Stablefee
Last updated
Last updated
The stablefee module manages the configuration and calculation of fees in a stable currency, converting them to the native chain currency (EMPE) using an exchange rate. It allows authorized providers to set the exchange rate and governance to update module parameters. Fees for operations are charged based on predefined rates and distributed to specified recipients, with any remainder sent to the module account.
The stablefee module provides the following key functionalities:
Exchange Rate Management: Authorized providers can update the exchange rate between the stable base currency (e.g., USD) and the native chain currency (EMPE).
Fee Calculation: Fees for operations (e.g., swaps, transfers) are defined in the stable currency and converted to EMPE using the current exchange rate.
Fee Distribution: Collected fees are distributed to predefined recipients with configurable fractions, with any remainder sent to the module account.
Parameter Updates: Governance can update module parameters, including fee pairs, distributions, and authorized exchange rate providers.
This message updates the exchange rate (EMPE per unit of base currency). Only authorized providers can execute this.
Definition:
Validation and Processing:
Sender
must be a valid Bech32 address and listed in ExchangeRateProviders
module parameters.
NewRate
must be a positive decimal value.
Upon success:
The exchange rate is updated in the module's state.
Emits an EventSetExchangeRate
event.
This message updates the module parameters via governance proposal.
Definition:
Validation and Processing:
Authority
must match the chain's governance address.
Params
are validated (e.g., base currency non-empty, valid distributions).
Upon success:
Module parameters are updated.
Emits an EventUpdateParams
event.
Returns the current module parameters, including base currency, fee pairs, and distributions.
Request:
Response:
CLI Command:
Returns the current exchange rate (EMPE per base currency unit).
Request:
Response:
CLI Command:
Calculates the fee in EMPE for a specific operation.
Request:
Response:
CLI Command:
Emitted when the exchange rate is updated.
Attributes:
sender
: Address of the provider who set the rate.
new_rate
: New exchange rate value.
Emitted when module parameters are updated.
Attributes:
authority
: Governance address that authorized the update.
params
: New parameters.
The module's parameters include:
BaseCurrency: Stable currency identifier (e.g., "USD").
Fees: List of FeePair
objects mapping operations to stable currency fees:
Distributions: List of FeeDistribution
recipients and fractions:
ExchangeRateProviders: Authorized addresses allowed to set exchange rates.
Parameters are updatable via governance using MsgUpdateParams
.
The genesis state includes:
Params: Initial module parameters.
ExchangeRate: Initial exchange rate (EMPE per base currency unit).
Genesis validation ensures:
Parameters are valid (non-empty base currency, valid distributions).
Exchange rate is positive.
Set Exchange Rate:
Update Parameters (via governance proposal):
Query Parameters:
Query Exchange Rate:
Query Fee for Operation:
The module includes simulation operations to test:
SimulateMsgSetExchangeRate: Generates random exchange rate updates from authorized providers.
Parameter Updates: Tests governance proposals with valid/invalid parameters.
Simulations validate fee distributions, exchange rate effects, and error handling.
Fee Conversion: Fees are calculated as (StableFee * ExchangeRate)
in EMPE, rounded down to the nearest integer.
Distribution Logic:
Fees are split proportionally to distribution fractions.
Remainder (after distributions) is sent to the module account.
Security:
Only governance can update parameters.
Exchange rate providers are explicitly whitelisted.