]
 109    outgoing_tx: mpsc::UnboundedSender<proto::Message>,
 110    next_message_id: Arc<AtomicU32>,
 111    #[allow(clippy::type_complexity)]
 112    #[serde(skip)]
 113    response_channels: Arc<
 114        Mutex<
 115            Option<
 116                HashMap<
 117                    u32,
 118                    oneshot::Sender<(proto::Envelope, std::time::Instant, oneshot::Sender<()>)>,
 119                >,
 120            >,
 121        >,
 122    >,
 123    #[allow(clippy::type_complexity)]
 124    #[serde(skip)]
 125    stream_response_channels: Arc<
 126        Mutex<
 127            Option<
 128                HashMap<u32, mpsc::UnboundedSender<(Result<proto::Envelope>, oneshot::Sender<()>)>>,
 129            >,
 130        >,
 131    >,
 132}
 133
 134const KEEPALIVE_INTERVAL: Duration = Duration::from_secs(1);
 135const WRITE_TIMEOUT: Duration = Duration::from_secs(2);
 136pub const RECEIVE_TIMEOUT: Duration = Duration::from_secs(10);
 137
 138impl Peer {
 139    pub fn new(epoch: u32) -> Arc<Self> {
 140        Arc::new(Self {
 141            epoch: AtomicU32::new(epoch),
 142            connections: Default::default(),
 143            next_connection_id: Default::default(),
 144        })
 145    }
 146
 147    pub fn epoch(&self) -> u32 {
 148        self.epoch.load(SeqCst)
 149    }
 150
 151    #[instrument(skip_all)]
 152    pub fn add_connection<F, Fut, Out>(
 153        self: &Arc<Self>,
 154        connection: Connection,
 155        create_timer: F,
 156    ) -> (
 157        ConnectionId,
 158        impl Future<Output = anyhow::Result<()>> + Send,
 159        BoxStream<'static, Box<dyn AnyTypedEnvelope>>,
 160    )
 161    where
 162        F: Send + Fn(Duration) -> Fut,
 163        Fut: Send + Future<Output = Out>,
 164        Out: Send,
 165    {
 166        // For outgoing messages, use an unbounded channel so that application code
 167        // can always send messages without yielding. For incoming messages, use a
 168        // bounded channel so that other peers will receive backpressure if they send
 169        // messages faster than this peer can process them.
 170        #[cfg(any(test, feature = "test-support"))]
 171        const INCOMING_BUFFER_SIZE: usize = 1;
 172        #[cfg(not(any(test, feature = "test-support")))]
 173        const INCOMING_BUFFER_SIZE: usize = 256;
 174        let (mut incoming_tx, incoming_rx) = mpsc::channel(INCOMING_BUFFER_SIZE);
 175        let (outgoing_tx, mut outgoing_rx) = mpsc::unbounded();
 176
 177        let connection_id = ConnectionId {
 178            owner_id: self.epoch.load(SeqCst),
 179            id: self.next_connection_id.fetch_add(1, SeqCst),
 180        };
 181        let connection_state = ConnectionState {
 182            outgoing_tx,
 183            next_message_id: Default::default(),
 184            response_channels: Arc::new(Mutex::new(Some(Default::default()))),
 185            stream_response_channels: Arc::new(Mutex::new(Some(Default::default()))),
 186        };
 187        let mut writer = MessageStream::new(connection.tx);
 188        let mut reader = MessageStream::new(connection.rx);
 189
 190        let this = self.clone();
 191        let response_channels = connection_state.response_channels.clone();
 192        let stream_response_channels = connection_state.stream_response_channels.clone();
 193
 194        let handle_io = async move {
 195            tracing::trace!(%connection_id, "handle io future: start");
 196
 197            let _end_connection = util::defer(|| {
 198                response_channels.lock().take();
 199                if let Some(channels) = stream_response_channels.lock().take() {
 200                    for channel in channels.values() {
 201                        let _ = channel.unbounded_send((
 202                            Err(anyhow!("connection closed")),
 203                            oneshot::channel().0,
 204                        ));
 205                    }
 206                }
 207                this.connections.write().remove(&connection_id);
 208                tracing::trace!(%connection_id, "handle io future: end");
 209            });
 210
 211            // Send messages on this frequency so the connection isn't closed.
 212            let keepalive_timer = create_timer(KEEPALIVE_INTERVAL).fuse();
 213            futures::pin_mut!(keepalive_timer);
 214
 215            // Disconnect if we don't receive messages at least this frequently.
 216            let receive_timeout = create_timer(RECEIVE_TIMEOUT).fuse();
 217            futures::pin_mut!(receive_timeout);
 218
 219            loop {
 220                tracing::trace!(%connection_id, "outer loop iteration start");
 221                let read_message = reader.read().fuse();
 222                futures::pin_mut!(read_message);
 223
 224                loop {
 225                    tracing::trace!(%connection_id, "inner loop iteration start");
 226                    futures::select_biased! {
 227                        outgoing = outgoing_rx.next().fuse() => match outgoing {
 228                            Some(outgoing) => {
 229                                tracing::trace!(%connection_id, "outgoing rpc message: writing");
 230                                futures::select_biased! {
 231                                    result = writer.write(outgoing).fuse() => {
 232                                        tracing::trace!(%connection_id, "outgoing rpc message: done writing");
 233                                        result.context("failed to write RPC message")?;
 234                                        tracing::trace!(%connection_id, "keepalive interval: resetting after sending message");
 235                                        keepalive_timer.set(create_timer(KEEPALIVE_INTERVAL).fuse());
 236                                    }
 237                                    _ = create_timer(WRITE_TIMEOUT).fuse() => {
 238                                        tracing::trace!(%connection_id, "outgoing rpc message: writing timed out");
 239                                        Err(anyhow!("timed out writing message"))?;
 240                                    }
 241                                }
 242                            }
 243                            None => {
 244                                tracing::trace!(%connection_id, "outgoing rpc message: channel closed");
 245                                return Ok(())
 246                            },
 247                        },
 248                        _ = keepalive_timer => {
 249                            tracing::trace!(%connection_id, "keepalive interval: pinging");
 250                            futures::select_biased! {
 251                                result = writer.write(proto::Message::Ping).fuse() => {
 252                                    tracing::trace!(%connection_id, "keepalive interval: done pinging");
 253                                    result.context("failed to send keepalive")?;
 254                                    tracing::trace!(%connection_id, "keepalive interval: resetting after pinging");
 255                                    keepalive_timer.set(create_timer(KEEPALIVE_INTERVAL).fuse());
 256                                }
 257                                _ = create_timer(WRITE_TIMEOUT).fuse() => {
 258                                    tracing::trace!(%connection_id, "keepalive interval: pinging timed out");
 259                                    Err(anyhow!("timed out sending keepalive"))?;
 260                                }
 261                            }
 262                        }
 263                        incoming = read_message => {
 264                            let incoming = incoming.context("error reading rpc message from socket")?;
 265                            tracing::trace!(%connection_id, "incoming rpc message: received");
 266                            tracing::trace!(%connection_id, "receive timeout: resetting");
 267                            receive_timeout.set(create_timer(RECEIVE_TIMEOUT).fuse());
 268                            if let (proto::Message::Envelope(incoming), received_at) = incoming {
 269                                tracing::trace!(%connection_id, "incoming rpc message: processing");
 270                                futures::select_biased! {
 271                                    result = incoming_tx.send((incoming, received_at)).fuse() => match result {
 272                                        Ok(_) => {
 273                                            tracing::trace!(%connection_id, "incoming rpc message: processed");
 274                                        }
 275                                        Err(_) => {
 276                                            tracing::trace!(%connection_id, "incoming rpc message: channel closed");
 277                                            return Ok(())
 278                                        }
 279                                    },
 280                                    _ = create_timer(WRITE_TIMEOUT).fuse() => {
 281                                        tracing::trace!(%connection_id, "incoming rpc message: processing timed out");
 282                                        Err(anyhow!("timed out processing incoming message"))?
 283                                    }
 284                                }
 285                            }
 286                            break;
 287                        },
 288                        _ = receive_timeout => {
 289                            tracing::trace!(%connection_id, "receive timeout: delay between messages too long");
 290                            Err(anyhow!("delay between messages too long"))?
 291                        }
 292                    }
 293                }
 294            }
 295        };
 296
 297        let response_channels = connection_state.response_channels.clone();
 298        let stream_response_channels = connection_state.stream_response_channels.clone();
 299        self.connections
 300            .write()
 301            .insert(connection_id, connection_state);
 302
 303        let incoming_rx = incoming_rx.filter_map(move |(incoming, received_at)| {
 304            let response_channels = response_channels.clone();
 305            let stream_response_channels = stream_response_channels.clone();
 306            async move {
 307                let message_id = incoming.id;
 308                tracing::trace!(?incoming, "incoming message future: start");
 309                let _end = util::defer(move || {
 310                    tracing::trace!(%connection_id, message_id, "incoming message future: end");
 311                });
 312
 313                if let Some(responding_to) = incoming.responding_to {
 314                    tracing::trace!(
 315                        %connection_id,
 316                        message_id,
 317                        responding_to,
 318                        "incoming response: received"
 319                    );
 320                    let response_channel =
 321                        response_channels.lock().as_mut()?.remove(&responding_to);
 322                    let stream_response_channel = stream_response_channels
 323                        .lock()
 324                        .as_ref()?
 325                        .get(&responding_to)
 326                        .cloned();
 327
 328                    if let Some(tx) = response_channel {
 329                        let requester_resumed = oneshot::channel();
 330                        if let Err(error) = tx.send((incoming, received_at, requester_resumed.0)) {
 331                            tracing::trace!(
 332                                %connection_id,
 333                                message_id,
 334                                responding_to = responding_to,
 335                                ?error,
 336                                "incoming response: request future dropped",
 337                            );
 338                        }
 339
 340                        tracing::trace!(
 341                            %connection_id,
 342                            message_id,
 343                            responding_to,
 344                            "incoming response: waiting to resume requester"
 345                        );
 346                        let _ = requester_resumed.1.await;
 347                        tracing::trace!(
 348                            %connection_id,
 349                            message_id,
 350                            responding_to,
 351                            "incoming response: requester resumed"
 352                        );
 353                    } else if let Some(tx) = stream_response_channel {
 354                        let requester_resumed = oneshot::channel();
 355                        if let Err(error) = tx.unbounded_send((Ok(incoming), requester_resumed.0)) {
 356                            tracing::debug!(
 357                                %connection_id,
 358                                message_id,
 359                                responding_to = responding_to,
 360                                ?error,
 361                                "incoming stream response: request future dropped",
 362                            );
 363                        }
 364
 365                        tracing::debug!(
 366                            %connection_id,
 367                            message_id,
 368                            responding_to,
 369                            "incoming stream response: waiting to resume requester"
 370                        );
 371                        let _ = requester_resumed.1.await;
 372                        tracing::debug!(
 373                            %connection_id,
 374                            message_id,
 375                            responding_to,
 376                            "incoming stream response: requester resumed"
 377                        );
 378                    } else {
 379                        let message_type =
 380                            proto::build_typed_envelope(connection_id, received_at, incoming)
 381                                .map(|p| p.payload_type_name());
 382                        tracing::warn!(
 383                            %connection_id,
 384                            message_id,
 385                            responding_to,
 386                            message_type,
 387                            "incoming response: unknown request"
 388                        );
 389                    }
 390
 391                    None
 392                } else {
 393                    tracing::trace!(%connection_id, message_id, "incoming message: received");
 394                    proto::build_typed_envelope(connection_id, received_at, incoming).or_else(
 395                        || {
 396                            tracing::error!(
 397                                %connection_id,
 398                                message_id,
 399                                "unable to construct a typed envelope"
 400                            );
 401                            None
 402                        },
 403                    )
 404                }
 405            }
 406        });
 407        (connection_id, handle_io, incoming_rx.boxed())
 408    }
 409
 410    #[cfg(any(test, feature = "test-support"))]
 411    pub fn add_test_connection(
 412        self: &Arc<Self>,
 413        connection: Connection,
 414        executor: gpui::BackgroundExecutor,
 415    ) -> (
 416        ConnectionId,
 417        impl Future<Output = anyhow::Result<()>> + Send,
 418        BoxStream<'static, Box<dyn AnyTypedEnvelope>>,
 419    ) {
 420        let executor = executor.clone();
 421        self.add_connection(connection, move |duration| executor.timer(duration))
 422    }
 423
 424    pub fn disconnect(&self, connection_id: ConnectionId) {
 425        self.connections.write().remove(&connection_id);
 426    }
 427
 428    #[cfg(any(test, feature = "test-support"))]
 429    pub fn reset(&self, epoch: u32) {
 430        self.next_connection_id.store(0, SeqCst);
 431        self.epoch.store(epoch, SeqCst);
 432    }
 433
 434    pub fn teardown(&self) {
 435        self.connections.write().clear();
 436    }
 437
 438    pub fn request<T: RequestMessage>(
 439        &self,
 440        receiver_id: ConnectionId,
 441        request: T,
 442    ) -> impl Future<Output = Result<T::Response>> {
 443        self.request_internal(None, receiver_id, request)
 444            .map_ok(|envelope| envelope.payload)
 445    }
 446
 447    pub fn request_envelope<T: RequestMessage>(
 448        &self,
 449        receiver_id: ConnectionId,
 450        request: T,
 451    ) -> impl Future<Output = Result<TypedEnvelope<T::Response>>> {
 452        self.request_internal(None, receiver_id, request)
 453    }
 454
 455    pub fn forward_request<T: RequestMessage>(
 456        &self,
 457        sender_id: ConnectionId,
 458        receiver_id: ConnectionId,
 459        request: T,
 460    ) -> impl Future<Output = Result<T::Response>> {
 461        self.request_internal(Some(sender_id), receiver_id, request)
 462            .map_ok(|envelope| envelope.payload)
 463    }
 464
 465    pub fn request_internal<T: RequestMessage>(
 466        &self,
 467        original_sender_id: Option<ConnectionId>,
 468        receiver_id: ConnectionId,
 469        request: T,
 470    ) -> impl Future<Output = Result<TypedEnvelope<T::Response>>> {
 471        let (tx, rx) = oneshot::channel();
 472        let send = self.connection_state(receiver_id).and_then(|connection| {
 473            let message_id = connection.next_message_id.fetch_add(1, SeqCst);
 474            connection
 475                .response_channels
 476                .lock()
 477                .as_mut()
 478                .ok_or_else(|| anyhow!("connection was closed"))?
 479                .insert(message_id, tx);
 480            connection
 481                .outgoing_tx
 482                .unbounded_send(proto::Message::Envelope(request.into_envelope(
 483                    message_id,
 484                    None,
 485                    original_sender_id.map(Into::into),
 486                )))
 487                .map_err(|_| anyhow!("connection was closed"))?;
 488            Ok(())
 489        });
 490        async move {
 491            send?;
 492            let (response, received_at, _barrier) =
 493                rx.await.map_err(|_| anyhow!("connection was closed"))?;
 494
 495            if let Some(proto::envelope::Payload::Error(error)) = &response.payload {
 496                Err(RpcError::from_proto(&error, T::NAME))
 497            } else {
 498                Ok(TypedEnvelope {
 499                    message_id: response.id,
 500                    sender_id: receiver_id,
 501                    original_sender_id: response.original_sender_id,
 502                    payload: T::Response::from_envelope(response)
 503                        .ok_or_else(|| anyhow!("received response of the wrong type"))?,
 504                    received_at,
 505                })
 506            }
 507        }
 508    }
 509
 510    pub fn request_stream<T: RequestMessage>(
 511        &self,
 512        receiver_id: ConnectionId,
 513        request: T,
 514    ) -> impl Future<Output = Result<impl Unpin + Stream<Item = Result<T::Response>>>> {
 515        let (tx, rx) = mpsc::unbounded();
 516        let send = self.connection_state(receiver_id).and_then(|connection| {
 517            let message_id = connection.next_message_id.fetch_add(1, SeqCst);
 518            let stream_response_channels = connection.stream_response_channels.clone();
 519            stream_response_channels
 520                .lock()
 521                .as_mut()
 522                .ok_or_else(|| anyhow!("connection was closed"))?
 523                .insert(message_id, tx);
 524            connection
 525                .outgoing_tx
 526                .unbounded_send(proto::Message::Envelope(
 527                    request.into_envelope(message_id, None, None),
 528                ))
 529                .map_err(|_| anyhow!("connection was closed"))?;
 530            Ok((message_id, stream_response_channels))
 531        });
 532
 533        async move {
 534            let (message_id, stream_response_channels) = send?;
 535            let stream_response_channels = Arc::downgrade(&stream_response_channels);
 536
 537            Ok(rx.filter_map(move |(response, _barrier)| {
 538                let stream_response_channels = stream_response_channels.clone();
 539                future::ready(match response {
 540                    Ok(response) => {
 541                        if let Some(proto::envelope::Payload::Error(error)) = &response.payload {
 542                            Some(Err(anyhow!(
 543                                "RPC request {} failed - {}",
 544                                T::NAME,
 545                                error.message
 546                            )))
 547                        } else if let Some(proto::envelope::Payload::EndStream(_)) =
 548                            &response.payload
 549                        {
 550                            // Remove the transmitting end of the response channel to end the stream.
 551                            if let Some(channels) = stream_response_channels.upgrade() {
 552                                if let Some(channels) = channels.lock().as_mut() {
 553                                    channels.remove(&message_id);
 554                                }
 555                            }
 556                            None
 557                        } else {
 558                            Some(
 559                                T::Response::from_envelope(response)
 560                                    .ok_or_else(|| anyhow!("received response of the wrong type")),
 561                            )
 562                        }
 563                    }
 564                    Err(error) => Some(Err(error)),
 565                })
 566            }))
 567        }
 568    }
 569
 570    pub fn send<T: EnvelopedMessage>(&self, receiver_id: ConnectionId, message: T) -> Result<()> {
 571        let connection = self.connection_state(receiver_id)?;
 572        let message_id = connection
 573            .next_message_id
 574            .fetch_add(1, atomic::Ordering::SeqCst);
 575        connection
 576            .outgoing_tx
 577            .unbounded_send(proto::Message::Envelope(
 578                message.into_envelope(message_id, None, None),
 579            ))?;
 580        Ok(())
 581    }
 582
 583    pub fn forward_send<T: EnvelopedMessage>(
 584        &self,
 585        sender_id: ConnectionId,
 586        receiver_id: ConnectionId,
 587        message: T,
 588    ) -> Result<()> {
 589        let connection = self.connection_state(receiver_id)?;
 590        let message_id = connection
 591            .next_message_id
 592            .fetch_add(1, atomic::Ordering::SeqCst);
 593        connection
 594            .outgoing_tx
 595            .unbounded_send(proto::Message::Envelope(message.into_envelope(
 596                message_id,
 597                None,
 598                Some(sender_id.into()),
 599            )))?;
 600        Ok(())
 601    }
 602
 603    pub fn respond<T: RequestMessage>(
 604        &self,
 605        receipt: Receipt<T>,
 606        response: T::Response,
 607    ) -> Result<()> {
 608        let connection = self.connection_state(receipt.sender_id)?;
 609        let message_id = connection
 610            .next_message_id
 611            .fetch_add(1, atomic::Ordering::SeqCst);
 612        connection
 613            .outgoing_tx
 614            .unbounded_send(proto::Message::Envelope(response.into_envelope(
 615                message_id,
 616                Some(receipt.message_id),
 617                None,
 618            )))?;
 619        Ok(())
 620    }
 621
 622    pub fn end_stream<T: RequestMessage>(&self, receipt: Receipt<T>) -> Result<()> {
 623        let connection = self.connection_state(receipt.sender_id)?;
 624        let message_id = connection
 625            .next_message_id
 626            .fetch_add(1, atomic::Ordering::SeqCst);
 627
 628        let message = proto::EndStream {};
 629
 630        connection
 631            .outgoing_tx
 632            .unbounded_send(proto::Message::Envelope(message.into_envelope(
 633                message_id,
 634                Some(receipt.message_id),
 635                None,
 636            )))?;
 637        Ok(())
 638    }
 639
 640    pub fn respond_with_error<T: RequestMessage>(
 641        &self,
 642        receipt: Receipt<T>,
 643        response: proto::Error,
 644    ) -> Result<()> {
 645        let connection = self.connection_state(receipt.sender_id)?;
 646        let message_id = connection
 647            .next_message_id
 648            .fetch_add(1, atomic::Ordering::SeqCst);
 649        connection
 650            .outgoing_tx
 651            .unbounded_send(proto::Message::Envelope(response.into_envelope(
 652                message_id,
 653                Some(receipt.message_id),
 654                None,
 655            )))?;
 656        Ok(())
 657    }
 658
 659    pub fn respond_with_unhandled_message(
 660        &self,
 661        envelope: Box<dyn AnyTypedEnvelope>,
 662    ) -> Result<()> {
 663        let connection = self.connection_state(envelope.sender_id())?;
 664        let response = ErrorCode::Internal
 665            .message(format!(
 666                "message {} was not handled",
 667                envelope.payload_type_name()
 668            ))
 669            .to_proto();
 670        let message_id = connection
 671            .next_message_id
 672            .fetch_add(1, atomic::Ordering::SeqCst);
 673        connection
 674            .outgoing_tx
 675            .unbounded_send(proto::Message::Envelope(response.into_envelope(
 676                message_id,
 677                Some(envelope.message_id()),
 678                None,
 679            )))?;
 680        Ok(())
 681    }
 682
 683    fn connection_state(&self, connection_id: ConnectionId) -> Result<ConnectionState> {
 684        let connections = self.connections.read();
 685        let connection = connections
 686            .get(&connection_id)
 687            .ok_or_else(|| anyhow!("no such connection: {}", connection_id))?;
 688        Ok(connection.clone())
 689    }
 690}
 691
 692impl Serialize for Peer {
 693    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
 694    where
 695        S: serde::Serializer,
 696    {
 697        let mut state = serializer.serialize_struct("Peer", 2)?;
 698        state.serialize_field("connections", &*self.connections.read())?;
 699        state.end()
 700    }
 701}
 702
 703#[cfg(test)]
 704mod tests {
 705    use super::*;
 706    use crate::TypedEnvelope;
 707    use async_tungstenite::tungstenite::Message as WebSocketMessage;
 708    use gpui::TestAppContext;
 709
 710    fn init_logger() {
 711        if std::env::var("RUST_LOG").is_ok() {
 712            env_logger::init();
 713        }
 714    }
 715
 716    #[gpui::test(iterations = 50)]
 717    async fn test_request_response(cx: &mut TestAppContext) {
 718        init_logger();
 719
 720        let executor = cx.executor();
 721
 722        // create 2 clients connected to 1 server
 723        let server = Peer::new(0);
 724        let client1 = Peer::new(0);
 725        let client2 = Peer::new(0);
 726
 727        let (client1_to_server_conn, server_to_client_1_conn, _kill) =
 728            Connection::in_memory(cx.executor());
 729        let (client1_conn_id, io_task1, client1_incoming) =
 730            client1.add_test_connection(client1_to_server_conn, cx.executor());
 731        let (_, io_task2, server_incoming1) =
 732            server.add_test_connection(server_to_client_1_conn, cx.executor());
 733
 734        let (client2_to_server_conn, server_to_client_2_conn, _kill) =
 735            Connection::in_memory(cx.executor());
 736        let (client2_conn_id, io_task3, client2_incoming) =
 737            client2.add_test_connection(client2_to_server_conn, cx.executor());
 738        let (_, io_task4, server_incoming2) =
 739            server.add_test_connection(server_to_client_2_conn, cx.executor());
 740
 741        executor.spawn(io_task1).detach();
 742        executor.spawn(io_task2).detach();
 743        executor.spawn(io_task3).detach();
 744        executor.spawn(io_task4).detach();
 745        executor
 746            .spawn(handle_messages(server_incoming1, server.clone()))
 747            .detach();
 748        executor
 749            .spawn(handle_messages(client1_incoming, client1.clone()))
 750            .detach();
 751        executor
 752            .spawn(handle_messages(server_incoming2, server.clone()))
 753            .detach();
 754        executor
 755            .spawn(handle_messages(client2_incoming, client2.clone()))
 756            .detach();
 757
 758        assert_eq!(
 759            client1
 760                .request(client1_conn_id, proto::Ping {},)
 761                .await
 762                .unwrap(),
 763            proto::Ack {}
 764        );
 765
 766        assert_eq!(
 767            client2
 768                .request(client2_conn_id, proto::Ping {},)
 769                .await
 770                .unwrap(),
 771            proto::Ack {}
 772        );
 773
 774        assert_eq!(
 775            client1
 776                .request(client1_conn_id, proto::Test { id: 1 },)
 777                .await
 778                .unwrap(),
 779            proto::Test { id: 1 }
 780        );
 781
 782        assert_eq!(
 783            client2
 784                .request(client2_conn_id, proto::Test { id: 2 })
 785                .await
 786                .unwrap(),
 787            proto::Test { id: 2 }
 788        );
 789
 790        client1.disconnect(client1_conn_id);
 791        client2.disconnect(client1_conn_id);
 792
 793        async fn handle_messages(
 794            mut messages: BoxStream<'static, Box<dyn AnyTypedEnvelope>>,
 795            peer: Arc<Peer>,
 796        ) -> Result<()> {
 797            while let Some(envelope) = messages.next().await {
 798                let envelope = envelope.into_any();
 799                if let Some(envelope) = envelope.downcast_ref::<TypedEnvelope<proto::Ping>>() {
 800                    let receipt = envelope.receipt();
 801                    peer.respond(receipt, proto::Ack {})?
 802                } else if let Some(envelope) = envelope.downcast_ref::<TypedEnvelope<proto::Test>>()
 803                {
 804                    peer.respond(envelope.receipt(), envelope.payload.clone())?
 805                } else {
 806                    panic!("unknown message type");
 807                }
 808            }
 809
 810            Ok(())
 811        }
 812    }
 813
 814    #[gpui::test(iterations = 50)]
 815    async fn test_order_of_response_and_incoming(cx: &mut TestAppContext) {
 816        let executor = cx.executor();
 817        let server = Peer::new(0);
 818        let client = Peer::new(0);
 819
 820        let (client_to_server_conn, server_to_client_conn, _kill) =
 821            Connection::in_memory(executor.clone());
 822        let (client_to_server_conn_id, io_task1, mut client_incoming) =
 823            client.add_test_connection(client_to_server_conn, executor.clone());
 824
 825        let (server_to_client_conn_id, io_task2, mut server_incoming) =
 826            server.add_test_connection(server_to_client_conn, executor.clone());
 827
 828        executor.spawn(io_task1).detach();
 829        executor.spawn(io_task2).detach();
 830
 831        executor
 832            .spawn(async move {
 833                let future = server_incoming.next().await;
 834                let request = future
 835                    .unwrap()
 836                    .into_any()
 837                    .downcast::<TypedEnvelope<proto::Ping>>()
 838                    .unwrap();
 839
 840                server
 841                    .send(
 842                        server_to_client_conn_id,
 843                        ErrorCode::Internal
 844                            .message("message 1".to_string())
 845                            .to_proto(),
 846                    )
 847                    .unwrap();
 848                server
 849                    .send(
 850                        server_to_client_conn_id,
 851                        ErrorCode::Internal
 852                            .message("message 2".to_string())
 853                            .to_proto(),
 854                    )
 855                    .unwrap();
 856                server.respond(request.receipt(), proto::Ack {}).unwrap();
 857
 858                // Prevent the connection from being dropped
 859                server_incoming.next().await;
 860            })
 861            .detach();
 862
 863        let events = Arc::new(Mutex::new(Vec::new()));
 864
 865        let response = client.request(client_to_server_conn_id, proto::Ping {});
 866        let response_task = executor.spawn({
 867            let events = events.clone();
 868            async move {
 869                response.await.unwrap();
 870                events.lock().push("response".to_string());
 871            }
 872        });
 873
 874        executor
 875            .spawn({
 876                let events = events.clone();
 877                async move {
 878                    let incoming1 = client_incoming
 879                        .next()
 880                        .await
 881                        .unwrap()
 882                        .into_any()
 883                        .downcast::<TypedEnvelope<proto::Error>>()
 884                        .unwrap();
 885                    events.lock().push(incoming1.payload.message);
 886                    let incoming2 = client_incoming
 887                        .next()
 888                        .await
 889                        .unwrap()
 890                        .into_any()
 891                        .downcast::<TypedEnvelope<proto::Error>>()
 892                        .unwrap();
 893                    events.lock().push(incoming2.payload.message);
 894
 895                    // Prevent the connection from being dropped
 896                    client_incoming.next().await;
 897                }
 898            })
 899            .detach();
 900
 901        response_task.await;
 902        assert_eq!(
 903            &*events.lock(),
 904            &[
 905                "message 1".to_string(),
 906                "message 2".to_string(),
 907                "response".to_string()
 908            ]
 909        );
 910    }
 911
 912    #[gpui::test(iterations = 50)]
 913    async fn test_dropping_request_before_completion(cx: &mut TestAppContext) {
 914        let executor = cx.executor();
 915        let server = Peer::new(0);
 916        let client = Peer::new(0);
 917
 918        let (client_to_server_conn, server_to_client_conn, _kill) =
 919            Connection::in_memory(cx.executor());
 920        let (client_to_server_conn_id, io_task1, mut client_incoming) =
 921            client.add_test_connection(client_to_server_conn, cx.executor());
 922        let (server_to_client_conn_id, io_task2, mut server_incoming) =
 923            server.add_test_connection(server_to_client_conn, cx.executor());
 924
 925        executor.spawn(io_task1).detach();
 926        executor.spawn(io_task2).detach();
 927
 928        executor
 929            .spawn(async move {
 930                let request1 = server_incoming
 931                    .next()
 932                    .await
 933                    .unwrap()
 934                    .into_any()
 935                    .downcast::<TypedEnvelope<proto::Ping>>()
 936                    .unwrap();
 937                let request2 = server_incoming
 938                    .next()
 939                    .await
 940                    .unwrap()
 941                    .into_any()
 942                    .downcast::<TypedEnvelope<proto::Ping>>()
 943                    .unwrap();
 944
 945                server
 946                    .send(
 947                        server_to_client_conn_id,
 948                        ErrorCode::Internal
 949                            .message("message 1".to_string())
 950                            .to_proto(),
 951                    )
 952                    .unwrap();
 953                server
 954                    .send(
 955                        server_to_client_conn_id,
 956                        ErrorCode::Internal
 957                            .message("message 2".to_string())
 958                            .to_proto(),
 959                    )
 960                    .unwrap();
 961                server.respond(request1.receipt(), proto::Ack {}).unwrap();
 962                server.respond(request2.receipt(), proto::Ack {}).unwrap();
 963
 964                // Prevent the connection from being dropped
 965                server_incoming.next().await;
 966            })
 967            .detach();
 968
 969        let events = Arc::new(Mutex::new(Vec::new()));
 970
 971        let request1 = client.request(client_to_server_conn_id, proto::Ping {});
 972        let request1_task = executor.spawn(request1);
 973        let request2 = client.request(client_to_server_conn_id, proto::Ping {});
 974        let request2_task = executor.spawn({
 975            let events = events.clone();
 976            async move {
 977                request2.await.unwrap();
 978                events.lock().push("response 2".to_string());
 979            }
 980        });
 981
 982        executor
 983            .spawn({
 984                let events = events.clone();
 985                async move {
 986                    let incoming1 = client_incoming
 987                        .next()
 988                        .await
 989                        .unwrap()
 990                        .into_any()
 991                        .downcast::<TypedEnvelope<proto::Error>>()
 992                        .unwrap();
 993                    events.lock().push(incoming1.payload.message);
 994                    let incoming2 = client_incoming
 995                        .next()
 996                        .await
 997                        .unwrap()
 998                        .into_any()
 999                        .downcast::<TypedEnvelope<proto::Error>>()
1000                        .unwrap();
1001                    events.lock().push(incoming2.payload.message);
1002
1003                    // Prevent the connection from being dropped
1004                    client_incoming.next().await;
1005                }
1006            })
1007            .detach();
1008
1009        // Allow the request to make some progress before dropping it.
1010        cx.executor().simulate_random_delay().await;
1011        drop(request1_task);
1012
1013        request2_task.await;
1014        assert_eq!(
1015            &*events.lock(),
1016            &[
1017                "message 1".to_string(),
1018                "message 2".to_string(),
1019                "response 2".to_string()
1020            ]
1021        );
1022    }
1023
1024    #[gpui::test(iterations = 50)]
1025    async fn test_disconnect(cx: &mut TestAppContext) {
1026        let executor = cx.executor();
1027
1028        let (client_conn, mut server_conn, _kill) = Connection::in_memory(executor.clone());
1029
1030        let client = Peer::new(0);
1031        let (connection_id, io_handler, mut incoming) =
1032            client.add_test_connection(client_conn, executor.clone());
1033
1034        let (io_ended_tx, io_ended_rx) = oneshot::channel();
1035        executor
1036            .spawn(async move {
1037                io_handler.await.ok();
1038                io_ended_tx.send(()).unwrap();
1039            })
1040            .detach();
1041
1042        let (messages_ended_tx, messages_ended_rx) = oneshot::channel();
1043        executor
1044            .spawn(async move {
1045                incoming.next().await;
1046                messages_ended_tx.send(()).unwrap();
1047            })
1048            .detach();
1049
1050        client.disconnect(connection_id);
1051
1052        let _ = io_ended_rx.await;
1053        let _ = messages_ended_rx.await;
1054        assert!(server_conn
1055            .send(WebSocketMessage::Binary(vec![]))
1056            .await
1057            .is_err());
1058    }
1059
1060    #[gpui::test(iterations = 50)]
1061    async fn test_io_error(cx: &mut TestAppContext) {
1062        let executor = cx.executor();
1063        let (client_conn, mut server_conn, _kill) = Connection::in_memory(executor.clone());
1064
1065        let client = Peer::new(0);
1066        let (connection_id, io_handler, mut incoming) =
1067            client.add_test_connection(client_conn, executor.clone());
1068        executor.spawn(io_handler).detach();
1069        executor
1070            .spawn(async move { incoming.next().await })
1071            .detach();
1072
1073        let response = executor.spawn(client.request(connection_id, proto::Ping {}));
1074        let _request = server_conn.rx.next().await.unwrap().unwrap();
1075
1076        drop(server_conn);
1077        assert_eq!(
1078            response.await.unwrap_err().to_string(),
1079            "connection was closed"
1080        );
1081    }
1082}