Chopsticks

Chopsticks, a tool developed and maintained by the Acala Foundation, has become an essential resource for developers building on Polkadot. By enabling local chain forking and comprehensive block analysis, Chopsticks simplifies complex development workflows, providing an efficient and flexible solution for blockchain experimentation and testing.

What is Chopsticks?

Chopsticks is designed to address critical challenges in blockchain development by offering:

1. Local Chain Forking: Create localized versions of existing chains to test configurations without impacting live networks.
2. Block Replay & Analysis: Investigate extrinsic impacts on chain state by replaying specific blocks.
3. Multi-Block Forking for XCM Testing: Simulate Cross-Consensus Messaging (XCM) interactions between chains for thorough validation.

This tool enables developers to explore new ideas, debug issues, and build innovative solutions with reduced risk and cost.

Key Features of Chopsticks

1. Lightweight and Efficient. Chopsticks leverages the Smoldot light client, making it efficient for local chain interactions. However, it supports only the native Polkadot SDK API, limiting its use for Ethereum JSON-RPC-based interactions.
2. Comprehensive Configuration Options. Users can customize their local fork with parameters such as:
   • Genesis file: Define the raw genesis data.
   • Block number or hash: Specify the block to fork.
   • Custom runtime: Use a specific Wasm runtime for advanced scenarios.
   • Storage overrides: Modify chain storage values for testing.
3. Developer-Oriented Tools. Chopsticks integrates seamlessly with popular tools like Polkadot.js, enabling intuitive interaction with forked chains. Developers can:
   • Use Polkadot.js Apps to explore and interact with local forks.
   • Leverage the Polkadot.js library for programmatic interactions.
4. XCM Testing Made Simple. Chopsticks supports local simulation of XCM messages between multiple parachains and relay chains, facilitating robust multi-chain testing environments.

Setup Chopsticks

Here’s a quick summary of how to get started with Chopsticks. For detailed instructions and additional information, refer to the official README file in the GitHub repository provided by the authors.

Installation and Setup

Prerequisites:

To use Chopsticks, ensure you have the following installed:

• Node.js: The JavaScript runtime environment.
• npm or Yarn: Package managers for Node.js.

Installation:

You can install Chopsticks globally or locally in your project.

• Global Installation:

npm i -g @acala-network/chopsticks@latest

• Local Installation:

mkdir my-chopsticks-project
cd my-chopsticks-project
npm init -y
npm i @acala-network/chopsticks@latest

• Run Chopsticks locally:

npx @acala-network/chopsticks

Chopsticks Usage Examples

1. Forking a Network: Fork the Polkadot network at block 100:

npx @acala-network/chopsticks --endpoint wss://rpc.polkadot.io --block 100

2. Replay Blocks: Replay block 1000 of Moonbeam and save output to a JSON file:

npx @acala-network/chopsticks run-block \
  --endpoint wss://wss.api.moonbeam.network \
  --block 1000 \
  --output-path=./moonbeam-output.json

3. XCM Simulation: Simulate interactions between Polkadot, Moonbeam, and Astar:

npx @acala-network/chopsticks xcm \
  --r polkadot \
  --p moonbeam \
  --p astar

Developer Utilities

Chopsticks provides a robust WebSocket API to manage local chains programmatically:

• dev_newBlock: Create new blocks.
• dev_setStorage: Modify on-chain storage values.
• dev_timeTravel: Set timestamps for future blocks.

These utilities are particularly useful for testing governance mechanisms, extrinsic dispatching, and state transitions.

Conclusion

Chopsticks has emerged as an indispensable tool for developers working on Substrate-based blockchains. By facilitating local testing, debugging, and multi-chain interaction simulations, it empowers developers to innovate confidently in the Polkadot ecosystem.