dc619a8fa0
Currently, if the remote closes the connection at the same time that the pool selects it to use for a new request, the connection may actually hang. This fix will now more allow the keep-alive read to check the socket even when the `Conn` think it's busy. If the connection was closed before the request write happened, returns back an `Error::Cancel`, letting the user know they could safely retry it. Closes #1439
472 lines
16 KiB
Rust
472 lines
16 KiB
Rust
use std::io;
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use futures::{Async, AsyncSink, Future, Poll, Stream};
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use futures::sync::oneshot;
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use tokio_io::{AsyncRead, AsyncWrite};
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use tokio_service::Service;
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use proto::{Body, Conn, KeepAlive, Http1Transaction, MessageHead, RequestHead, ResponseHead};
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use ::StatusCode;
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pub struct Dispatcher<D, Bs, I, B, T, K> {
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conn: Conn<I, B, T, K>,
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dispatch: D,
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body_tx: Option<::proto::body::ChunkSender>,
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body_rx: Option<Bs>,
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is_closing: bool,
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}
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pub trait Dispatch {
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type PollItem;
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type PollBody;
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type RecvItem;
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fn poll_msg(&mut self) -> Poll<Option<(Self::PollItem, Option<Self::PollBody>)>, ::Error>;
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fn recv_msg(&mut self, msg: ::Result<(Self::RecvItem, Option<Body>)>) -> ::Result<()>;
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fn poll_ready(&mut self) -> Poll<(), ()>;
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fn should_poll(&self) -> bool;
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}
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pub struct Server<S: Service> {
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in_flight: Option<S::Future>,
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service: S,
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}
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pub struct Client<B> {
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callback: Option<oneshot::Sender<::Result<::Response>>>,
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rx: ClientRx<B>,
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}
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pub type ClientMsg<B> = (RequestHead, Option<B>);
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type ClientRx<B> = ::client::dispatch::Receiver<ClientMsg<B>, ::Response>;
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impl<D, Bs, I, B, T, K> Dispatcher<D, Bs, I, B, T, K>
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where
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D: Dispatch<PollItem=MessageHead<T::Outgoing>, PollBody=Bs, RecvItem=MessageHead<T::Incoming>>,
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I: AsyncRead + AsyncWrite,
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B: AsRef<[u8]>,
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T: Http1Transaction,
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K: KeepAlive,
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Bs: Stream<Item=B, Error=::Error>,
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{
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pub fn new(dispatch: D, conn: Conn<I, B, T, K>) -> Self {
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Dispatcher {
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conn: conn,
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dispatch: dispatch,
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body_tx: None,
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body_rx: None,
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is_closing: false,
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}
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}
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pub fn disable_keep_alive(&mut self) {
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self.conn.disable_keep_alive()
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}
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fn poll2(&mut self) -> Poll<(), ::Error> {
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self.poll_read()?;
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self.poll_write()?;
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self.poll_flush()?;
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if self.is_done() {
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try_ready!(self.conn.shutdown());
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self.conn.take_error()?;
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trace!("Dispatch::poll done");
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Ok(Async::Ready(()))
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} else {
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Ok(Async::NotReady)
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}
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}
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fn poll_read(&mut self) -> Poll<(), ::Error> {
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loop {
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if self.is_closing {
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return Ok(Async::Ready(()));
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} else if self.conn.can_read_head() {
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try_ready!(self.poll_read_head());
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} else if let Some(mut body) = self.body_tx.take() {
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if self.conn.can_read_body() {
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match body.poll_ready() {
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Ok(Async::Ready(())) => (),
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Ok(Async::NotReady) => {
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self.body_tx = Some(body);
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return Ok(Async::NotReady);
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},
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Err(_canceled) => {
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// user doesn't care about the body
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// so we should stop reading
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trace!("body receiver dropped before eof, closing");
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self.conn.close_read();
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return Ok(Async::Ready(()));
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}
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}
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match self.conn.read_body() {
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Ok(Async::Ready(Some(chunk))) => {
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match body.start_send(Ok(chunk)) {
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Ok(AsyncSink::Ready) => {
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self.body_tx = Some(body);
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},
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Ok(AsyncSink::NotReady(_chunk)) => {
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unreachable!("mpsc poll_ready was ready, start_send was not");
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}
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Err(_canceled) => {
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if self.conn.can_read_body() {
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trace!("body receiver dropped before eof, closing");
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self.conn.close_read();
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}
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}
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}
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},
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Ok(Async::Ready(None)) => {
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// just drop, the body will close automatically
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},
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Ok(Async::NotReady) => {
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self.body_tx = Some(body);
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return Ok(Async::NotReady);
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}
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Err(e) => {
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let _ = body.start_send(Err(::Error::Io(e)));
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}
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}
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} else {
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// just drop, the body will close automatically
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}
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} else {
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return self.conn.read_keep_alive().map(Async::Ready);
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}
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}
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}
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fn poll_read_head(&mut self) -> Poll<(), ::Error> {
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// can dispatch receive, or does it still care about, an incoming message?
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match self.dispatch.poll_ready() {
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Ok(Async::Ready(())) => (),
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Ok(Async::NotReady) => unreachable!("dispatch not ready when conn is"),
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Err(()) => {
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trace!("dispatch no longer receiving messages");
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self.close();
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return Ok(Async::Ready(()));
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}
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}
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// dispatch is ready for a message, try to read one
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match self.conn.read_head() {
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Ok(Async::Ready(Some((head, has_body)))) => {
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let body = if has_body {
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let (mut tx, rx) = ::proto::body::channel();
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let _ = tx.poll_ready(); // register this task if rx is dropped
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self.body_tx = Some(tx);
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Some(rx)
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} else {
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None
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};
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self.dispatch.recv_msg(Ok((head, body)))?;
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Ok(Async::Ready(()))
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},
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Ok(Async::Ready(None)) => {
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// read eof, conn will start to shutdown automatically
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Ok(Async::Ready(()))
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}
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Ok(Async::NotReady) => Ok(Async::NotReady),
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Err(err) => {
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debug!("read_head error: {}", err);
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self.dispatch.recv_msg(Err(err))?;
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// if here, the dispatcher gave the user the error
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// somewhere else. we still need to shutdown, but
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// not as a second error.
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Ok(Async::Ready(()))
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}
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}
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}
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fn poll_write(&mut self) -> Poll<(), ::Error> {
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loop {
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if self.is_closing {
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return Ok(Async::Ready(()));
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} else if self.body_rx.is_none() && self.dispatch.should_poll() {
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if let Some((head, body)) = try_ready!(self.dispatch.poll_msg()) {
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self.conn.write_head(head, body.is_some());
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self.body_rx = body;
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} else {
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self.close();
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return Ok(Async::Ready(()));
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}
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} else if !self.conn.can_buffer_body() {
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try_ready!(self.poll_flush());
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} else if let Some(mut body) = self.body_rx.take() {
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let chunk = match body.poll()? {
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Async::Ready(Some(chunk)) => {
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self.body_rx = Some(body);
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chunk
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},
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Async::Ready(None) => {
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if self.conn.can_write_body() {
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self.conn.write_body(None)?;
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}
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continue;
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},
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Async::NotReady => {
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self.body_rx = Some(body);
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return Ok(Async::NotReady);
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}
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};
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if self.conn.can_write_body() {
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assert!(self.conn.write_body(Some(chunk))?.is_ready());
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// This allows when chunk is `None`, or `Some([])`.
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} else if chunk.as_ref().len() == 0 {
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// ok
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} else {
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warn!("unexpected chunk when body cannot write");
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}
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} else {
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return Ok(Async::NotReady);
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}
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}
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}
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fn poll_flush(&mut self) -> Poll<(), ::Error> {
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self.conn.flush().map_err(|err| {
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debug!("error writing: {}", err);
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err.into()
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})
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}
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fn close(&mut self) {
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self.is_closing = true;
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self.conn.close_read();
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self.conn.close_write();
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}
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fn is_done(&self) -> bool {
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if self.is_closing {
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return true;
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}
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let read_done = self.conn.is_read_closed();
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if !T::should_read_first() && read_done {
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// a client that cannot read may was well be done.
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true
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} else {
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let write_done = self.conn.is_write_closed() ||
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(!self.dispatch.should_poll() && self.body_rx.is_none());
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read_done && write_done
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}
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}
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}
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impl<D, Bs, I, B, T, K> Future for Dispatcher<D, Bs, I, B, T, K>
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where
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D: Dispatch<PollItem=MessageHead<T::Outgoing>, PollBody=Bs, RecvItem=MessageHead<T::Incoming>>,
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I: AsyncRead + AsyncWrite,
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B: AsRef<[u8]>,
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T: Http1Transaction,
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K: KeepAlive,
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Bs: Stream<Item=B, Error=::Error>,
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{
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type Item = ();
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type Error = ::Error;
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#[inline]
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fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
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trace!("Dispatcher::poll");
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self.poll2().or_else(|e| {
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// An error means we're shutting down either way.
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// We just try to give the error to the user,
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// and close the connection with an Ok. If we
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// cannot give it to the user, then return the Err.
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self.dispatch.recv_msg(Err(e)).map(Async::Ready)
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})
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}
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}
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// ===== impl Server =====
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impl<S> Server<S> where S: Service {
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pub fn new(service: S) -> Server<S> {
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Server {
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in_flight: None,
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service: service,
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}
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}
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}
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impl<S, Bs> Dispatch for Server<S>
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where
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S: Service<Request=::Request, Response=::Response<Bs>, Error=::Error>,
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Bs: Stream<Error=::Error>,
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Bs::Item: AsRef<[u8]>,
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{
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type PollItem = MessageHead<StatusCode>;
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type PollBody = Bs;
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type RecvItem = RequestHead;
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fn poll_msg(&mut self) -> Poll<Option<(Self::PollItem, Option<Self::PollBody>)>, ::Error> {
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if let Some(mut fut) = self.in_flight.take() {
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let resp = match fut.poll()? {
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Async::Ready(res) => res,
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Async::NotReady => {
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self.in_flight = Some(fut);
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return Ok(Async::NotReady);
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}
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};
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let (head, body) = ::proto::response::split(resp);
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Ok(Async::Ready(Some((head.into(), body))))
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} else {
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unreachable!("poll_msg shouldn't be called if no inflight");
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}
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}
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fn recv_msg(&mut self, msg: ::Result<(Self::RecvItem, Option<Body>)>) -> ::Result<()> {
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let (msg, body) = msg?;
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let req = ::proto::request::from_wire(None, msg, body);
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self.in_flight = Some(self.service.call(req));
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Ok(())
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}
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fn poll_ready(&mut self) -> Poll<(), ()> {
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if self.in_flight.is_some() {
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Ok(Async::NotReady)
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} else {
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Ok(Async::Ready(()))
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}
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}
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fn should_poll(&self) -> bool {
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self.in_flight.is_some()
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}
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}
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// ===== impl Client =====
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impl<B> Client<B> {
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pub fn new(rx: ClientRx<B>) -> Client<B> {
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Client {
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callback: None,
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rx: rx,
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}
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}
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}
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impl<B> Dispatch for Client<B>
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where
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B: Stream<Error=::Error>,
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B::Item: AsRef<[u8]>,
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{
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type PollItem = RequestHead;
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type PollBody = B;
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type RecvItem = ResponseHead;
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fn poll_msg(&mut self) -> Poll<Option<(Self::PollItem, Option<Self::PollBody>)>, ::Error> {
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match self.rx.poll() {
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Ok(Async::Ready(Some(((head, body), mut cb)))) => {
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// check that future hasn't been canceled already
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match cb.poll_cancel().expect("poll_cancel cannot error") {
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Async::Ready(()) => {
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trace!("request canceled");
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Ok(Async::Ready(None))
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},
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Async::NotReady => {
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self.callback = Some(cb);
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Ok(Async::Ready(Some((head, body))))
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}
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}
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},
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Ok(Async::Ready(None)) => {
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trace!("client tx closed");
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// user has dropped sender handle
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Ok(Async::Ready(None))
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},
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Ok(Async::NotReady) => return Ok(Async::NotReady),
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Err(_) => unreachable!("receiver cannot error"),
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}
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}
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fn recv_msg(&mut self, msg: ::Result<(Self::RecvItem, Option<Body>)>) -> ::Result<()> {
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match msg {
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Ok((msg, body)) => {
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if let Some(cb) = self.callback.take() {
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let res = ::proto::response::from_wire(msg, body);
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let _ = cb.send(Ok(res));
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Ok(())
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} else {
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Err(::Error::Io(io::Error::new(io::ErrorKind::InvalidData, "response received without matching request")))
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}
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},
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Err(err) => {
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if let Some(cb) = self.callback.take() {
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let _ = cb.send(Err(err));
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Ok(())
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} else if let Ok(Async::Ready(Some((_, cb)))) = self.rx.poll() {
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// in this case, the message was never even started, so it's safe to tell
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// the user that the request was completely canceled
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let _ = cb.send(Err(::Error::new_canceled(Some(err))));
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Ok(())
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} else {
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Err(err)
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}
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}
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}
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}
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fn poll_ready(&mut self) -> Poll<(), ()> {
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match self.callback {
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Some(ref mut cb) => match cb.poll_cancel() {
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Ok(Async::Ready(())) => {
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trace!("callback receiver has dropped");
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Err(())
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},
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Ok(Async::NotReady) => Ok(Async::Ready(())),
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Err(_) => unreachable!("oneshot poll_cancel cannot error"),
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},
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None => Err(()),
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}
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}
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fn should_poll(&self) -> bool {
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self.callback.is_none()
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}
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}
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#[cfg(test)]
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mod tests {
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extern crate pretty_env_logger;
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use super::*;
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use mock::AsyncIo;
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use proto::ClientTransaction;
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#[test]
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fn client_read_bytes_before_writing_request() {
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let _ = pretty_env_logger::try_init();
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::futures::lazy(|| {
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let io = AsyncIo::new_buf(b"HTTP/1.1 200 OK\r\n\r\n".to_vec(), 100);
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let (tx, rx) = ::client::dispatch::channel();
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let conn = Conn::<_, ::Chunk, ClientTransaction>::new(io, Default::default());
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let mut dispatcher = Dispatcher::new(Client::new(rx), conn);
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let req = RequestHead {
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version: ::HttpVersion::Http11,
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subject: ::proto::RequestLine::default(),
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headers: Default::default(),
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};
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let res_rx = tx.send((req, None::<::Body>)).unwrap();
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let a1 = dispatcher.poll().expect("error should be sent on channel");
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assert!(a1.is_ready(), "dispatcher should be closed");
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let err = res_rx.wait()
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.expect("callback poll")
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.expect_err("callback response");
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match err {
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::Error::Cancel(_) => (),
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other => panic!("expected Cancel(_), got {:?}", other),
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}
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Ok::<(), ()>(())
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}).wait().unwrap();
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}
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}
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