lending

package
v1.22.21 Latest Latest
Warning

This package is not in the latest version of its module.

 Go to latest Published: Dec 20, 2025 License: BSD-3-Clause Imports: 5 Imported by: 0

Documentation

Overview

Package lending provides a DeFi lending protocol for the DEX VM. It supports collateralized borrowing with dynamic interest rates.

Index

Constants

View Source 
const (
	// Scale factors
	Scale18 = 1e18 // Standard 18 decimal scaling
	Scale8  = 1e8  // 8 decimal scaling for some rates

	// Seconds per year for interest calculations
	SecondsPerYear = 365 * 24 * 60 * 60

	// Default parameters (scaled by 1e18)
	DefaultBaseRate             = 0.02e18 // 2% base rate
	DefaultMultiplier           = 0.1e18  // 10% multiplier
	DefaultJumpMultiplier       = 3e18    // 300% jump multiplier
	DefaultKink                 = 0.8e18  // 80% utilization kink
	DefaultCollateralFactor     = 0.75e18 // 75% collateral factor
	DefaultLiquidationBonus     = 0.08e18 // 8% liquidation bonus
	DefaultLiquidationThreshold = 0.8e18  // 80% liquidation threshold
	DefaultReserveFactor        = 0.1e18  // 10% reserve factor

	// Minimum health factor before liquidation
	MinHealthFactor = 1e18 // 1.0
)

Constants for scaling

Variables

View Source 
var (
	// Errors
	ErrPoolNotFound           = errors.New("lending pool not found")
	ErrPoolAlreadyExists      = errors.New("lending pool already exists")
	ErrInsufficientLiquidity  = errors.New("insufficient liquidity in pool")
	ErrInsufficientCollateral = errors.New("insufficient collateral for borrow")
	ErrInsufficientBalance    = errors.New("insufficient balance")
	ErrInvalidAmount          = errors.New("invalid amount")
	ErrAccountNotFound        = errors.New("account not found")
	ErrHealthFactorTooLow     = errors.New("health factor would be too low")
	ErrNotLiquidatable        = errors.New("position is not liquidatable")
	ErrCollateralNotEnabled   = errors.New("collateral not enabled for this asset")
	ErrZeroPrice              = errors.New("asset price is zero")
)

Functions

func NewBigInt 

func NewBigInt(v int64) *big.Int

NewBigInt creates a new big.Int from an int64.

func Scale18Int 

func Scale18Int(v int64) *big.Int

Scale18Int returns a big.Int scaled by 1e18.

Types

type CollateralPosition 

type CollateralPosition struct {
	User      ids.ShortID `json:"user"`
	Asset     string      `json:"asset"`
	Amount    *big.Int    `json:"amount"`    // Collateral amount
	IsEnabled bool        `json:"isEnabled"` // Whether used as collateral
	UpdatedAt time.Time   `json:"updatedAt"`
}

CollateralPosition represents a user's collateral in the lending system.

type Engine 

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

Engine is the core lending protocol engine.

func NewEngine 

func NewEngine(oracle PriceOracle) *Engine

NewEngine creates a new lending engine.

func (*Engine) AccrueAllInterest 

func (e *Engine) AccrueAllInterest()

AccrueAllInterest accrues interest for all pools (called during block processing).

func (*Engine) Borrow 

func (e *Engine) Borrow(user ids.ShortID, asset string, amount *big.Int) error

Borrow takes a loan from a lending pool.

func (*Engine) CreatePool 

func (e *Engine) CreatePool(config *PoolConfig) (*LendingPool, error)

CreatePool creates a new lending pool for an asset.

func (*Engine) EnableCollateral 

func (e *Engine) EnableCollateral(user ids.ShortID, asset string, enabled bool) error

EnableCollateral enables or disables an asset as collateral.

func (*Engine) GetAccount 

func (e *Engine) GetAccount(user ids.ShortID) (*UserAccount, error)

GetAccount returns a user's lending account.

func (*Engine) GetAllPools 

func (e *Engine) GetAllPools() []*LendingPool

GetAllPools returns all lending pools.

func (*Engine) GetPool 

func (e *Engine) GetPool(asset string) (*LendingPool, error)

GetPool returns a lending pool by asset.

func (*Engine) GetStats 

func (e *Engine) GetStats() *LendingStats

GetStats returns aggregate lending statistics.

func (*Engine) Liquidate 

func (e *Engine) Liquidate(
	liquidator ids.ShortID,
	borrower ids.ShortID,
	debtAsset string,
	collateralAsset string,
	debtAmount *big.Int,
) (*LiquidationEvent, error)

Liquidate liquidates an undercollateralized position.

func (*Engine) Repay 

func (e *Engine) Repay(user ids.ShortID, asset string, amount *big.Int) error

Repay pays back a loan.

func (*Engine) Supply 

func (e *Engine) Supply(user ids.ShortID, asset string, amount *big.Int) error

Supply adds liquidity to a lending pool.

func (*Engine) Withdraw 

func (e *Engine) Withdraw(user ids.ShortID, asset string, amount *big.Int) error

Withdraw removes liquidity from a lending pool.

type InterestRateModel 

type InterestRateModel struct {
	BaseRate       *big.Int // Base rate at 0% utilization
	Multiplier     *big.Int // Slope below kink
	JumpMultiplier *big.Int // Slope above kink
	Kink           *big.Int // Utilization rate at kink point
}

InterestRateModel defines the interest rate calculation model.

type LendingPool 

type LendingPool struct {
	// Pool identification
	ID    ids.ID `json:"id"`
	Asset string `json:"asset"` // Asset symbol (e.g., "LUX", "USDT")

	// Supply side
	TotalSupply        *big.Int `json:"totalSupply"`        // Total assets supplied
	TotalBorrows       *big.Int `json:"totalBorrows"`       // Total assets borrowed
	AvailableLiquidity *big.Int `json:"availableLiquidity"` // Supply - Borrows

	// Interest rates (scaled by 1e18)
	SupplyRate *big.Int `json:"supplyRate"` // APY for suppliers
	BorrowRate *big.Int `json:"borrowRate"` // APY for borrowers

	// Utilization (scaled by 1e18)
	UtilizationRate *big.Int `json:"utilizationRate"` // Borrows / Supply

	// Interest rate model parameters
	BaseRate       *big.Int `json:"baseRate"`       // Base interest rate
	Multiplier     *big.Int `json:"multiplier"`     // Rate increase per utilization
	JumpMultiplier *big.Int `json:"jumpMultiplier"` // Rate increase above kink
	Kink           *big.Int `json:"kink"`           // Utilization threshold for jump

	// Collateral parameters
	CollateralFactor     *big.Int `json:"collateralFactor"`     // Max borrow against collateral (e.g., 0.75 = 75%)
	LiquidationBonus     *big.Int `json:"liquidationBonus"`     // Bonus for liquidators (e.g., 0.08 = 8%)
	LiquidationThreshold *big.Int `json:"liquidationThreshold"` // Health factor threshold

	// Reserve
	ReserveFactor *big.Int `json:"reserveFactor"` // Fraction of interest to reserves
	TotalReserves *big.Int `json:"totalReserves"` // Accumulated reserves

	// Timestamps
	LastUpdateTime time.Time `json:"lastUpdateTime"`
	CreatedAt      time.Time `json:"createdAt"`
}

LendingPool represents a single asset lending pool.

type LendingStats 

type LendingStats struct {
	TotalSupplyUSD   *big.Int `json:"totalSupplyUSD"`
	TotalBorrowsUSD  *big.Int `json:"totalBorrowsUSD"`
	TotalReservesUSD *big.Int `json:"totalReservesUSD"`
	PoolCount        int      `json:"poolCount"`
	UserCount        int      `json:"userCount"`
	LiquidationCount int      `json:"liquidationCount"`
}

LendingStats provides aggregate statistics for the lending protocol.

type LiquidationEvent 

type LiquidationEvent struct {
	ID               ids.ID      `json:"id"`
	Liquidator       ids.ShortID `json:"liquidator"`
	Borrower         ids.ShortID `json:"borrower"`
	DebtAsset        string      `json:"debtAsset"`
	CollateralAsset  string      `json:"collateralAsset"`
	DebtRepaid       *big.Int    `json:"debtRepaid"`
	CollateralSeized *big.Int    `json:"collateralSeized"`
	LiquidatorBonus  *big.Int    `json:"liquidatorBonus"`
	Timestamp        time.Time   `json:"timestamp"`
}

LiquidationEvent represents a liquidation that occurred.

type PoolConfig 

type PoolConfig struct {
	Asset                string
	BaseRate             *big.Int
	Multiplier           *big.Int
	JumpMultiplier       *big.Int
	Kink                 *big.Int
	CollateralFactor     *big.Int
	LiquidationBonus     *big.Int
	LiquidationThreshold *big.Int
	ReserveFactor        *big.Int
}

PoolConfig holds configuration for creating a new lending pool.

func DefaultPoolConfig 

func DefaultPoolConfig(asset string) *PoolConfig

DefaultPoolConfig returns a default configuration for a lending pool.

type PriceOracle 

type PriceOracle interface {
	GetPrice(asset string) (*big.Int, error) // Returns price in USD (scaled by 1e18)
}

PriceOracle provides asset prices for the lending protocol.

type SimplePriceOracle 

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

SimplePriceOracle is a simple in-memory price oracle for testing.

func NewSimplePriceOracle 

func NewSimplePriceOracle() *SimplePriceOracle

NewSimplePriceOracle creates a new simple price oracle.

func (*SimplePriceOracle) GetPrice 

func (o *SimplePriceOracle) GetPrice(asset string) (*big.Int, error)

GetPrice returns the price for an asset.

func (*SimplePriceOracle) SetPrice 

func (o *SimplePriceOracle) SetPrice(asset string, price *big.Int)

SetPrice sets the price for an asset.

type UserAccount 

type UserAccount struct {
	User               ids.ShortID                    `json:"user"`
	Supplies           map[string]*UserSupply         `json:"supplies"`           // Asset -> Supply
	Borrows            map[string]*UserBorrow         `json:"borrows"`            // Asset -> Borrow
	Collateral         map[string]*CollateralPosition `json:"collateral"`         // Asset -> Collateral
	HealthFactor       *big.Int                       `json:"healthFactor"`       // Account health (scaled by 1e18)
	TotalCollateralUSD *big.Int                       `json:"totalCollateralUSD"` // In USD value
	TotalBorrowsUSD    *big.Int                       `json:"totalBorrowsUSD"`    // In USD value
	BorrowCapacityUSD  *big.Int                       `json:"borrowCapacityUSD"`  // Max additional borrow
	CreatedAt          time.Time                      `json:"createdAt"`
	UpdatedAt          time.Time                      `json:"updatedAt"`
}

UserAccount represents a user's complete lending account.

type UserBorrow 

type UserBorrow struct {
	User        ids.ShortID `json:"user"`
	Pool        ids.ID      `json:"pool"`
	Asset       string      `json:"asset"`
	Principal   *big.Int    `json:"principal"`   // Initial borrow amount
	Balance     *big.Int    `json:"balance"`     // Current balance with interest
	BorrowIndex *big.Int    `json:"borrowIndex"` // Index at last update
	UpdatedAt   time.Time   `json:"updatedAt"`
}

UserBorrow represents a user's borrow position in a pool.

type UserSupply 

type UserSupply struct {
	User        ids.ShortID `json:"user"`
	Pool        ids.ID      `json:"pool"`
	Asset       string      `json:"asset"`
	Principal   *big.Int    `json:"principal"`   // Initial supply amount
	Balance     *big.Int    `json:"balance"`     // Current balance with interest
	SupplyIndex *big.Int    `json:"supplyIndex"` // Index at last update
	UpdatedAt   time.Time   `json:"updatedAt"`
}

UserSupply represents a user's supply position in a pool.

Source Files

View all Source files

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL
go.dev uses cookies from Google to deliver and enhance the quality of its services and to analyze traffic. Learn more.