mint

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Published: Feb 22, 2023 License: Apache-2.0, Apache-2.0 Imports: 16 Imported by: 0

README


title: "Mint" excerpt: "" category: 6392913957c533007128548e

The Mint Module

The x/mint module mints tokens at the end of epochs.

The x/distribution module is responsible for allocating tokens to stakers, community pool, etc.

The mint module uses time basis epochs from the x/epochs module.

The x/mint module is designed by Osmosis. It is used to handle the regular printing of new tokens within a chain. Its core function is to:

  • Mint new tokens once per epoch (default one week)
  • Have a "Reductioning factor" every period, which reduces the amount of rewards per epoch. (default: period is 3 years, where a year is 52 epochs. The next period's rewards are 2/3 of the prior period's rewards)

Params

Minting params are held in the global params store.

type Params struct {
    MintDenom               string                  // type of coin to mint
    GenesisEpochProvisions  sdk.Dec                 // initial epoch provisions at genesis
    EpochIdentifier         string                  // identifier of epoch
    ReductionPeriodInEpochs int64                   // number of epochs between reward reductions
    ReductionFactor         sdk.Dec                 // reduction multiplier to execute on each period
 DistributionProportions DistributionProportions // distribution_proportions defines the proportion of the minted denom
 WeightedDeveloperRewardsReceivers    []WeightedAddress // address to receive developer rewards
 MintingRewardsDistributionStartEpoch int64             // start epoch to distribute minting rewards
}

The minting module contains the following parameters:

Key Type Example
mint_denom string "uosmo"
genesis_epoch_provisions string (dec) "500000000"
epoch_identifier string "weekly"
reduction_period_in_epochs int64 156
reduction_factor string (dec) "0.6666666666666"
distribution_proportions.staking string (dec) "0.4"
distribution_proportions.pool_incentives string (dec) "0.3"
distribution_proportions.developer_rewards string (dec) "0.2"
distribution_proportions.community_pool string (dec) "0.1"
weighted_developer_rewards_receivers array [{"address": "osmoxx", "weight": "1"}]
minting_rewards_distribution_start_epoch int64 10

EpochProvision

Calculate the provisions generated for each epoch based on current epoch provisions. The provisions are then minted by the mint module's ModuleMinterAccount. These rewards are transferred to a FeeCollector, which handles distributing the rewards per the chains needs. (See TODO.md for details) This fee collector is specified as the auth module's FeeCollector ModuleAccount.

func (m Minter) EpochProvision(params Params) sdk.Coin {
    provisionAmt := m.EpochProvisions.QuoInt(sdkmath.NewInt(int64(params.EpochsPerYear)))
    return sdk.NewCoin(params.MintDenom, provisionAmt.TruncateInt())
}

Notes

  1. mint_denom defines denom for minting token - uosmo
  2. genesis_epoch_provisions provides minting tokens per epoch at genesis.
  3. epoch_identifier defines the epoch identifier to be used for mint module e.g. "weekly"
  4. reduction_period_in_epochs defines the number of epochs to pass to reduce mint amount
  5. reduction_factor defines the reduction factor of tokens at every reduction_period_in_epochs
  6. distribution_proportions defines distribution rules for minted tokens, when developer rewards address is empty, it distribute tokens to community pool.
  7. weighted_developer_rewards_receivers provides the addresses that receives developer rewards by weight
  8. minting_rewards_distribution_start_epoch defines the start epoch of minting to make sure minting start after initial pools are set

Begin-Epoch

Minting parameters are recalculated and inflation paid at the beginning of each epoch. An epoch is signalled by x/epochs

NextEpochProvisions

The target epoch provision is recalculated on each reduction period (default 3 years). At the time of reduction, the current provision is multiplied by reduction factor (default 2/3), to calculate the provisions for the next epoch. Consequently, the rewards of the next period will be lowered by 1 - reduction factor.

func (m Minter) NextEpochProvisions(params Params) sdk.Dec {
    return m.EpochProvisions.Mul(params.ReductionFactor)
}

Reductioning factor

This is a generalization over the Bitcoin style halvenings. Every year, the amount of rewards issued per week will reduce by a governance specified factor, instead of a fixed 1/2. So RewardsPerEpochNextPeriod = ReductionFactor * CurrentRewardsPerEpoch). When ReductionFactor = 1/2, the Bitcoin halvenings are recreated. We default to having a reduction factor of 2/3, and thus reduce rewards at the end of every year by 33%.

The implication of this is that the total supply is finite, according to the following formula:

$$Total\ Supply = InitialSupply + EpochsPerPeriod * \frac{InitialRewardsPerEpoch}{1 - ReductionFactor} $$

Events

The minting module emits the following events:

End of Epoch

Type Attribute Key Attribute Value
mint epoch_number {epochNumber}
mint epoch_provisions {epochProvisions}
mint amount {amount}

Minter

The minter is a space for holding current rewards information.

type Minter struct {
    EpochProvisions sdk.Dec   // Rewards for the current epoch
}

Documentation

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func ExportGenesis

func ExportGenesis(ctx sdk.Context, keeper keeper.Keeper) *types.GenesisState

ExportGenesis returns a GenesisState for a given context and keeper.

func InitGenesis

func InitGenesis(ctx sdk.Context, keeper keeper.Keeper, ak types.AccountKeeper, bk types.BankKeeper, data *types.GenesisState)

InitGenesis new mint genesis.

Types

type AppModule

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

AppModule implements an application module for the mint module.

func NewAppModule

func NewAppModule(cdc codec.Codec, keeper keeper.Keeper, ak types.AccountKeeper, bk types.BankKeeper) AppModule

NewAppModule creates a new AppModule object.

func (AppModule) BeginBlock

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

BeginBlock returns the begin blocker for the mint module.

func (AppModule) ConsensusVersion

func (AppModule) ConsensusVersion() uint64

ConsensusVersion implements AppModule/ConsensusVersion.

func (AppModule) EndBlock

EndBlock returns the end blocker for the mint module. It returns no validator updates.

func (AppModule) ExportGenesis

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

ExportGenesis returns the exported genesis state as raw bytes for the mint module.

func (AppModule) InitGenesis

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

InitGenesis performs genesis initialization for the mint module. It returns no validator updates.

func (AppModule) LegacyQuerierHandler

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

LegacyQuerierHandler returns the x/mint module's sdk.Querier.

func (AppModule) Name

func (AppModule) Name() string

Name returns the mint module's name.

func (AppModule) ProposalContents

func (AppModule) ProposalContents(simState module.SimulationState) []simtypes.WeightedProposalContent

ProposalContents doesn't return any content functions for governance proposals.

func (AppModule) QuerierRoute

func (AppModule) QuerierRoute() string

QuerierRoute returns the mint module's querier route name.

func (AppModule) RegisterInvariants

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

RegisterInvariants registers the mint module 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 (AppModule) Route() sdk.Route

Route returns the message routing key for the mint module.

func (AppModule) WeightedOperations

func (AppModule) WeightedOperations(_ module.SimulationState) []simtypes.WeightedOperation

WeightedOperations doesn't return any mint module operation.

type AppModuleBasic

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

AppModuleBasic defines the basic application module used by the mint module.

func (AppModuleBasic) DefaultGenesis

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

DefaultGenesis returns default genesis state as raw bytes for the mint module.

func (AppModuleBasic) GetQueryCmd

func (AppModuleBasic) GetQueryCmd() *cobra.Command

GetQueryCmd returns the root query command for the mint module.

func (AppModuleBasic) GetTxCmd

func (AppModuleBasic) GetTxCmd() *cobra.Command

GetTxCmd returns no root tx command for the mint module.

func (AppModuleBasic) Name

func (AppModuleBasic) Name() string

Name returns the mint module's name.

func (AppModuleBasic) RegisterGRPCGatewayRoutes

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

RegisterGRPCGatewayRoutes registers the gRPC Gateway routes for the mint module.

func (AppModuleBasic) RegisterInterfaces

func (b AppModuleBasic) RegisterInterfaces(_ cdctypes.InterfaceRegistry)

RegisterInterfaces registers the module's interface types.

func (AppModuleBasic) RegisterLegacyAminoCodec

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

RegisterLegacyAminoCodec registers the mint module's types on the given LegacyAmino codec.

func (AppModuleBasic) RegisterRESTRoutes

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

RegisterRESTRoutes registers the REST routes for the mint module.

func (AppModuleBasic) ValidateGenesis

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

ValidateGenesis performs genesis state validation for the mint module.

Directories

Path Synopsis
client
cli
Package types is a reverse proxy.
Package types is a reverse proxy.

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