Transaction Fee Module (#1648)

* wip

* Split bytes fee charging and charging by amount into different traits.

* Move to edition 2018.

* Implemented charge fee traits for fees module.

* Implemented 'on_finalise' for fee module.

* Updated fees finalize impl.

* Renaming and documentation update.

* Added overflow & underflow check for fee calculation.

* Added mock and unit tests for fee module.

* More unit tests for fees module.

* Fixed srml-executive unit tests.

* Remove transaction base/bytes fee from balances module, fix unit tests.

* fix compile error

* Fixed unit test.

* Minor fixes.

* Bump spec version.

* Bump spec version.

* Updated fees module and runtime wasm.

* Fees module code style improvement; updated runtime wasm.

* Bump spec and impl version.

substrate/node-template/runtime/Cargo.toml

@@ -16,6 +16,7 @@ version = { package = "sr-version", path = "../../core/sr-version", default_feat
 support = { package = "srml-support", path = "../../srml/support", default_features = false }
 primitives = { package = "substrate-primitives", path = "../../core/primitives", default_features = false }
 balances = { package = "srml-balances", path = "../../srml/balances", default_features = false }
+fees = { package = "srml-fees", path = "../../srml/fees", default_features = false }
 consensus = { package = "srml-consensus", path = "../../srml/consensus", default_features = false }
 aura = { package = "srml-aura", path = "../../srml/aura", default_features = false }
 executive = { package = "srml-executive", path = "../../srml/executive", default_features = false }
@@ -38,6 +39,7 @@ std = [
 	"runtime-io/std",
 	"support/std",
 	"balances/std",
+	"fees/std",
 	"executive/std",
 	"aura/std",
 	"indices/std",

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

@@ -164,6 +164,12 @@ impl balances::Trait for Runtime {
 	type Event = Event;
 }
 
+impl fees::Trait for Runtime {
+	type Amount = u128;
+	type TransferAsset = Balances;
+	type Event = Event;
+}
+
 impl sudo::Trait for Runtime {
 	/// The uniquitous event type.
 	type Event = Event;
@@ -188,6 +194,7 @@ construct_runtime!(
 		Indices: indices,
 		Balances: balances,
 		Sudo: sudo,
+		Fees: fees::{Module, Storage, Config<T>, Event<T>},
 		// Used for the module template in `./template.rs`
 		TemplateModule: template::{Module, Call, Storage, Event<T>},
 	}
@@ -208,7 +215,7 @@ pub type UncheckedExtrinsic = generic::UncheckedMortalCompactExtrinsic<Address,
 /// Extrinsic type that has already been checked.
 pub type CheckedExtrinsic = generic::CheckedExtrinsic<AccountId, Nonce, Call>;
 /// Executive: handles dispatch to the various modules.
-pub type Executive = executive::Executive<Runtime, Block, Context, Balances, AllModules>;
+pub type Executive = executive::Executive<Runtime, Block, Context, Fees, AllModules>;
 
 // Implement our runtime API endpoints. This is just a bunch of proxying.
 impl_runtime_apis! {

substrate/node-template/runtime/wasm/Cargo.lock

@@ -655,6 +655,7 @@ dependencies = [
  "srml-balances 0.1.0",
  "srml-consensus 0.1.0",
  "srml-executive 0.1.0",
+ "srml-fees 0.1.0",
  "srml-indices 0.1.0",
  "srml-sudo 0.1.0",
  "srml-support 0.1.0",
@@ -1333,6 +1334,22 @@ dependencies = [
  "srml-system 0.1.0",
 ]
 
+[[package]]
+name = "srml-fees"
+version = "0.1.0"
+dependencies = [
+ "hex-literal 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec-derive 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.85 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-io 0.1.0",
+ "sr-primitives 0.1.0",
+ "sr-std 0.1.0",
+ "srml-support 0.1.0",
+ "srml-system 0.1.0",
+ "substrate-primitives 0.1.0",
+]
+
 [[package]]
 name = "srml-indices"
 version = "0.1.0"

substrate/node-template/src/chain_spec.rs

@@ -1,7 +1,7 @@
 use primitives::{Ed25519AuthorityId, ed25519};
 use node_template_runtime::{
 	AccountId, GenesisConfig, ConsensusConfig, TimestampConfig, BalancesConfig,
-	SudoConfig, IndicesConfig
+	SudoConfig, IndicesConfig, FeesConfig,
 };
 use substrate_service;
 
@@ -90,8 +90,6 @@ fn testnet_genesis(initial_authorities: Vec<Ed25519AuthorityId>, endowed_account
 			ids: endowed_accounts.clone(),
 		}),
 		balances: Some(BalancesConfig {
-			transaction_base_fee: 1,
-			transaction_byte_fee: 0,
 			existential_deposit: 500,
 			transfer_fee: 0,
 			creation_fee: 0,
@@ -101,5 +99,9 @@ fn testnet_genesis(initial_authorities: Vec<Ed25519AuthorityId>, endowed_account
 		sudo: Some(SudoConfig {
 			key: root_key,
 		}),
+		fees: Some(FeesConfig {
+			transaction_base_fee: 1,
+			transaction_byte_fee: 0,
+		})
 	}
 }