CREC SDK Extension: DVP

A Go SDK extension for Delivery versus Payment (DvP) settlement operations on CRE Connect. The DvP (Delivery vs. Payment) service allows for the secure and trustless transfer of assets between parties.

Installation

go get github.com/smartcontractkit/crec-sdk-ext-dvp

Overview

This extension provides utilities for preparing DvP (Delivery versus Payment) settlement operations, enabling atomic exchange of assets between counterparties on blockchain networks.

Features

• Propose settlements with optional token approvals or holds
• Accept and execute settlements
• Compute settlement hashes for verification
• Support for ERC20 and ERC3643 token types
• ISO 4217 currency code mapping

Usage

Basic Setup

import (
    "github.com/smartcontractkit/crec-sdk-ext-dvp/operations"
)

ext, err := operations.New(&operations.Options{
    CCIPDVPCoordinatorAddress: "0x...",
    AccountAddress:             "0x...",
})
if err != nil {
    log.Fatal(err)
}

Proposing a Settlement

import (
    "github.com/smartcontractkit/crec-sdk-ext-dvp/currency"
    "github.com/smartcontractkit/crec-sdk-ext-dvp/events"
    "github.com/ethereum/go-ethereum/common"
    "math/big"
)

// Create settlement details
settlement := &events.Settlement{
    SettlementId: big.NewInt(1),
    PartyInfo: events.PartyInfo{
        BuyerSourceAddress:       common.HexToAddress("0xBuyer..."),
        BuyerDestinationAddress:  common.HexToAddress("0xBuyer..."),
        SellerSourceAddress:      common.HexToAddress("0xSeller..."),
        SellerDestinationAddress: common.HexToAddress("0xSeller..."),
        ExecutorAddress:          common.HexToAddress("0xExecutor..."),
    },
    TokenInfo: events.TokenInfo{
        PaymentTokenSourceAddress:      common.HexToAddress("0xPaymentToken..."),
        PaymentTokenDestinationAddress: common.HexToAddress("0xPaymentToken..."),
        AssetTokenSourceAddress:        common.HexToAddress("0xAssetToken..."),
        AssetTokenDestinationAddress:   common.HexToAddress("0xAssetToken..."),
        PaymentTokenAmount:             big.NewInt(1000000),
        AssetTokenAmount:               big.NewInt(1000000000000000000),
        PaymentCurrency:                currency.Map["USD"],
        PaymentLockType:                events.LockTypeERC20,
        AssetLockType:                  events.LockTypeERC20,
    },
    DeliveryInfo: events.DeliveryInfo{
        PaymentSourceChainSelector:      uint64(1),
        PaymentDestinationChainSelector: uint64(1),
        AssetSourceChainSelector:        uint64(1),
        AssetDestinationChainSelector:   uint64(1),
    },
    SecretHash:           common.Hash{},
    ExecuteAfter:         big.NewInt(0),
    Expiration:           big.NewInt(9999999999),
    CcipCallbackGasLimit: 0,
    Data:                 []byte{},
}

// Option 1: Propose without token approval (assumes approval exists)
op, err := ext.PrepareProposeSettlementOperation(settlement)

// Option 2: Propose with automatic token approval
op, err := ext.PrepareProposeSettlementWithTokenApprovalOperation(settlement)

// Option 3: Propose with token hold (ERC3643 only)
op, err := ext.PrepareProposeSettlementWithTokenHoldOperation(settlement, holdManagerAddress)

Accepting a Settlement

settlementHash := common.HexToHash("0x...")
op, err := ext.PrepareAcceptSettlementOperation([32]byte(settlementHash))

Executing a Settlement

settlementHash := common.HexToHash("0x...")
op, err := ext.PrepareExecuteSettlementOperation([32]byte(settlementHash))

Computing Settlement Hash

hash, err := ext.HashSettlement(settlement)
fmt.Printf("Settlement hash: %s\n", hash.Hex())

Lock Types

Constant	Value	Description
LockTypeNone	0	No lock type specified
LockTypeERC20	1	Standard ERC20 token
LockTypeERC3643	2	Security token (T-REX)

Settlement Status

Constant	Value	Description
SettlementStatusNew	0	Settlement created
SettlementStatusOpen	1	Settlement proposed
SettlementStatusAccepted	2	Settlement accepted
SettlementStatusClosing	3	Settlement in closing state
SettlementStatusSettled	4	Settlement completed
SettlementStatusCanceled	5	Settlement canceled

Currency Codes

The currency package provides ISO 4217 currency codes for off-chain payment specifications:

import "github.com/smartcontractkit/crec-sdk-ext-dvp/currency"

usdCode := currency.Map["USD"]  // Returns 147

Decoding Events

Decode typed events from raw CREC watcher events:

import dvp "github.com/smartcontractkit/crec-sdk-ext-dvp"

decoded, err := dvp.DecodeFromEvent(ctx, event)
switch decoded.EventName() {
case events.EventSettlementOpened:
    ev := decoded.ConcreteEvent.(*events.SettlementOpened)
    fmt.Printf("Settlement %s opened\n", ev.SettlementId)
case events.EventSettlementSettled:
    ev := decoded.ConcreteEvent.(*events.SettlementSettled)
    fmt.Printf("Settlement %s settled\n", ev.SettlementId)
}

License

BUSL