Deploying Contracts

To deploy a contract written in Rust using the Stylus SDK, the Arbitrum Stylus team created cargo-stylus. For now, this CLI tool doesn’t support deploying contracts with constructors.

We implemented koba, a solution you can use today to write constructors in Solidity for your Rust smart contracts.

Deploying oppenzeppelin-stylus contracts must be done using koba. Using cargo-stylus directly may initialize storage with unexpected values.

This solution is meant to be temporary. In the near future, we expect support for constructors to be implemented in cargo-stylus or the Stylus VM itself.

Constructors

Deployment transactions in Ethereum are composed of three sections:

  • A prelude - The bytecode prefix whose execution gets triggered by the deployment transaction.

  • A runtime - The bytecode of the smart contract stored on-chain.

  • Constructor arguments - ABI-encoded arguments received by the constructor.

The prelude section is a smart contract constructor compiled to bytecode. The runtime is the rest of the smart contract. All three sections combined are called binary.

Deployment transactions with an input of only compressed wasm are not yet supported in Stylus. That is, only the runtime is actual webassembly.

Moreover, the prelude of deployment transactions using cargo-stylus is hard-coded.

koba solves this by putting together the Solidity constructor, the compiled webassembly and the abi-encoded constructor arguments. It can be used both as a CLI tool or as a library in Rust projects. For a complete example of using koba as a library, see the basic token example. For an example of deploying a contract using the command line see koba’s README.

Usage

For a contract like this:

sol_storage! {
    #[entrypoint]
    pub struct Counter {
        uint256 number;
    }
}

#[external]
impl Counter {
    pub fn number(&self) -> U256 {
        self.number.get()
    }

    pub fn increment(&mut self) {
        let number = self.number.get();
        self.set_number(number + U256::from(1));
    }
}

and a constructor like this:

contract Counter {
    uint256 private _number;

    constructor() {
        _number = 5;
    }
}

The following command will deploy your contract:

$ koba deploy --sol <path-to-constructor> --wasm <path-to-wasm> --args <constructor-arguments> -e <rpc-url> --private-key <private-key>
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