Allow fee calculation to happen off-chain

bin/node-template/runtime/src/lib.rs

@@ -15,7 +15,7 @@ use sp_runtime::{
 	transaction_validity::{TransactionValidity, TransactionSource},
 };
 use sp_runtime::traits::{
-	BlakeTwo256, Block as BlockT, IdentityLookup, Verify, ConvertInto, IdentifyAccount, NumberFor,
+	BlakeTwo256, Block as BlockT, IdentityLookup, Verify, IdentifyAccount, NumberFor,
 };
 use sp_api::impl_runtime_apis;
 use sp_consensus_aura::sr25519::AuthorityId as AuraId;
@@ -35,7 +35,7 @@ pub use frame_support::{
 	construct_runtime, parameter_types, StorageValue,
 	traits::{KeyOwnerProofSystem, Randomness},
 	weights::{
-		Weight,
+		Weight, IdentityFee,
 		constants::{BlockExecutionWeight, ExtrinsicBaseWeight, RocksDbWeight, WEIGHT_PER_SECOND},
 	},
 };
@@ -233,10 +233,11 @@ parameter_types! {
 }
 
 impl transaction_payment::Trait for Runtime {
+	type Event = Event;
 	type Currency = balances::Module<Runtime>;
 	type OnTransactionPayment = ();
 	type TransactionByteFee = TransactionByteFee;
-	type WeightToFee = ConvertInto;
+	type WeightToFee = IdentityFee<Balance>;
 	type FeeMultiplierUpdate = ();
 }
 
@@ -262,7 +263,7 @@ construct_runtime!(
 		Aura: aura::{Module, Config<T>, Inherent(Timestamp)},
 		Grandpa: grandpa::{Module, Call, Storage, Config, Event},
 		Balances: balances::{Module, Call, Storage, Config<T>, Event<T>},
-		TransactionPayment: transaction_payment::{Module, Storage},
+		TransactionPayment: transaction_payment::{Module, Storage, Event},
 		Sudo: sudo::{Module, Call, Config<T>, Storage, Event<T>},
 		// Used for the module template in `./template.rs`
 		TemplateModule: template::{Module, Call, Storage, Event<T>},

bin/node/executor/Cargo.toml

@@ -24,6 +24,7 @@ trie-root = "0.16.0"
 frame-benchmarking = { version = "2.0.0-dev", path = "../../../frame/benchmarking" }
 
 [dev-dependencies]
+assert_matches = "1.3.0"
 criterion = "0.3.0"
 frame-support = { version = "2.0.0-dev", path = "../../../frame/support" }
 frame-system = { version = "2.0.0-dev", path = "../../../frame/system" }

bin/node/executor/tests/basic.rs

@@ -19,12 +19,15 @@ use codec::{Encode, Decode, Joiner};
 use frame_support::{
 	StorageValue, StorageMap,
 	traits::Currency,
-	weights::{GetDispatchInfo, DispatchInfo, DispatchClass, constants::ExtrinsicBaseWeight},
+	weights::{
+		GetDispatchInfo, DispatchInfo, DispatchClass, constants::ExtrinsicBaseWeight,
+		WeightToFeePolynomial,
+	},
 };
 use sp_core::{NeverNativeValue, traits::Externalities, storage::well_known_keys};
 use sp_runtime::{
 	ApplyExtrinsicResult, Fixed128,
-	traits::{Hash as HashT, Convert},
+	traits::Hash as HashT,
 	transaction_validity::InvalidTransaction,
 };
 use pallet_contracts::ContractAddressFor;
@@ -38,6 +41,7 @@ use node_runtime::{
 use node_primitives::{Balance, Hash};
 use wabt;
 use node_testing::keyring::*;
+use assert_matches::assert_matches;
 
 pub mod common;
 use self::common::{*, sign};
@@ -54,9 +58,9 @@ fn transfer_fee<E: Encode>(extrinsic: &E, fee_multiplier: Fixed128) -> Balance {
 	let length_fee = TransactionByteFee::get() * (extrinsic.encode().len() as Balance);
 
 	let base_weight = ExtrinsicBaseWeight::get();
-	let base_fee = <Runtime as pallet_transaction_payment::Trait>::WeightToFee::convert(base_weight);
+	let base_fee = <Runtime as pallet_transaction_payment::Trait>::WeightToFee::calc(&base_weight);
 	let weight = default_transfer_call().get_dispatch_info().weight;
-	let weight_fee = <Runtime as pallet_transaction_payment::Trait>::WeightToFee::convert(weight);
+	let weight_fee = <Runtime as pallet_transaction_payment::Trait>::WeightToFee::calc(&weight);
 
 	base_fee + fee_multiplier.saturated_multiply_accumulate(length_fee + weight_fee)
 }
@@ -355,7 +359,18 @@ fn full_native_block_import_works() {
 				topics: vec![],
 			},
 		];
-		assert_eq!(System::events(), events);
+		let mut is_events = System::events();
+		assert_matches!(
+			is_events.remove(0),
+			EventRecord {
+				phase: Phase::Initialization,
+				event: Event::pallet_transaction_payment(
+					pallet_transaction_payment::Event::PaymentParameters(_)
+				),
+				topics: top
+			} if top == vec![]
+		);
+		assert_eq!(is_events, events);
 	});
 
 	fm = t.execute_with(TransactionPayment::next_fee_multiplier);
@@ -436,7 +451,18 @@ fn full_native_block_import_works() {
 				topics: vec![],
 			},
 		];
-		assert_eq!(System::events(), events);
+		let mut is_events = System::events();
+		assert_matches!(
+			is_events.remove(0),
+			EventRecord {
+				phase: Phase::Initialization,
+				event: Event::pallet_transaction_payment(
+					pallet_transaction_payment::Event::PaymentParameters(_)
+				),
+				topics: top
+			} if top == vec![]
+		);
+		assert_eq!(is_events, events);
 	});
 }
 

bin/node/executor/tests/fees.rs

@@ -19,16 +19,15 @@ use codec::{Encode, Joiner};
 use frame_support::{
 	StorageValue, StorageMap,
 	traits::Currency,
-	weights::{GetDispatchInfo, constants::ExtrinsicBaseWeight},
+	weights::{GetDispatchInfo, constants::ExtrinsicBaseWeight, IdentityFee, WeightToFeePolynomial},
 };
 use sp_core::NeverNativeValue;
-use sp_runtime::{Fixed128, Perbill, traits::Convert};
+use sp_runtime::{Fixed128, Perbill};
 use node_runtime::{
 	CheckedExtrinsic, Call, Runtime, Balances, TransactionPayment,
-	TransactionByteFee, WeightFeeCoefficient,
+	TransactionByteFee,
 	constants::currency::*,
 };
-use node_runtime::impls::LinearWeightToFee;
 use node_primitives::Balance;
 use node_testing::keyring::*;
 
@@ -181,13 +180,13 @@ fn transaction_fee_is_correct_ultimate() {
 		let mut balance_alice = (100 - 69) * DOLLARS;
 
 		let base_weight = ExtrinsicBaseWeight::get();
-		let base_fee = LinearWeightToFee::<WeightFeeCoefficient>::convert(base_weight);
+		let base_fee = IdentityFee::<Balance>::calc(&base_weight);
 
 		let length_fee = TransactionByteFee::get() * (xt.clone().encode().len() as Balance);
 		balance_alice -= length_fee;
 
 		let weight = default_transfer_call().get_dispatch_info().weight;
-		let weight_fee = LinearWeightToFee::<WeightFeeCoefficient>::convert(weight);
+		let weight_fee = IdentityFee::<Balance>::calc(&weight);
 
 		// we know that weight to fee multiplier is effect-less in block 1.
 		// current weight of transfer = 200_000_000