Enable Fee Delegation #5768
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,35 @@ | ||
| package simapp | ||
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| import ( | ||
| sdk "github.com/cosmos/cosmos-sdk/types" | ||
| "github.com/cosmos/cosmos-sdk/x/auth" | ||
| authante "github.com/cosmos/cosmos-sdk/x/auth/ante" | ||
| "github.com/cosmos/cosmos-sdk/x/feegrant" | ||
| feegrantante "github.com/cosmos/cosmos-sdk/x/feegrant/ante" | ||
| ) | ||
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| // NewAnteHandler returns an AnteHandler that checks and increments sequence | ||
| // numbers, checks signatures & account numbers, and deducts fees from the first | ||
| // signer. | ||
| func NewAnteHandler( | ||
| ak auth.AccountKeeper, supplyKeeper feegrant.SupplyKeeper, feeGrantKeeper feegrant.Keeper, | ||
| sigGasConsumer auth.SignatureVerificationGasConsumer, | ||
| ) sdk.AnteHandler { | ||
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| return sdk.ChainAnteDecorators( | ||
| authante.NewSetUpContextDecorator(), // outermost AnteDecorator. SetUpContext must be called first | ||
| authante.NewMempoolFeeDecorator(), | ||
| authante.NewValidateBasicDecorator(), | ||
| authante.NewValidateMemoDecorator(ak), | ||
| authante.NewConsumeGasForTxSizeDecorator(ak), | ||
| // DeductGrantedFeeDecorator will create an empty account if we sign with no | ||
| // tokens but valid validation. This must be before SetPubKey, ValidateSigCount, | ||
| // SigVerification, which error if account doesn't exist yet. | ||
| feegrantante.NewDeductGrantedFeeDecorator(ak, supplyKeeper, feeGrantKeeper), | ||
| authante.NewSetPubKeyDecorator(ak), // SetPubKeyDecorator must be called before all signature verification decorators | ||
| authante.NewValidateSigCountDecorator(ak), | ||
| authante.NewSigGasConsumeDecorator(ak, sigGasConsumer), | ||
| authante.NewSigVerificationDecorator(ak), | ||
| authante.NewIncrementSequenceDecorator(ak), // innermost AnteDecorator | ||
| ) | ||
| } | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,66 @@ | ||
| package feegrant | ||
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| import ( | ||
| "github.com/cosmos/cosmos-sdk/x/feegrant/ante" | ||
| "github.com/cosmos/cosmos-sdk/x/feegrant/keeper" | ||
| "github.com/cosmos/cosmos-sdk/x/feegrant/types" | ||
| ) | ||
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| // nolint | ||
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| const ( | ||
| DefaultCodespace = types.DefaultCodespace | ||
| EventTypeUseFeeGrant = types.EventTypeUseFeeGrant | ||
| EventTypeRevokeFeeGrant = types.EventTypeRevokeFeeGrant | ||
| EventTypeSetFeeGrant = types.EventTypeSetFeeGrant | ||
| AttributeKeyGranter = types.AttributeKeyGranter | ||
| AttributeKeyGrantee = types.AttributeKeyGrantee | ||
| ModuleName = types.ModuleName | ||
| StoreKey = types.StoreKey | ||
| RouterKey = types.RouterKey | ||
| QuerierRoute = types.QuerierRoute | ||
| QueryGetFeeAllowances = keeper.QueryGetFeeAllowances | ||
| ) | ||
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| var ( | ||
| NewDeductGrantedFeeDecorator = ante.NewDeductGrantedFeeDecorator | ||
| RegisterCodec = types.RegisterCodec | ||
| ExpiresAtTime = types.ExpiresAtTime | ||
| ExpiresAtHeight = types.ExpiresAtHeight | ||
| ClockDuration = types.ClockDuration | ||
| BlockDuration = types.BlockDuration | ||
| FeeAllowanceKey = types.FeeAllowanceKey | ||
| FeeAllowancePrefixByGrantee = types.FeeAllowancePrefixByGrantee | ||
| NewMsgRevokeFeeAllowance = types.NewMsgRevokeFeeAllowance | ||
| NewFeeGrantTx = types.NewFeeGrantTx | ||
| CountSubKeys = types.CountSubKeys | ||
| NewGrantedFee = types.NewGrantedFee | ||
| StdSignBytes = types.StdSignBytes | ||
| NewKeeper = keeper.NewKeeper | ||
| NewQuerier = keeper.NewQuerier | ||
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| ModuleCdc = types.ModuleCdc | ||
| ErrFeeLimitExceeded = types.ErrFeeLimitExceeded | ||
| ErrFeeLimitExpired = types.ErrFeeLimitExpired | ||
| ErrInvalidDuration = types.ErrInvalidDuration | ||
| ErrNoAllowance = types.ErrNoAllowance | ||
| FeeAllowanceKeyPrefix = types.FeeAllowanceKeyPrefix | ||
| ) | ||
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| type ( | ||
| GrantedFeeTx = ante.GrantedFeeTx | ||
| DeductGrantedFeeDecorator = ante.DeductGrantedFeeDecorator | ||
| BasicFeeAllowance = types.BasicFeeAllowance | ||
| ExpiresAt = types.ExpiresAt | ||
| Duration = types.Duration | ||
| FeeAllowance = types.FeeAllowance | ||
| FeeAllowanceGrant = types.FeeAllowanceGrant | ||
| MsgGrantFeeAllowance = types.MsgGrantFeeAllowance | ||
| MsgRevokeFeeAllowance = types.MsgRevokeFeeAllowance | ||
| PeriodicFeeAllowance = types.PeriodicFeeAllowance | ||
| FeeGrantTx = types.FeeGrantTx | ||
|
There was a problem hiding this comment. type name will be used as feegrant.FeeGrantTx by other packages, and that stutters; consider calling this Tx (from |
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| GrantedFee = types.GrantedFee | ||
| DelegatedSignDoc = types.DelegatedSignDoc | ||
| SupplyKeeper = types.SupplyKeeper | ||
| Keeper = keeper.Keeper | ||
| ) | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,98 @@ | ||
| package ante | ||
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| import ( | ||
| "fmt" | ||
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| sdk "github.com/cosmos/cosmos-sdk/types" | ||
| sdkerrors "github.com/cosmos/cosmos-sdk/types/errors" | ||
| "github.com/cosmos/cosmos-sdk/x/auth" | ||
| "github.com/cosmos/cosmos-sdk/x/feegrant/keeper" | ||
| "github.com/cosmos/cosmos-sdk/x/feegrant/types" | ||
| ) | ||
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| var ( | ||
| _ GrantedFeeTx = (*types.FeeGrantTx)(nil) // assert FeeGrantTx implements GrantedFeeTx | ||
| ) | ||
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| // GrantedFeeTx defines the interface to be implemented by Tx to use the GrantedFeeDecorator | ||
| type GrantedFeeTx interface { | ||
| sdk.Tx | ||
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| GetGas() uint64 | ||
| GetFee() sdk.Coins | ||
| FeePayer() sdk.AccAddress | ||
| MainSigner() sdk.AccAddress | ||
| } | ||
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| // DeductGrantedFeeDecorator deducts fees from the first signer of the tx | ||
| // If the first signer does not have the funds to pay for the fees, return with InsufficientFunds error | ||
| // Call next AnteHandler if fees successfully deducted | ||
| // CONTRACT: Tx must implement GrantedFeeTx interface to use DeductGrantedFeeDecorator | ||
| type DeductGrantedFeeDecorator struct { | ||
| ak types.AccountKeeper | ||
| k keeper.Keeper | ||
| sk types.SupplyKeeper | ||
| } | ||
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| func NewDeductGrantedFeeDecorator(ak types.AccountKeeper, sk types.SupplyKeeper, k keeper.Keeper) DeductGrantedFeeDecorator { | ||
| return DeductGrantedFeeDecorator{ | ||
| ak: ak, | ||
| k: k, | ||
| sk: sk, | ||
| } | ||
| } | ||
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| // AnteHandle performs a decorated ante-handler responsible for deducting transaction | ||
| // fees. Fees will be deducted from the account designated by the FeePayer on a | ||
| // transaction by default. However, if the fee payer differs from the transaction | ||
| // signer, the handler will check if a fee grant has been authorized. If the | ||
| // transaction's signer does not exist, it will be created. | ||
| func (d DeductGrantedFeeDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (newCtx sdk.Context, err error) { | ||
| feeTx, ok := tx.(GrantedFeeTx) | ||
| if !ok { | ||
| return ctx, sdkerrors.Wrap(sdkerrors.ErrTxDecode, "Tx must be a GrantedFeeTx") | ||
| } | ||
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| // sanity check from DeductFeeDecorator | ||
| if addr := d.sk.GetModuleAddress(auth.FeeCollectorName); addr == nil { | ||
| panic(fmt.Sprintf("%s module account has not been set", auth.FeeCollectorName)) | ||
| } | ||
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| fee := feeTx.GetFee() | ||
| feePayer := feeTx.FeePayer() | ||
| txSigner := feeTx.MainSigner() | ||
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| // ensure the grant is allowed, if we request a different fee payer | ||
| if !txSigner.Equals(feePayer) { | ||
| err := d.k.UseGrantedFees(ctx, feePayer, txSigner, fee) | ||
| if err != nil { | ||
| return ctx, sdkerrors.Wrapf(err, "%s not allowed to pay fees from %s", txSigner, feePayer) | ||
| } | ||
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| // if there was a valid grant, ensure that the txSigner account exists (we create it if needed) | ||
| signerAcc := d.ak.GetAccount(ctx, txSigner) | ||
| if signerAcc == nil { | ||
| signerAcc = d.ak.NewAccountWithAddress(ctx, txSigner) | ||
| d.ak.SetAccount(ctx, signerAcc) | ||
| } | ||
| } | ||
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| // now, either way, we know that we are authorized to deduct the fees from the feePayer account | ||
| feePayerAcc := d.ak.GetAccount(ctx, feePayer) | ||
| if feePayerAcc == nil { | ||
| return ctx, sdkerrors.Wrapf(sdkerrors.ErrUnknownAddress, "fee payer address: %s does not exist", feePayer) | ||
| } | ||
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| // move on if there is no fee to deduct | ||
| if fee.IsZero() { | ||
| return next(ctx, tx, simulate) | ||
| } | ||
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| // deduct fee if non-zero | ||
| err = auth.DeductFees(d.sk, ctx, feePayerAcc, fee) | ||
| if err != nil { | ||
| return ctx, err | ||
| } | ||
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| return next(ctx, tx, simulate) | ||
| } |
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@aaronc @ethanfrey please verify the ante-handler and order here.
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It has been a while, but this looks good.
NewSetPubKeyDecoratorposition is key, as otherwise an empty account could never use a grant until it had some tokens (which is not the behavior we wanted)There was a problem hiding this comment.
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Starting to take a look at this work again as I'm trying to figure out how to deal with account numbers and sequences starting from 1 (which was a part of ADR 020).
So one thing that I'm aware of here is that if we create the account in the
DeduceGrantedFeeDecoratorthat account number will differ from the one use for tx signing. So it seems like the correct approach to doing this is to allow accounts that don't yet exist in state to use some zero-value for account number to do signing. Since we want to avoid0as a value for account number, it sounds like1would become the zero value and2would be the first number of any real account in state.What do you think?
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Another alternative is that accounts get created (if they don't exist) whenever fee grants are created. That might be a bit cleaner in some ways.
Although, conceptually the idea that there is some way for accounts that aren't in state to sign transactions sounds desirable to me.