๐๏ธ Scaffold Balancer v3
A starter kit for building on top of Balancer v3. Accelerate the process of creating custom pools and hooks contracts. Concentrate on mastering the core concepts within a swift and responsive environment augmented by a local fork and a frontend pool operations playground.
๐ Development Life Cycle
- Learn the core concepts for building on top of Balancer v3
- Configure and deploy factories, pools, and hooks contracts to a local anvil fork of Sepolia
- Interact with pools via a frontend that runs at localhost:3000
๐ชง Table Of Contents
๐งโ๐ป Environment Setup
1. Requirements ๐
2. Quickstart ๐
-
Ensure you have the latest version of foundry installed
foundryup
-
Clone this repo & install dependencies
git clone https://github.com/balancer/scaffold-balancer-v3.git
cd scaffold-balancer-v3
yarn install
- Set the necessary environment variables in a
packages/foundry/.env
file [^1]
[^1]: The DEPLOYER_PRIVATE_KEY
must start with 0x
and must possess enough Sepolia ETH to deploy the contracts. The SEPOLIA_RPC_URL
facilitates running a local fork and sending transactions to sepolia testnet
DEPLOYER_PRIVATE_KEY=0x...
SEPOLIA_RPC_URL=...
- Start a local anvil fork of the Sepolia testnet
yarn fork
- Deploy the mock tokens, pool factories, pool hooks, and custom pools contracts [^2]
[^2]: The
DEPLOYER_PRIVATE_KEY
wallet receives the mock tokens and resulting BPT from pool initialization
yarn deploy
- Start the nextjs frontend
yarn start
- Explore the frontend
- Run the Foundry tests
yarn test
3. Scaffold ETH 2 Tips ๐๏ธ
SE-2 offers a variety of configuration options for connecting an account, choosing networks, and deploying contracts
๐ฅ Burner Wallet
If you do not have an active wallet extension connected to your web browser, then scaffold eth will automatically connect to a "burner wallet" that is randomly generated on the frontend and saved to the browser's local storage. When using the burner wallet, transactions will be instantly signed, which is convenient for quick iterative development.
To force the use of burner wallet, disable your browsers wallet extensions and refresh the page. Note that the burner wallet comes with 0 ETH to pay for gas so you will need to click the faucet button in top right corner. Also the mock tokens for the pool are minted to your deployer account set in `.env` so you will want to navigate to the "Debug Contracts" page to mint your burner wallet some mock tokens to use with the pool.
![Burner Wallet](https://github.com/Dev-Rel-as-a-Service/scaffold-balancer-v3/assets/73561520/0a1f3456-f22a-46b5-9e05-0ef5cd17cce7)
![Debug Tab Mint](https://github.com/Dev-Rel-as-a-Service/scaffold-balancer-v3/assets/73561520/fbb53772-8f6d-454d-a153-0e7a2925ef9f)
๐ Browser Extension Wallet
- To use your preferred browser extension wallet, ensure that the account you are using matches the PK you previously provided in the `foundry/.env` file
- You may need to add a local development network with rpc url `http://127.0.0.1:8545/` and chain id `31337`. Also, you may need to reset the nonce data for your wallet exension if it gets out of sync.
๐ Debug Contracts Page
The [Debug Contracts Page](http://localhost:3000/debug) can be useful for viewing and interacting with all of the externally avaiable read and write functions of a contract. The page will automatically hot reload with contracts that are deployed via the `01_DeployConstantSumFactory.s.sol` script. We use this handy setup to mint `mockERC20` tokens to any connected wallet
๐ Changing The Frontend Network Connection
- The network the frontend points at is set via `targetNetworks` in the `scaffold.config.ts` file using `chains` from viem.
- By default, the frontend runs on a local node at `http://127.0.0.1:8545`
```typescript
const scaffoldConfig = {
targetNetworks: [chains.foundry],
```
๐ด Changing The Forked Network
- By default, the `yarn fork` command points at sepolia, but any of the network aliases from the `[rpc_endpoints]` of `foundry.toml` can be used to modify the `"fork"` alias in the `packages/foundry/package.json` file
```json
"fork": "anvil --fork-url ${0:-sepolia} --chain-id 31337 --config-out localhost.json",
```
- To point the frontend at a different forked network, change the `targetFork` in `scaffold.config.ts`
```typescript
const scaffoldConfig = {
// The networks the frontend can connect to
targetNetworks: [chains.foundry],
// If using chains.foundry as your targetNetwork, you must specify a network to fork
targetFork: chains.sepolia,
```
๐ฉโ๐ซ Learn Core Concepts
๐ต๏ธ Explore the Examples
Each of the following examples have turn key deploy scripts that can be found in the foundry/script/ directory
1. Constant Sum Pool with Dynamic Swap Fee Hook
The swap fee percentage is altered by the hook contract before the pool calculates the amount for the swap
2. Constant Product Pool with Lottery Hook
An after swap hook makes a request to an oracle contract for a random number
3. Weighted Pool with Exit Fee Hook
An after remove liquidity hook adjusts the amounts before the vault transfers tokens to the user
๐ Create a Custom Pool
1. Review the Docs ๐
2. Recall the Key Requirements ๐
- Must inherit from
IBasePool
and BalancerPoolToken
- Must implement
onSwap
, computeInvariant
, and computeBalance
- Must implement
getMaximumSwapFeePercentage
and getMinimumSwapFeePercentage
3. Write a Custom Pool Contract ๐
- To get started, edit the
ConstantSumPool.sol
contract directly or make a copy
๐ญ Create a Pool Factory
After designing a pool contract, the next step is to prepare a factory contract because Balancer's off-chain infrastructure uses the factory address as a means to identify the type of pool, which is important for integration into the UI, SDK, and external aggregators
1. Review the Docs ๐
2. Recall the Key Requirements ๐
- A pool factory contract must inherit from BasePoolFactory
- Use the internal
_create
function to deploy a new pool
- Use the internal
_registerPoolWithVault
fuction to register a pool immediately after creation
3. Write a Factory Contract ๐
- To get started, edit the
ConstantSumFactory.sol
contract directly or make a copy
๐ช Create a Pool Hook
1. Review the Docs ๐
2. Recall the Key Requirements ๐
- A hooks contract must inherit from BasePoolHooks.sol
- A hooks contract should also inherit from VaultGuard.sol
- Must implement
onRegister
to determine if a pool is allowed to use the hook contract
- Must implement
getHookFlags
to define which hooks are supported
- The
onlyVault
modifier should be applied to all hooks functions (i.e. onRegister
, onBeforeSwap
, onAfterSwap
ect.)
3. Write a Hook Contract ๐
- To get started, edit the
VeBALFeeDiscountHook.sol
contract directly or make a copy
๐ข Deploy the Contracts
The deploy scripts are located in the foundry/script/ directory. To better understand the lifecycle of deploying a pool that uses a hooks contract, see the diagram below
1. Modifying the Deploy Scripts ๐ ๏ธ
For all the scaffold integrations to work properly, each deploy script must be imported into Deploy.s.sol
and inherited by the DeployScript
contract in Deploy.s.sol
2. Broadcast the Transactions ๐ก
To run all the deploy scripts
yarn deploy
๐ To deploy to the live sepolia testnet, add the --network sepolia
flag
๐งช Test the Contracts
The balancer-v3-monorepo provides testing utility contracts like BasePoolTest and BaseVaultTest. Therefore, the best way to begin writing tests for custom factories, pools, and hooks contracts is to leverage the examples established by the source code.
1. Testing Factories ๐จโ๐ฌ
The ConstantSumFactoryTest
roughly mirrors the WeightedPool8020FactoryTest
yarn test --match-contract ConstantSumFactoryTest
2. Testing Pools ๐
The ConstantSumPoolTest
roughly mirrors the WeightedPoolTest
yarn test --match-contract ConstantSumPoolTest
3. Testing Hooks ๐ฃ
The VeBALFeeDiscountHookExampleTest
mirrors the VeBALFeeDiscountHookExampleTest
yarn test --match-contract VeBALFeeDiscountHookExampleTest