Crate stream_throttle

Provides a Stream combinator, to limit the rate at which items are produced.

Key Features

• Throttling is implemented via poll(), and not via any sort of buffering.
• The throttling behaviour can be applied to both Stream’s and Future’s.
• Multiple streams/futures can be throttled together as a group.
• Feature flags to use various timer implementations.

Feature Flags

• timer-tokio: Uses the tokio::time::delay_for() timer (default).
• timer-futures-timer: Uses the futures_timer::Delay timer.

If you don’t use the default timer (tokio), make sure to set default-features = false in your Cargo.toml, when you add stream_throttle as a dependency.

Example throttling of Stream

// allow no more than 5 items every 1 second
let rate = ThrottleRate::new(5, Duration::new(1, 0));
let pool = ThrottlePool::new(rate);

let work = futures::stream::repeat(())
  .throttle(pool)
  .then(|_| futures::future::ready("do something else"))
  .for_each(|_| futures::future::ready(()));

futures::executor::block_on(work);

Example throttling of Future

let rate = ThrottleRate::new(5, Duration::new(1, 0));
let pool = ThrottlePool::new(rate);

let work = pool.queue()
  .then(|_| futures::future::ready("do something else"));

futures::executor::block_on(work);

Structs

ThrottlePool	A clonable object which is used to throttle one or more streams, according to a shared rate.
ThrottleRate	Defines the the throttle rate.
Throttled	A stream combinator which throttles its elements via a shared ThrottlePool.

Traits

ThrottledStream

Provides a throttle() method on all Stream’s.