txfees

README

Txfees

The txfees modules allows nodes to easily support many tokens for usage as txfees, while letting node operators only specify their tx fee parameters for a single "base" asset. This is done by having this module maintain an allow-list of token denoms which can be used as tx fees, each with some associated metadata. Then this metadata is used in tandem with a "Spot Price Calculator" provided to the module, to convert the provided tx fees into their equivalent value in the base denomination. Currently the only supported metadata & spot price calculator is using a GAMM pool ID & the GAMM keeper.

State Changes

• Adds a whitelist of tokens that can be used as fees on the chain.
  • Any token not on this list cannot be provided as a tx fee.
  • Any fee that is paid with a token that is on this list but is not the base denom will be collected in a separate module account to be batched and swapped into the base denom at the end of each epoch.
• Adds a new SDK message for creating governance proposals for adding new TxFee denoms.

Local Mempool Filters Added

• If you specify a min-tx-fee in the $BASEDENOM then
  • Your node will allow any tx w/ tx fee in the whitelist of fees, and a sufficient perco-equivalent price to enter your mempool
  • The perco-equivalent price for determining sufficiency is rechecked after every block. (During the mempools RecheckTx)
    • TODO: further consider if we want to take this tradeoff. Allows someone who manipulates price for one block to flush txs using that asset as fee from most of the networks' mempools.
    • The simple alternative is only check fee equivalency at a txs entry into the mempool, which allows someone to manipulate price down to have many txs enter the chain at low cost.
    • Another alternative is to use TWAP instead of Spot Price once it is available on-chain
    • The former concern isn't very worrisome as long as some nodes have 0 min tx fees.
• A separate min-gas-fee can be set on every node for arbitrage txs. Methods of detecting an arb tx atm
  • does start token of a swap = final token of swap (definitionally correct)
  • does it have multiple swap messages, with different tx ins. If so, we assume its an arb.
    • This has false positives, but is intended to avoid the obvious solution of splitting an arb into multiple messages.
  • We record all denoms seen across all swaps, and see if any duplicates. (TODO)
  • Contains both JoinPool and ExitPool messages in one tx.
    • Has some false positives.
  • These false positives seem like they primarily will get hit during batching of many distinct operations, not really in one atomic action.
• A max wanted gas per any tx can be set to filter out attack txes.
• If tx wanted gas > than predefined threshold of 1M, then separate 'min-gas-price-for-high-gas-tx' option used to calculate min gas price.

Queries

base-denom

• Query the base fee denom

denom-pool-id

• Query the pool id associated with a specific whitelisted fee token

fee-tokens

• Query the list of non-basedenom fee tokens and their associated pool ids

Future directions

• Want to add in a system to add in general "tx fee credits" for different on-chain usages
  • e.g. making 0 fee txs under certain usecases
• If other chains would like to use this, we should brainstorm mechanisms for extending the metadata proto fields

Documentation

Overview

The txfees modules allows nodes to easily support many tokens for usage as txfees, while letting node operators only specify their tx fee parameters for a single "base" asset.

- Adds a whitelist of tokens that can be used as fees on the chain. - Any token not on this list cannot be provided as a tx fee. - Adds a new SDK message for creating governance proposals for adding new TxFee denoms.

Index

• Constants
• func NewUpdateFeeTokenProposalHandler(k keeper.Keeper) govtypes.Handler
• type AppModule
  • func NewAppModule(keeper keeper.Keeper) AppModule
  • func (am AppModule) BeginBlock(_ sdk.Context, _ abci.RequestBeginBlock)
  • func (AppModule) ConsensusVersion() uint64
  • func (am AppModule) EndBlock(_ sdk.Context, _ abci.RequestEndBlock) []abci.ValidatorUpdate
  • func (am AppModule) ExportGenesis(ctx sdk.Context, cdc codec.JSONCodec) json.RawMessage
  • func (am AppModule) InitGenesis(ctx sdk.Context, cdc codec.JSONCodec, gs json.RawMessage) []abci.ValidatorUpdate
  • func (am AppModule) LegacyQuerierHandler(legacyQuerierCdc *codec.LegacyAmino) sdk.Querier
  • func (am AppModule) Name() string
  • func (AppModule) QuerierRoute() string
  • func (am AppModule) RegisterInvariants(_ sdk.InvariantRegistry)
  • func (am AppModule) RegisterServices(cfg module.Configurator)
  • func (am AppModule) Route() sdk.Route
• type AppModuleBasic
  • func NewAppModuleBasic() AppModuleBasic
  • func (AppModuleBasic) DefaultGenesis(cdc codec.JSONCodec) json.RawMessage
  • func (AppModuleBasic) GetQueryCmd() *cobra.Command
  • func (a AppModuleBasic) GetTxCmd() *cobra.Command
  • func (AppModuleBasic) Name() string
  • func (AppModuleBasic) RegisterGRPCGatewayRoutes(clientCtx client.Context, mux *runtime.ServeMux)
  • func (a AppModuleBasic) RegisterInterfaces(reg cdctypes.InterfaceRegistry)
  • func (AppModuleBasic) RegisterLegacyAminoCodec(cdc *codec.LegacyAmino)
  • func (AppModuleBasic) RegisterRESTRoutes(clientCtx client.Context, rtr *mux.Router)
  • func (AppModuleBasic) ValidateGenesis(cdc codec.JSONCodec, config client.TxEncodingConfig, bz json.RawMessage) error

Constants

const ModuleName = types.ModuleName

Functions

func NewUpdateFeeTokenProposalHandler

func NewUpdateFeeTokenProposalHandler(k keeper.Keeper) govtypes.Handler

Types

type AppModule

type AppModule struct {
	AppModuleBasic
	// contains filtered or unexported fields
}

AppModule implements the AppModule interface for the txfees module.

func NewAppModule

func NewAppModule(keeper keeper.Keeper) AppModule

func (AppModule) BeginBlock

func (am AppModule) BeginBlock(_ sdk.Context, _ abci.RequestBeginBlock)

BeginBlock executes all ABCI BeginBlock logic respective to the txfees module.

func (AppModule) ConsensusVersion

func (AppModule) ConsensusVersion() uint64

ConsensusVersion implements AppModule/ConsensusVersion.

func (AppModule) EndBlock

func (am AppModule) EndBlock(_ sdk.Context, _ abci.RequestEndBlock) []abci.ValidatorUpdate

EndBlock executes all ABCI EndBlock logic respective to the txfees module. It returns no validator updates.

func (AppModule) ExportGenesis

func (am AppModule) ExportGenesis(ctx sdk.Context, cdc codec.JSONCodec) json.RawMessage

ExportGenesis returns the txfees module's exported genesis state as raw JSON bytes.

func (AppModule) InitGenesis

func (am AppModule) InitGenesis(ctx sdk.Context, cdc codec.JSONCodec, gs json.RawMessage) []abci.ValidatorUpdate

InitGenesis performs the txfees module's genesis initialization It returns no validator updates.

func (AppModule) LegacyQuerierHandler

func (am AppModule) LegacyQuerierHandler(legacyQuerierCdc *codec.LegacyAmino) sdk.Querier

LegacyQuerierHandler is a no-op. Needed to meet AppModule interface.

func (AppModule) Name

func (am AppModule) Name() string

Name returns the txfees module's name.

func (AppModule) QuerierRoute

func (AppModule) QuerierRoute() string

QuerierRoute returns the txfees module's query routing key.

func (AppModule) RegisterInvariants

func (am AppModule) RegisterInvariants(_ sdk.InvariantRegistry)

RegisterInvariants registers the txfees module's invariants.

func (AppModule) RegisterServices

func (am AppModule) RegisterServices(cfg module.Configurator)

RegisterServices registers a GRPC query service to respond to the module-specific GRPC queries.

func (AppModule) Route

func (am AppModule) Route() sdk.Route

Route returns the txfees module's message routing key.

type AppModuleBasic

type AppModuleBasic struct{}

AppModuleBasic implements the AppModuleBasic interface for the txfees module.

func NewAppModuleBasic

func NewAppModuleBasic() AppModuleBasic

func (AppModuleBasic) DefaultGenesis

func (AppModuleBasic) DefaultGenesis(cdc codec.JSONCodec) json.RawMessage

DefaultGenesis returns the txfees module's default genesis state.

func (AppModuleBasic) GetQueryCmd

func (AppModuleBasic) GetQueryCmd() *cobra.Command

GetQueryCmd returns the txfees module's root query command.

func (AppModuleBasic) GetTxCmd

func (a AppModuleBasic) GetTxCmd() *cobra.Command

GetTxCmd returns the txfees module's root tx command.

func (AppModuleBasic) Name

func (AppModuleBasic) Name() string

Name returns the txfees module's name.

func (AppModuleBasic) RegisterGRPCGatewayRoutes

func (AppModuleBasic) RegisterGRPCGatewayRoutes(clientCtx client.Context, mux *runtime.ServeMux)

RegisterGRPCGatewayRoutes registers the gRPC Gateway routes for the module.

func (AppModuleBasic) RegisterInterfaces

func (a AppModuleBasic) RegisterInterfaces(reg cdctypes.InterfaceRegistry)

RegisterInterfaces registers the module's interface types.

func (AppModuleBasic) RegisterLegacyAminoCodec

func (AppModuleBasic) RegisterLegacyAminoCodec(cdc *codec.LegacyAmino)

func (AppModuleBasic) RegisterRESTRoutes

func (AppModuleBasic) RegisterRESTRoutes(clientCtx client.Context, rtr *mux.Router)

RegisterRESTRoutes is a no-op. Needed to meet AppModuleBasic interface.

func (AppModuleBasic) ValidateGenesis

func (AppModuleBasic) ValidateGenesis(cdc codec.JSONCodec, config client.TxEncodingConfig, bz json.RawMessage) error

ValidateGenesis performs genesis state validation for the txfee module.