garage/src/net/client.rs

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Rust
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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<mpsc::UnboundedSender<SendItem>>,
next_query_number: AtomicU32,
inflight: Mutex<HashMap<RequestID, oneshot::Sender<ByteStream>>>,
}
impl ClientConn {
pub(crate) async fn init(
netapp: Arc<NetApp>,
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<T>(
self: Arc<Self>,
req: Req<T>,
path: &str,
prio: RequestPriority,
) -> Result<Resp<T>, 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<Self>, 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<SendItem>,
}
impl CancelOnDrop {
fn new(id: RequestID, query_send: mpsc::UnboundedSender<SendItem>) -> Self {
Self { id, query_send }
}
fn for_stream(self, stream: ByteStream) -> CancelOnDropStream {
CancelOnDropStream {
cancel: Some(self),
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<CancelOnDrop>,
#[pin]
stream: ByteStream,
}
impl Stream for CancelOnDropStream {
type Item = Packet;
fn poll_next(
self: Pin<&mut Self>,
cx: &mut std::task::Context<'_>,
) -> Poll<Option<Self::Item>> {
let this = self.project();
let res = this.stream.poll_next(cx);
if matches!(res, Poll::Ready(None)) {
if let Some(c) = this.cancel.take() {
std::mem::forget(c)
}
}
res
}
fn size_hint(&self) -> (usize, Option<usize>) {
self.stream.size_hint()
}
}