netapp/src/util.rs

use serde::Serialize;

use log::info;

use tokio::sync::watch;

pub type NodeID = sodiumoxide::crypto::sign::ed25519::PublicKey;

/// Utility function: encodes any serializable value in MessagePack binary format
/// using the RMP library.
///
/// Field names and variant names are included in the serialization.
/// This is used internally by the netapp communication protocol.
pub fn rmp_to_vec_all_named<T>(val: &T) -> Result<Vec<u8>, rmp_serde::encode::Error>
where
	T: Serialize + ?Sized,
{
	let mut wr = Vec::with_capacity(128);
	let mut se = rmp_serde::Serializer::new(&mut wr)
		.with_struct_map()
		.with_string_variants();
	val.serialize(&mut se)?;
	Ok(wr)
}

/// This async function returns only when a true signal was received
/// from a watcher that tells us when to exit.
/// Usefull in a select statement to interrupt another
/// future:
/// ```
/// select!(
///     _ = a_long_task() => Success,
///     _ = await_exit(must_exit) => Interrupted,
/// )
/// ```
pub async fn await_exit(mut must_exit: watch::Receiver<bool>) {
	while !*must_exit.borrow_and_update() {
		if must_exit.changed().await.is_err() {
			break;
		}
	}
}

pub fn watch_ctrl_c() -> watch::Receiver<bool> {
	let (send_cancel, watch_cancel) = watch::channel(false);
	tokio::spawn(async move {
		tokio::signal::ctrl_c()
			.await
			.expect("failed to install CTRL+C signal handler");
		info!("Received CTRL+C, shutting down.");
		send_cancel.send(true).unwrap();
	});
	watch_cancel
}