Interact with Rootstock using Rust

Rust is a fast and memory-efficient language, it can power performance-critical services, run on embedded devices, and easily integrate with other languages.

This tutorial helps to get started on Rootstock using Rust by performing basic operations such as sending transactions and calling contracts using Alloy crate, similiar to ethers.

Introduction to Alloy

Alloy connects applications to blockchains, it serves as an entry point to connect with evm compatible blockchains. It is a rewrite of ethers-rs library from the ground up, with new features, high performance, etc. An example is Foundry, a tool written in Rust which uses Alloy as a dependency to connect with blockchains.

For more information, see Alloy Examples to help you get started.

Prerequisites

• Rust
  • Install the latest version of Rust. If you already have Rust installed, make sure to use the latest version or update using the rustup toolchain.

Getting Started

Create a Rust project

Run the command below using cargo to create a starter project.

cargo new rootstock-rs

Next step is to update cargo.toml file with dependencies explained in next section.

Setup Alloy

To install Alloy run the following command below in the root directory of the project:

cd rootstock-rs
cargo add alloy --git https://github.com/alloy-rs/alloy

Find more about Alloy setup using meta crate

Note: All the dependencies required are mentioned in the .toml file below. Copy and paste into the cargo.toml file.

[package]
name = "rootstock-alloy"
version = "0.1.0"
edition = "2021"

[dependencies]
alloy = { git = "https://github.com/alloy-rs/alloy", version = "0.1.3", default-features = true, features = ["providers", "rpc-client", "transport-http", "sol-types", "json", "contract", "rpc-types", "rpc-types-eth", "network", "signers", "signer-local"] }
eyre = "0.6.12"
futures-util = "0.3.30"
tokio = { version = "1", features = ["full"] }

The types and import statements in Alloy dependencies are expected to change. If you face any type related errors while running the given examples in this tutorial, its recommended to check the Alloy repo and documentation.

Connect to the Rootstock node

To connect to the Rootstock node., we will require a provider setup. A Provider is an abstraction of a connection to the Rootstock network, it provides a concise, and consistent interface to standard Ethereum node functionality.

To run this program, use cargo run in the root of the project:

cd rootstock-rs
cargo run

The response should look like this:

Finished `dev` profile [unoptimized + debuginfo] target(s) in 29.28s
    Running `target/debug/rootstock-alloy`
Hello, world!

Next, update the rootstock-rs/src/main.rs file with the program below:

Info

Replace API_KEY with your RPC API Key. To get an API_KEY, see the RPC Docs.

use alloy::providers::{ Provider, ProviderBuilder };
use eyre::Result;

#[tokio::main]
async fn main() -> eyre::Result<()> {
    // Set up the HTTP transport which is consumed by the RPC client.
    let rpc_url = "https://rpc.testnet.rootstock.io/{YOUR_APIKEY}".parse()?;

    // Create a provider with the HTTP transport using the `reqwest` crate.
    let provider = ProviderBuilder::new().on_http(rpc_url);

    // Get chain id
    let chain_id = provider.get_chain_id().await?;

    println!("chain id: {chain_id}");

    // Get latest block number.
    let latest_block = provider.get_block_number().await?;

    println!("Latest block number: {latest_block}");

    Ok(())
}

The response should look like this:

Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.43s
    Running `target/debug/rootstock-alloy`
chain id: 31
Latest block number: 5292505

Get RBTC / RIF balance

After setting up the provider, interact with Rootstock node, fetch balance of an address or call a contract. Now, copy and paste the code below.

We will do the following:

• Codegen from ABI file to interact with the contract.
• Create an abi directory in the root of the project and put RIF token abi in rif.json file.

Run the below commands in the root folder:

mkdir abi
touch rif.json

Replace rootstock-rs/abi/rif.json file with the RIF Abi below:

[ { "constant": true, "inputs": [ { "name": "_owner", "type": "address" } ], "name": "balanceOf", "outputs": [ { "name": "balance", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": false, "inputs": [ { "name": "_to", "type": "address" }, { "name": "_value", "type": "uint256" } ], "name": "transfer", "outputs": [ { "name": "", "type": "bool" } ], "payable": false, "stateMutability": "nonpayable", "type": "function" } ]

Update the rootstock-rs/src/main.rs file with this program:

use alloy::providers::{Provider, ProviderBuilder};
use alloy::sol;
use alloy::primitives::{ address, utils::format_units  };
 
sol!(
    #[allow(missing_docs)]
    #[sol(rpc)]
    RIF,
    "abi/rif.json"
);

#[tokio::main]
async fn main() -> eyre::Result<()> {
    // Set up the HTTP transport which is consumed by the RPC client.
    let rpc_url = "https://rpc.testnet.rootstock.io/{YOUR_APIKEY}".parse()?;

    // Create a provider with the HTTP transport using the `reqwest` crate.
    let provider = ProviderBuilder::new().on_http(rpc_url);

    // Address without 0x prefix
    let alice = address!("8F1C0185bB6276638774B9E94985d69D3CDB444a");

    let rbtc = provider.get_balance(alice).await?;

    let formatted_balance: String = format_units(rbtc, "ether")?;

    println!("Balance of alice: {formatted_balance} rbtc");

    // Using rif testnet contract address
    let contract = RIF::new("0x19f64674D8a5b4e652319F5e239EFd3bc969a1FE".parse()?, provider);


    let RIF::balanceOfReturn { balance } = contract.balanceOf(alice).call().await?;

    println!("Rif balance: {:?}", balance);

    Ok(())
}

Info

Replace API_KEY with your RPC API Key. To get an API_KEY, see the RPC Docs. Also replace RIF Testnet contract addresses with your own address as you would be required to use a private key later.

Note: Run the cargo command in the root of the project:

cd rootstock-rs
cargo run

You should get the following response:

Finished `dev` profile [unoptimized + debuginfo] target(s) in 3.01s
    Running `target/debug/rootstock-alloy`
Balance of alice: 0.315632721175825996 rbtc
Rif balance: 183000000000000000000

Send a transaction

The following program sends tRBTC from one account to the other using TransactionRequest Builder.

Running this program will require setting your PRIVATE_KEY env variable and then run the program using cargo run in root.

cd rootstock-rs
PRIVATE_KEY=0x12... cargo run

Replace PRIVATE_KEY with your private key in the command above to run this program.

You should see the following response:

% cargo run
Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.35s
    Running `target/debug/rootstock-alloy`
Balance of alice: 0.315632721175825996 rbtc
Rif balance: 183000000000000000000

Next, update the rootstock-rs/src/main.rs file with this program:

use alloy::{
    network::{EthereumWallet, TransactionBuilder},
    primitives::{address, U256},
    providers::{Provider, ProviderBuilder},
    rpc::types::TransactionRequest,
    signers::local::PrivateKeySigner,
};
use eyre::Result;
use std::env;

#[tokio::main]
async fn main() -> Result<()> {

    // Get private key
    let mut pk = String::new();

    match env::var("PRIVATE_KEY") {
        Ok(value) => {
            pk.push_str(value.as_str());
        },
        Err(_e) => {
            panic!("Private key not setup");
        },
    }
    
    // Set up the HTTP transport which is consumed by the RPC client.
    let rpc_url = "https://rpc.testnet.rootstock.io/{YOUR_APIKEY}".parse()?;

    let signer: PrivateKeySigner = pk.parse().unwrap();

    let wallet = EthereumWallet::from(signer);

    // Create a provider with the HTTP transport using the `reqwest` crate.
    let provider = ProviderBuilder::new()
    .wallet(wallet)
    .on_http(rpc_url);

    // Get chain id
    let chain_id = provider.get_chain_id().await?;

   // Create two users, Alice and Bob.
   // Address without 0x prefix
   let alice = address!("8F1C0185bB6276638774B9E94985d69D3CDB444a");
   let bob = address!("8F1C0185bB6276638774B9E94985d69D3CDB444a");

   let nonce = provider.get_transaction_count(alice).await?;

    // Build a transaction to send 100 wei from Alice to Bob.
    let tx = TransactionRequest::default()
        .with_from(alice)
        .with_to(bob)
        .with_chain_id(chain_id)
        .with_nonce(nonce)
        .with_value(U256::from(100))  // To see value in rbtc: 100 / 10 ** 18 RBTC
        .with_gas_price(65_164_000) // provider.estimate_gas(&tx).await? * 1.1 as u128 / 100)
        .with_gas_limit(21_000);    // Change this value if you face gas related issues

    // Send the transaction and wait for the receipt.
    let pending_tx = provider.send_transaction(tx).await?;

    println!("Pending transaction... {}", pending_tx.tx_hash());

    // Wait for the transaction to be included.
    
    let receipt = pending_tx.get_receipt().await?;

    println!(
        "Transaction included in block {}",
        receipt.block_number.expect("Failed to get block number")
    );

    // assert_eq!(receipt.from, alice);
    // assert_eq!(receipt.to, Some(bob));

    Ok(())
}

• ERROR: deserialization error: missing field effectiveGasPrice at line 1 column 959
  • It's expected that you will encounter a missing effectiveGasPrice error.
    • Kindly ignore above error. RSKj team is familiar with this error and fix would be part of new release. This error does not block the sending of a transaction. Transaction will be mined successfully.

Transfer ERC20 Token

This program setups up wallet with provider and sends RIF from one account to the other. Run this program using: cargo run.

Update the rootstock-rs/src/main.rs file with this program:

use alloy::{
    network::{EthereumWallet},
    primitives::{address, U256},
    providers::{Provider, ProviderBuilder},
    signers::local::PrivateKeySigner,
};
use eyre::Result;
use std::env;
use alloy::sol;

// Codegen from ABI file to interact with the contract.
// Make a abi directory in the root of the project and put RIF token abi in rif.json file.
 
sol!(
    #[allow(missing_docs)]
    #[sol(rpc)]
    RIF,
    "abi/rif.json"
);

// See the contents of rootstock-rs/abi/rif.json file below.
/*
[ { "constant": true, "inputs": [ { "name": "_owner", "type": "address" } ], "name": "balanceOf", "outputs": [ { "name": "balance", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": false, "inputs": [ { "name": "_to", "type": "address" }, { "name": "_value", "type": "uint256" } ], "name": "transfer", "outputs": [ { "name": "", "type": "bool" } ], "payable": false, "stateMutability": "nonpayable", "type": "function" } ]
*/

#[tokio::main]
async fn main() -> eyre::Result<()> {
    // Get private key
    let mut pk = String::new();

    match env::var("PRIVATE_KEY") {
        Ok(value) => {
            pk.push_str(value.as_str());
        }
        Err(_e) => {
            panic!("Private key not setup");
        }
    }

    // Set up the HTTP transport which is consumed by the RPC client.
    let rpc_url = "https://rpc.testnet.rootstock.io/{YOUR_APIKEY}".parse()?;

    let signer: PrivateKeySigner = pk.parse().unwrap();

    let wallet = EthereumWallet::from(signer);

    // Create a provider with the HTTP transport using the `reqwest` crate.
    let provider = ProviderBuilder::new()
        .wallet(wallet)
        .on_http(rpc_url);

    // Address without 0x prefix
    let alice = address!("8F1C0185bB6276638774B9E94985d69D3CDB444a");

    let nonce = provider.get_transaction_count(alice).await?;
    let chain_id = provider.get_chain_id().await?;

    let contract = RIF::new(
        "0x19f64674D8a5b4e652319F5e239EFd3bc969a1FE".parse()?,
        provider,
    );

    let RIF::balanceOfReturn { balance } = contract.balanceOf(alice).call().await?;

    println!("Rif balance: {:?}", balance);

    // Transfer
    let amount = U256::from(100);
    let receipt = contract
        .transfer(alice, amount)
        .chain_id(chain_id)
        .nonce(nonce)
        .gas_price(65_164_000) // gas price: provider.estimate_gas(&tx).await? * 1.1 as u128 / 100)
        .gas(25_000)  // Change this value according to tx type if you face gas related issues
        .send()
        .await?
        .get_receipt()
        .await?;

    println!("Send transaction: {}", receipt.transaction_hash);

    Ok(())
}

Run the below command to transfer an ERC20 Token:

cd rootstock-rs
PRIVATE_KEY=0x12... cargo run

Note to replace PRIVATE_KEY with your private key in the command above to run this program.

For more details, see the complete code example

See foundry codebase for more advanced usage of Rust and Alloy to interact with EVM compatible blockchains including Rootstock.

Useful Resources

• Alloy website
• See Alloy reference documentation
• Code examples using Alloy visit this repo
• Alloy GitHub repo