Deploying smart contract using Private Network
Introduction
In this guide, we will walk you through the process of deploying a Greeter contract on a private Kaia network using Kaia Hardhat Utils. By following this guide, you'll learn how to:
- Set up a Hardhat project.
- Launch a private network simulating the Kairos Testnet.
- Utilize Hardhat utils to deploy smart contracts on this private network.
Prerequisite
To follow this tutorial, the following are the prerequisites:
- Code editor: a source-code editor such as VS Code.
- Docker: if you don’t have docker installed, kindly install using this link
- Node.js and npm: Node version 18 and above.
Setting Up your Development Environment
In this section, we will install hardhat, Kaia hardhat utils and other necessary dependencies needed for bootstrapping our project.
Step 1: Create a project directory
mkdir $HOME/kaia-greetercd kaia-greeter
Step 2: Initialize an npm project
npm init -y
Step 3: Install hardhat, hardhat-utils and other dependencies
- Copy and paste the code below in your terminal to install hardhat and hardhat-utils
npm i hardhat @klaytn/hardhat-utils
- Copy and paste the code below to install other dependencies
npm install @nomiclabs/hardhat-ethers hardhat-deploy dotenv
The hardhat-utils plugin depends on hardhat-ethers and hardhat-deploy plugin. Make sure to require or import them in your hardhat.config.js or hardhat.config.ts.
(Recommended) Install hardhat shorthand. But you can still use the tasks with npx hardhat.
npm install hardhat-shorthand --save
Step 4: Initialize a hardhat project
Run the command below to initiate an hardhat project:
npx hardhat init
For this guide, you'll be selecting "create an empty hardhat.config.js" project as seen below:
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Step 5: Create a .env file
Now create your .env file in the project folder. This file helps us load environment variables from an .env file into process.env.
Copy and paste this command in your terminal to create a .env file
touch .env
Configure your .env file to look like this:
PRIVATE_KEY="COPY & PASTE ANY OF THE PRIVATE KEY PROVIDED BY LOCAL PRIVATE NETWORK"
When you launch the private network in the next section, you will be able to access the private key provided by the local network.
Step 6: Setup Hardhat Configs
Modify your hardhat.config.js with the following configurations:
require("@nomiclabs/hardhat-ethers");require("hardhat-deploy");require("@klaytn/hardhat-utils");require('dotenv').config()const accounts = [ process.env.PRIVATE_KEY];/** @type import('hardhat/config').HardhatUserConfig */module.exports = { solidity: "0.8.24", networks: { localhost: { url: process.env.RPC_URL || "http://localhost:8545", accounts: accounts, }, kairos: { url: process.env.RPC_URL || "https://public-en-kairos.node.kaia.io", accounts: accounts, }, kaia: { url: process.env.RPC_URL || "https://public-en.node.kaia.io", accounts: accounts, } }, namedAccounts: { deployer: { default: 0, // here this will by default take the first account as deployer }, },};
Launching the Private Network
To launch a private network, the hardhat utils plugin provides us a task to easily launch one viz:
hh klaytn-node
Attaching Console
The private network comes with a JavaScript console. From the console command line, you can initiate part of Kaia API calls to your network. To attach to the JavaScript console, execute the following command:
hh klaytn-node --attach
Type kaia or personal to get the list of available functions.
Checking the Balance in your account
When we launched the private network, it provided us with a list of accounts, private key and pre-funded values for each account.
To see the balance of the account, execute the following command.
kaia.getBalance("0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266")
Configuring hardhat network environment
Now that we are running a stand alone local network, which external clients (wallets, dApp) can connect to, we need to configure hardhat to use this network by running this command:
export HARDHAT_NETWORK=localhosthh accounts
hh --network localhost accounts
Creating KaiaGreeter Smart Contract
In this section, you will create a KaiaGreeter smart contract.
Step 1: Create a new folder named contracts folder in the Explorer pane, click the New File button and create a new file named KaiaGreeter.sol
Step 2: Open the file and paste the following code:
// SPDX-License-Identifier: UNLICENSEDpragma solidity ^0.8.0;import "hardhat/console.sol";contract KaiaGreeter { uint256 totalGreetings; constructor() { console.log("Yo yo, Welcome to Kaia"); } function greet() public { totalGreetings += 1; console.log(msg.sender, "says hello kaia!"); } function getTotalGreetings() public view returns (uint256) { console.log("We have %d total waves!", totalGreetings); return totalGreetings; }}
Deploying KaiaGreeter
In this section we will use the hardhat-deploy plugin to deploy our contracts.
Step 1: In the Explorer pane, Create a new folder called deploy and click the New File button to create a new file named deploy.js.
Step 2: Copy and paste the following code inside the file.
module.exports = async ({getNamedAccounts, deployments}) => { const {deploy} = deployments; const {deployer} = await getNamedAccounts(); await deploy('KaiaGreeter', { from: deployer, args: [], log: true, });};module.exports.tags = ['KaiaGreeter'];
Step 3: In the terminal, run the following command which tells Hardhat to deploy your KaiaGreeter contract on the private network.
hh deploy
Verifying transaction using Block Explorer
Step 1: To verify our transactions using a local blockscout explorer, run the command below in a new terminal:
hh explorer --network localhost
[+] Using env: { DOCKER_RPC_HTTP_URL: 'http://host.docker.internal:8545/', DOCKER_LISTEN: '0.0.0.0:4000', DOCKER_DISABLE_TRACER: 'false', DOCKER_DEBUG: '0'}[+] Open in the browser: http://localhost:4000 Network blockscout_default Creating Network blockscout_default Created Container blockscout-db-1 Creating Container blockscout-frontend-1 Creating Container blockscout-smart-contract-verifier-1 Creating Container blockscout-redis_db-1 Creating Container blockscout-smart-contract-verifier-1 Created Container blockscout-db-1 Created Container blockscout-frontend-1 Created Container blockscout-redis_db-1 Created Container blockscout-backend-1 Creating Container blockscout-backend-1 Created Container blockscout-frontend-1 Starting Container blockscout-redis_db-1 Starting Container blockscout-smart-contract-verifier-1 Starting Container blockscout-db-1 Starting Container blockscout-db-1 Started Container blockscout-redis_db-1 Started Container blockscout-smart-contract-verifier-1 Started Container blockscout-backend-1 Starting Container blockscout-frontend-1 Started Container blockscout-backend-1 Started
Step 2: To access this block explorer, open up http://localhost:4000 in your browser.
Step 3: Copy and paste the deployed contract address in the search field and press Enter. You should see the recently deployed contract.
Interacting with deployed contract
using hardhat utils contract task
- To call a read-only function of the deployed contract, run the command below:
hh call KaiaGreeter getTotalGreetings
- To send a function invoking transaction to the deployed contract, run the command below:
hh send KaiaGreeter greet
using Kaia SDK
Step 1: To interact with the deployed contract using Kaia SDK, you need to install Kaia SDK by running this command:
npm install --save @kaiachain/ethers-ext
Step 2: In the Explorer pane, Create a new folder called "utils" and click the New File button to create a new file named kaia-sdk.js in the utils folder.
Step 3: Copy and paste the following code inside the file.
const { JsonRpcProvider, Wallet } = require("@kaiachain/ethers-ext");const { ethers } = require("ethers");require('dotenv').config()const provider = new JsonRpcProvider("http://127.0.0.1:8545/")const privKey = process.env.PRIVATE_KEY;const signer = new ethers.Wallet(privKey, provider);const contractAddress = "0x5FbDB2315678afecb367f032d93F642f64180aa3" // PASTE DEPLOYED CONTRACT ADDRESS;const KaiaGreeterABI = require("../artifacts/contracts/KaiaGreeter.sol/KaiaGreeter.json").abi;async function getCode(ca) { const tx = await provider.getCode(ca); console.log(tx);}async function greet(ca) { const klaytnGreeter = new ethers.Contract(ca, KaiaGreeterABI, signer); const tx = await klaytnGreeter.greet(); console.log( tx);}async function getTotalGreetings(ca) { const klaytnGreeter = new ethers.Contract(ca, KaiaGreeterABI, provider); const value = await klaytnGreeter.getTotalGreetings(); console.log(value.toString());}// getCode(contractAddress);getTotalGreetings(contractAddress);// greet(contractAddress);
Step 4: To execute any of the functions declared in this file, make sure to uncomment them as we did for the getTotalGreetings() function, then run the following command in your terminal.
node utils/kaia-sdk.js
For a more in-depth guide on hardhat-utils, please refer to hardhat-utils github. Also, you can find the full implementation of the code for this guide on GitHub