feat: pallet asset-rate

Cargo.toml

@@ -166,6 +166,7 @@ members = [
 	"frame/transaction-payment/rpc/runtime-api",
 	"frame/transaction-storage",
 	"frame/treasury",
+	"frame/treasury-oracle",
 	"frame/tips",
 	"frame/uniques",
 	"frame/utility",

frame/treasury-oracle/Cargo.toml

@@ -0,0 +1,42 @@
+[package]
+name = "pallet-treasury-oracle"
+version = "4.0.0-dev"
+description = "Convert whitelisted assets to native balance"
+authors = ["Centrifuge <[email protected]>"]
+homepage = "https://substrate.io"
+edition = "2021"
+license = "Unlicense"
+publish = false
+repository = "https://github.com/paritytech/substrate/"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "3.2.2", default-features = false, features = [
+	"derive",
+] }
+scale-info = { version = "2.1.1", default-features = false, features = ["derive"] }
+frame-benchmarking = { version = "4.0.0-dev", default-features = false, optional = true, path = "../benchmarking" }
+frame-support = { version = "4.0.0-dev", default-features = false, path = "../support" }
+frame-system = { version = "4.0.0-dev", default-features = false, path = "../system" }
+sp-runtime = { version = "7.0.0", path = "../../primitives/runtime" }
+
+[dev-dependencies]
+pallet-balances = { version = "4.0.0-dev", default-features = false, path = "../balances" }
+sp-core = { version = "7.0.0", path = "../../primitives/core" }
+sp-io = { version = "7.0.0", path = "../../primitives/io" }
+
+[features]
+default = ["std"]
+std = [
+	"codec/std",
+	"frame-benchmarking?/std",
+	"frame-support/std",
+	"frame-system/std",
+	"pallet-balances/std",
+	"scale-info/std",
+	"sp-runtime/std",
+]
+runtime-benchmarks = ["frame-benchmarking/runtime-benchmarks"]
+try-runtime = ["frame-support/try-runtime"]

frame/treasury-oracle/src/lib.rs

@@ -0,0 +1,226 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! A simple oracle pallet for the treasury.
+//!
+//! ## Overview
+//!
+//! The TreasuryOracle pallet provides means of setting conversion rates
+//! for some asset to native balance.
+//!
+//! The supported dispatchable functions are documented in the [`Call`] enum.
+//!
+//! ### Terminology
+//!
+//! * **Asset balance**: The balance type of an arbitrary asset. The network might only know about
+//!   identifier of the asset and nothing more.
+//! * **Native balance**: The balance type of the network's native currency.
+//! * **Treasury spend**: A payment from the treasury after the corresponding proposal has been
+//!   approved.
+//!
+//! ### Goals
+//!
+//! The treasury-oracle system in Substrate is designed to make the following possible:
+//!
+//! * Whitelisting assets other than the native currency which can be accepted for Treasury spends.
+//! * Providing a soft conversion for the balance of whitelisted assets to native.
+//! * Updating existing conversion rates.
+//!
+//! ## Interface
+//!
+//! ### Permissioned Functions
+//!
+//! * `create`: Creates a new asset conversion rate.
+//! * `remove`: Removes an existing asset conversion rate.
+//! * `update`: Overwrites an existing assert conversion rate.
+//!
+//! Please refer to the [`Call`] enum and its associated variants for documentation on each
+//! function.
+//!
+//! ### Assumptions
+//!
+//! * Conversion rates will not be used to determine the payment amount in another asset.
+//! * Conversion rates will be used to determine the tier of the spender status, e.g.
+//!   `SmallSpender`, `MediumSpender` or `BigSpender`.
+//! * Conversion rates are only required from some asset to native.
+//!
+//! ## Related Modules
+//! * [`Treasury`](../treasury/index.html)
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use frame_support::traits::{
+	fungible::Inspect,
+	tokens::{Balance, BalanceConversion},
+};
+use frame_system::WeightInfo;
+use sp_runtime::{traits::Zero, FixedPointNumber, FixedPointOperand, FixedU128};
+
+pub use pallet::*;
+
+#[cfg(test)]
+mod mock;
+
+#[cfg(test)]
+mod tests;
+
+// #[cfg(feature = "runtime-benchmarks")]
+// mod benchmarking;
+
+// Type alias for `frame_system`'s account id.
+type AccountIdOf<T> = <T as frame_system::Config>::AccountId;
+// This pallet's asset id and balance type.
+type AssetIdOf<T> = <T as Config>::AssetId;
+// Generic fungible balance type.
+type BalanceOf<T> = <<T as Config>::Currency as Inspect<AccountIdOf<T>>>::Balance;
+
+// #[frame_support::pallet]
+// TODO: Remove
+#[frame_support::pallet(dev_mode)]
+pub mod pallet {
+	use super::*;
+	use frame_support::pallet_prelude::*;
+	use frame_system::pallet_prelude::*;
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(_);
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {
+		/// The Weight information for extrinsics in this pallet.
+		type WeightInfo: WeightInfo;
+
+		/// The runtime event type.
+		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;
+
+		/// The origin permissioned to create a conversion rate for an asset.
+		type CreateOrigin: EnsureOrigin<Self::RuntimeOrigin>;
+
+		/// The origin permissioned to remove an existing conversion rate for an asset.
+		type RemoveOrigin: EnsureOrigin<Self::RuntimeOrigin>;
+
+		/// The origin permissioned to update an existiing conversion rate for an asset.
+		type UpdateOrigin: EnsureOrigin<Self::RuntimeOrigin>;
+
+		/// The units in which we record balances.
+		type Balance: Balance + FixedPointOperand;
+
+		/// The currency mechanism for this pallet.
+		type Currency: Inspect<Self::AccountId, Balance = Self::Balance>;
+
+		/// The identifier for the class of asset.
+		type AssetId: Member + Parameter + Copy + MaybeSerializeDeserialize + MaxEncodedLen;
+	}
+
+	#[pallet::storage]
+	#[pallet::getter(fn conversion_rate_to_native)]
+	/// Maps an asset to its fixed point representation in the native balance.
+	pub(super) type ConversionRateToNative<T: Config> =
+		StorageMap<_, Blake2_128Concat, T::AssetId, FixedU128, OptionQuery>;
+
+	#[pallet::event]
+	#[pallet::generate_deposit(pub(super) fn deposit_event)]
+	pub enum Event<T: Config> {
+		// Some `asset_id` conversion rate was created.
+		Created { asset_id: T::AssetId, rate: FixedU128 },
+		// Some `asset_id` conversion rate was removed.
+		Removed { asset_id: T::AssetId },
+		// Some existing `asset_id` conversion rate was updated from `old` to `new`.
+		Updated { asset_id: T::AssetId, old: FixedU128, new: FixedU128 },
+	}
+
+	#[pallet::error]
+	pub enum Error<T> {
+		/// The given asset ID is unknown.
+		Unknown,
+		/// The given asset ID already has an assigned conversion rate and cannot be re-created.
+		AlreadyExists,
+	}
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
+		#[pallet::call_index(0)]
+		pub fn create(
+			origin: OriginFor<T>,
+			asset_id: T::AssetId,
+			rate: FixedU128,
+		) -> DispatchResult {
+			T::CreateOrigin::ensure_origin(origin)?;
+
+			ensure!(
+				!ConversionRateToNative::<T>::contains_key(asset_id),
+				Error::<T>::AlreadyExists
+			);
+			ConversionRateToNative::<T>::set(asset_id, Some(rate));
+
+			Self::deposit_event(Event::Created { asset_id, rate });
+			Ok(())
+		}
+
+		#[pallet::call_index(1)]
+		pub fn update(
+			origin: OriginFor<T>,
+			asset_id: T::AssetId,
+			rate: FixedU128,
+		) -> DispatchResult {
+			T::UpdateOrigin::ensure_origin(origin)?;
+
+			let mut old = FixedU128::zero();
+			ConversionRateToNative::<T>::mutate(asset_id, |maybe_rate| {
+				if let Some(r) = maybe_rate {
+					old = *r;
+					*r = rate;
+
+					Ok(())
+				} else {
+					Err(Error::<T>::Unknown)
+				}
+			})?;
+
+			Self::deposit_event(Event::Updated { asset_id, old, new: rate });
+			Ok(())
+		}
+
+		#[pallet::call_index(2)]
+		pub fn remove(origin: OriginFor<T>, asset_id: T::AssetId) -> DispatchResult {
+			T::RemoveOrigin::ensure_origin(origin)?;
+
+			ensure!(ConversionRateToNative::<T>::contains_key(asset_id), Error::<T>::Unknown);
+			ConversionRateToNative::<T>::remove(asset_id);
+
+			Self::deposit_event(Event::Removed { asset_id });
+			Ok(())
+		}
+	}
+}
+
+impl<T> BalanceConversion<BalanceOf<T>, AssetIdOf<T>, BalanceOf<T>> for Pallet<T>
+where
+	T: Config,
+	BalanceOf<T>: FixedPointOperand + Zero,
+{
+	type Error = pallet::Error<T>;
+
+	fn to_asset_balance(
+		balance: BalanceOf<T>,
+		asset_id: AssetIdOf<T>,
+	) -> Result<BalanceOf<T>, pallet::Error<T>> {
+		let rate = Pallet::<T>::conversion_rate_to_native(asset_id)
+			.ok_or(pallet::Error::<T>::Unknown.into())?;
+		Ok(rate.saturating_mul_int(balance))
+	}
+}

frame/treasury-oracle/src/mock.rs

@@ -0,0 +1,96 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The crate's mock.
+
+use crate as pallet_treasury_oracle;
+use frame_support::traits::{ConstU16, ConstU64};
+use sp_core::H256;
+use sp_runtime::{
+	testing::Header,
+	traits::{BlakeTwo256, IdentityLookup},
+};
+
+type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
+type Block = frame_system::mocking::MockBlock<Test>;
+
+frame_support::construct_runtime!(
+	pub enum Test where
+		Block = Block,
+		NodeBlock = Block,
+		UncheckedExtrinsic = UncheckedExtrinsic,
+	{
+		System: frame_system,
+		TreasuryOracle: pallet_treasury_oracle,
+		Balances: pallet_balances,
+	}
+);
+
+impl frame_system::Config for Test {
+	type BaseCallFilter = frame_support::traits::Everything;
+	type BlockWeights = ();
+	type BlockLength = ();
+	type DbWeight = ();
+	type RuntimeOrigin = RuntimeOrigin;
+	type RuntimeCall = RuntimeCall;
+	type Index = u64;
+	type BlockNumber = u64;
+	type Hash = H256;
+	type Hashing = BlakeTwo256;
+	type AccountId = u64;
+	type Lookup = IdentityLookup<Self::AccountId>;
+	type Header = Header;
+	type RuntimeEvent = RuntimeEvent;
+	type BlockHashCount = ConstU64<250>;
+	type Version = ();
+	type PalletInfo = PalletInfo;
+	type AccountData = pallet_balances::AccountData<u64>;
+	type OnNewAccount = ();
+	type OnKilledAccount = ();
+	type SystemWeightInfo = ();
+	type SS58Prefix = ConstU16<42>;
+	type OnSetCode = ();
+	type MaxConsumers = frame_support::traits::ConstU32<16>;
+}
+
+impl pallet_balances::Config for Test {
+	type Balance = u64;
+	type DustRemoval = ();
+	type RuntimeEvent = RuntimeEvent;
+	type ExistentialDeposit = ConstU64<1>;
+	type AccountStore = System;
+	type WeightInfo = ();
+	type MaxLocks = ();
+	type MaxReserves = ();
+	type ReserveIdentifier = [u8; 8];
+}
+
+impl pallet_treasury_oracle::Config for Test {
+	type WeightInfo = ();
+	type RuntimeEvent = RuntimeEvent;
+	type CreateOrigin = frame_system::EnsureRoot<u64>;
+	type RemoveOrigin = frame_system::EnsureSigned<u64>;
+	type UpdateOrigin = frame_system::EnsureSigned<u64>;
+	type Balance = u64;
+	type Currency = Balances;
+	type AssetId = u32;
+}
+
+// Build genesis storage according to the mock runtime.
+pub fn new_test_ext() -> sp_io::TestExternalities {
+	frame_system::GenesisConfig::default().build_storage::<Test>().unwrap().into()
+}