Implement basic upward & downward messages (#118)

* Start by replacing branch names and set `DownwardMessage`

* Add the upward-message crate

* Add Kusama & Polkadot

* More work on getting the upward messages working

* Fix build

* Begin to integrate it into the test Parachain

* Update

* Make everything compile again

* Switch to westend and print parachain account on startup

* Use MultiSignature etc

* Fix validate block

* Some downward messages work

* Update git reference

* More downward messages integration

* Update test runtime for downward messages

* Enable downward message handler and withdraw send tokens

* Add some docs

* Begin to implement simple XCMP

* More work

* Fixes and make parachain id configurable

* Make parachain ID be part of the genesis

* Finishing the XCMP message demo

* Update and fixes tests

* Update branch

cumulus/test/parachain/runtime/Cargo.toml

@@ -25,7 +25,6 @@ frame-support = { git = "https://github.com/paritytech/substrate", default-featu
 frame-executive = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "cumulus-branch" }
 frame-system = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "cumulus-branch" }
 pallet-balances = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "cumulus-branch" }
-pallet-indices = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "cumulus-branch" }
 pallet-randomness-collective-flip = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "cumulus-branch" }
 pallet-timestamp = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "cumulus-branch" }
 pallet-sudo = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "cumulus-branch" }
@@ -34,35 +33,48 @@ pallet-transaction-payment = { git = "https://github.com/paritytech/substrate",
 # Cumulus dependencies
 cumulus-runtime = { path = "../../../runtime", default-features = false }
 cumulus-parachain-upgrade = { path = "../../../parachain-upgrade", default-features = false }
+cumulus-message-broker = { path = "../../../message-broker", default-features = false }
+cumulus-upward-message = { path = "../../../upward-message", default-features = false }
+cumulus-primitives = { path = "../../../primitives", default-features = false }
+
+# Polkadot dependencies
+polkadot-parachain = { git = "https://github.com/paritytech/polkadot", branch = "cumulus-branch", default-features = false }
 
 [build-dependencies]
 wasm-builder-runner = { package = "substrate-wasm-builder-runner", version = "1.0.6" }
 
 [features]
-default = ['std']
+default = [ "std" ]
 std = [
-	'codec/std',
-	'serde',
-	'sp-api/std',
-	'sp-std/std',
-	'sp-io/std',
-	'sp-core/std',
-	'sp-runtime/std',
-	'sp-version/std',
-	'sp-offchain/std',
-	'sp-session/std',
-	'sp-block-builder/std',
-	'sp-transaction-pool/std',
-	'sp-inherents/std',
-	'frame-support/std',
-	'frame-executive/std',
-	'frame-system/std',
-	'pallet-balances/std',
-	'pallet-indices/std',
-	'pallet-randomness-collective-flip/std',
-	'pallet-timestamp/std',
-	'pallet-sudo/std',
-	'pallet-transaction-payment/std',
-	'cumulus-runtime/std',
-	'cumulus-parachain-upgrade/std',
+	"codec/std",
+	"serde",
+	"sp-api/std",
+	"sp-std/std",
+	"sp-io/std",
+	"sp-core/std",
+	"sp-runtime/std",
+	"sp-version/std",
+	"sp-offchain/std",
+	"sp-session/std",
+	"sp-block-builder/std",
+	"sp-transaction-pool/std",
+	"sp-inherents/std",
+	"frame-support/std",
+	"frame-executive/std",
+	"frame-system/std",
+	"pallet-balances/std",
+	"pallet-randomness-collective-flip/std",
+	"pallet-timestamp/std",
+	"pallet-sudo/std",
+	"pallet-transaction-payment/std",
+	"cumulus-runtime/std",
+	"cumulus-parachain-upgrade/std",
+	"cumulus-message-broker/std",
+	"cumulus-upward-message/std",
+	"cumulus-primitives/std",
+	"polkadot-parachain/std",
+]
+# Will be enabled by the `wasm-builder` when building the runtime for WASM.
+runtime-wasm = [
+	"cumulus-upward-message/runtime-wasm",
 ]

cumulus/test/parachain/runtime/src/lib.rs

@@ -26,20 +26,22 @@ use sp_api::impl_runtime_apis;
 use sp_core::OpaqueMetadata;
 use sp_runtime::{
 	create_runtime_str, generic, impl_opaque_keys,
-	traits::{BlakeTwo256, Block as BlockT, Saturating, StaticLookup, Verify},
+	traits::{BlakeTwo256, Block as BlockT, IdentifyAccount, IdentityLookup, Saturating, Verify},
 	transaction_validity::{TransactionSource, TransactionValidity},
-	AnySignature, ApplyExtrinsicResult,
+	ApplyExtrinsicResult, MultiSignature,
 };
 use sp_std::prelude::*;
 #[cfg(feature = "std")]
 use sp_version::NativeVersion;
 use sp_version::RuntimeVersion;
 
+mod message_example;
+
 // A few exports that help ease life for downstream crates.
 pub use frame_support::{
 	construct_runtime, parameter_types,
 	traits::Randomness,
-	weights::{IdentityFee, Weight},
+	weights::{constants::WEIGHT_PER_SECOND, IdentityFee, Weight},
 	StorageValue,
 };
 pub use pallet_balances::Call as BalancesCall;
@@ -52,11 +54,11 @@ pub use sp_runtime::{Perbill, Permill};
 pub type BlockNumber = u32;
 
 /// Alias to 512-bit hash when used in the context of a transaction signature on the chain.
-pub type Signature = AnySignature;
+pub type Signature = MultiSignature;
 
 /// Some way of identifying an account on the chain. We intentionally make it equivalent
 /// to the public key of our transaction signing scheme.
-pub type AccountId = <Signature as Verify>::Signer;
+pub type AccountId = <<Signature as Verify>::Signer as IdentifyAccount>::AccountId;
 
 /// The type for looking up accounts. We don't expect more than 4 billion of them, but you
 /// never know...
@@ -122,6 +124,12 @@ pub const DAYS: BlockNumber = HOURS * 24;
 // 1 in 4 blocks (on average, not counting collisions) will be primary babe blocks.
 pub const PRIMARY_PROBABILITY: (u64, u64) = (1, 4);
 
+#[derive(codec::Encode, codec::Decode)]
+pub enum XCMPMessage<XAccountId, XBalance> {
+	/// Transfer tokens to the given account from the Parachain account.
+	TransferToken(XAccountId, XBalance),
+}
+
 /// The version infromation used to identify this runtime when compiled natively.
 #[cfg(feature = "std")]
 pub fn native_version() -> NativeVersion {
@@ -133,7 +141,7 @@ pub fn native_version() -> NativeVersion {
 
 parameter_types! {
 	pub const BlockHashCount: BlockNumber = 250;
-	pub const MaximumBlockWeight: Weight = 1_000_000;
+	pub const MaximumBlockWeight: Weight = 2 * WEIGHT_PER_SECOND;
 	/// Assume 10% of weight for average on_initialize calls.
 	pub MaximumExtrinsicWeight: Weight = AvailableBlockRatio::get()
 		.saturating_sub(Perbill::from_percent(10)) * MaximumBlockWeight::get();
@@ -149,7 +157,7 @@ impl frame_system::Trait for Runtime {
 	/// The aggregated dispatch type that is available for extrinsics.
 	type Call = Call;
 	/// The lookup mechanism to get account ID from whatever is passed in dispatchers.
-	type Lookup = Indices;
+	type Lookup = IdentityLookup<AccountId>;
 	/// The index type for storing how many extrinsics an account has signed.
 	type Index = Index;
 	/// The index type for blocks.
@@ -178,24 +186,13 @@ impl frame_system::Trait for Runtime {
 	type ModuleToIndex = ModuleToIndex;
 	type AccountData = pallet_balances::AccountData<Balance>;
 	type OnNewAccount = ();
-	type OnKilledAccount = Balances;
+	type OnKilledAccount = ();
 	type DbWeight = ();
 	type ExtrinsicBaseWeight = ExtrinsicBaseWeight;
 	type BlockExecutionWeight = ();
 	type MaximumExtrinsicWeight = MaximumExtrinsicWeight;
 }
 
-parameter_types! {
-	pub const IndexDeposit: Balance = 1;
-}
-
-impl pallet_indices::Trait for Runtime {
-	type AccountIndex = u32;
-	type Event = Event;
-	type Currency = Balances;
-	type Deposit = IndexDeposit;
-}
-
 parameter_types! {
 	pub const MinimumPeriod: u64 = SLOT_DURATION / 2;
 }
@@ -242,6 +239,27 @@ impl cumulus_parachain_upgrade::Trait for Runtime {
 	type OnValidationFunctionParams = ();
 }
 
+parameter_types! {
+	pub storage ParachainId: cumulus_primitives::ParaId = 100.into();
+}
+
+impl cumulus_message_broker::Trait for Runtime {
+	type Event = Event;
+	type DownwardMessageHandlers = TokenDealer;
+	type UpwardMessage = cumulus_upward_message::WestendUpwardMessage;
+	type ParachainId = ParachainId;
+	type XCMPMessage = XCMPMessage<AccountId, Balance>;
+	type XCMPMessageHandlers = TokenDealer;
+}
+
+impl message_example::Trait for Runtime {
+	type Event = Event;
+	type UpwardMessageSender = MessageBroker;
+	type UpwardMessage = cumulus_upward_message::WestendUpwardMessage;
+	type Currency = Balances;
+	type XCMPMessageSender = MessageBroker;
+}
+
 construct_runtime! {
 	pub enum Runtime where
 		Block = Block,
@@ -250,16 +268,18 @@ construct_runtime! {
 	{
 		System: frame_system::{Module, Call, Storage, Config, Event<T>},
 		Timestamp: pallet_timestamp::{Module, Call, Storage, Inherent},
-		Indices: pallet_indices::{Module, Call, Storage, Config<T>, Event<T>},
 		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
 		Sudo: pallet_sudo::{Module, Call, Storage, Config<T>, Event<T>},
 		RandomnessCollectiveFlip: pallet_randomness_collective_flip::{Module, Call, Storage},
 		ParachainUpgrade: cumulus_parachain_upgrade::{Module, Call, Storage, Inherent, Event},
+		MessageBroker: cumulus_message_broker::{Module, Call, Inherent, Event<T>},
+		TokenDealer: message_example::{Module, Call, Event<T>, Config},
+		TransactionPayment: pallet_transaction_payment::{Module, Storage},
 	}
 }
 
 /// The address format for describing accounts.
-pub type Address = <Indices as StaticLookup>::Source;
+pub type Address = AccountId;
 /// Block header type as expected by this runtime.
 pub type Header = generic::Header<BlockNumber, BlakeTwo256>;
 /// Block type as expected by this runtime.

cumulus/test/parachain/runtime/src/message_example.rs

@@ -0,0 +1,179 @@
+// Copyright 2020 Parity Technologies (UK) Ltd.
+// This file is part of Cumulus.
+
+// Cumulus 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.
+
+// Cumulus 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/>.
+
+//! Example Pallet that shows how to send upward messages and how to receive
+//! downward messages.
+
+use frame_support::{
+	decl_event, decl_module, decl_storage,
+	traits::{Currency, ExistenceRequirement, WithdrawReason},
+};
+use frame_system::ensure_signed;
+
+use crate::XCMPMessage;
+use codec::{Decode, Encode};
+use cumulus_primitives::{
+	relay_chain::DownwardMessage,
+	xcmp::{XCMPMessageHandler, XCMPMessageSender},
+	DownwardMessageHandler, ParaId, UpwardMessageOrigin, UpwardMessageSender,
+};
+use cumulus_upward_message::BalancesMessage;
+use polkadot_parachain::primitives::AccountIdConversion;
+use sp_runtime::DispatchResult;
+
+type BalanceOf<T> =
+	<<T as Trait>::Currency as Currency<<T as frame_system::Trait>::AccountId>>::Balance;
+
+/// Configuration trait of this pallet.
+pub trait Trait: frame_system::Trait {
+	/// Event type used by the runtime.
+	type Event: From<Event<Self>> + Into<<Self as frame_system::Trait>::Event>;
+
+	/// The sender of upward messages.
+	type UpwardMessageSender: UpwardMessageSender<Self::UpwardMessage>;
+
+	/// The upward message type used by the Parachain runtime.
+	type UpwardMessage: codec::Codec + BalancesMessage<Self::AccountId, BalanceOf<Self>>;
+
+	/// Currency of the runtime.
+	type Currency: Currency<Self::AccountId>;
+
+	/// The sender of XCMP messages.
+	type XCMPMessageSender: XCMPMessageSender<XCMPMessage<Self::AccountId, BalanceOf<Self>>>;
+}
+
+// This pallet's storage items.
+decl_storage! {
+	trait Store for Module<T: Trait> as ParachainUpgrade {}
+	add_extra_genesis {
+		config(parachain_id): ParaId;
+		build(|config: &Self| {
+			// This is basically a hack to make the parachain id easily configurable.
+			// Could also be done differently, but yeah..
+			crate::ParachainId::set(&config.parachain_id);
+		});
+	}
+}
+
+decl_event! {
+	pub enum Event<T> where
+		AccountId = <T as frame_system::Trait>::AccountId,
+		Balance = BalanceOf<T>
+	{
+		/// Transferred tokens to the account on the relay chain.
+		TransferredTokensToRelayChain(AccountId, Balance),
+		/// Transferred tokens to the account on request from the relay chain.
+		TransferredTokensFromRelayChain(AccountId, Balance),
+		/// Transferred tokens to the account from the given parachain account.
+		TransferredTokensViaXCMP(ParaId, AccountId, Balance, DispatchResult),
+	}
+}
+
+decl_module! {
+	pub struct Module<T: Trait> for enum Call where origin: T::Origin, system = frame_system {
+		/// Transfer `amount` of tokens on the relay chain from the Parachain account to
+		/// the given `dest` account.
+		#[weight = 10]
+		fn transfer_tokens_to_relay_chain(origin, dest: T::AccountId, amount: BalanceOf<T>) {
+			let who = ensure_signed(origin)?;
+
+			let _ = T::Currency::withdraw(
+				&who,
+				amount,
+				WithdrawReason::Transfer.into(),
+				ExistenceRequirement::AllowDeath,
+			)?;
+
+			let msg = <T as Trait>::UpwardMessage::transfer(dest.clone(), amount.clone());
+			<T as Trait>::UpwardMessageSender::send_upward_message(&msg, UpwardMessageOrigin::Signed)
+				.expect("Should not fail; qed");
+
+			Self::deposit_event(Event::<T>::TransferredTokensToRelayChain(dest, amount));
+		}
+
+		/// Transfer `amount` of tokens to another parachain.
+		#[weight = 10]
+		fn transfer_tokens_to_parachain_chain(
+			origin,
+			para_id: u32,
+			dest: T::AccountId,
+			amount: BalanceOf<T>,
+		) {
+			//TODO we don't make sure that the parachain has some tokens on the other parachain.
+			let who = ensure_signed(origin)?;
+
+			let _ = T::Currency::withdraw(
+				&who,
+				amount,
+				WithdrawReason::Transfer.into(),
+				ExistenceRequirement::AllowDeath,
+			)?;
+
+			T::XCMPMessageSender::send_xcmp_message(
+				para_id.into(),
+				&XCMPMessage::TransferToken(dest, amount),
+			).expect("Should not fail; qed");
+		}
+
+		fn deposit_event() = default;
+	}
+}
+
+/// This is a hack to convert from one generic type to another where we are sure that both are the
+/// same type/use the same encoding.
+fn convert_hack<O: Decode>(input: &impl Encode) -> O {
+	input.using_encoded(|e| Decode::decode(&mut &e[..]).expect("Must be compatible; qed"))
+}
+
+impl<T: Trait> DownwardMessageHandler for Module<T> {
+	fn handle_downward_message(msg: &DownwardMessage) {
+		match msg {
+			DownwardMessage::TransferInto(dest, amount, _) => {
+				let dest = convert_hack(&dest);
+				let amount: BalanceOf<T> = convert_hack(amount);
+
+				let _ = T::Currency::deposit_creating(&dest, amount.clone());
+
+				Self::deposit_event(Event::<T>::TransferredTokensFromRelayChain(dest, amount));
+			}
+			_ => {}
+		}
+	}
+}
+
+impl<T: Trait> XCMPMessageHandler<XCMPMessage<T::AccountId, BalanceOf<T>>> for Module<T> {
+	fn handle_xcmp_message(src: ParaId, msg: &XCMPMessage<T::AccountId, BalanceOf<T>>) {
+		match msg {
+			XCMPMessage::TransferToken(dest, amount) => {
+				let para_account = src.clone().into_account();
+
+				let res = T::Currency::transfer(
+					&para_account,
+					dest,
+					amount.clone(),
+					ExistenceRequirement::AllowDeath,
+				);
+
+				Self::deposit_event(Event::<T>::TransferredTokensViaXCMP(
+					src,
+					dest.clone(),
+					amount.clone(),
+					res,
+				));
+			}
+		}
+	}
+}