Overseer

Cargo.toml

@@ -27,6 +27,7 @@ members = [
 	"erasure-coding",
 	"network",
 	"network/test",
+	"overseer",
 	"primitives",
 	"runtime/common",
 	"runtime/polkadot",

overseer/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "overseer"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+
+[dependencies]
+futures = "0.3.5"
+log = "0.4.8"
+
+[dev-dependencies]
+futures = { version = "0.3.5", features = ["thread-pool"] }
+futures-timer = "3.0.2"
+femme = "2.0.1"
+log = "0.4.8"
+kv-log-macro = "1.0.6"

overseer/examples/minimal-example.rs

@@ -0,0 +1,133 @@
+// Copyright 2020 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Shows a basic usage of the `Overseer`:
+//!   * Spawning subsystems and subsystem child jobs
+//!   * Establishing message passing
+
+use std::time::Duration;
+use futures::{pending, executor};
+use futures_timer::Delay;
+use kv_log_macro as log;
+
+use overseer::{Overseer, Subsystem, SubsystemContext, SubsystemJob};
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq, std::hash::Hash)]
+pub enum SubsystemId {
+	Subsystem1,
+	Subsystem2,
+	Subsystem3,
+}
+
+struct Subsystem1;
+
+impl Subsystem1 {
+	async fn run(mut ctx: SubsystemContext<usize, SubsystemId>)  {
+		loop {
+			match ctx.try_recv().await {
+				Ok(Some(msg)) => {
+					log::info!("Subsystem1 received message {}", msg);
+				}
+				Ok(None) => (),
+				Err(_) => {}
+			}
+
+			Delay::new(Duration::from_secs(1)).await;
+			ctx.send_msg(10).await;
+		}
+	}
+
+	fn new() -> Self {
+		Self
+	}
+}
+
+impl Subsystem<usize, SubsystemId> for Subsystem1 {
+	fn start(&mut self, ctx: SubsystemContext<usize, SubsystemId>) -> SubsystemJob {
+		SubsystemJob(Box::pin(async move {
+			Self::run(ctx).await;
+		}))
+	}
+}
+
+struct Subsystem2;
+
+impl Subsystem2 {
+	async fn run(mut ctx: SubsystemContext<usize, SubsystemId>)  {
+		let ss3 = Box::new(Subsystem3);
+
+		let ss3_id = ctx.spawn((SubsystemId::Subsystem3, ss3)).await;
+		log::info!("Received subsystem id {:?}", ss3_id);
+		loop {
+			match ctx.try_recv().await {
+				Ok(Some(msg)) => {
+					log::info!("Subsystem2 received message {}", msg);
+					continue;
+				}
+				Ok(None) => { pending!(); }
+				Err(_) => {}
+			}
+		}
+	}
+
+	fn new() -> Self {
+		Self
+	}
+}
+
+impl Subsystem<usize, SubsystemId> for Subsystem2 {
+	fn start(&mut self, ctx: SubsystemContext<usize, SubsystemId>) -> SubsystemJob {
+		SubsystemJob(Box::pin(async move {
+			Self::run(ctx).await;
+		}))
+	}
+}
+
+struct Subsystem3;
+
+impl Subsystem<usize, SubsystemId> for Subsystem3 {
+	fn start(&mut self, mut ctx: SubsystemContext<usize, SubsystemId>) -> SubsystemJob {
+		SubsystemJob(Box::pin(async move {
+			// TODO: ctx actually has to be used otherwise the channels are dropped
+			loop {
+				// ignore all incoming msgs
+				while let Ok(Some(_)) = ctx.try_recv().await {
+				}
+				log::info!("Subsystem3 tick");
+				Delay::new(Duration::from_secs(1)).await;
+
+				pending!();
+			}
+		}))
+	}
+
+	fn can_recv_msg(&self, _msg: &usize) -> bool { false }
+}
+
+fn main() {
+	femme::with_level(femme::LevelFilter::Trace);
+	let spawner = executor::ThreadPool::new().unwrap();
+
+	futures::executor::block_on(async {
+		let subsystems: Vec<(SubsystemId, Box<dyn Subsystem<usize, SubsystemId> + Send>)> = vec![
+			(SubsystemId::Subsystem1, Box::new(Subsystem1::new())),
+			(SubsystemId::Subsystem2, Box::new(Subsystem2::new())),
+		];
+
+		let overseer = Overseer::new(subsystems, spawner);
+		overseer.run().await;
+	});
+}