watchexec/lib/examples/readme.rs

use miette::{IntoDiagnostic, Result};
use watchexec::{
	action::{Action, Outcome},
	config::{InitConfig, RuntimeConfig},
	handler::PrintDebug,
	Watchexec,
};

#[tokio::main]
async fn main() -> Result<()> {
	let mut init = InitConfig::default();
	init.on_error(PrintDebug(std::io::stderr()));

	let mut runtime = RuntimeConfig::default();
	runtime.pathset(["watchexec.conf"]);

	let conf = YourConfigFormat::load_from_file("watchexec.conf")
		.await
		.into_diagnostic()?;
	conf.apply(&mut runtime);

	let we = Watchexec::new(init, runtime.clone())?;
	let w = we.clone();

	let c = runtime.clone();
	runtime.on_action(move |action: Action| {
		let mut c = c.clone();
		let w = w.clone();
		async move {
			for event in action.events.iter() {
				if event.paths().any(|(p, _)| p.ends_with("/watchexec.conf")) {
					let conf = YourConfigFormat::load_from_file("watchexec.conf").await?;

					conf.apply(&mut c);
					let _ = w.reconfigure(c.clone());
					// tada! self-reconfiguring watchexec on config file change!

					break;
				}
			}

			action.outcome(Outcome::if_running(
				Outcome::DoNothing,
				Outcome::both(Outcome::Clear, Outcome::Start),
			));

			Ok::<(), std::io::Error>(())
		}
	});

	let _ = we.main().await.into_diagnostic()?;
	Ok(())
}

struct YourConfigFormat;
impl YourConfigFormat {
	async fn load_from_file(_path: impl AsRef<std::path::Path>) -> std::io::Result<Self> {
		Ok(Self)
	}

	fn apply(&self, _config: &mut RuntimeConfig) {
		// ...
	}
}