Asset Conversion pallet (#12984)

* Add pallet dex

* Fmt

* Add RPC endpoint

* Fix RPC

* Fix the build

* Some more fixes

* Add a method to topup pallet's account

* Add support for multi-currency into Uniques

* Fix the build

* Add [transactional] + setup() + fix balances

* Improve tests

* Fix price quotation

* Code clean up

* Validate swaps

* Fmt

* Update README

* add test

* mint LP assets in a different instance

* remove transactional as now the default

AssetsLocal renamed to Assets

* merge master

* Revert "Merge master"

* fix tests post merge.

* attempt to set create origin

* Internally allocate lp asset id.

* Simplify

* Bump to be in line

* additional bumps to make compile

* fix compile

* less bounds

* use fungible crates

* multiasset enum

* only allow native currency pairs

* added slippage tests

* transfer into separate method

(Also fee not set in 2 places now.)

Added test where lp and user are different users.

* Add benchmarks + weights

* Typos

* Clean up

* More tests,

split error into two because it wasn't clear which parameter.

renamed liquidity to lp_tokens_minted or lp_tokens_burned in events.

* tighten up naming

* Default, zero, square root traits not needed

Also let's not force people to be compact

* add keep-alive param

* add insufficient liquidity test

* Fix quote() to support u64

* Avoid recording balances twice

* cargo fmt

* Didn't mean to change error type

* temp

* Less

* Rework get_amount_in/get_amount_out

* Convert other places

* Rework the last piece

* Typo

* Fix benchmarks

* use hash trait

* Extract a native asset check into the runtime setting

* Don't set the metadata

* Remove spec file

* Enable multi-assets swaps by default

* Refactor conversion into u128

* Add path param to swap_token_for_exact_tokens

* Fix typo + a bit of refactoring

* Implement path param for swap_exact_tokens_for_tokens()

* Deref

* Minor fixes

* Add test with sensible scale values

* Use .windows()

* Fix benchmarks

* update docs

* Fix everything :)

* Chore

* Revert

* Chore

* prev way of creating sub accounts lead to collisions

* Update frame/dex/src/lib.rs

Co-authored-by: Jegor Sidorenko <5252494+jsidorenko@users.noreply.github.com>

* Update frame/dex/src/lib.rs

Co-authored-by: Jegor Sidorenko <5252494+jsidorenko@users.noreply.github.com>

* Chore

* Fmt fix on Uniques

* add call_index

bring code up to date with latest master

* revert readme changes

* add cr

* revert uniques changes

* reducing noise

* no need for deadline (#12990)

(there's generic transaction deadline functionality already)

* fix kitchen sink (#12991)

* fix kitchen sink

* Only the dex can mint lp_tokens

* add BenchmarkHelper for second instance (#12998)

* update mock to latest master

* less indirections (#13012)

* remove dex PR's custom RPC (#13050)

* As we have state_call we don't need a custom RPC

* fix docs

* no longer a need to upgrade rpc version (#13053)

* add CallbackHadle

* quote bugfix (#13191)

quote was giving same price in both directions as we were inverting needlessly.

* merging in dex specific changes due to pay by dex

* update lock file

* merging in kitchen sink changes

* Add get_reserves() api method

* Partial updating of the benchmarks

* Fix tests

* clippy

* Temp fix weights

* Fix benchmarks

* Add pool setup fee

* Money upfront

* Address some comments

* Use u128 in mock

* Fix benchmarks

* Change error message

* Update comments

* Change error names

* Implement PartialOrd for NativeOrAssetId

* add note

* Update errors

* More tests for assets sorting

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_dex

* Change the way we generate pool accounts

* Improve the liquidity removal method

* Extract MintMinLiquidity to config, rework all tests

* Add comments

* Validate provided amount

* Rename to asset-conversion

* Validate ED

* Improve handling the ED related errors

* typos

* Try to fix benchmarks

* Another try

* Another day, another try

* Fix benchmarks

* Expose fee related params

* Validate token's minimal amount the same way as ED

* fix typo

* Use longer path for swaps in benchmarks

* need to ref sp_std's vec.

* Remove From<u32> requirement when benchmarking

* impl BenchmarkHelper for ()

* only for runtime benchmarks

* MultiLocation: !MaybeDisplay

Looks like we might not need this bound from initial testing.

* Update frame/asset-conversion/src/lib.rs

Co-authored-by: Jegor Sidorenko <5252494+jsidorenko@users.noreply.github.com>

* Update frame/asset-conversion/src/lib.rs

Co-authored-by: Jegor Sidorenko <5252494+jsidorenko@users.noreply.github.com>

* Add documentation links

* add collision test

* Revert "[Enhancement] Throw an error when there are too many pallets (#13763)"

This reverts commit 9b8e6e7.

* [Enhancement] Throw an error when there are too many pallets (#13763)

* [Enhancement] Throw an error when there are too many pallets

* fix ui test

* fix PR comments

* Update frame/support/procedural/src/construct_runtime/mod.rs

Co-authored-by: Bastian Köcher <git@kchr.de>

* Update frame/support/procedural/src/construct_runtime/mod.rs

Co-authored-by: Bastian Köcher <git@kchr.de>

* ".git/.scripts/commands/fmt/fmt.sh"

---------

Co-authored-by: Bastian Köcher <git@kchr.de>
Co-authored-by: command-bot <>

* add benchmark helper

+ doc fix

* cargo fmt

* Fix adding liquidity to non-empty pool

* Fix compilation error

* Fix params ordering issue

* additional docs

* The swap path elements should be unique

* Fix account collision

* Validate all the pool in a swap path are unique

* Change the way we add liquidity to empty pools

* Improve docs

* remove unnessisary Display impl

* cargo fmt

* remove unused imports

* Make api consistent

* Chore

* Touch the pool account so it could hold the pair tokens

* Check the balance before touching the pool's account

* Introduce liquidity provision fee

* Touch the pool acc one more time

* Apply suggestions from code review

Co-authored-by: Sam Johnson <sam@durosoft.com>

* Update frame/asset-conversion/README.md

Co-authored-by: Sam Johnson <sam@durosoft.com>

* Use ContainsPair instead of the balance checker

* Remove old Currency trait

* Add liquidity withdrawal fee

* Update docs

* Use 0 withdrawal fee in mock

* Rename vars

* asset id not clone

* fix: shadow var was being used

* correct tests

* fix benches

* merge master

* neater

---------

Co-authored-by: Jegor Sidorenko <jegor@parity.io>
Co-authored-by: Jegor Sidorenko <5252494+jsidorenko@users.noreply.github.com>
Co-authored-by: parity-processbot <>
Co-authored-by: Roman Useinov <roman.useinov@gmail.com>
Co-authored-by: Bastian Köcher <git@kchr.de>
Co-authored-by: Sam Johnson <sam@durosoft.com>

Cargo.toml

@@ -74,6 +74,7 @@ members = [
 	"client/transaction-pool/api",
 	"client/utils",
 	"frame/alliance",
+	"frame/asset-conversion",
 	"frame/assets",
 	"frame/atomic-swap",
 	"frame/aura",

bin/node/cli/Cargo.toml

@@ -88,6 +88,7 @@ sc-storage-monitor = { version = "0.1.0", path = "../../../client/storage-monito
 frame-system = { version = "4.0.0-dev", path = "../../../frame/system" }
 frame-system-rpc-runtime-api = { version = "4.0.0-dev", path = "../../../frame/system/rpc/runtime-api" }
 pallet-transaction-payment = { version = "4.0.0-dev", path = "../../../frame/transaction-payment" }
+pallet-asset-conversion = { version = "4.0.0-dev", path = "../../../frame/asset-conversion" }
 pallet-assets = { version = "4.0.0-dev", path = "../../../frame/assets/" }
 pallet-asset-tx-payment = { version = "4.0.0-dev", path = "../../../frame/transaction-payment/asset-tx-payment/" }
 pallet-im-online = { version = "4.0.0-dev", default-features = false, path = "../../../frame/im-online" }

bin/node/cli/src/chain_spec.rs

@@ -363,6 +363,7 @@ pub fn testnet_genesis(
 			assets: vec![(9, get_account_id_from_seed::<sr25519::Public>("Alice"), true, 1)],
 			..Default::default()
 		},
+		pool_assets: Default::default(),
 		transaction_storage: Default::default(),
 		transaction_payment: Default::default(),
 		alliance: Default::default(),

bin/node/runtime/Cargo.toml

@@ -24,6 +24,9 @@ scale-info = { version = "2.5.0", default-features = false, features = ["derive"
 static_assertions = "1.1.0"
 log = { version = "0.4.17", default-features = false }
 
+# pallet-asset-conversion: turn on "num-traits" feature
+primitive-types = { version = "0.12.0", default-features = false, features = ["codec", "scale-info", "num-traits"] }
+
 # primitives
 sp-authority-discovery = { version = "4.0.0-dev", default-features = false, path = "../../../primitives/authority-discovery" }
 sp-consensus-babe = { version = "0.10.0-dev", default-features = false, path = "../../../primitives/consensus/babe" }
@@ -54,6 +57,7 @@ frame-election-provider-support = { version = "4.0.0-dev", default-features = fa
 frame-system-rpc-runtime-api = { version = "4.0.0-dev", default-features = false, path = "../../../frame/system/rpc/runtime-api/" }
 frame-try-runtime = { version = "0.10.0-dev", default-features = false, path = "../../../frame/try-runtime", optional = true }
 pallet-alliance = { version = "4.0.0-dev", default-features = false, path = "../../../frame/alliance" }
+pallet-asset-conversion = { version = "4.0.0-dev", default-features = false, path = "../../../frame/asset-conversion" }
 pallet-asset-rate = { version = "4.0.0-dev", default-features = false, path = "../../../frame/asset-rate" }
 pallet-assets = { version = "4.0.0-dev", default-features = false, path = "../../../frame/assets" }
 pallet-authority-discovery = { version = "4.0.0-dev", default-features = false, path = "../../../frame/authority-discovery" }
@@ -137,6 +141,7 @@ std = [
 	"frame-system-benchmarking?/std",
 	"frame-election-provider-support/std",
 	"sp-authority-discovery/std",
+	"pallet-asset-conversion/std",
 	"pallet-assets/std",
 	"pallet-authority-discovery/std",
 	"pallet-authorship/std",
@@ -236,6 +241,7 @@ runtime-benchmarks = [
 	"frame-system/runtime-benchmarks",
 	"sp-runtime/runtime-benchmarks",
 	"pallet-alliance/runtime-benchmarks",
+	"pallet-asset-conversion/runtime-benchmarks",
 	"pallet-assets/runtime-benchmarks",
 	"pallet-babe/runtime-benchmarks",
 	"pallet-bags-list/runtime-benchmarks",
@@ -297,6 +303,7 @@ try-runtime = [
 	"frame-system/try-runtime",
 	"frame-support/try-runtime",
 	"pallet-alliance/try-runtime",
+	"pallet-asset-conversion/try-runtime",
 	"pallet-assets/try-runtime",
 	"pallet-authority-discovery/try-runtime",
 	"pallet-authorship/try-runtime",

bin/node/runtime/src/lib.rs

@@ -29,6 +29,8 @@ use frame_election_provider_support::{
 use frame_support::{
 	construct_runtime,
 	dispatch::DispatchClass,
+	instances::{Instance1, Instance2},
+	ord_parameter_types,
 	pallet_prelude::Get,
 	parameter_types,
 	traits::{
@@ -48,10 +50,11 @@ use frame_support::{
 };
 use frame_system::{
 	limits::{BlockLength, BlockWeights},
-	EnsureRoot, EnsureRootWithSuccess, EnsureSigned, EnsureWithSuccess,
+	EnsureRoot, EnsureRootWithSuccess, EnsureSigned, EnsureSignedBy, EnsureWithSuccess,
 };
 pub use node_primitives::{AccountId, Signature};
 use node_primitives::{AccountIndex, Balance, BlockNumber, Hash, Index, Moment};
+use pallet_asset_conversion::{NativeOrAssetId, NativeOrAssetIdConverter};
 use pallet_election_provider_multi_phase::SolutionAccuracyOf;
 use pallet_im_online::sr25519::AuthorityId as ImOnlineId;
 use pallet_nfts::PalletFeatures;
@@ -69,8 +72,8 @@ use sp_runtime::{
 	curve::PiecewiseLinear,
 	generic, impl_opaque_keys,
 	traits::{
-		self, BlakeTwo256, Block as BlockT, Bounded, ConvertInto, NumberFor, OpaqueKeys,
-		SaturatedConversion, StaticLookup,
+		self, AccountIdConversion, BlakeTwo256, Block as BlockT, Bounded, ConvertInto, NumberFor,
+		OpaqueKeys, SaturatedConversion, StaticLookup,
 	},
 	transaction_validity::{TransactionPriority, TransactionSource, TransactionValidity},
 	ApplyExtrinsicResult, FixedPointNumber, FixedU128, Perbill, Percent, Permill, Perquintill,
@@ -482,7 +485,7 @@ 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>,
+		pallet_assets::BalanceToAssetBalance<Balances, Runtime, ConvertInto, Instance1>,
 		CreditToBlockAuthor,
 	>;
 }
@@ -1473,7 +1476,7 @@ parameter_types! {
 	pub const MetadataDepositPerByte: Balance = 1 * DOLLARS;
 }
 
-impl pallet_assets::Config for Runtime {
+impl pallet_assets::Config<Instance1> for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type Balance = u128;
 	type AssetId = u32;
@@ -1496,6 +1499,66 @@ 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 = u128;
+	type AssetId = u32;
+	type AssetIdParameter = codec::Compact<u32>;
+	type Currency = Balances;
+	type CreateOrigin = AsEnsureOriginWithArg<EnsureSignedBy<AssetConversionOrigin, AccountId>>;
+	type ForceOrigin = EnsureRoot<AccountId>;
+	type AssetDeposit = AssetDeposit;
+	type AssetAccountDeposit = ConstU128<DOLLARS>;
+	type MetadataDepositBase = MetadataDepositBase;
+	type MetadataDepositPerByte = MetadataDepositPerByte;
+	type ApprovalDeposit = ApprovalDeposit;
+	type StringLimit = StringLimit;
+	type Freezer = ();
+	type Extra = ();
+	type WeightInfo = pallet_assets::weights::SubstrateWeight<Runtime>;
+	type RemoveItemsLimit = ConstU32<1000>;
+	type CallbackHandle = ();
+	#[cfg(feature = "runtime-benchmarks")]
+	type BenchmarkHelper = ();
+}
+
+parameter_types! {
+	pub const AssetConversionPalletId: PalletId = PalletId(*b"py/ascon");
+	pub AllowMultiAssetPools: bool = true;
+	pub const PoolSetupFee: Balance = 1 * DOLLARS; // 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 = <Self as pallet_balances::Config>::Balance;
+	type HigherPrecisionBalance = sp_core::U256;
+	type Assets = Assets;
+	type Balance = u128;
+	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 = ();
+}
+
 parameter_types! {
 	pub const QueueCount: u32 = 300;
 	pub const MaxQueueLen: u32 = 1000;
@@ -1617,7 +1680,7 @@ impl pallet_nft_fractionalization::Config for Runtime {
 	type NftCollectionId = <Self as pallet_nfts::Config>::CollectionId;
 	type NftId = <Self as pallet_nfts::Config>::ItemId;
 	type AssetBalance = <Self as pallet_balances::Config>::Balance;
-	type AssetId = <Self as pallet_assets::Config>::AssetId;
+	type AssetId = <Self as pallet_assets::Config<Instance1>>::AssetId;
 	type Assets = Assets;
 	type Nfts = Nfts;
 	type PalletId = NftFractionalizationPalletId;
@@ -1838,7 +1901,8 @@ construct_runtime!(
 		Multisig: pallet_multisig,
 		Bounties: pallet_bounties,
 		Tips: pallet_tips,
-		Assets: pallet_assets,
+		Assets: pallet_assets::<Instance1>,
+		PoolAssets: pallet_assets::<Instance2>,
 		Mmr: pallet_mmr,
 		Lottery: pallet_lottery,
 		Nis: pallet_nis,
@@ -1861,6 +1925,7 @@ construct_runtime!(
 		NominationPools: pallet_nomination_pools,
 		RankedPolls: pallet_referenda::<Instance2>,
 		RankedCollective: pallet_ranked_collective,
+		AssetConversion: pallet_asset_conversion,
 		FastUnstake: pallet_fast_unstake,
 		MessageQueue: pallet_message_queue,
 		Pov: frame_benchmarking_pallet_pov,
@@ -1951,6 +2016,7 @@ mod benches {
 		[pallet_contracts, Contracts]
 		[pallet_core_fellowship, CoreFellowship]
 		[pallet_democracy, Democracy]
+		[pallet_asset_conversion, AssetConversion]
 		[pallet_election_provider_multi_phase, ElectionProviderMultiPhase]
 		[pallet_election_provider_support_benchmarking, EPSBench::<Runtime>]
 		[pallet_elections_phragmen, Elections]
@@ -2288,6 +2354,26 @@ 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_transaction_payment_rpc_runtime_api::TransactionPaymentCallApi<Block, Balance, RuntimeCall>
 		for Runtime
 	{

bin/node/testing/Cargo.toml

@@ -22,6 +22,7 @@ frame-system = { version = "4.0.0-dev", path = "../../../frame/system" }
 node-executor = { version = "3.0.0-dev", path = "../executor" }
 node-primitives = { version = "2.0.0", path = "../primitives" }
 kitchensink-runtime = { version = "3.0.0-dev", path = "../runtime" }
+pallet-asset-conversion = { version = "4.0.0-dev", path = "../../../frame/asset-conversion" }
 pallet-assets = { version = "4.0.0-dev", path = "../../../frame/assets" }
 pallet-asset-tx-payment = { version = "4.0.0-dev", path = "../../../frame/transaction-payment/asset-tx-payment" }
 pallet-transaction-payment = { version = "4.0.0-dev", path = "../../../frame/transaction-payment" }

bin/node/testing/src/genesis.rs

@@ -89,6 +89,7 @@ pub fn config_endowed(code: Option<&[u8]>, extra_endowed: Vec<AccountId>) -> Gen
 		society: SocietyConfig { members: vec![alice(), bob()], pot: 0, max_members: 999 },
 		vesting: Default::default(),
 		assets: AssetsConfig { assets: vec![(9, alice(), true, 1)], ..Default::default() },
+		pool_assets: Default::default(),
 		transaction_storage: Default::default(),
 		transaction_payment: Default::default(),
 		alliance: Default::default(),

frame/asset-conversion/Cargo.toml

@@ -0,0 +1,52 @@
+[package]
+name = "pallet-asset-conversion"
+version = "4.0.0-dev"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2021"
+license = "Apache-2.0"
+homepage = "https://substrate.io"
+repository = "https://github.com/paritytech/substrate/"
+description = "FRAME asset conversion pallet"
+readme = "README.md"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "3.0.0", default-features = false, features = ["derive"]  }
+frame-support = { version = "4.0.0-dev", default-features = false, path = "../support" }
+frame-system = { version = "4.0.0-dev", default-features = false, path = "../system" }
+frame-benchmarking = { version = "4.0.0-dev", default-features = false, path = "../benchmarking", optional = true }
+scale-info = { version = "2.0.0", default-features = false, features = ["derive"] }
+sp-api = { version = "4.0.0-dev", default-features = false, path = "../../primitives/api" }
+sp-io = { version = "7.0.0", default-features = false, path = "../../primitives/io" }
+sp-std = { version = "5.0.0", default-features = false, path = "../../primitives/std" }
+sp-runtime = { version = "7.0.0", default-features = false, path = "../../primitives/runtime" }
+sp-arithmetic = { version = "6.0.0", default-features = false, path = "../../primitives/arithmetic" }
+
+[dev-dependencies]
+pallet-balances = { version = "4.0.0-dev", path = "../balances" }
+pallet-assets = { version = "4.0.0-dev", path = "../assets" }
+primitive-types = { version = "0.12.0", default-features = false, features = ["codec", "scale-info", "num-traits"] }
+sp-std = { version = "5.0.0", path = "../../primitives/std" }
+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",
+	"scale-info/std",
+	"sp-std/std",
+	"sp-runtime/std",
+	"sp-arithmetic/std"
+]
+runtime-benchmarks = [
+	"frame-benchmarking/runtime-benchmarks",
+	"frame-system/runtime-benchmarks",
+	"sp-runtime/runtime-benchmarks",
+]
+try-runtime = ["frame-support/try-runtime"]