What is Truffle

Truffle is an Ethereum development framework that will help us debugging, deploying, and testing smart contracts, among other things.

http://truffleframework.com/docs/

Get start with Truffle

The first thing we’re going to do is to deploy a contract using Truffle. Let's create a new directory for this exercise and run the following commands to install Truffle and initialize our project. We won’t need a testrpc node running since Truffle already comes with a simulation node for development and testing purposes.

$ mkdir truffle-experiment
$ cd truffle-experiment/
$ npm install [email protected]
$ npx truffle init

You will see some folders and files were created. Our directory should look like:

truffle-experiment/
├── contracts/
│ └── Migrations.sol
├── migrations/
│ └── 1_initial_migration.js
├── test/
├── truffle.js
└── truffle-config.js

Thecontractsfolder is where the smart contracts should be. Themigrationsfolder will host javascript files that will help us deploying our contracts to the network. You may also have seen aMigrationscontract in the first folder, this is where the history of our migrations is going to be stored on-chain. Thetestfolder is initially empty and is intended to keep our test files. Finally, you will see atruffle.jsand atruffle-config.jsfiles. We will skip them by now, but you can read more in their documentation.

.Create MyToken.sol file inside the contractsfolder and we can use the example of token contract.

Then, create a new migration file called2_deploy_my_token.jsfile in migration folder and copy the following lines into it:

const MyToken = artifacts.require('./MyToken.sol')
module.exports = function(deployer) {
  deployer.deploy(MyToken)
}

Truffle already comes with a simulation node for development and testing purposes. We just need to open a development console runningnpx truffle developand run the migrations usingtruffle migrateinside it. Then, you should see an output like this:

truffle(develop)
>
 truffle migrate
Using network ‘develop’.
Running migration: 1_initial_migration.js
Deploying Migrations…
… 0xf5776c9f32a9b5b7600d88a6a24b0ef433f559c31aaeb5eaf6e2fc5e2f7fa669
Migrations: 0x8cdaf0cd259887258bc13a92c0a6da92698644c0
Saving successful migration to network…
… 0xd7bc86d31bee32fa3988f1c1eabce403a1b5d570340a3a9cdba53a472ee8c956
Saving artifacts…
Running migration: 2_deploy_my_token.js
Deploying MyToken…
… 0xc74019c2fe3b3ef1d4e2033c2e4b9fa13611f3150f8b6b37334a8e29e24b056c
MyToken: 0x345ca3e014aaf5dca488057592ee47305d9b3e10
Saving successful migration to network…
… 0xf36163615f41ef7ed8f4a8f192149a0bf633fe1a2398ce001bf44c43dc7bdda0
Saving artifacts…

We’ll just care about the lineMyToken: 0x345ca3e0...305d9b3e10, which tells us the address of our deployed token contract. By default, Truffle initializes the simulation node with 10 addresses with fake ETH as we saw when usingtestrpc, and we can access this array viaweb3.eth.accounts. Moreover, it deploys these contracts using the first address of this list (the one with index 0), which means that it will be the owner ofMyToken.

Given thatWeb3is available inside the Truffle console, you can just run the following commands to check the owner’s balance:

truffle(develop)>
owner = web3.eth.accounts[0]
truffle(develop)>
instance = MyToken.at('[DEPLOYED_ADDRESS]')
truffle(develop)>
instance.balanceOf(owner)