Crate timely_communication
source ·Expand description
A simple communication infrastructure providing typed exchange channels.
This crate is part of the timely dataflow system, used primarily for its inter-worker communication. It may be independently useful, but it is separated out mostly to make clear boundaries in the project.
Threads are spawned with an allocator::Generic
, whose
allocate
method returns a pair of several send endpoints and one
receive endpoint. Messages sent into a send endpoint will eventually be received by the corresponding worker,
if it receives often enough. The point-to-point channels are each FIFO, but with no fairness guarantees.
To be communicated, a type must implement the Serialize
trait when using the
bincode
feature or the Abomonation
trait when not.
Channel endpoints also implement a lower-level push
and pull
interface (through the Push
and Pull
traits), which is used for more precise control of resources.
Examples
use timely_communication::Allocate;
// configure for two threads, just one process.
let config = timely_communication::Config::Process(2);
// initializes communication, spawns workers
let guards = timely_communication::initialize(config, |mut allocator| {
println!("worker {} started", allocator.index());
// allocates a pair of senders list and one receiver.
let (mut senders, mut receiver) = allocator.allocate(0);
// send typed data along each channel
use timely_communication::Message;
senders[0].send(Message::from_typed(format!("hello, {}", 0)));
senders[1].send(Message::from_typed(format!("hello, {}", 1)));
// no support for termination notification,
// we have to count down ourselves.
let mut expecting = 2;
while expecting > 0 {
allocator.receive();
if let Some(message) = receiver.recv() {
use std::ops::Deref;
println!("worker {}: received: <{}>", allocator.index(), message.deref());
expecting -= 1;
}
allocator.release();
}
// optionally, return something
allocator.index()
});
// computation runs until guards are joined or dropped.
if let Ok(guards) = guards {
for guard in guards.join() {
println!("result: {:?}", guard);
}
}
else { println!("error in computation"); }
The should produce output like:
worker 0 started
worker 1 started
worker 0: received: <hello, 0>
worker 1: received: <hello, 1>
worker 0: received: <hello, 0>
worker 1: received: <hello, 1>
result: Ok(0)
result: Ok(1)
Re-exports
pub use allocator::Generic as Allocator;
pub use allocator::Allocate;
pub use initialize::initialize;
pub use initialize::initialize_from;
pub use initialize::Config;
pub use initialize::WorkerGuards;
pub use message::Message;
Modules
- Types and traits for the allocation of channels.
- A type that can unpark specific threads.
- Initialization logic for a generic instance of the
Allocate
channel allocation trait. - Configuration and events for communication logging.
- Types wrapping typed data.
- Networking code for sending and receiving fixed size
Vec<u8>
between machines.
Traits
- A composite trait for types that may be used with channels.
- Pulling elements of type
T
. - Pushing elements of type
T
.