Merge pull request #277 from peaqnetwork/feature/1207996900912929_upd…

…ate-evm-fees

Update evm fees

runtime/peaq/src/lib.rs

@@ -48,7 +48,7 @@ use sp_runtime::{
 	transaction_validity::{
 		InvalidTransaction, TransactionSource, TransactionValidity, TransactionValidityError,
 	},
-	ApplyExtrinsicResult, Perbill, Percent, Permill,
+	ApplyExtrinsicResult, FixedPointNumber, Perbill, Percent, Permill,
 };
 use sp_std::{marker::PhantomData, prelude::*, vec, vec::Vec};
 #[cfg(feature = "std")]
@@ -136,6 +136,32 @@ type Hash = peaq_primitives_xcm::Hash;
 /// Note: this is really wild! You can define it here, but not in peaq_primitives_xcm...?!
 pub type Block = generic::Block<Header, UncheckedExtrinsic>;
 
+// Implementation from Moonbeam
+/// peaq, the native token, uses 18 decimals of precision.
+pub mod currency {
+	use super::Balance;
+
+	// Provide a common factor between runtimes based on a supply of 10_000_000 tokens.
+	pub const SUPPLY_FACTOR: Balance = 100;
+
+	pub const WEI: Balance = 1;
+	pub const KILOWEI: Balance = 1_000;
+	pub const MEGAWEI: Balance = 1_000_000;
+	pub const GIGAWEI: Balance = 1_000_000_000;
+	pub const MICROPEAQ: Balance = 1_000_000_000_000;
+	pub const MILLIPEAQ: Balance = 1_000_000_000_000_000;
+	pub const PEAQ: Balance = 1_000_000_000_000_000_000;
+	pub const KILOPEAQ: Balance = 1_000_000_000_000_000_000_000;
+
+	pub const TRANSACTION_BYTE_FEE: Balance = GIGAWEI * SUPPLY_FACTOR;
+	pub const STORAGE_BYTE_FEE: Balance = 100 * MICROPEAQ * SUPPLY_FACTOR;
+	pub const WEIGHT_FEE: Balance = 40 * KILOWEI * SUPPLY_FACTOR;
+
+	// pub const fn deposit(items: u32, bytes: u32) -> Balance {
+	// 	items as Balance * 100 * MILLIPEAQ * SUPPLY_FACTOR + (bytes as Balance) * STORAGE_BYTE_FEE
+	// }
+}
+
 /// Opaque types. These are used by the CLI to instantiate machinery that don't need to know
 /// the specifics of the runtime. They can then be made to be agnostic over specific formats
 /// of data like extrinsics, allowing for them to continue syncing the network through upgrades
@@ -633,8 +659,30 @@ parameter_types! {
 	pub GasLimitStorageGrowthRatio: u64 = 1;
 }
 
+pub struct TransactionPaymentAsGasPrice;
+impl FeeCalculator for TransactionPaymentAsGasPrice {
+	fn min_gas_price() -> (U256, Weight) {
+		// note: transaction-payment differs from EIP-1559 in that its tip and length fees are not
+		//       scaled by the multiplier, which means its multiplier will be overstated when
+		//       applied to an ethereum transaction
+		// note: transaction-payment uses both a congestion modifier (next_fee_multiplier, which is
+		//       updated once per block in on_finalize) and a 'WeightToFee' implementation. Our
+		//       runtime implements this as a 'ConstantModifier', so we can get away with a simple
+		//       multiplication here.
+		// It is imperative that `saturating_mul_int` be performed as late as possible in the
+		// expression since it involves fixed point multiplication with a division by a fixed
+		// divisor. This leads to truncation and subsequent precision loss if performed too early.
+		// This can lead to min_gas_price being same across blocks even if the multiplier changes.
+		// There's still some precision loss when the final `gas_price` (used_gas * min_gas_price)
+		// is computed in frontier, but that's currently unavoidable.
+		let min_gas_price = TransactionPayment::next_fee_multiplier()
+			.saturating_mul_int(currency::WEIGHT_FEE.saturating_mul(WEIGHT_PER_GAS as u128));
+		(min_gas_price.into(), <Runtime as frame_system::Config>::DbWeight::get().reads(1))
+	}
+}
+
 impl pallet_evm::Config for Runtime {
-	type FeeCalculator = BaseFee;
+	type FeeCalculator = TransactionPaymentAsGasPrice;
 	type WeightPerGas = WeightPerGas;
 	type GasWeightMapping = PeaqGasWeightMapping;
 	type BlockHashMapping = pallet_ethereum::EthereumBlockHashMapping<Self>;