peer.rs

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