Struct Timeout

pub struct Timeout<T> { /* private fields */ }

Allows a Future or Stream to execute for a limited amount of time.

If the future or stream completes before the timeout has expired, then Timeout returns the completed value. Otherwise, Timeout returns an Error.

Futures and Streams

The exact behavor depends on if the inner value is a Future or a Stream. In the case of a Future, Timeout will require the future to complete by a fixed deadline. In the case of a Stream, Timeout will allow each item to take the entire timeout before returning an error.

In order to set an upper bound on the processing of the entire stream, then a timeout should be set on the future that processes the stream. For example:

// import the `timeout` function, usually this is done
// with `use tokio::prelude::*`
use tokio::prelude::FutureExt;
use futures::Stream;
use futures::sync::mpsc;
use std::time::Duration;

let (tx, rx) = mpsc::unbounded();

let process = rx.for_each(|item| {
    // do something with `item`
});

// Wrap the future with a `Timeout` set to expire in 10 milliseconds.
process.timeout(Duration::from_millis(10))

Cancelation

Cancelling a Timeout is done by dropping the value. No additional cleanup or other work is required.

The original future or stream may be obtained by calling Timeout::into_inner. This consumes the Timeout.

Implementations

impl<T> Timeout<T>

pub fn new(value: T, timeout: Duration) -> Timeout<T>

Create a new Timeout that allows value to execute for a duration of at most timeout.

The exact behavior depends on if value is a Future or a Stream.

See type level documentation for more details.

Examples

Create a new Timeout set to expire in 10 milliseconds.

use tokio::timer::Timeout;
use futures::Future;
use futures::sync::oneshot;
use std::time::Duration;

let (tx, rx) = oneshot::channel();

// Wrap the future with a `Timeout` set to expire in 10 milliseconds.
Timeout::new(rx, Duration::from_millis(10))

pub fn get_ref(&self) -> &T

Gets a reference to the underlying value in this timeout.

pub fn get_mut(&mut self) -> &mut T

Gets a mutable reference to the underlying value in this timeout.

pub fn into_inner(self) -> T

Consumes this timeout, returning the underlying value.

impl<T: Future> Timeout<T>

pub fn new_at(future: T, deadline: Instant) -> Timeout<T>

Create a new Timeout that completes when future completes or when deadline is reached.

This function differs from new in that:

• It only accepts Future arguments.
• It sets an explicit Instant at which the timeout expires.

Trait Implementations

impl<T: Debug> Debug for Timeout<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Future for Timeout<T>

where T: Future,

type Item = <T as Future>::Item

The type of value that this future will resolved with if it is successful.

type Error = Error<<T as Future>::Error>

The type of error that this future will resolve with if it fails in a normal fashion.

fn poll(&mut self) -> Poll<Self::Item, Self::Error>

Query this future to see if its value has become available, registering interest if it is not.

fn wait(self) -> Result<Self::Item, Self::Error>

where Self: Sized,

Block the current thread until this future is resolved.

fn map<F, U>(self, f: F) -> Map<Self, F>

where F: FnOnce(Self::Item) -> U, Self: Sized,

Map this future’s result to a different type, returning a new future of the resulting type.

fn map_err<F, E>(self, f: F) -> MapErr<Self, F>

where F: FnOnce(Self::Error) -> E, Self: Sized,

Map this future’s error to a different error, returning a new future.

fn from_err<E>(self) -> FromErr<Self, E>

where E: From<Self::Error>, Self: Sized,

Map this future’s error to any error implementing From for this future’s Error, returning a new future.

fn then<F, B>(self, f: F) -> Then<Self, B, F>

where F: FnOnce(Result<Self::Item, Self::Error>) -> B, B: IntoFuture, Self: Sized,

Chain on a computation for when a future finished, passing the result of the future to the provided closure f.

fn and_then<F, B>(self, f: F) -> AndThen<Self, B, F>

where F: FnOnce(Self::Item) -> B, B: IntoFuture<Error = Self::Error>, Self: Sized,

Execute another future after this one has resolved successfully.

fn or_else<F, B>(self, f: F) -> OrElse<Self, B, F>

where F: FnOnce(Self::Error) -> B, B: IntoFuture<Item = Self::Item>, Self: Sized,

Execute another future if this one resolves with an error.

fn select<B>(self, other: B) -> Select<Self, <B as IntoFuture>::Future>

where B: IntoFuture<Item = Self::Item, Error = Self::Error>, Self: Sized,

Waits for either one of two futures to complete.

fn select2<B>(self, other: B) -> Select2<Self, <B as IntoFuture>::Future>

where B: IntoFuture, Self: Sized,

Waits for either one of two differently-typed futures to complete.

fn join<B>(self, other: B) -> Join<Self, <B as IntoFuture>::Future>

where B: IntoFuture<Error = Self::Error>, Self: Sized,

Joins the result of two futures, waiting for them both to complete.

fn join3<B, C>( self, b: B, c: C, ) -> Join3<Self, <B as IntoFuture>::Future, <C as IntoFuture>::Future>

where B: IntoFuture<Error = Self::Error>, C: IntoFuture<Error = Self::Error>, Self: Sized,

Same as join, but with more futures.

fn join4<B, C, D>( self, b: B, c: C, d: D, ) -> Join4<Self, <B as IntoFuture>::Future, <C as IntoFuture>::Future, <D as IntoFuture>::Future>

where B: IntoFuture<Error = Self::Error>, C: IntoFuture<Error = Self::Error>, D: IntoFuture<Error = Self::Error>, Self: Sized,

Same as join, but with more futures.

fn join5<B, C, D, E>( self, b: B, c: C, d: D, e: E, ) -> Join5<Self, <B as IntoFuture>::Future, <C as IntoFuture>::Future, <D as IntoFuture>::Future, <E as IntoFuture>::Future>

where B: IntoFuture<Error = Self::Error>, C: IntoFuture<Error = Self::Error>, D: IntoFuture<Error = Self::Error>, E: IntoFuture<Error = Self::Error>, Self: Sized,

Same as join, but with more futures.

fn into_stream(self) -> IntoStream<Self>

where Self: Sized,

Convert this future into a single element stream.

fn flatten(self) -> Flatten<Self>

where Self::Item: IntoFuture, <Self::Item as IntoFuture>::Error: From<Self::Error>, Self: Sized,

Flatten the execution of this future when the successful result of this future is itself another future.

fn flatten_stream(self) -> FlattenStream<Self>

where Self::Item: Stream<Error = Self::Error>, Self: Sized,

Flatten the execution of this future when the successful result of this future is a stream.

fn fuse(self) -> Fuse<Self>

where Self: Sized,

Fuse a future such that poll will never again be called once it has completed.

fn inspect<F>(self, f: F) -> Inspect<Self, F>

where F: FnOnce(&Self::Item), Self: Sized,

Do something with the item of a future, passing it on.

fn catch_unwind(self) -> CatchUnwind<Self>

where Self: Sized + UnwindSafe,

Catches unwinding panics while polling the future.

fn shared(self) -> Shared<Self>

where Self: Sized,

Create a cloneable handle to this future where all handles will resolve to the same result.

impl<T> Stream for Timeout<T>

where T: Stream,

type Item = <T as Stream>::Item

The type of item this stream will yield on success.

type Error = Error<<T as Stream>::Error>

The type of error this stream may generate.

fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error>

Attempt to pull out the next value of this stream, returning None if the stream is finished.

fn wait(self) -> Wait<Self>

where Self: Sized,

Creates an iterator which blocks the current thread until each item of this stream is resolved.

fn into_future(self) -> StreamFuture<Self>

where Self: Sized,

Converts this stream into a Future.

fn map<U, F>(self, f: F) -> Map<Self, F>

where F: FnMut(Self::Item) -> U, Self: Sized,

Converts a stream of type T to a stream of type U.

fn map_err<U, F>(self, f: F) -> MapErr<Self, F>

where F: FnMut(Self::Error) -> U, Self: Sized,

Converts a stream of error type T to a stream of error type U.

fn filter<F>(self, f: F) -> Filter<Self, F>

where F: FnMut(&Self::Item) -> bool, Self: Sized,

Filters the values produced by this stream according to the provided predicate.

fn filter_map<F, B>(self, f: F) -> FilterMap<Self, F>

where F: FnMut(Self::Item) -> Option<B>, Self: Sized,

Filters the values produced by this stream while simultaneously mapping them to a different type.

fn then<F, U>(self, f: F) -> Then<Self, F, U>

where F: FnMut(Result<Self::Item, Self::Error>) -> U, U: IntoFuture, Self: Sized,

Chain on a computation for when a value is ready, passing the resulting item to the provided closure f.

fn and_then<F, U>(self, f: F) -> AndThen<Self, F, U>

where F: FnMut(Self::Item) -> U, U: IntoFuture<Error = Self::Error>, Self: Sized,

Chain on a computation for when a value is ready, passing the successful results to the provided closure f.

fn or_else<F, U>(self, f: F) -> OrElse<Self, F, U>

where F: FnMut(Self::Error) -> U, U: IntoFuture<Item = Self::Item>, Self: Sized,

Chain on a computation for when an error happens, passing the erroneous result to the provided closure f.

fn collect(self) -> Collect<Self>

where Self: Sized,

Collect all of the values of this stream into a vector, returning a future representing the result of that computation.

fn concat2(self) -> Concat2<Self>

where Self: Sized, Self::Item: Extend<<Self::Item as IntoIterator>::Item> + IntoIterator + Default,

Concatenate all results of a stream into a single extendable destination, returning a future representing the end result.

fn concat(self) -> Concat<Self>

where Self: Sized, Self::Item: Extend<<Self::Item as IntoIterator>::Item> + IntoIterator,

👎Deprecated since 0.1.14: please use Stream::concat2 instead

Concatenate all results of a stream into a single extendable destination, returning a future representing the end result.

fn fold<F, T, Fut>(self, init: T, f: F) -> Fold<Self, F, Fut, T>

where F: FnMut(T, Self::Item) -> Fut, Fut: IntoFuture<Item = T>, Self::Error: From<<Fut as IntoFuture>::Error>, Self: Sized,

Execute an accumulating computation over a stream, collecting all the values into one final result.

fn flatten(self) -> Flatten<Self>

where Self::Item: Stream, <Self::Item as Stream>::Error: From<Self::Error>, Self: Sized,

Flattens a stream of streams into just one continuous stream.

fn skip_while<P, R>(self, pred: P) -> SkipWhile<Self, P, R>

where P: FnMut(&Self::Item) -> R, R: IntoFuture<Item = bool, Error = Self::Error>, Self: Sized,

Skip elements on this stream while the predicate provided resolves to true.

fn take_while<P, R>(self, pred: P) -> TakeWhile<Self, P, R>

where P: FnMut(&Self::Item) -> R, R: IntoFuture<Item = bool, Error = Self::Error>, Self: Sized,

Take elements from this stream while the predicate provided resolves to true.

fn for_each<F, U>(self, f: F) -> ForEach<Self, F, U>

where F: FnMut(Self::Item) -> U, U: IntoFuture<Item = (), Error = Self::Error>, Self: Sized,

Runs this stream to completion, executing the provided closure for each element on the stream.

fn from_err<E>(self) -> FromErr<Self, E>

where E: From<Self::Error>, Self: Sized,

Map this stream’s error to any error implementing From for this stream’s Error, returning a new stream.

fn take(self, amt: u64) -> Take<Self>

where Self: Sized,

Creates a new stream of at most amt items of the underlying stream.

fn skip(self, amt: u64) -> Skip<Self>

where Self: Sized,

Creates a new stream which skips amt items of the underlying stream.

fn fuse(self) -> Fuse<Self>

where Self: Sized,

Fuse a stream such that poll will never again be called once it has finished.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Borrows a stream, rather than consuming it.

fn catch_unwind(self) -> CatchUnwind<Self>

where Self: Sized + UnwindSafe,

Catches unwinding panics while polling the stream.

fn buffered(self, amt: usize) -> Buffered<Self>

where Self::Item: IntoFuture<Error = Self::Error>, Self: Sized,

An adaptor for creating a buffered list of pending futures.

fn buffer_unordered(self, amt: usize) -> BufferUnordered<Self>

where Self::Item: IntoFuture<Error = Self::Error>, Self: Sized,

An adaptor for creating a buffered list of pending futures (unordered).

fn merge<S>(self, other: S) -> Merge<Self, S>

where S: Stream<Error = Self::Error>, Self: Sized,

👎Deprecated: functionality provided by select now

An adapter for merging the output of two streams.

fn zip<S>(self, other: S) -> Zip<Self, S>

where S: Stream<Error = Self::Error>, Self: Sized,

An adapter for zipping two streams together.

fn chain<S>(self, other: S) -> Chain<Self, S>

where S: Stream<Item = Self::Item, Error = Self::Error>, Self: Sized,

Adapter for chaining two stream.

fn peekable(self) -> Peekable<Self>

where Self: Sized,

Creates a new stream which exposes a peek method.

fn chunks(self, capacity: usize) -> Chunks<Self>

where Self: Sized,

An adaptor for chunking up items of the stream inside a vector.

fn select<S>(self, other: S) -> Select<Self, S>

where S: Stream<Item = Self::Item, Error = Self::Error>, Self: Sized,

Creates a stream that selects the next element from either this stream or the provided one, whichever is ready first.

fn forward<S>(self, sink: S) -> Forward<Self, S>

where S: Sink<SinkItem = Self::Item>, Self::Error: From<<S as Sink>::SinkError>, Self: Sized,

A future that completes after the given stream has been fully processed into the sink, including flushing.

fn inspect<F>(self, f: F) -> Inspect<Self, F>

where F: FnMut(&Self::Item), Self: Sized,

Do something with each item of this stream, afterwards passing it on.

fn inspect_err<F>(self, f: F) -> InspectErr<Self, F>

where F: FnMut(&Self::Error), Self: Sized,

Do something with the error of this stream, afterwards passing it on.