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How to re-deploy your Ethereum DApp to Celo

Learn how to re-deploy Ethereum Dapps on the Celo network
Celo
BeginnerTruffleJavascriptCLI< 1 hour
Written by Deepanshu Hooda

Introduction

This tutorial is designed for developers who have deployed dapps on ethereum before and now want to learn how to do the same with the Celo blockchain.
One of the biggest advantages of using Celo is that it is EVM compatible which means you can easily redeploy your dapps from ethereum blockchain to celo with a few changes in code (if at all required) and just changing the configuration file. In this tutorial, we will learn to do the same.
We will be redeploying the famous Pet Shop dApp. A complete walkthrough of pet shop is outside the scope of this tutorial, but you can find it here. The current tutorial is not limited to just this example and can be used as a guide to redeploy any other Ethereum smart contract to Celo.

Getting Started

Start by cloning the following repository
git clone https://github.com/trufflesuite/pet-shop-tutorial
After cloning the repository, we have all the contracts required to deploy Pet Shop Dapp.
Let's install all the dependencies of the dapp by using
npm install
Now we have all the tools to start on your journey.

Using the Celo CLI

First, we need to find a way to interact with Celo blockchain. For this tutorial, we will be using Celo CLI to do the same.
npm install -g @celo/celocli
CeloCLI makes it extremely easy to interact with Celo Blockchain. It is a very handy tool for all celo developers. More information about CeloCLI can be found here.
After installing it, we need to make sure it is pointing to the correct endpoint. Let's check that by
celocli config:get
Our node should be pointing to node: https://alfajores-forno.celo-testnet.org
In case your endpoint is something else, you can change it by using
celocli config:set --node https://alfajores-forno.celo-testnet.org
Now our celocli is connected to Alfajores Testnet. We need an account to work with. Let's use celocli for this. Use the following command to get a new account on testnet.
celocli account:new
Our terminal should look something like this. (Everyone will have different values though!)
As we don't want anybody to see our private key, it is an accepted practice among developers to use `.env` files to set up environment variables. During the time of uploading our project to any open source platform, we hide these files by adding them to `.gitignore` Create a .env file in the same directory and add the following line
PRIVATE_KEY=<YOUR_PRIVATE_KEY>
We will use this private key later on in this tutorial. Now that we have an account to work with, let's get some funds for signing transactions on the blockchain. Use Alfajores testnet faucet which can be found here. To check if we have received funds, use
celocli account:balance <YOUR_PUBLIC_ADDRESS>

Changing truffle-config.js

To deploy our dapp to the Celo blockchain, all we need to do now is to change the truffle-config.js so that it can work with Celo blockchain. We will be taking help of ContractKit and Wallet-local made by Celo. We also need to install dotenv to use our Private Key.
To install all of these, use
npm i --save @celo/contractkit @celo/wallet-local dotenv
ContractKit is a library to help developers and validators to interact with the celo-blockchain and is well suited to developers looking for an easy way to integrate Celo Smart Contracts within their applications. Wallet-Local provides a local wallet instance to connect with contractKit. the dotenv file will be used to import Private Key that we added to .env file above into truffle-config without hardcoding it.
Paste the following code into our truffle-config.js file:
// dotenv is used to import all the environment variables into the .env file
require("dotenv").config();
const ContractKit = require("@celo/contractkit");
const { LocalWallet } = require("@celo/wallet-local");

const PRIVATE_KEY = process.env.PRIVATE_KEY;
const testnetURL = "https://alfajores-forno.celo-testnet.org";
const localWallet = new LocalWallet();

/*
ContractKit is used to access web3 object to interact with node's Json RPC API.
It takes two arguments, first being a network URL such as the testnet URL and secondly, a wallet instance for signing transactions.
*/

const kit = ContractKit.newKit(testnetURL, localWallet);

async function setConfig() {
  kit.addAccount(PRIVATE_KEY);
  kit.defaultAccount = localWallet.getAccounts()[0];
}
setConfig();
module.exports = {
  networks: {
    testnet: {
      provider: kit.connection.web3.currentProvider, // to connect with Alfajores testnet
      network_id: 44787,
    },
  },
};
Now our configuration file is all set to work with the Celo Blockchain.
Let's compile our smart contracts using
truffle compile
and after compiling is completed, let's migrate our smart contracts to Celo.
truffle migrate --network testnet
Congratulations! With that, we have deployed our Ethereum DApp to Celo.
Now we can use the same process to deploy any DApp we want to Celo. Don't let anything stop you, try cloning any project on ethereum and deploy it on Celo. Celo has wonderful opportunities for new projects.
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