4 releases (2 breaking)

✓ Uses Rust 2018 edition

0.3.1 Oct 7, 2019
0.3.0 Sep 23, 2019
0.2.0 Sep 17, 2019
0.1.0 Sep 17, 2019

#159 in Asynchronous

31 downloads per month

MIT/Apache

125KB
2.5K SLoC

Rants

crates.io docs License License

An async NATS client library for the Rust programming language.

Note: Currently, rants requires a nightly version of the Rust compiler due to its use of async/await syntax, but it should work on stable soon!

The client aims to be an ergonomic, yet thin, wrapper over the NATS client protocol. The easiest way to learn to use the client is by reading the NATS client protocol documentation. The main entry point into the library's API is the Client struct.

Example

use futures::stream::StreamExt;
use rants::Client;
use tokio::runtime::Runtime;

let main_future = async {
   // A NATS server must be running on `127.0.0.1:4222`
   let address = "127.0.0.1:4222".parse().unwrap();
   let client = Client::new(vec![address]);

   // Configure the client to receive messages even if it sent the message
   client.connect_mut().await.echo(true);

   // Connect to the server
   client.connect().await;

   // Create a new subject called "test"
   let subject = "test".parse().unwrap();

   // Subscribe to the "test" subject
   let (_, mut subscription) = client.subscribe(&subject, 1024).await.unwrap();

   // Publish a message to the "test" subject
   client
       .publish(&subject, b"This is a message!")
       .await
       .unwrap();

   // Read a message from the subscription
   let message = subscription.next().await.unwrap();
   let message = String::from_utf8(message.into_payload()).unwrap();
   println!("Received '{}'", message);

   // Disconnect from the server
   client.disconnect().await;
};

let runtime = Runtime::new().expect("to create Runtime");
runtime.spawn(main_future);
runtime.shutdown_on_idle();

Development

The integration test suite requires the NATS server to be reachable at 127.0.0.1:4222:

> cargo test

The env_logger crate is used in integration test. To enable it and run a single test run:

> RUST_LOG=rants=trace cargo test ping_pong

Roadmap

  • Increase test coverage
  • TLS support
  • Explore automatically disconnecting the client when it is dropped
  • Support improved request-reply implementation
  • Benchmarks and performance

Alternatives

Dependencies

~4.5MB
~85K SLoC