moleculer-rs — work in progress

Inspired and compatible with Moleculer JS

You can currently do all the basics of emit, broadcast and call.

However it only works with the NATS transporter and JSON serializer/deserializer.

Getting Started

Available on crates: crates.io/moleculer

Simple example showing how to receive an event, for more check the examples folder

#[tokio::main]
async fn main() -> eyre::Result<()> {
    env_logger::init();
    color_eyre::install()?;

    // build config
    let config = ConfigBuilder {
        transporter: Transporter::nats("nats://localhost:4222"),
        ..ConfigBuilder::default()
    }
    .build();

    // create the first event
    let print_hi = EventBuilder::new("printHi").add_callback(print_hi).build();

    // create the second event
    let print_name = EventBuilder::new("printName")
        .add_callback(print_name)
        .build();

    // create a service with events
    let greeter_service = Service::new("rustGreeter")
        .add_event(print_hi)
        .add_event(print_name);

    // create service broker with service
    let service_broker = ServiceBroker::new(config).add_service(greeter_service);

    // start the service broker
    service_broker.start().await;

    Ok(())
}

// callback for first event, will be called whenever "printHi" event is received
fn print_hi(_ctx: Context<Event>) -> Result<(), Box<dyn Error>> {
    println!("Hello from Rust");
    Ok(())
}

// callback for second event, will be called whenever "printName" event is received
fn print_name(ctx: Context<Event>) -> Result<(), Box<dyn Error>> {
    let msg: PrintNameMessage = serde_json::from_value(ctx.params)?;

    println!("Hello to: {} from Rust", msg.name);

    Ok(())
}

#[derive(Deserialize)]
struct PrintNameMessage {
    name: String,
}

Current Status

What it does

• Is discoverable by other moleculer clients
• Only NATS transporter
• Only JSON serialization/deserialization
• Can emit and broadcast events
• Can respond to events from other molecular clients using callbacks (see: simple event example)
• Can create actions, and respond to requests (#19)
• Can call to send request and wait for response (#20)

Big missing pieces:

• Documentation #16
• Tests #17