Struct async_local::runtime::Builder

pub struct Builder { /* private fields */ }

Available on crate features tokio-runtime or barrier-protected-runtime only.

Builds Tokio runtime configured with a shutdown barrier

Implementations

impl Builder

pub fn new_current_thread() -> Builder

Returns a new builder with the current thread scheduler selected.

pub fn new_multi_thread() -> Builder

Returns a new builder with the multi thread scheduler selected.

pub fn enable_all(&mut self) -> &mut Self

Enables both I/O and time drivers.

pub fn worker_threads(&mut self, val: usize) -> &mut Self

Sets the number of worker threads the Runtime will use.

This can be any number above 0 though it is advised to keep this value on the smaller side.

This will override the value read from environment variable TOKIO_WORKER_THREADS.

Default

The default value is the number of cores available to the system.

When using the current_thread runtime this method has no effect.

Examples

Multi threaded runtime with 4 threads

use async_local::runtime;

// This will spawn a work-stealing runtime with 4 worker threads.
let rt = runtime::Builder::new_multi_thread()
  .worker_threads(4)
  .build()
  .unwrap();

rt.spawn(async move {});

Current thread runtime (will only run on the current thread via Runtime::block_on)

use async_local::runtime;

// Create a runtime that _must_ be driven from a call
// to `Runtime::block_on`.
let rt = runtime::Builder::new_current_thread().build().unwrap();

// This will run the runtime and future on the current thread
rt.block_on(async move {});

Panics

This will panic if val is not larger than 0.

pub fn build(&mut self) -> Result<Runtime>

Creates a Tokio Runtime configured with a barrier that rendezvous worker threads during shutdown as to ensure tasks never outlive local data owned by worker threads