Merge commit '392447f5c8f986ded2559a78457f4cd87942f393' into update-bridges-subtree-r/w

2026-05-31 12:11:02 +00:00 · 2021-12-01 09:46:14 +01:00
parent e16f71b7b6 392447f5c8
commit 5228731ae8
321 changed files with 28385 additions and 10466 deletions
@@ -0,0 +1,243 @@
+// Copyright 2019-2021 Parity Technologies (UK) Ltd.
+// This file is part of Parity Bridges Common.
+
+// Parity Bridges Common 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.
+
+// Parity Bridges Common 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 Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Tools for updating conversion rate that is stored in the runtime storage.
+
+use relay_utils::metrics::F64SharedRef;
+use std::{future::Future, time::Duration};
+
+/// Duration between updater iterations.
+const SLEEP_DURATION: Duration = Duration::from_secs(60);
+
+/// Update-conversion-rate transaction status.
+#[derive(Debug, Clone, Copy, PartialEq)]
+enum TransactionStatus {
+	/// We have not submitted any transaction recently.
+	Idle,
+	/// We have recently submitted transaction that should update conversion rate.
+	Submitted(f64),
+}
+
+/// Run infinite conversion rate updater loop.
+///
+/// The loop is maintaining the Left -> Right conversion rate, used as `RightTokens = LeftTokens *
+/// Rate`.
+pub fn run_conversion_rate_update_loop<
+	SubmitConversionRateFuture: Future<Output = anyhow::Result<()>> + Send + 'static,
+>(
+	left_to_right_stored_conversion_rate: F64SharedRef,
+	left_to_base_conversion_rate: F64SharedRef,
+	right_to_base_conversion_rate: F64SharedRef,
+	max_difference_ratio: f64,
+	submit_conversion_rate: impl Fn(f64) -> SubmitConversionRateFuture + Send + 'static,
+) {
+	async_std::task::spawn(async move {
+		let mut transaction_status = TransactionStatus::Idle;
+		loop {
+			async_std::task::sleep(SLEEP_DURATION).await;
+			let maybe_new_conversion_rate = maybe_select_new_conversion_rate(
+				&mut transaction_status,
+				&left_to_right_stored_conversion_rate,
+				&left_to_base_conversion_rate,
+				&right_to_base_conversion_rate,
+				max_difference_ratio,
+			)
+			.await;
+			if let Some((prev_conversion_rate, new_conversion_rate)) = maybe_new_conversion_rate {
+				let submit_conversion_rate_future = submit_conversion_rate(new_conversion_rate);
+				match submit_conversion_rate_future.await {
+					Ok(()) => {
+						transaction_status = TransactionStatus::Submitted(prev_conversion_rate);
+					},
+					Err(error) => {
+						log::trace!(target: "bridge", "Failed to submit conversion rate update transaction: {:?}", error);
+					},
+				}
+			}
+		}
+	});
+}
+
+/// Select new conversion rate to submit to the node.
+async fn maybe_select_new_conversion_rate(
+	transaction_status: &mut TransactionStatus,
+	left_to_right_stored_conversion_rate: &F64SharedRef,
+	left_to_base_conversion_rate: &F64SharedRef,
+	right_to_base_conversion_rate: &F64SharedRef,
+	max_difference_ratio: f64,
+) -> Option<(f64, f64)> {
+	let left_to_right_stored_conversion_rate =
+		(*left_to_right_stored_conversion_rate.read().await)?;
+	match *transaction_status {
+		TransactionStatus::Idle => (),
+		TransactionStatus::Submitted(previous_left_to_right_stored_conversion_rate) => {
+			// we can't compare float values from different sources directly, so we only care
+			// whether the stored rate has been changed or not. If it has been changed, then we
+			// assume that our proposal has been accepted.
+			//
+			// float comparison is ok here, because we compare same-origin (stored in runtime
+			// storage) values and if they are different, it means that the value has actually been
+			// updated
+			#[allow(clippy::float_cmp)]
+			if previous_left_to_right_stored_conversion_rate == left_to_right_stored_conversion_rate
+			{
+				// the rate has not been changed => we won't submit any transactions until it is
+				// accepted, or the rate is changed by someone else
+				return None
+			}
+
+			*transaction_status = TransactionStatus::Idle;
+		},
+	}
+
+	let left_to_base_conversion_rate = (*left_to_base_conversion_rate.read().await)?;
+	let right_to_base_conversion_rate = (*right_to_base_conversion_rate.read().await)?;
+	let actual_left_to_right_conversion_rate =
+		right_to_base_conversion_rate / left_to_base_conversion_rate;
+
+	let rate_difference =
+		(actual_left_to_right_conversion_rate - left_to_right_stored_conversion_rate).abs();
+	let rate_difference_ratio = rate_difference / left_to_right_stored_conversion_rate;
+	if rate_difference_ratio < max_difference_ratio {
+		return None
+	}
+
+	Some((left_to_right_stored_conversion_rate, actual_left_to_right_conversion_rate))
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use async_std::sync::{Arc, RwLock};
+
+	fn test_maybe_select_new_conversion_rate(
+		mut transaction_status: TransactionStatus,
+		stored_conversion_rate: Option<f64>,
+		left_to_base_conversion_rate: Option<f64>,
+		right_to_base_conversion_rate: Option<f64>,
+		max_difference_ratio: f64,
+	) -> (Option<(f64, f64)>, TransactionStatus) {
+		let stored_conversion_rate = Arc::new(RwLock::new(stored_conversion_rate));
+		let left_to_base_conversion_rate = Arc::new(RwLock::new(left_to_base_conversion_rate));
+		let right_to_base_conversion_rate = Arc::new(RwLock::new(right_to_base_conversion_rate));
+		let result = async_std::task::block_on(maybe_select_new_conversion_rate(
+			&mut transaction_status,
+			&stored_conversion_rate,
+			&left_to_base_conversion_rate,
+			&right_to_base_conversion_rate,
+			max_difference_ratio,
+		));
+		(result, transaction_status)
+	}
+
+	#[test]
+	fn rate_is_not_updated_when_transaction_is_submitted() {
+		assert_eq!(
+			test_maybe_select_new_conversion_rate(
+				TransactionStatus::Submitted(10.0),
+				Some(10.0),
+				Some(1.0),
+				Some(1.0),
+				0.0
+			),
+			(None, TransactionStatus::Submitted(10.0)),
+		);
+	}
+
+	#[test]
+	fn transaction_state_is_changed_to_idle_when_stored_rate_shanges() {
+		assert_eq!(
+			test_maybe_select_new_conversion_rate(
+				TransactionStatus::Submitted(1.0),
+				Some(10.0),
+				Some(1.0),
+				Some(1.0),
+				100.0
+			),
+			(None, TransactionStatus::Idle),
+		);
+	}
+
+	#[test]
+	fn transaction_is_not_submitted_when_left_to_base_rate_is_unknown() {
+		assert_eq!(
+			test_maybe_select_new_conversion_rate(
+				TransactionStatus::Idle,
+				Some(10.0),
+				None,
+				Some(1.0),
+				0.0
+			),
+			(None, TransactionStatus::Idle),
+		);
+	}
+
+	#[test]
+	fn transaction_is_not_submitted_when_right_to_base_rate_is_unknown() {
+		assert_eq!(
+			test_maybe_select_new_conversion_rate(
+				TransactionStatus::Idle,
+				Some(10.0),
+				Some(1.0),
+				None,
+				0.0
+			),
+			(None, TransactionStatus::Idle),
+		);
+	}
+
+	#[test]
+	fn transaction_is_not_submitted_when_stored_rate_is_unknown() {
+		assert_eq!(
+			test_maybe_select_new_conversion_rate(
+				TransactionStatus::Idle,
+				None,
+				Some(1.0),
+				Some(1.0),
+				0.0
+			),
+			(None, TransactionStatus::Idle),
+		);
+	}
+
+	#[test]
+	fn transaction_is_not_submitted_when_difference_is_below_threshold() {
+		assert_eq!(
+			test_maybe_select_new_conversion_rate(
+				TransactionStatus::Idle,
+				Some(1.0),
+				Some(1.0),
+				Some(1.01),
+				0.02
+			),
+			(None, TransactionStatus::Idle),
+		);
+	}
+
+	#[test]
+	fn transaction_is_submitted_when_difference_is_above_threshold() {
+		assert_eq!(
+			test_maybe_select_new_conversion_rate(
+				TransactionStatus::Idle,
+				Some(1.0),
+				Some(1.0),
+				Some(1.03),
+				0.02
+			),
+			(Some((1.0, 1.03)), TransactionStatus::Idle),
+		);
+	}
+}