Environment Setup - Hardhat on Rinkeby

Create a project directory

mkdir my_solidity_project
cd my_solidity_project

Initialize the directory with npm

npm init -y

Install hardhat

npm install --save-dev hardhat

Initialize the project

npx hardhat

It will probably look something like this

❯ npx hardhat
888    888                      888 888               888
888    888                      888 888               888
888    888                      888 888               888
8888888888  8888b.  888d888 .d88888 88888b.   8888b.  888888
888    888     "88b 888P"  d88" 888 888 "88b     "88b 888
888    888 .d888888 888    888  888 888  888 .d888888 888
888    888 888  888 888    Y88b 888 888  888 888  888 Y88b.
888    888 "Y888888 888     "Y88888 888  888 "Y888888  "Y888

👷 Welcome to Hardhat v2.6.4 👷‍

? What do you want to do? …
❯ Create a basic sample project
  Create an advanced sample project
  Create an empty hardhat.config.js
  Quit

If you choose sample project, it will create the basic directory structure that we need. I picked that option.

Install dotenv to keep keys secure

npm install dotenv

This will enable us to store our keys locally, but they won’t be included in our git repository. Double check that you have .env listed in the .gitignore which hardhat created.

Create a .env file

RINKEBY_PRIVATE_KEY = "YOUR_KEY_HERE"
ALCHEMY_API_KEY = "YOUR_API_KEY_HERE"

Getting these keys

ALCHEMY_API_KEY

https://www.alchemy.com/ Sign up for an account and create a project Select view key, your ALCHEMY_API_KEY will be the value after https://eth-rinkeby.alchemyapi.io/v2/

RINKEBY_PRIVATE_KEY

To export your private key from Metamask, open Metamask and go to Account Details > Export Private Key Be aware of NEVER putting real Ether into testing accounts

Setup hardhat.config.js for Rinkeby deploy

/**
 * @type import('hardhat/config').HardhatUserConfig
 */

require('dotenv').config();
require('@nomiclabs/hardhat-waffle');
module.exports = {
	solidity: '0.8.4',
	networks: {
		rinkeby: {
			url: `https://eth-rinkeby.alchemyapi.io/v2/${process.env.ALCHEMY_API_KEY}`,
			accounts: [`0x${process.env.RINKEBY_PRIVATE_KEY}`]
		}
	}
};

A quick contract to ensure deploy works

This contract, which hardhat supplies, is a sample project. You should remove this file when you get going.

// contracts/Greeter.sol
pragma solidity ^0.8.0;

import "hardhat/console.sol";

contract Greeter {
    string private greeting;

    constructor(string memory _greeting) {
        console.log("Deploying a Greeter with greeting:", _greeting);
        greeting = _greeting;
    }

    function greet() public view returns (string memory) {
        return greeting;
    }

    function setGreeting(string memory _greeting) public {
        console.log("Changing greeting from '%s' to '%s'", greeting, _greeting);
        greeting = _greeting;
    }
}

Deployment script

This script comes from the sample project as well. I would personally rename it to deploy.js as that’s its real function.

// scripts/sample-script.js
// We require the Hardhat Runtime Environment explicitly here. This is optional
// but useful for running the script in a standalone fashion through `node <script>`.
//
// When running the script with `npx hardhat run <script>` you'll find the Hardhat
// Runtime Environment's members available in the global scope.
const hre = require('hardhat');

async function main() {
	// Hardhat always runs the compile task when running scripts with its command
	// line interface.
	//
	// If this script is run directly using `node` you may want to call compile
	// manually to make sure everything is compiled
	// await hre.run('compile');

	// We get the contract to deploy
	const Greeter = await hre.ethers.getContractFactory('Greeter');
	const greeter = await Greeter.deploy('Hello, Hardhat!');

	await greeter.deployed();

	console.log('Greeter deployed to:', greeter.address);
}

// We recommend this pattern to be able to use async/await everywhere
// and properly handle errors.
main()
	.then(() => process.exit(0))
	.catch((error) => {
		console.error(error);
		process.exit(1);
	});

Deploy!

This will deploy the greeter contract to the Rinkeby test network.

npx hardhat run scripts/sample-script.js --network rinkeby