Implement Collator

collator/Cargo.toml

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+[package]
+name = "cumulus-collator"
+version = "0.1.0"
+authors = ["Parity Technologies <[email protected]>"]
+edition = "2018"
+
+[dependencies]
+# Substrate dependencies
+runtime-primitives = { package = "sr-primitives", git = "https://github.com/paritytech/substrate", branch = "bkchr-cumulus-branch" }
+consensus-common = { package = "substrate-consensus-common", git = "https://github.com/paritytech/substrate", branch = "bkchr-cumulus-branch" }
+inherents = { package = "substrate-inherents", git = "https://github.com/paritytech/substrate", branch = "bkchr-cumulus-branch" }
+
+# Polkadot dependencies
+polkadot-collator = { git = "https://github.com/paritytech/polkadot", branch = "bkchr-cumulus-branch" }
+polkadot-primitives = { git = "https://github.com/paritytech/polkadot", branch = "bkchr-cumulus-branch" }
+
+# other deps
+log = "0.4.6"
+codec = { package = "parity-codec", version = "3.5.1", features = [ "derive" ] }
+futures = "0.1.27"

collator/src/lib.rs

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+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate 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.
+
+// Substrate 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 Cumulus.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Cumulus Collator implementation for Substrate.
+
+use runtime_primitives::traits::Block as BlockT;
+use consensus_common::{Environment, Proposer};
+
+use polkadot_collator::{InvalidHead, ParachainContext};
+use polkadot_primitives::parachain::{self, BlockData, Message, Id as ParaId, Extrinsic};
+
+use codec::{Decode, Encode};
+use log::error;
+use futures::{Future, future::IntoFuture};
+
+use std::{sync::Arc, marker::PhantomData, time::Duration};
+
+/// The head data of the parachain, stored in the relay chain.
+#[derive(Decode, Encode, Debug)]
+struct HeadData<Block: BlockT> {
+	header: Block::Header,
+}
+
+/// The implementation of the Cumulus `Collator`.
+pub struct Collator<Block, PF> {
+	proposer_factory: Arc<PF>,
+	_phantom: PhantomData<Block>,
+	inherent_data_providers: inherents::InherentDataProviders,
+}
+
+impl<Block: BlockT, PF: Environment<Block>> Collator<Block, PF> {
+	/// Create a new instance.
+	fn new(
+		proposer_factory: Arc<PF>,
+		inherent_data_providers: inherent_data::InherentDataProviders
+	) -> Self {
+		Self {
+			proposer_factory,
+			inherent_data_providers,
+			_phantom: PhantomData,
+		}
+	}
+}
+
+impl<Block, PF> Clone for Collator<Block, PF> {
+	fn clone(&self) -> Self {
+		Self {
+			proposer_factory: self.proposer_factory.clone(),
+			inherent_data_providers: self.inherent_data_providers.clone(),
+			_phantom: PhantomData,
+		}
+	}
+}
+
+impl<Block, PF> ParachainContext for Collator<Block, PF>
+where
+	Block: BlockT,
+	PF: Environment<Block> + 'static,
+	PF::Error: std::fmt::Debug,
+{
+	type ProduceCandidate = Box<
+		dyn Future<Item=(BlockData, parachain::HeadData, Extrinsic), Error=InvalidHead>
+	>;
+
+	fn produce_candidate<I: IntoIterator<Item=(ParaId, Message)>>(
+		&self,
+		last_head: parachain::HeadData,
+		_: I,
+	) -> Self::ProduceCandidate {
+		let factory = self.proposer_factory.clone();
+		let inherent_providers = self.inherent_data_providers.clone();
+
+		let res = HeadData::<Block>::decode(&mut &last_head.0[..])
+			.ok_or_else(|| InvalidHead).into_future()
+			.and_then(move |last_head|
+				factory.init(&last_head.header).map_err(|e| {
+					//TODO: Do we want to return the real error?
+					error!("Could not create proposer: {:?}", e);
+					InvalidHead
+				})
+			)
+			.and_then(move |proposer|
+				inherent_providers.create_inherent_data()
+					.map(|id| (proposer, id))
+					.map_err(|e| {
+						error!("Failed to create inherent data: {:?}", e);
+						InvalidHead
+					})
+			)
+			.and_then(|(proposer, inherent_data)| {
+				proposer.propose(
+					inherent_data,
+					Default::default(),
+					//TODO: Fix this.
+					Duration::from_secs(6),
+				)
+				.into_future()
+				.map_err(|e| {
+					error!("Proposing failed: {:?}", e);
+					InvalidHead
+				})
+			})
+			.map(|b| {
+				let block_data = BlockData(b.encode());
+				let head_data = HeadData::<Block> { header: b.deconstruct().0 };
+				let extrinsic = Extrinsic { outgoing_messages: Vec::new() };
+
+				(block_data, parachain::HeadData(head_data.encode()), extrinsic)
+			});
+
+		Box::new(res)
+	}
+}

test/runtime/build.rs

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+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate 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.
+
+// Substrate 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 Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+use wasm_builder_runner::{build_current_project, WasmBuilderSource};
+
+fn main() {
+	build_current_project(
+		"wasm_binary.rs",
+		WasmBuilderSource::Git {
+			repo: "https://github.com/paritytech/substrate",
+			rev: "c7fa536d85df5d6a0fc5cdc3f82b6e5a1a2db640",
+		}
+	);
+}