Truffle

In this tutorial, we'll walk through creating a basic Truffle project and deploying a token contract.

Here's a video walkthrough:

Prerequisites

Before you begin, ensure you've:

1. Set up your wallet
2. Funded your wallet with Linea ETH on either the testnet or mainnet
3. Installed Truffle using the recommended installation procedure.

Create a Truffle project

To create an empty Truffle project, run:

truffle init linea-tutorial

Change into the new directory:

cd linea-tutorial

Write the smart contract

Create your smart contract in the contracts directory by either creating a new file Token.sol or calling truffle create contract Token. Then, add the following code:

pragma solidity 0.8.17;

// SPDX-License-Identifier: MIT

contract Token {
  string public name = "My Token";
  string public symbol = "MTK";
  uint8 public decimals = 18;
  uint256 public totalSupply = 100000000;

  mapping (address => uint256) public balances;
  address public owner;

  constructor() {
    owner = msg.sender;
    balances[owner] = totalSupply;
  }

  function transfer(address recipient, uint256 amount) public {
    require(balances[msg.sender] >= amount, "Insufficient balance.");
    balances[msg.sender] -= amount;
    balances[recipient] += amount;
  }
}

You can check if it compiles by running truffle compile from the root folder.

Write the migration script

To tell Truffle how we want to deploy our smart contracts, and in what order, we need to write a migration script.

Create 1_deploy_token.js in the migrations directory, and add the following code:

const Token = artifacts.require("Token");

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

Deploy your contract

Truffle allows you to deploy through the Truffle Dashboard using your MetaMask wallet!

Truffle Dashboard

Truffle Dashboard allows you to forgo saving your private keys locally, instead connecting to your MetaMask wallet for deployments. To deploy with Truffle Dashboard, you need to:

1. Run truffle dashboard in your terminal, which will open a window on port 24012.
2. Navigate to localhost:24012 in your browser. Please ensure that Dashboard is connected to the Linea testnet by connecting your MetaMask wallet to Linea. For reference, the Linea testnet network ID is 59140.

1. Run truffle migrate --network dashboard in a separate terminal.
2. Navigate back to localhost:24012. You should see a prompt asking you to confirm the deployment. Click Confirm.

truffle-config.js

You can deploy with Truffle using the command line, by specifying Linea testnet in truffle-config.js. To do so, you need to:

1. Create a .env file in the root folder with your wallet's mnemonic. This is your secret recovery phrase.

   MNEMONIC=<MNEMONIC>
   danger

   Please do not check your keys into source control. Please add .env to your .gitignore

2. Download dotenv and @truffle/hdwallet-provider

   npm i -D dotenv
   npm i -D @truffle/hdwallet-provider

3. Add the Linea testnet to your truffle-config.js file:

   Infura

   To use Infura, you'll need to get an API key. Add it to the .env file as follows:

   MNEMONIC=MNEMONIC
   INFURA_API_KEY=INFURA_API_KEY

   Then, modify truffle-config.js like so:

   require("dotenv").config();
   const { MNEMONIC, INFURA_API_KEY } = process.env;
   
   const HDWalletProvider = require("@truffle/hdwallet-provider");
   
   module.exports = {
     networks: {
       linea_testnet: {
         provider: () => {
           return new HDWalletProvider(
             MNEMONIC,
             `https://linea-goerli.infura.io/v3/${INFURA_API_KEY}`,
           );
         },
         network_id: "59140",
       },
       linea_mainnet: {
         provider: () => {
           return new HDWalletProvider(
             MNEMONIC,
             `https://linea-mainnet.infura.io/v3/${INFURA_API_KEY}`,
           );
         },
         network_id: "59140",
       },
     },
     // ... rest of truffle-config.js
   };

   Public Endpoint

   The public endpoints are rate limited and not meant for production systems. However, you can use the public endpoints by modifying truffle-config.js as follows:

   require("dotenv").config();
   const { MNEMONIC } = process.env;
   
   const HDWalletProvider = require("@truffle/hdwallet-provider");
   
   module.exports = {
     networks: {
       linea_testnet: {
         provider: () => {
           return new HDWalletProvider(
             MNEMONIC,
             `https://rpc.goerli.linea.build/`,
           );
         },
         network_id: "59140",
       },
       linea_mainnet: {
         provider: () => {
           return new HDWalletProvider(
             MNEMONIC,
             `https://rpc.linea.build/`,
           );
         },
         network_id: "59140",
       },
     },
     // ... rest of truffle-config.js
   };

4. Call truffle migrate --network linea_testnet or truffle migrate --network linea_mainnet from the CLI.

   Your output should look similar to the following:

   Compiling your contracts...
   ===========================
   > Everything is up to date, there is nothing to compile.
   
   Starting migrations...
   ======================
   > Network name:    'linea'
   > Network id:      59140
   > Block gas limit: 30000000 (0x1c9c380)
   
   1_deploy_token.js
   =================
   
     Deploying 'Token'
     -----------------
     > transaction hash:    0x412d58eaf4cc387fe1efa52b105f6fadac36db934b1617d04eaefc1947197525
     > Blocks: 0            Seconds: 0
     > contract address:    0x33b4D321Fc300E4f402820052EFA0958272D2AE5
     > block number:        143419
     > block timestamp:     1677366505
     > account:             YOUR_ACCOUNT_NUMBER
     > balance:             0.088400819995522296
     > gas used:            639672 (0x9c2b8)
     > gas price:           2.500000007 gwei
     > value sent:          0 ETH
     > total cost:          0.001599180004477704 ETH
   
     > Saving artifacts
     -------------------------------------
     > Total cost:     0.001599180004477704 ETH
   
   Summary
   =======
   > Total deployments:   1
   > Final cost:          0.001599180004477704 ETH
   ``` -->

Next, you can optionally verify your contract on the network.