Repeated events

Events are once by default. Set multi: true when one entity instance may emit the same event repeatedly.

YAML model

quent: alpha
model: repeated_events

entities:
  Task:
    events:
      started:
        attributes:
          command: string
      progress:
        multi: true
        attributes:
          items_processed: u64
      ended:
        attributes:
          success: bool

Instrumentation API

The same Task handle emits progress more than once. Repeating started or ended on that handle would return an error.

// SPDX-FileCopyrightText: Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
// SPDX-License-Identifier: Apache-2.0

#[allow(unused)]
mod instrumentation {
    include!(concat!(env!("OUT_DIR"), "/repeated_events.rs"));
}

use instrumentation::{Context, Noop, RepeatedEvents, Task};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let context = Context::<RepeatedEvents>::try_new(Noop)?;
    let mut task = context.observer::<Task>().handle();

    task.started("compile".to_owned())?;
    // `started` is a once event, so a second call would return an error.
    // task.started("compile".to_owned())?;
    task.progress(64)?;
    task.progress(128)?;
    task.ended(true)?;

    Ok(())
}