feat: add asset conversion pallet

Cargo.toml

@@ -137,6 +137,7 @@ pallet-utility = { version = "25.0.0", default-features = false }
 pallet-treasury = { version = "24.0.0", default-features = false }
 pallet-safe-mode = { version = "6.0.0", default-features = false }
 pallet-tx-pause = { version = "6.0.0", default-features = false }
+pallet-asset-conversion = { version = "7.0.0", default-features = false }
 
 # Cumulus client dependencies
 cumulus-client-cli = "0.4.0"

node/src/chain_spec/stout.rs

@@ -25,7 +25,8 @@ use sc_service::ChainType;
 use sp_core::sr25519;
 use stout_runtime::{
 	constants::currency::EXISTENTIAL_DEPOSIT, AccountId, AssetsConfig, AuraId, BalancesConfig,
-	CouncilConfig, RuntimeGenesisConfig, SessionConfig, SessionKeys, SudoConfig, SystemConfig,
+	CouncilConfig, PoolAssetsConfig, RuntimeGenesisConfig, SessionConfig, SessionKeys, SudoConfig,
+	SystemConfig,
 };
 
 const DEFAULT_PROTOCOL_ID: &str = "stout";
@@ -156,5 +157,6 @@ pub fn testnet_genesis(
 			members: invulnerables.into_iter().map(|x| x.0).collect::<Vec<_>>(),
 			phantom: Default::default(),
 		},
+		pool_assets: PoolAssetsConfig { assets: vec![], accounts: vec![], metadata: vec![] },
 	}
 }

node/src/chain_spec/trappist.rs

@@ -24,7 +24,8 @@ use sc_service::ChainType;
 use sp_core::{crypto::UncheckedInto, sr25519};
 use trappist_runtime::{
 	constants::currency::EXISTENTIAL_DEPOSIT, AccountId, AssetsConfig, AuraId, BalancesConfig,
-	CouncilConfig, RuntimeGenesisConfig, SessionConfig, SessionKeys, SudoConfig, SystemConfig,
+	CouncilConfig, PoolAssetsConfig, RuntimeGenesisConfig, SessionConfig, SessionKeys, SudoConfig,
+	SystemConfig,
 };
 
 const DEFAULT_PROTOCOL_ID: &str = "hop";
@@ -214,6 +215,7 @@ pub fn testnet_genesis(
 		treasury: Default::default(),
 		safe_mode: Default::default(),
 		tx_pause: Default::default(),
+		pool_assets: PoolAssetsConfig { assets: vec![], accounts: vec![], metadata: vec![] },
 		transaction_payment: Default::default(),
 	}
 }
@@ -331,6 +333,7 @@ fn trappist_live_genesis(
 		treasury: Default::default(),
 		safe_mode: Default::default(),
 		tx_pause: Default::default(),
+		pool_assets: PoolAssetsConfig { assets: vec![], accounts: vec![], metadata: vec![] },
 		transaction_payment: Default::default(),
 	}
 }

runtime/stout/Cargo.toml

@@ -46,6 +46,7 @@ frame-system-benchmarking = { workspace = true, optional = true }
 frame-system-rpc-runtime-api = { workspace = true }
 
 ## Substrate Pallet Dependencies
+pallet-asset-conversion = { workspace = true }
 pallet-assets = { workspace = true }
 pallet-asset-tx-payment = { workspace = true }
 pallet-aura = { workspace = true }
@@ -68,6 +69,7 @@ pallet-uniques = { workspace = true }
 pallet-utility = { workspace = true }
 
 # Cumulus dependencies
+assets-common = { workspace = true }
 cumulus-pallet-aura-ext = { workspace = true }
 cumulus-pallet-dmp-queue = { workspace = true }
 cumulus-pallet-parachain-system = { workspace = true }
@@ -121,6 +123,7 @@ std = [
 	"frame-system-rpc-runtime-api/std",
 	"frame-system-benchmarking?/std",
 	"pallet-assets/std",
+	"pallet-asset-conversion/std",
 	"pallet-asset-tx-payment/std",
 	"pallet-aura/std",
 	"pallet-authorship/std",
@@ -141,6 +144,7 @@ std = [
 	"pallet-uniques/std",
 	"pallet-utility/std",
 	"pallet-xcm/std",
+	"assets-common/std",
 	"cumulus-pallet-aura-ext/std",
 	"cumulus-pallet-parachain-system/std",
 	"cumulus-pallet-xcm/std",
@@ -166,6 +170,7 @@ runtime-benchmarks = [
 	"frame-system-benchmarking/runtime-benchmarks",
 	"frame-support/runtime-benchmarks",
 	"frame-system/runtime-benchmarks",
+	"pallet-asset-conversion/runtime-benchmarks",
 	"pallet-assets/runtime-benchmarks",
 	"pallet-asset-registry/runtime-benchmarks",
 	"pallet-balances/runtime-benchmarks",
@@ -182,6 +187,7 @@ runtime-benchmarks = [
 	"cumulus-pallet-session-benchmarking/runtime-benchmarks",
 	"cumulus-pallet-xcmp-queue/runtime-benchmarks",
 	"cumulus-pallet-parachain-system/runtime-benchmarks",
+	"assets-common/runtime-benchmarks",
 ]
 parameterized-consensus-hook = [
 	"cumulus-pallet-parachain-system/parameterized-consensus-hook",

runtime/stout/src/lib.rs

@@ -18,30 +18,28 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 #![recursion_limit = "256"]
 
-// Make the WASM binary available.
-#[cfg(feature = "std")]
-include!(concat!(env!("OUT_DIR"), "/wasm_binary.rs"));
-
-pub mod constants;
-mod contracts;
-pub mod xcm_config;
+#[cfg(feature = "runtime-benchmarks")]
+#[macro_use]
+extern crate frame_benchmarking;
 
 use common::AssetIdForTrustBackedAssets;
 use cumulus_pallet_parachain_system::RelayNumberStrictlyIncreases;
 use sp_api::impl_runtime_apis;
 use sp_core::{crypto::KeyTypeId, ConstBool, ConstU8, OpaqueMetadata};
 use sp_runtime::{
 	create_runtime_str, generic, impl_opaque_keys,
-	traits::{AccountIdLookup, BlakeTwo256, Block as BlockT, ConvertInto},
+	traits::{AccountIdConversion, AccountIdLookup, BlakeTwo256, Block as BlockT, ConvertInto},
 	transaction_validity::{TransactionSource, TransactionValidity},
-	ApplyExtrinsicResult, Perbill,
+	ApplyExtrinsicResult, Perbill, Permill,
 };
 
 use constants::{currency::*, fee::WeightToFee};
+use frame_support::instances::{Instance1, Instance2};
+use frame_support::traits::fungibles::{Balanced, Credit};
 use frame_support::{
 	construct_runtime,
 	dispatch::DispatchClass,
-	parameter_types,
+	ord_parameter_types, parameter_types,
 	traits::{
 		AsEnsureOriginWithArg, ConstU128, ConstU16, ConstU32, ConstU64, EitherOfDiverse,
 		EqualPrivilegeOnly, Everything,
@@ -52,34 +50,39 @@ use frame_support::{
 	},
 	PalletId,
 };
+pub use frame_system::Call as SystemCall;
 use frame_system::{
 	limits::{BlockLength, BlockWeights},
-	EnsureRoot, EnsureSigned,
+	EnsureRoot, EnsureSigned, EnsureSignedBy,
 };
-
+use pallet_asset_conversion::{NativeOrAssetId, NativeOrAssetIdConverter};
+use pallet_asset_tx_payment::HandleCredit;
+use pallet_identity::simple::IdentityInfo;
+use pallet_xcm::{EnsureXcm, IsMajorityOfBody};
 pub use parachains_common as common;
 pub use parachains_common::{
 	impls::{AssetsToBlockAuthor, DealWithFees},
 	opaque, AccountId, AuraId, Balance, BlockNumber, Hash, Header, Signature,
 	AVERAGE_ON_INITIALIZE_RATIO, HOURS, MAXIMUM_BLOCK_WEIGHT, MINUTES, NORMAL_DISPATCH_RATIO,
 	SLOT_DURATION,
 };
+pub use polkadot_runtime_common::BlockHashCount;
+use polkadot_runtime_common::SlowAdjustingFeeUpdate;
 use sp_std::prelude::*;
 #[cfg(feature = "std")]
 use sp_version::NativeVersion;
 use sp_version::RuntimeVersion;
+use xcm::latest::prelude::BodyId;
+
 use xcm_config::{CollatorSelectionUpdateOrigin, RelayLocation};
 
-pub use frame_system::Call as SystemCall;
-use pallet_identity::simple::IdentityInfo;
-#[cfg(any(feature = "std", test))]
-pub use sp_runtime::BuildStorage;
+// Make the WASM binary available.
+#[cfg(feature = "std")]
+include!(concat!(env!("OUT_DIR"), "/wasm_binary.rs"));
 
-// Polkadot imports
-use pallet_xcm::{EnsureXcm, IsMajorityOfBody};
-pub use polkadot_runtime_common::BlockHashCount;
-use polkadot_runtime_common::SlowAdjustingFeeUpdate;
-use xcm::latest::prelude::BodyId;
+pub mod constants;
+mod contracts;
+pub mod xcm_config;
 
 pub const MICROUNIT: Balance = 1_000_000;
 
@@ -249,12 +252,24 @@ impl pallet_transaction_payment::Config for Runtime {
 	type FeeMultiplierUpdate = SlowAdjustingFeeUpdate<Self>;
 }
 
+/// A `HandleCredit` implementation that naively transfers the fees to the block author.
+/// Will drop and burn the assets in case the transfer fails.
+pub struct CreditToBlockAuthor;
+impl HandleCredit<AccountId, Assets> for CreditToBlockAuthor {
+	fn handle_credit(credit: Credit<AccountId, Assets>) {
+		if let Some(author) = pallet_authorship::Pallet::<Runtime>::author() {
+			// Drop the result which will trigger the `OnDrop` of the imbalance in case of error.
+			let _ = Assets::resolve(&author, credit);
+		}
+	}
+}
+
 impl pallet_asset_tx_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type Fungibles = Assets;
 	type OnChargeAssetTransaction = pallet_asset_tx_payment::FungiblesAdapter<
-		pallet_assets::BalanceToAssetBalance<Balances, Runtime, ConvertInto>,
-		AssetsToBlockAuthor<Runtime, ()>,
+		pallet_assets::BalanceToAssetBalance<Balances, Runtime, ConvertInto, Instance1>,
+		CreditToBlockAuthor,
 	>;
 }
 
@@ -387,12 +402,12 @@ pub type AssetsForceOrigin =
 
 pub type AssetBalance = Balance;
 
-impl pallet_assets::Config for Runtime {
+impl pallet_assets::Config<Instance1> for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type Balance = AssetBalance;
 	type RemoveItemsLimit = ConstU32<1000>;
 	type AssetId = AssetIdForTrustBackedAssets;
-	type AssetIdParameter = parity_scale_codec::Compact<u32>;
+	type AssetIdParameter = parity_scale_codec::Compact<AssetIdForTrustBackedAssets>;
 	type Currency = Balances;
 	type CreateOrigin = AsEnsureOriginWithArg<EnsureSigned<AccountId>>;
 	type ForceOrigin = AssetsForceOrigin;
@@ -410,6 +425,33 @@ impl pallet_assets::Config for Runtime {
 	type BenchmarkHelper = ();
 }
 
+ord_parameter_types! {
+	pub const AssetConversionOrigin: AccountId = AccountIdConversion::<AccountId>::into_account_truncating(&AssetConversionPalletId::get());
+}
+
+impl pallet_assets::Config<Instance2> for Runtime {
+	type RuntimeEvent = RuntimeEvent;
+	type Balance = AssetBalance;
+	type RemoveItemsLimit = ConstU32<1000>;
+	type AssetId = AssetIdForTrustBackedAssets;
+	type AssetIdParameter = parity_scale_codec::Compact<AssetIdForTrustBackedAssets>;
+	type Currency = Balances;
+	type CreateOrigin = AsEnsureOriginWithArg<EnsureSignedBy<AssetConversionOrigin, AccountId>>;
+	type ForceOrigin = AssetsForceOrigin;
+	type AssetDeposit = ConstU128<{ UNITS }>;
+	type AssetAccountDeposit = ConstU128<{ UNITS }>;
+	type MetadataDepositBase = ConstU128<{ UNITS }>;
+	type MetadataDepositPerByte = ConstU128<{ 10 * CENTS }>;
+	type ApprovalDeposit = ConstU128<{ 10 * CENTS }>;
+	type StringLimit = ConstU32<50>;
+	type Freezer = ();
+	type Extra = ();
+	type CallbackHandle = ();
+	type WeightInfo = pallet_assets::weights::SubstrateWeight<Runtime>;
+	#[cfg(feature = "runtime-benchmarks")]
+	type BenchmarkHelper = ();
+}
+
 parameter_types! {
 	pub MaxProposalWeight: Weight = Perbill::from_percent(50) * RuntimeBlockWeights::get().max_block;
 }
@@ -548,6 +590,45 @@ impl pallet_asset_registry::Config for Runtime {
 	type BenchmarkHelper = AssetRegistryBenchmarkHelper;
 }
 
+parameter_types! {
+	pub const AssetDeposit: Balance = UNITS;
+	pub const AssetAccountDeposit: Balance = deposit(1, 16);
+	pub const ApprovalDeposit: Balance = EXISTENTIAL_DEPOSIT;
+	pub const AssetsStringLimit: u32 = 50;
+	pub const MetadataDepositBase: Balance = deposit(1, 68);
+	pub const MetadataDepositPerByte: Balance = deposit(0, 1);
+	pub const AssetConversionPalletId: PalletId = PalletId(*b"py/ascon");
+	pub AllowMultiAssetPools: bool = true;
+	pub const PoolSetupFee: Balance = EXISTENTIAL_DEPOSIT; // should be more or equal to the existential deposit
+	pub const MintMinLiquidity: Balance = 100;  // 100 is good enough when the main currency has 10-12 decimals.
+	pub const LiquidityWithdrawalFee: Permill = Permill::from_percent(0);  // should be non-zero if AllowMultiAssetPools is true, otherwise can be zero.
+}
+
+impl pallet_asset_conversion::Config for Runtime {
+	type RuntimeEvent = RuntimeEvent;
+	type Currency = Balances;
+	type AssetBalance = Balance;
+	type HigherPrecisionBalance = u128;
+	type Assets = Assets;
+	type Balance = Balance;
+	type PoolAssets = PoolAssets;
+	type AssetId = <Self as pallet_assets::Config<Instance1>>::AssetId;
+	type MultiAssetId = NativeOrAssetId<u32>;
+	type PoolAssetId = <Self as pallet_assets::Config<Instance2>>::AssetId;
+	type PalletId = AssetConversionPalletId;
+	type LPFee = ConstU32<3>; // means 0.3%
+	type PoolSetupFee = PoolSetupFee;
+	type PoolSetupFeeReceiver = AssetConversionOrigin;
+	type LiquidityWithdrawalFee = LiquidityWithdrawalFee;
+	type WeightInfo = pallet_asset_conversion::weights::SubstrateWeight<Runtime>;
+	type AllowMultiAssetPools = AllowMultiAssetPools;
+	type MaxSwapPathLength = ConstU32<4>;
+	type MintMinLiquidity = MintMinLiquidity;
+	type MultiAssetIdConverter = NativeOrAssetIdConverter<u32>;
+	#[cfg(feature = "runtime-benchmarks")]
+	type BenchmarkHelper = ();
+}
+
 // Create the runtime by composing the FRAME pallets that were previously configured.
 construct_runtime!(
 	pub struct Runtime {
@@ -582,23 +663,22 @@ construct_runtime!(
 		Sudo: pallet_sudo = 40,
 		Contracts: pallet_contracts = 41,
 		Council: pallet_collective::<Instance1> = 42,
-		Assets: pallet_assets = 43,
+		Assets: pallet_assets::<Instance1> = 43,
 		Identity: pallet_identity = 44,
 		Uniques: pallet_uniques = 45,
 		Scheduler: pallet_scheduler = 46,
 		Utility: pallet_utility = 47,
 		Preimage: pallet_preimage = 48,
 		Multisig: pallet_multisig = 49,
+		// 50 was the old pallet-dex
+		AssetConversion: pallet_asset_conversion = 51,
 
 		Spambot: cumulus_ping::{Pallet, Call, Storage, Event<T>} = 99,
 		AssetRegistry: pallet_asset_registry::{Pallet, Call, Storage, Event<T>} = 111,
+		PoolAssets: pallet_assets::<Instance2> = 112,
 	}
 );
 
-#[cfg(feature = "runtime-benchmarks")]
-#[macro_use]
-extern crate frame_benchmarking;
-
 #[cfg(feature = "runtime-benchmarks")]
 mod benches {
 	define_benchmarks!(
@@ -610,6 +690,7 @@ mod benches {
 		[pallet_contracts, Contracts]
 		[pallet_collective, Council]
 		[pallet_assets, Assets]
+		[pallet_asset_conversion, AssetConversion]
 		[pallet_identity, Identity]
 		[pallet_multisig, Multisig]
 		[pallet_uniques, Uniques]
@@ -744,6 +825,17 @@ impl_runtime_apis! {
 		}
 	}
 
+	impl pallet_asset_conversion::AssetConversionApi<Block, Balance, u128, NativeOrAssetId<u32>> for Runtime {
+		fn quote_price_exact_tokens_for_tokens(asset1: NativeOrAssetId<u32>, asset2: NativeOrAssetId<u32>, amount: u128, include_fee: bool) -> Option<Balance> {
+			AssetConversion::quote_price_exact_tokens_for_tokens(asset1, asset2, amount, include_fee)
+		}
+		fn quote_price_tokens_for_exact_tokens(asset1: NativeOrAssetId<u32>, asset2: NativeOrAssetId<u32>, amount: u128, include_fee: bool) -> Option<Balance> {
+			AssetConversion::quote_price_tokens_for_exact_tokens(asset1, asset2, amount, include_fee)
+		}
+		fn get_reserves(asset1: NativeOrAssetId<u32>, asset2: NativeOrAssetId<u32>) -> Option<(Balance, Balance)> {
+			AssetConversion::get_reserves(&asset1, &asset2).ok()
+		}
+	}
 
 	impl pallet_contracts::ContractsApi<Block, AccountId, Balance, BlockNumber, Hash, EventRecord> for Runtime {
 		fn call(