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Setting Up Your Environment Using Truffle#

Truffle is a blockchain development environment, which you can use to create and test smart contracts by leveraging the Ethereum Virtual Machine (EVM), aiming to make life as a developer easier.

This article shows you how to set up Truffle and use it to build and deploy a smart contract on the Flare network.

Guide#

1. Set up the Environment#

Install the following dependencies:

Once the above dependencies are installed, install Truffle:

npm install -g truffle

To verify that Truffle is installed properly, type truffle version into the terminal.

2. Create a Truffle Project#

In this article you will use one of Truffle's boilerplate projects which you can find on the Truffle Boxes page. MetaCoin box is an example of a completed coin-like contract.

Create a new directory for this Truffle project by running:

mkdir flare-truffle-tutorial
cd flare-truffle-tutorial

Then install the MetaCoin box:

truffle unbox metacoin

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

Truffle Project structure

Truffle Project structure.

Finally, install the following dependencies which will be needed to deploy contracts:

npm i @truffle/hdwallet-provider dotenv

3. Compile the Contract#

In the contracts folder you should find two sample source files called MetaCoin.sol and ConvertLib.sol.

To compile them, simply run:

truffle compile

Upon successful compilation, you should see the following output:

Truffle compilation output

Truffle compilation output.

4. Test the Contract#

In the test folder you should find examples for testing your smart contracts in both JavaScript and Solidity that verify the contracts work as expected.

To run tests:

truffle test

When successful, the output should look like this:

Truffle test output

Truffle test output.

5. Configure the Project#

In order to be deployed on any of the Flare networks, the project needs to be configured. Edit the truffle-config.js file and replace its contents with the following:

const HDWalletProvider = require('@truffle/hdwallet-provider');
require('dotenv').config();
const fs = require('fs');

module.exports = {

  networks: {
    development: {
      host: "127.0.0.1",     // Localhost (default: none)
      port: 8545,            // Standard Ethereum port (default: none)
      network_id: "*",       // Any network (default: none)
    },
    flare: {
      provider: () => new HDWalletProvider(process.env.PRIVATE_KEY, `https://flare-api.flare.network/ext/C/rpc`),
      network_id: 14,
      timeoutBlocks: 200,
      skipDryRun: true
    },
    coston2: {
      provider: () => new HDWalletProvider(process.env.PRIVATE_KEY, `https://coston2-api.flare.network/ext/C/rpc`),
      network_id: 114,
      timeoutBlocks: 200,
      skipDryRun: true
    },

  },

  // Set default mocha options here, use special reporters etc.
  mocha: {
    // timeout: 100000
  },

  // Configure your compilers
  compilers: {
    solc: {
      version: "0.8.13",      // Fetch exact version from solc-bin
    }
  }
};

Then, create a file called .env at the root of you project (where the truffle-config.js file resides) to store the private key for the account to use for testing.

PRIVATE_KEY="d8936f6eae35c73a14ea7c1aabb8d068e16889a7f516c8abc482ba4e1489f4cd"

.env files are useful to store local information which should not be committed into the source repository.

Caution

Make sure you never upload your .env file to a remote repository.

For this reason, the .gitignore file that Truffle created for you already ignores .env files.

6. Deploy the Contract#

Important

You are going to deploy the contract on the Coston 2 network. Make sure you have enough C2FLR in the account that will deploy the contract to pay the gas fees!

You can add C2FLR to any account using the Coston 2 Faucet.

Run this command in the root folder of the project:

truffle migrate --network coston2

You should get an output similar to:

Truffle deployment output

Truffle deployment output.

You can check the status of the contract by copy and pasting the contract address: in the Block Explorer.

Last update: 2023-06-06