Network fee distribution and Incentive Pools

modules/cdp-engine/Cargo.toml

@@ -18,6 +18,7 @@ sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "polkad
 sp-std = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.24", default-features = false }
 support = { package = "module-support", path = "../support", default-features = false }
 loans = { package = "module-loans", path = "../loans", default-features = false }
+module-fees = { path = "../fees", default-features = false }
 primitives = { package = "acala-primitives", path = "../../primitives", default-features = false }
 rand_chacha = { version = "0.2", default-features = false }
 nutsfinance-stable-asset = { version = "0.1.0", default-features = false, path = "../../ecosystem-modules/stable-asset/lib/stable-asset", package = "nutsfinance-stable-asset" }
@@ -46,6 +47,7 @@ std = [
 	"sp-std/std",
 	"support/std",
 	"loans/std",
+	"module-fees/std",
 	"primitives/std",
 	"orml-utilities/std",
 ]

modules/cdp-engine/src/lib.rs

@@ -36,7 +36,7 @@ use frame_system::{
 };
 use orml_traits::{Change, GetByKey, MultiCurrency};
 use orml_utilities::OffchainErr;
-use primitives::{Amount, Balance, CurrencyId, Position};
+use primitives::{Amount, Balance, CurrencyId, IncomeSource, Position};
 use rand_chacha::{
 	rand_core::{RngCore, SeedableRng},
 	ChaChaRng,
@@ -56,8 +56,8 @@ use sp_runtime::{
 };
 use sp_std::prelude::*;
 use support::{
-	CDPTreasury, CDPTreasuryExtended, DEXManager, EmergencyShutdown, ExchangeRate, Price, PriceProvider, Rate, Ratio,
-	RiskManager, Swap, SwapLimit,
+	CDPTreasury, CDPTreasuryExtended, DEXManager, EmergencyShutdown, ExchangeRate, OnFeeDeposit, Price, PriceProvider,
+	Rate, Ratio, RiskManager, Swap, SwapLimit,
 };
 
 mod mock;
@@ -186,6 +186,9 @@ pub mod module {
 		/// Swap
 		type Swap: Swap<Self::AccountId, Balance, CurrencyId>;
 
+		/// Where the fees are go to.
+		type OnFeeDeposit: OnFeeDeposit<Self::AccountId, CurrencyId, Balance>;
+
 		/// Weight information for the extrinsics in this module.
 		type WeightInfo: WeightInfo;
 	}
@@ -553,8 +556,12 @@ impl<T: Config> Pallet<T> {
 						let debit_exchange_rate_increment = debit_exchange_rate.saturating_mul(rate_to_accumulate);
 						let issued_stable_coin_balance = debit_exchange_rate_increment.saturating_mul_int(total_debits);
 
-						// issue stablecoin to surplus pool
-						let res = <T as Config>::CDPTreasury::on_system_surplus(issued_stable_coin_balance);
+						// Staking rewards goes to T::OnFeeDeposit
+						let res = T::OnFeeDeposit::on_fee_deposit(
+							IncomeSource::HonzonStabilityFee,
+							T::GetStableCurrencyId::get(),
+							issued_stable_coin_balance,
+						);
 						match res {
 							Ok(_) => {
 								// update exchange rate when issue success

modules/cdp-engine/src/mock.rs

@@ -26,7 +26,7 @@ use frame_support::{
 	traits::{ConstU128, ConstU32, ConstU64, Everything, Nothing},
 	PalletId,
 };
-use frame_system::EnsureSignedBy;
+use frame_system::{EnsureRoot, EnsureSignedBy};
 use orml_traits::parameter_type_with_key;
 use primitives::{DexShare, Moment, TokenSymbol, TradingPair};
 use sp_core::H256;
@@ -122,6 +122,7 @@ pub type AdaptedBasicCurrency = orml_currencies::BasicCurrencyAdapter<Runtime, P
 
 parameter_types! {
 	pub const GetNativeCurrencyId: CurrencyId = ACA;
+	pub const GetStakingCurrencyId: CurrencyId = DOT;
 }
 
 impl orml_currencies::Config for Runtime {
@@ -305,6 +306,18 @@ parameter_types! {
 	pub MaxSwapSlippageCompareToOracle: Ratio = Ratio::saturating_from_rational(50, 100);
 }
 
+impl module_fees::Config for Runtime {
+	type Event = Event;
+	type UpdateOrigin = EnsureRoot<AccountId>;
+	type Currency = PalletBalances;
+	type Currencies = Currencies;
+	type NativeCurrencyId = GetNativeCurrencyId;
+	type AllocationPeriod = ConstU64<10>;
+	type DEX = ();
+	type DexSwapJointList = AlternativeSwapPathJointList;
+	type WeightInfo = ();
+}
+
 impl Config for Runtime {
 	type Event = Event;
 	type PriceSource = MockPriceSource;
@@ -323,6 +336,7 @@ impl Config for Runtime {
 	type Currency = Currencies;
 	type DEX = DEXModule;
 	type Swap = SpecificJointsSwap<DEXModule, AlternativeSwapPathJointList>;
+	type OnFeeDeposit = Fees;
 	type WeightInfo = ();
 }
 
@@ -335,15 +349,16 @@ construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Pallet, Call, Storage, Config, Event<T>},
-		CDPEngineModule: cdp_engine::{Pallet, Storage, Call, Event<T>, Config, ValidateUnsigned},
-		CDPTreasuryModule: cdp_treasury::{Pallet, Storage, Call, Config, Event<T>},
-		Currencies: orml_currencies::{Pallet, Call},
-		Tokens: orml_tokens::{Pallet, Storage, Event<T>, Config<T>},
-		LoansModule: loans::{Pallet, Storage, Call, Event<T>},
-		PalletBalances: pallet_balances::{Pallet, Call, Storage, Event<T>},
-		DEXModule: dex::{Pallet, Storage, Call, Event<T>, Config<T>},
-		Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent},
+		System: frame_system,
+		CDPEngineModule: cdp_engine,
+		CDPTreasuryModule: cdp_treasury,
+		Currencies: orml_currencies,
+		Tokens: orml_tokens,
+		LoansModule: loans,
+		PalletBalances: pallet_balances,
+		DEXModule: dex,
+		Timestamp: pallet_timestamp,
+		Fees: module_fees,
 	}
 );
 

modules/cdp-engine/src/tests.rs

@@ -23,6 +23,7 @@
 use super::*;
 use frame_support::{assert_noop, assert_ok};
 use mock::{Call as MockCall, Event, *};
+use module_fees::PoolPercent;
 use orml_traits::MultiCurrency;
 use sp_core::offchain::{testing, OffchainDbExt, OffchainWorkerExt, TransactionPoolExt};
 use sp_io::offchain;
@@ -58,6 +59,17 @@ fn setup_default_collateral(currency_id: CurrencyId) {
 	));
 }
 
+fn setup_fees_distribution() {
+	assert_ok!(Fees::set_income_fee(
+		Origin::root(),
+		IncomeSource::HonzonStabilityFee,
+		vec![PoolPercent {
+			pool: BOB,
+			rate: Rate::one(),
+		}],
+	));
+}
+
 #[test]
 fn check_cdp_status_work() {
 	ExtBuilder::default().build().execute_with(|| {
@@ -1347,6 +1359,8 @@ fn compound_interest_rate_work() {
 #[test]
 fn accumulate_interest_work() {
 	ExtBuilder::default().build().execute_with(|| {
+		setup_fees_distribution();
+
 		assert_ok!(CDPEngineModule::set_collateral_params(
 			Origin::signed(1),
 			BTC,
@@ -1862,3 +1876,77 @@ fn minimal_collateral_works() {
 		assert_ok!(CDPEngineModule::adjust_position(&ALICE, BTC, 0, 0));
 	});
 }
+
+#[test]
+fn accumulated_interest_goes_to_on_fee_deposit() {
+	ExtBuilder::default().build().execute_with(|| {
+		setup_fees_distribution();
+
+		assert_ok!(CDPEngineModule::set_collateral_params(
+			Origin::signed(1),
+			BTC,
+			Change::NewValue(Some(Rate::saturating_from_rational(1, 100))),
+			Change::NewValue(Some(Ratio::saturating_from_rational(2, 1))),
+			Change::NewValue(Some(Rate::zero())),
+			Change::NewValue(Some(Ratio::saturating_from_rational(2, 1))),
+			Change::NewValue(10000),
+		));
+		assert_ok!(CDPEngineModule::set_collateral_params(
+			Origin::signed(1),
+			DOT,
+			Change::NewValue(Some(Rate::one())),
+			Change::NewValue(Some(Ratio::saturating_from_rational(2, 1))),
+			Change::NewValue(Some(Rate::zero())),
+			Change::NewValue(Some(Ratio::saturating_from_rational(2, 1))),
+			Change::NewValue(10000),
+		));
+		assert_eq!(
+			CDPEngineModule::get_interest_rate_per_sec(BTC),
+			Ok(Rate::saturating_from_rational(1, 100))
+		);
+		assert_eq!(CDPEngineModule::get_interest_rate_per_sec(DOT), Ok(Rate::one()));
+
+		// Treasury starts off empty.
+		assert_eq!(Currencies::free_balance(AUSD, &BOB), 0);
+
+		CDPEngineModule::accumulate_interest(1, 0);
+
+		// No debit generates no interest.
+		assert_eq!(Currencies::free_balance(AUSD, &BOB), 0);
+
+		assert_ok!(CDPEngineModule::adjust_position(&ALICE, BTC, 1000, 1000));
+		assert_ok!(CDPEngineModule::adjust_position(&ALICE, DOT, 1000, 1000));
+
+		CDPEngineModule::accumulate_interest(2, 1);
+		assert_eq!(CDPEngineModule::last_accumulation_secs(), 2);
+
+		// Generated interest = debit * debit_exchange_rate * interest_rate
+		//  = 1000 * 0.1 * 0.01 + 1000 * 0.1 * 1 = 101
+		assert_eq!(Currencies::free_balance(AUSD, &BOB), 101);
+
+		assert_eq!(
+			CDPEngineModule::get_debit_exchange_rate(BTC),
+			ExchangeRate::saturating_from_rational(101, 1000)
+		);
+		assert_eq!(
+			CDPEngineModule::get_debit_exchange_rate(DOT),
+			ExchangeRate::saturating_from_rational(2, 10)
+		);
+
+		CDPEngineModule::accumulate_interest(3, 2);
+		assert_eq!(CDPEngineModule::last_accumulation_secs(), 3);
+
+		// Generated interest = debit * debit_exchange_rate * interest_rate
+		//  = 1000 * 0.101 * 0.01 + 1000 * 0.2 * 1 = 201
+		assert_eq!(Currencies::free_balance(AUSD, &BOB), 302);
+
+		assert_eq!(
+			CDPEngineModule::get_debit_exchange_rate(BTC),
+			ExchangeRate::saturating_from_rational(10201, 100000)
+		);
+		assert_eq!(
+			CDPEngineModule::get_debit_exchange_rate(DOT),
+			ExchangeRate::saturating_from_rational(4, 10)
+		);
+	});
+}

modules/fees/Cargo.toml

@@ -0,0 +1,49 @@
+[package]
+name = "module-fees"
+version = "2.6.3"
+authors = ["Acala Developers"]
+edition = "2021"
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "3.0.0", default-features = false }
+scale-info = { version = "2.1", default-features = false, features = ["derive"] }
+serde = { version = "1.0.136", optional = true }
+
+frame-support = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.24", default-features = false }
+frame-system = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.24", default-features = false }
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.24", default-features = false }
+sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.24", default-features = false }
+sp-std = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.24", default-features = false }
+
+orml-traits = { package = "orml-traits", path = "../../orml/traits", default-features = false }
+orml-tokens = { package = "orml-tokens", path = "../../orml/tokens", default-features = false }
+
+support = { package = "module-support", path = "../support", default-features = false }
+primitives = { package = "acala-primitives", path = "../../primitives", default-features = false }
+
+paste = "1.0"
+
+[dev-dependencies]
+sp-io = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.24" }
+pallet-balances = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.24" }
+orml-tokens = { path = "../../orml/tokens" }
+module-currencies = { path = "../../modules/currencies" }
+module-dex = { path = "../../modules/dex" }
+
+[features]
+default = ["std"]
+std = [
+	"serde",
+	"codec/std",
+	"scale-info/std",
+	"sp-runtime/std",
+	"frame-support/std",
+	"frame-system/std",
+	"sp-core/std",
+	"sp-std/std",
+	"orml-traits/std",
+	"orml-tokens/std",
+	"support/std",
+	"primitives/std",
+]
+try-runtime = ["frame-support/try-runtime"]