0g-chain/x/cdp/keeper/seize.go
Nick DeLuca ba73f69688
Fix CDP keeper liquidation collateral ratio check (#1488)
* add test for exact collateral ratio; fix bug that allows cdps created at
the limit to be liquidated by a keeper; update spec

* touch up spec to be more clear

* adjust test name to better reflect what we are testing
2023-03-07 20:19:29 -07:00

170 lines
6.5 KiB
Go

package keeper
import (
"fmt"
sdk "github.com/cosmos/cosmos-sdk/types"
sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
"github.com/kava-labs/kava/x/cdp/types"
)
// AttemptKeeperLiquidation liquidates the cdp with the input collateral type and owner if it is below the required collateralization ratio
// if the cdp is liquidated, the keeper that sent the transaction is rewarded a percentage of the collateral according to that collateral types'
// keeper reward percentage.
func (k Keeper) AttemptKeeperLiquidation(ctx sdk.Context, keeper, owner sdk.AccAddress, collateralType string) error {
cdp, found := k.GetCdpByOwnerAndCollateralType(ctx, owner, collateralType)
if !found {
return sdkerrors.Wrapf(types.ErrCdpNotFound, "owner %s, denom %s", owner, collateralType)
}
k.hooks.BeforeCDPModified(ctx, cdp)
cdp = k.SynchronizeInterest(ctx, cdp)
err := k.ValidateLiquidation(ctx, cdp.Collateral, cdp.Type, cdp.Principal, cdp.AccumulatedFees)
if err != nil {
return err
}
cdp, err = k.payoutKeeperLiquidationReward(ctx, keeper, cdp)
if err != nil {
return err
}
return k.SeizeCollateral(ctx, cdp)
}
// SeizeCollateral liquidates the collateral in the input cdp.
// the following operations are performed:
// 1. Collateral for all deposits is sent from the cdp module to the liquidator module account
// 2. The liquidation penalty is applied
// 3. Debt coins are sent from the cdp module to the liquidator module account
// 4. The total amount of principal outstanding for that collateral type is decremented
// (this is the equivalent of saying that fees are no longer accumulated by a cdp once it gets liquidated)
func (k Keeper) SeizeCollateral(ctx sdk.Context, cdp types.CDP) error {
// Calculate the previous collateral ratio
oldCollateralToDebtRatio := k.CalculateCollateralToDebtRatio(ctx, cdp.Collateral, cdp.Type, cdp.GetTotalPrincipal())
// Move debt coins from cdp to liquidator account
deposits := k.GetDeposits(ctx, cdp.ID)
debt := cdp.GetTotalPrincipal().Amount
modAccountDebt := k.getModAccountDebt(ctx, types.ModuleName)
debt = sdk.MinInt(debt, modAccountDebt)
debtCoin := sdk.NewCoin(k.GetDebtDenom(ctx), debt)
err := k.bankKeeper.SendCoinsFromModuleToModule(ctx, types.ModuleName, types.LiquidatorMacc, sdk.NewCoins(debtCoin))
if err != nil {
return err
}
// liquidate deposits and send collateral from cdp to liquidator
for _, dep := range deposits {
if err := k.bankKeeper.SendCoinsFromModuleToModule(ctx, types.ModuleName, types.LiquidatorMacc, sdk.NewCoins(dep.Amount)); err != nil {
return err
}
k.DeleteDeposit(ctx, dep.CdpID, dep.Depositor)
ctx.EventManager().EmitEvent(
sdk.NewEvent(
types.EventTypeCdpLiquidation,
sdk.NewAttribute(sdk.AttributeKeyModule, types.AttributeValueCategory),
sdk.NewAttribute(types.AttributeKeyCdpID, fmt.Sprintf("%d", cdp.ID)),
sdk.NewAttribute(types.AttributeKeyDeposit, dep.String()),
),
)
}
err = k.AuctionCollateral(ctx, deposits, cdp.Type, debt, cdp.Principal.Denom)
if err != nil {
return err
}
// Decrement total principal for this collateral type
coinsToDecrement := cdp.GetTotalPrincipal()
k.DecrementTotalPrincipal(ctx, cdp.Type, coinsToDecrement)
// Delete CDP from state
k.RemoveCdpOwnerIndex(ctx, cdp)
k.RemoveCdpCollateralRatioIndex(ctx, cdp.Type, cdp.ID, oldCollateralToDebtRatio)
return k.DeleteCDP(ctx, cdp)
}
// LiquidateCdps seizes collateral from all CDPs below the input liquidation ratio
func (k Keeper) LiquidateCdps(ctx sdk.Context, marketID string, collateralType string, liquidationRatio sdk.Dec, count sdk.Int) error {
price, err := k.pricefeedKeeper.GetCurrentPrice(ctx, marketID)
if err != nil {
return err
}
priceDivLiqRatio := price.Price.Quo(liquidationRatio)
if priceDivLiqRatio.IsZero() {
priceDivLiqRatio = sdk.SmallestDec()
}
// price = $0.5
// liquidation ratio = 1.5
// normalizedRatio = (1/(0.5/1.5)) = 3
normalizedRatio := sdk.OneDec().Quo(priceDivLiqRatio)
cdpsToLiquidate := k.GetSliceOfCDPsByRatioAndType(ctx, count, normalizedRatio, collateralType)
for _, c := range cdpsToLiquidate {
k.hooks.BeforeCDPModified(ctx, c)
err := k.SeizeCollateral(ctx, c)
if err != nil {
return err
}
}
return nil
}
// ApplyLiquidationPenalty multiplies the input debt amount by the liquidation penalty
func (k Keeper) ApplyLiquidationPenalty(ctx sdk.Context, collateralType string, debt sdk.Int) sdk.Int {
penalty := k.getLiquidationPenalty(ctx, collateralType)
return sdk.NewDecFromInt(debt).Mul(penalty).RoundInt()
}
// ValidateLiquidation validate that adding the input principal puts the cdp below the liquidation ratio
func (k Keeper) ValidateLiquidation(ctx sdk.Context, collateral sdk.Coin, collateralType string, principal sdk.Coin, fees sdk.Coin) error {
collateralizationRatio, err := k.CalculateCollateralizationRatio(ctx, collateral, collateralType, principal, fees, liquidation)
if err != nil {
return err
}
liquidationRatio := k.getLiquidationRatio(ctx, collateralType)
if collateralizationRatio.GTE(liquidationRatio) {
return sdkerrors.Wrapf(types.ErrNotLiquidatable, "collateral %s, collateral ratio %s, liquidation ratio %s", collateral.Denom, collateralizationRatio, liquidationRatio)
}
return nil
}
func (k Keeper) getModAccountDebt(ctx sdk.Context, accountName string) sdk.Int {
macc := k.accountKeeper.GetModuleAccount(ctx, accountName)
return k.bankKeeper.GetBalance(ctx, macc.GetAddress(), k.GetDebtDenom(ctx)).Amount
}
func (k Keeper) payoutKeeperLiquidationReward(ctx sdk.Context, keeper sdk.AccAddress, cdp types.CDP) (types.CDP, error) {
collateralParam, found := k.GetCollateral(ctx, cdp.Type)
if !found {
return types.CDP{}, sdkerrors.Wrapf(types.ErrInvalidCollateral, "%s", cdp.Type)
}
reward := cdp.Collateral.Amount.ToDec().Mul(collateralParam.KeeperRewardPercentage).RoundInt()
rewardCoin := sdk.NewCoin(cdp.Collateral.Denom, reward)
paidReward := false
deposits := k.GetDeposits(ctx, cdp.ID)
for _, dep := range deposits {
if dep.Amount.IsGTE(rewardCoin) {
dep.Amount = dep.Amount.Sub(rewardCoin)
k.SetDeposit(ctx, dep)
paidReward = true
break
}
}
if !paidReward {
return cdp, nil
}
err := k.bankKeeper.SendCoinsFromModuleToAccount(ctx, types.ModuleName, keeper, sdk.NewCoins(rewardCoin))
if err != nil {
return types.CDP{}, err
}
cdp.Collateral = cdp.Collateral.Sub(rewardCoin)
ratio := k.CalculateCollateralToDebtRatio(ctx, cdp.Collateral, cdp.Type, cdp.GetTotalPrincipal())
err = k.UpdateCdpAndCollateralRatioIndex(ctx, cdp, ratio)
if err != nil {
return types.CDP{}, err
}
return cdp, nil
}