Crate pallet_transaction_payment

Transaction Payment Pallet

This pallet provides the basic logic needed to pay the absolute minimum amount needed for a transaction to be included. This includes:

• base fee: This is the minimum amount a user pays for a transaction. It is declared as a base weight in the runtime and converted to a fee using WeightToFee.
• weight fee: A fee proportional to amount of weight a transaction consumes.
• length fee: A fee proportional to the encoded length of the transaction.
• tip: An optional tip. Tip increases the priority of the transaction, giving it a higher chance to be included by the transaction queue.

The base fee and adjusted weight and length fees constitute the inclusion fee, which is the minimum fee for a transaction to be included in a block.

The formula of final fee:

inclusion_fee = base_fee + length_fee + [targeted_fee_adjustment * weight_fee];
final_fee = inclusion_fee + tip;

• targeted_fee_adjustment: This is a multiplier that can tune the final fee based on the congestion of the network.

Additionally, this pallet allows one to configure:

• The mapping between one unit of weight to one unit of fee via Config::WeightToFee.
• A means of updating the fee for the next block, via defining a multiplier, based on the final state of the chain at the end of the previous block. This can be configured via Config::FeeMultiplierUpdate
• How the fees are paid via Config::OnChargeTransaction.

Re-exports

pub use pallet::*;

Modules

pallet

The module that hosts all the FRAME types needed to add this pallet to a runtime.

Structs

ChargeTransactionPayment

Require the transactor pay for themselves and maybe include a tip to gain additional priority in the queue.

CurrencyAdapter

Implements the transaction payment for a pallet implementing the Currency trait (eg. the pallet_balances) using an unbalance handler (implementing OnUnbalanced).

FeeDetails

The FeeDetails is composed of:

InclusionFee

The base fee and adjusted weight and length fees constitute the inclusion fee.

RuntimeDispatchInfo

Information related to a dispatchable’s class, weight, and fee that can be queried from the runtime.

TargetedFeeAdjustment

A struct to update the weight multiplier per block. It implements Convert<Multiplier, Multiplier>, meaning that it can convert the previous multiplier to the next one. This should be called on on_finalize of a block, prior to potentially cleaning the weight data from the system pallet.

Traits

MultiplierUpdate

Something that can convert the current multiplier to the next one.

OnChargeTransaction

Handle withdrawing, refunding and depositing of transaction fees.

Type Definitions

Multiplier

Fee multiplier.