Companion for Substrate#8526 (#2845)

* Update branch * Make it compile * Compile * gate approval-checking logic (#2470) * Fix build * Updates * Fix merge * Adds missing crate * Companion for Substrate#8386 https://github.com/paritytech/substrate/pull/8386 * Fix fix fix * Fix * Fix compilation * Rewrite to `ParachainsInherentDataProvider` * Make it compile * Renamings * Revert stuff * Remove stale file * Guide updates * Update node/core/parachains-inherent/src/lib.rs Co-authored-by: Andronik Ordian <write@reusable.software> * Update node/core/parachains-inherent/src/lib.rs Co-authored-by: Andronik Ordian <write@reusable.software> * Apply suggestions from code review * Reset accidental changes * More * Remove stale file * update Substrate Co-authored-by: Robert Habermeier <rphmeier@gmail.com> Co-authored-by: Andronik Ordian <write@reusable.software> Co-authored-by: parity-processbot <>
2026-05-30 15:11:02 +00:00 · 2021-05-03 17:21:13 +02:00
parent 774d612eef
commit 7830bae524
16 changed files with 402 additions and 549 deletions
@@ -0,0 +1,138 @@
+// Copyright 2021 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/>.
+
+//! The parachain inherent data provider
+//!
+//! Parachain backing and approval is an off-chain process, but the parachain needs to progress on chain as well. To
+//! make it progress on chain a block producer needs to forward information about the state of a parachain to the
+//! runtime. This information is forwarded through an inherent to the runtime. Here we provide the
+//! [`ParachainInherentDataProvider`] that requests the relevant data from the provisioner subsystem and creates the
+//! the inherent data that the runtime will use to create an inherent.
+
+#![deny(unused_crate_dependencies, unused_results)]
+
+use futures::{select, FutureExt};
+use polkadot_node_subsystem::{
+	messages::{AllMessages, ProvisionerMessage}, SubsystemError,
+};
+use polkadot_overseer::OverseerHandler;
+use polkadot_primitives::v1::{
+	Block, Hash, InherentData as ParachainsInherentData,
+};
+use sp_blockchain::HeaderBackend;
+use sp_runtime::generic::BlockId;
+use std::time;
+
+/// How long to wait for the provisioner, before giving up.
+const PROVISIONER_TIMEOUT: time::Duration = core::time::Duration::from_millis(2500);
+
+/// Provides the parachains inherent data.
+pub struct ParachainsInherentDataProvider {
+	inherent_data: ParachainsInherentData,
+}
+
+impl ParachainsInherentDataProvider {
+	/// Create a new instance of the [`ParachainsInherentDataProvider`].
+	pub async fn create<C: HeaderBackend<Block>>(
+		client: &C,
+		mut overseer: OverseerHandler,
+		parent: Hash,
+	) -> Result<Self, Error> {
+		let pid = async {
+			let (sender, receiver) = futures::channel::oneshot::channel();
+			overseer.wait_for_activation(parent, sender).await;
+			receiver.await.map_err(|_| Error::ClosedChannelAwaitingActivation)?.map_err(Error::Subsystem)?;
+
+			let (sender, receiver) = futures::channel::oneshot::channel();
+			overseer.send_msg(AllMessages::Provisioner(
+				ProvisionerMessage::RequestInherentData(parent, sender),
+			)).await;
+
+			receiver.await.map_err(|_| Error::ClosedChannelAwaitingInherentData)
+		};
+
+		let mut timeout = futures_timer::Delay::new(PROVISIONER_TIMEOUT).fuse();
+
+		let parent_header = match client.header(BlockId::Hash(parent)) {
+			Ok(Some(h)) => h,
+			Ok(None) => return Err(Error::ParentHeaderNotFound(parent)),
+			Err(err) => return Err(Error::Blockchain(err)),
+		};
+
+		let res = select! {
+			pid = pid.fuse() => pid,
+			_ = timeout => Err(Error::Timeout),
+		};
+
+		let inherent_data = match res {
+			Ok(pd) => ParachainsInherentData {
+				bitfields: pd.bitfields,
+				backed_candidates: pd.backed_candidates,
+				disputes: pd.disputes,
+				parent_header,
+			},
+			Err(err) => {
+				tracing::debug!(
+					?err,
+					"Could not get provisioner inherent data; injecting default data",
+				);
+				ParachainsInherentData {
+					bitfields: Vec::new(),
+					backed_candidates: Vec::new(),
+					disputes: Vec::new(),
+					parent_header,
+				}
+			}
+		};
+
+		Ok(Self { inherent_data })
+	}
+}
+
+#[async_trait::async_trait]
+impl sp_inherents::InherentDataProvider for ParachainsInherentDataProvider {
+	fn provide_inherent_data(&self, inherent_data: &mut sp_inherents::InherentData) -> Result<(), sp_inherents::Error> {
+		inherent_data.put_data(
+			polkadot_primitives::v1::PARACHAINS_INHERENT_IDENTIFIER,
+			&self.inherent_data,
+		)
+	}
+
+	async fn try_handle_error(
+		&self,
+		_: &sp_inherents::InherentIdentifier,
+		_: &[u8],
+	) -> Option<Result<(), sp_inherents::Error>> {
+		// Inherent isn't checked and can not return any error
+		None
+	}
+}
+
+#[derive(thiserror::Error, Debug)]
+pub enum Error {
+	#[error("Blockchain error")]
+	Blockchain(sp_blockchain::Error),
+	#[error("Timeout: provisioner did not return inherent data after {:?}", PROVISIONER_TIMEOUT)]
+	Timeout,
+	#[error("Could not find the parent header in the blockchain: {:?}", _0)]
+	ParentHeaderNotFound(Hash),
+	#[error("Closed channel from overseer when awaiting activation")]
+	ClosedChannelAwaitingActivation,
+	#[error("Closed channel from provisioner when awaiting inherent data")]
+	ClosedChannelAwaitingInherentData,
+	#[error("Subsystem failed")]
+	Subsystem(SubsystemError),
+}