Struct tk_listen::BindMany

pub struct BindMany<S> { /* private fields */ }

This stream replaces tokio_core::net::Incoming and listens many sockets

It receives a stream of lists of addresses as an input. When a new value received on a stream it adapts:

1. Removes sockets not in set we’re already received (already established connections aren’t interfered in any way)
2. Adds sockets to set which wasn’t listened before

Instead of failing on bind error it logs the error and retries in a second (you can change the delay using BindMany::retry_interval)

It’s good idea to pass a stream with a Void error, because on receiving error BindMany will log a message (that doesn’t contain an error) and will shutdown. It’s better to log specific error and send end-of-stream instead, but that is user’s responsibility.

Note: we track identity of the sockets by SocketAddr used to bind it, this means 0.0.0.0 and 127.0.0.1 for example can be bound/unbound independently despite the fact that 0.0.0.0 can accept connections for 127.0.0.1.

Example

Simple example:

  lp.run(
      BindMany::new(address_stream)
      .sleep_on_error(TIME_TO_WAIT_ON_ERROR, &h2)
      .map(move |(mut socket, _addr)| {
           // Your future is here:
           Proto::new(socket)
           // Errors should not pass silently
           // common idea is to log them
           .map_err(|e| error!("Protocol error: {}", e))
      })
      .listen(MAX_SIMULTANEOUS_CONNECTIONS)
  ).unwrap(); // stream doesn't end in this case

Example using name resolution via abstract-ns + ns-env-config:

    extern crate ns_env_config;

    let mut lp = Core::new().unwrap();
    let ns = ns_env_config::init(&lp.handle()).unwrap();
    lp.run(
        BindMany::new(ns.resolve_auto("localhost", 8080)
           .map(|addr| addr.addresses_at(0)))
        .sleep_on_error(TIME_TO_WAIT_ON_ERROR, &h2)
        .map(move |(mut socket, _addr)| {
             // Your future is here:
             Proto::new(socket)
             // Errors should not pass silently
             // common idea is to log them
             .map_err(|e| eprintln!("Protocol error: {}", e))
        })
        .listen(MAX_SIMULTANEOUS_CONNECTIONS)
    ).unwrap(); // stream doesn't end in this case

Implementations

impl<S> BindMany<S>

pub fn new(s: S) -> BindMany<S>

Create a new instance

pub fn retry_interval(&mut self, interval: Duration) -> &mut Self

Sets the retry interval

Each time binding socket fails (including he first one on start) istead of immediately failing we log the error and sleep this interval to retry (by default 1 second).

This behavior is important because if your configuration changes number of listening sockets, and one of them is either invalid or just DNS is temporarily down, you still need to serve other addresses.

This also helps if you have failover IP which can only be listened at when IP attached to the host, but server must be ready to listen it anyway (this one might be better achieved by non-local bind though).

Trait Implementations

impl<S> Stream for BindMany<S>where
    S: Stream,
    S::Item: IntoIterator<Item = SocketAddr>,

type Item = TcpStream

The type of item this stream will yield on success.

type Error = Error

The type of error this stream may generate.

fn poll(&mut self) -> Result<Async<Option<Self::Item>>, 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 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 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 Selfwhere
    Self: Sized,

Borrows a stream, rather than consuming it.

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.