README.md

Balancer V2 Vault

This package contains the source code of Balancer V2's main contract, the Vault, as well as all core interfaces.

The Vault interface itself is required for multiple tasks, including swaps, joins and exits, but some scenarios require functionality provided through other contracts. Particularly useful interfaces include:

• IBasePool, IGeneralPool and IMinimalSwapInfoPool for developing Pools
• IFlashLoanRecipient for performing Flash Loans
• IProtocolFeesCollector for querying protocol fee percentages

Overview

Installation

$ npm install @balancer-labs/v2-vault

Usage

The main purpose of this package is to provide the Solidity interfaces of core components, which are found in the [/contracts/interfaces](./contracts/interfaces] directory. The Vault contract itself is also useful for testing.

To get the address of deployed contracts in both mainnet and various test networks, see v2-deployments.

Sample contract that performs Internal Balance deposits:

pragma solidity ^0.7.0;

import "@balancer-labs/v2-vault/contracts/interfaces/IVault.sol";

contract SimpleDepositor {
    IVault private constant vault = "0xBA12222222228d8Ba445958a75a0704d566BF2C8";

    function depositFunds(
        IERC20[] memory tokens,
        uint256[] memory amounts,
    ) external {
      IVault.UserBalanceOp[] memory ops = new IVault.UserBalanceOp[](tokens.length);

      for (uint256 i = 0; i < tokens.length; ++i) {
        ops[i] = IVault.UserBalanceOp({
          kind: IVault.UserBalanceOpKind.DEPOSIT_INTERNAL,
          asset: IAsset(tokens[i]),
          amount: amounts[i],
          sender: address(this),
          recipient: address(this)
        });
      }

      vault.manageUserBalance(ops);
    }
}

Sample contract that performs Flash Loans:

pragma solidity ^0.7.0;

import "@balancer-labs/v2-vault/contracts/interfaces/IVault.sol";
import "@balancer-labs/v2-vault/contracts/interfaces/IFlashLoanRecipient.sol";

contract FlashLoanRecipient is IFlashLoanRecipient {
    IVault private constant vault = "0xBA12222222228d8Ba445958a75a0704d566BF2C8";

    function makeFlashLoan(
        IERC20[] memory tokens,
        uint256[] memory amounts,
        bytes memory userData
    ) external {
      vault.flashLoan(this, tokens, amounts, userData);
    }

    function receiveFlashLoan(
        IERC20[] memory tokens,
        uint256[] memory amounts,
        uint256[] memory feeAmounts,
        bytes memory userData
    ) external override {
        require(msg.sender == vault);
        ...
    }
}

Licensing

GNU General Public License Version 3 (GPL v3).