Signed commitments rpc pubsub (#26)

* move beefy application crypto to primitives

* make primitives compile under no_std

* add beefy pallet that maintains authority set

* add beefy pallet to node example runtime

* tabify node-example cargo.toml files

* use double quotes in Cargo.toml files

* add missing hex-literal dependency

* add runtime api to fetch BEEFY authorities

* fix clippy warnings

* gadget: use commitment and signedcommitment

* gadget: send notifications for signed commitments

* gadget: add rpc pubsub for signed commitments

* node-example: enable beefy rpc

* gadget: fix clippy warnings

* rename beefy-pallet to pallet-beefy

* sort dependencies in node-example/runtime/Cargo.toml

* gadget: add documentation on SignedCommitment rpc wrapper type

* gadget: add todos about dummy beefy commitments

* gadget: remove redundant closure

Co-authored-by: Tomasz Drwięga <[email protected]>

Co-authored-by: Tomasz Drwięga <[email protected]>

client/beefy/Cargo.toml

@@ -20,6 +20,7 @@ sp-consensus = { git = "https://github.com/paritytech/substrate", branch = "mast
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-keystore = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-utils = { git = "https://github.com/paritytech/substrate", branch = "master" }
 
 sc-client-api = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sc-keystore = { git = "https://github.com/paritytech/substrate", branch = "master" }

client/beefy/rpc/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "beefy-gadget-rpc"
+version = "0.1.0"
+authors = ["Parity Technologies <[email protected]>"]
+edition = "2018"
+license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
+
+[dependencies]
+beefy-gadget = { path = "../." }
+beefy-primitives = { path = "../../primitives" }
+
+codec = { version = "1.3.5", package = "parity-scale-codec", features = ["derive"] }
+sc-rpc = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master" }
+jsonrpc-core = "15.1.0"
+jsonrpc-core-client = "15.1.0"
+jsonrpc-derive = "15.1.0"
+jsonrpc-pubsub = "15.1.0"
+futures = { version = "0.3.4", features = ["compat"] }
+serde = { version = "1.0.105", features = ["derive"] }
+serde_json = "1.0.50"
+log = "0.4.8"

client/beefy/rpc/src/lib.rs

@@ -0,0 +1,119 @@
+// Copyright (C) 2020 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program 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.
+
+// This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! RPC API for BEEFY.
+
+#![warn(missing_docs)]
+
+use codec::Encode;
+use futures::{StreamExt, TryStreamExt};
+use jsonrpc_core::futures::{
+	future::Executor as Executor01, future::Future as Future01, sink::Sink as Sink01, stream::Stream as Stream01,
+};
+use jsonrpc_derive::rpc;
+use jsonrpc_pubsub::{manager::SubscriptionManager, typed::Subscriber, SubscriptionId};
+use log::warn;
+use std::sync::Arc;
+
+mod notification;
+
+use sp_runtime::traits::Block as BlockT;
+
+use beefy_gadget::notification::BeefySignedCommitmentStream;
+
+/// Provides RPC methods for interacting with BEEFY.
+#[allow(clippy::needless_return)]
+#[rpc]
+pub trait BeefyApi<Notification, Hash> {
+	/// RPC Metadata
+	type Metadata;
+
+	/// Returns the block most recently finalized by BEEFY, alongside side its justification.
+	#[pubsub(
+		subscription = "beefy_justifications",
+		subscribe,
+		name = "beefy_subscribeJustifications"
+	)]
+	fn subscribe_justifications(&self, metadata: Self::Metadata, subscriber: Subscriber<Notification>);
+
+	/// Unsubscribe from receiving notifications about recently finalized blocks.
+	#[pubsub(
+		subscription = "beefy_justifications",
+		unsubscribe,
+		name = "beefy_unsubscribeJustifications"
+	)]
+	fn unsubscribe_justifications(
+		&self,
+		metadata: Option<Self::Metadata>,
+		id: SubscriptionId,
+	) -> jsonrpc_core::Result<bool>;
+}
+
+/// Implements the BeefyApi RPC trait for interacting with BEEFY.
+pub struct BeefyRpcHandler<Block: BlockT, Signature> {
+	signed_commitment_stream: BeefySignedCommitmentStream<Block, Signature>,
+	manager: SubscriptionManager,
+}
+
+impl<Block: BlockT, Signature> BeefyRpcHandler<Block, Signature> {
+	/// Creates a new BeefyRpcHandler instance.
+	pub fn new<E>(signed_commitment_stream: BeefySignedCommitmentStream<Block, Signature>, executor: E) -> Self
+	where
+		E: Executor01<Box<dyn Future01<Item = (), Error = ()> + Send>> + Send + Sync + 'static,
+	{
+		let manager = SubscriptionManager::new(Arc::new(executor));
+		Self {
+			signed_commitment_stream,
+			manager,
+		}
+	}
+}
+
+impl<Block, Signature> BeefyApi<notification::SignedCommitment, Block> for BeefyRpcHandler<Block, Signature>
+where
+	Block: BlockT,
+	Signature: Clone + Encode + Send + 'static,
+{
+	type Metadata = sc_rpc::Metadata;
+
+	fn subscribe_justifications(
+		&self,
+		_metadata: Self::Metadata,
+		subscriber: Subscriber<notification::SignedCommitment>,
+	) {
+		let stream = self
+			.signed_commitment_stream
+			.subscribe()
+			.map(|x| Ok::<_, ()>(notification::SignedCommitment::new::<Block, Signature>(x)))
+			.map_err(|e| warn!("Notification stream error: {:?}", e))
+			.compat();
+
+		self.manager.add(subscriber, |sink| {
+			let stream = stream.map(Ok);
+			sink.sink_map_err(|e| warn!("Error sending notifications: {:?}", e))
+				.send_all(stream)
+				.map(|_| ())
+		});
+	}
+
+	fn unsubscribe_justifications(
+		&self,
+		_metadata: Option<Self::Metadata>,
+		id: SubscriptionId,
+	) -> jsonrpc_core::Result<bool> {
+		Ok(self.manager.cancel(id))
+	}
+}

client/beefy/rpc/src/notification.rs

@@ -0,0 +1,38 @@
+// Copyright (C) 2020 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program 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.
+
+// This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
+
+use codec::Encode;
+use serde::{Deserialize, Serialize};
+
+use sp_runtime::traits::Block as BlockT;
+
+/// An encoded signed commitment proving that the given header has been finalized.
+/// The given bytes should be the SCALE-encoded representation of a
+/// `beefy_primitives::SignedCommitment`.
+#[derive(Clone, Serialize, Deserialize)]
+pub struct SignedCommitment(sp_core::Bytes);
+
+impl SignedCommitment {
+	pub fn new<Block, Signature>(
+		signed_commitment: beefy_gadget::notification::SignedCommitment<Block, Signature>,
+	) -> Self
+	where
+		Block: BlockT,
+		Signature: Encode,
+	{
+		SignedCommitment(signed_commitment.encode().into())
+	}
+}