Module tarantool::fiber::async::watch

A single-producer, multi-consumer channel that only retains the last sent value.

This channel is useful for watching for changes to a value from multiple points in the code base, for example, changes to configuration values.

Usage

channel returns a Sender / Receiver pair. These are the producer and sender halves of the channel. The channel is created with an initial value. The latest value stored in the channel is accessed with Receiver::borrow(). Awaiting Receiver::changed() waits for a new value to sent by the Sender half.

Example

use tarantool::fiber::r#async::watch;
use tarantool::fiber;

let (tx, mut rx) = watch::channel::<i32>(10);
tx.send(20).unwrap();
let value = fiber::block_on(async move {
    rx.changed().await.unwrap();
    rx.get()
});

Closing

Sender::is_closed allows the producer to detect when all Receiver handles have been dropped. This indicates that there is no further interest in the values being produced and work can be stopped.

Structs

Notification

Future that returns when a new value is published in Sender.

Receiver

Receives values from the associated Sender.

SendError

Error produced when sending a value fails.

Sender

Sends values to the associated Receiver.

Value

ValueRef

Returns a reference to the inner value.

Functions

channel

Creates a new watch channel, returning the “send” and “receive” handles.