Truffle

Truffle

A world class development environment, testing framework and asset pipeline for blockchains using the Ethereum Virtual Machine (EVM), aiming to make life as a developer easier.

This page will take you through the basics of creating a Truffle project and deploying a smart contract to a blockchain.

Note: This page is just a quick start based on a sample program; please refer to Truffle's documentation for more information on Truffle installation.

Install Truffle

Requirements

• Node.js v14 - v18

• Windows, Linux, or macOS

Install Truffle

Warning: Avoid using the sudo command when installing Truffle, this can cause permission errors.

In a terminal, use NPM to install Truffle:

npm install -g truffle

You may receive a list of warnings during installation. To confirm that Truffle was installed correctly, run:

truffle version

Creating a Project

After ensuring Truffle is installed successfully, create your own project and name it something like "truffleApp".

Create a new directory for your Truffle project

mkdir truffleApp
cd truffleApp

Initialize your project

truffle init

Once this operation is complete, you’ll now have a project structure with the following items:

1. contracts/: Directory for Solidity contracts

2. migrations/: Directory for scriptable deployment files

3. test/: Directory for test files for testing your application and contracts

4. truffle-config.js: Truffle configuration file

5. build (visible after compile): Compiled Solidity contracts with bytecode and ABI

Create Contract

Make sure you install HDWalletProvider which we will use later:

npm install @truffle/hdwallet-provider --save

we create a file for smart contract called HelloKura.sol inside the contracts directory:

pragma solidity ^0.8.0;

contract HelloKura {
   string public greet = "Hello Kura!";
}

Coding Migrations

To deploy our HelloKura contract on Kura Testnet, we have to create a migration to get the contract on the network. Create a file in the migrations folder named “1_deploy_contract.js”.

var HelloKura = artifacts.require("HelloKura");

module.exports = function (deployer) {
    deployer.deploy(HelloKura);
};

Configuring Truffle For Kura Testnet

1. Go to truffle-config.js (located in root directory)

2. Update with Kura Testnet details

require('dotenv').config();
const mnemonic = process.env.MNEMONIC;
const HDWalletProvider = require('@truffle/hdwallet-provider');

module.exports = {
  networks: {
    kura: {
      provider: () => new HDWalletProvider(mnemonic, `https://rpc-kura.cross.technology/`),
      network_id: 5555,
      confirmations: 10,
      timeoutBlocks: 200,
      skipDryRun: true,
      from: "0x(your kura testnet account address)"
    }
  },
  compilers: {
    solc: {
      version: "0.8.0"
    }
  }
};

Be aware that we need to declare mnemonic which is used by HDWalletProvider in the truffle-config.js file to verify the account supplying funds during contract deployment. To set mnemonic variable, you would set it as an environment variable in .env file in the root directory.

npm i dotenv

MNEMONIC="(Your secret recovery phase)"

We can find our secret recovery phase for our account in the Metamask by going through Settings, Security & Privacy, and then Reveal Secret Recovery Phrase.

Deployment

Finally, we have everything ready and we can compile the smart contract we made:

truffle compile

truffle migrate --network kura

We would see something like below to confirm our smart contract is deployed on Kura testnet.

We can confirm this also by looking at the explorer Subscan.

Reference​

• Official Document for Truffle