Workshop Recap: Cheap contract deployment through Clones
The workshop was recorded on the 27th February 2021 and led by Hadrien Croubois – Smart Contract Engineer at OpenZeppelin.
The workshop covers the following:
- Typical use cases: Uniswap pairs & Argent wallets
- Walkthrough building a contract factory using the Clones library
- Gas cost comparisons
- Create vs Create2, when to use each one
- Comparison with other proxies
You can watch the video, view the slides, try the code from the workshop.
Clones (minimal proxies) as described in ERC1167, are very small, and cheap to deploy, smart-contracts that delegate all incoming calls to an implementation (template) contract containing the functionality. The address of this implementation contract is stored directly in the contract code, so no
sload is required.
Using clones, significant gas savings can be made for deployments when more than one of a family of smart contracts will be deployed over time e.g. multiple ERC20, Uniswap pairs or smart contract wallets.
The Clones library in OpenZeppelin Contracts includes functions to deploy a proxy using either create (traditional deployment) or create2 (salted deterministic deployment). It also includes functions to predict the addresses of clones deployed using the deterministic method. The Clones library has been available since OpenZeppelin Contracts 3.4.
Code for the workshop
The workshop code consists of the following examples of deploying using the Clones library, along with tests and gas usage reports showing the difference in deployment and usage gas costs between the standard case and using Clones:
- Uniswap pair
- Argent wallet
The code can be found in the OpenZeppelin workshops mono-repository:
See the instructions in the repository to run the workshop code.
Deep dive into the Minimal Proxy: blog.openzeppelin.com/deep-dive-into-the-minimal-proxy-contract.