Deploy with Truffle

In this section we will show you how to utilize the Truffle Suite to develop Smart Contracts for SwapDEX. Tuffle, in short, is a solidity suite that helps you to test your code.

Let's start with installing the technical requirements.

Installing Technical Requirements

To use Truffle we need to install NodeJS v8.9.4 or later and we need a running eth-client.

Note

Since SwapDEX is fully Ethereum compatible you can use Ganache as the preferred eth-client

Please go ahead and install NodeJS and Ganache.

After you installed NodeJS and Ganache, you can execute the following command in your Terminal to install Truffle

npm install -g truffle

Creating a Project

In this guide we will utilize the MetaCoin Truffle Box, which is a Truffle project template. The MetaCoin Box allows us to create an ERC-20 token on SwapDEX that can be transferred between accounts.

Create a new folder for your Truffle project and navigate into it:

mkdir MetaCoin
cd MetaCoin

Download und unbox the MetaCoin Box

truffle unbox metacoin

Hint

You can use the truffe unbox <box-name> command to download and unbox any truffle box

Hint

If you want to start from scratch please use truffle init

Once you unboxed MetaCoin, you will be greeted with a project structure like this:

contracts/: Directory for Solidity Contracts
migrations/: Directory for scriptable deployment files
test/: Directory for test files for testing your application and contracts
truffle.js: Truffle configuration file

Exploring the Project

Open the contracts/MetaCoin.sol file in a text editor. This is a smart contract (written in Solidity) that creates a MetaCoin token. Note that this also references another Solidity file contracts/ConvertLib.sol in the same directory.
Open the contracts/Migrations.sol file. This is a separate Solidity file that manages and updates the status of your deployed smart contract. This file comes with every Truffle project, and is usually not edited.
Open the migrations/1_initial_migration.js file. This file is the migration (deployment) script for the Migrations contract found in the Migrations.sol file.
Open the migrations/2_deploy_contracts.js file. This file is the migration script for the MetaCoin contract. (Migration scripts are run in order, so the file beginning with 2 will be run after the file beginning with 1.)
Open the test/TestMetaCoin.sol file. This is a test file written in Solidity which ensures that your contract is working as expected.
Open the test/metacoin.js file. This is a test file written in JavaScript which performs a similar function to the Solidity test above.
Open the truffle-config.js file. This is the Truffle configuration file, for setting network information and other project-related settings. The file is blank, but this is okay, as we'll be using a Truffle command that has some defaults built-in.

Hint

We will adjust the truffle-config.js later to deploy the Token to Ganache and later to SwapDEX

Testing

Testing your smart contracts is an important step in the development pipeline. To run a test of the MetaCoin contract open up a terminal and run the solidity test:

Run the Solidity Test

truffle test ./test/TestMetaCoin.sol

you will see the following output:

  TestMetaCoin
    √ testInitialBalanceUsingDeployedContract (607ms)
    √ testInitialBalanceWithNewMetaCoin (457ms)


  2 passing (16s)

*Run the Javascript Test

truffle test ./test/metacoin.js

You will see the following output:

  Contract: MetaCoin
    √ should put 10000 MetaCoin in the first account (126ms)
    √ should call a function that depends on a linked library (258ms)
    √ should send coin correctly (976ms)


  3 passing (1s)

Success

The solidity and javascript test were successfull!

Compiling the Smart Contract

After the successfull test we are ready to compile the smart contracts within the contracts/ folder.

truffle compile

You will see the following output:

Compiling your contracts...
===========================
> Compiling .\contracts\ConvertLib.sol
> Compiling .\contracts\MetaCoin.sol
> Compiling .\contracts\Migrations.sol
> Artifacts written to .\build\contracts
> Compiled successfully using:

Migrating with Ganache

To migrate or upload your smart contract to the Ganache Blockchain you need to tell truffle where it to deploy the contract. We do this by adjusting the truffle-config.js file as follows:

Open truffle-config.js in a text editor and replace the content with the following:

module.exports = {
  networks: {
    development: {
      host: "127.0.0.1",
      port: 7545,
      network_id: "*"
    }
  }
};

Save and close the file

Launch Ganache

Mirgrate to Ganache

Now that we told truffle where to migrate the contracts we can migrate.

truffle migrate

You will see the following output:

Compiling your contracts...
===========================
> Compiling .\contracts\ConvertLib.sol
> Compiling .\contracts\MetaCoin.sol
> Compiling .\contracts\Migrations.sol
> Artifacts written to C:\Users\petar\Documents\SwapDex\EVM-Tutorial\build\contracts
> Compiled successfully using:
   - solc: 0.5.16+commit.9c3226ce.Emscripten.clang

PS C:\Users\petar\Documents\SwapDex\EVM-Tutorial> truffle migrate

Compiling your contracts...
===========================
> Compiling .\contracts\ConvertLib.sol
> Compiling .\contracts\MetaCoin.sol
> Compiling .\contracts\Migrations.sol
> Artifacts written to C:\Users\petar\Documents\SwapDex\EVM-Tutorial\build\contracts
> Compiled successfully using:
   - solc: 0.5.16+commit.9c3226ce.Emscripten.clang



Starting migrations...
======================
> Network name:    'development'
> Network id:      5777
> Block gas limit: 6721975 (0x6691b7)


1_initial_migration.js
======================

   Deploying 'Migrations'
   ----------------------
   > transaction hash:    0x7f94b5d6852bae542f3c2d89e335a309243e54da0bbe96a3c1b863b40a4f547b
   > Blocks: 0            Seconds: 0
   > contract address:    0x475D507822741736A110e25698612C9Eb4ECc635
   > block number:        1
   > block timestamp:     1634129141
   > account:             0x456ad8e2CBF08FCde3C75D169ddF9C20e00F51F4
   > balance:             99.9967165
   > gas used:            164175 (0x2814f)
   > gas price:           20 gwei
   > value sent:          0 ETH
   > total cost:          0.0032835 ETH


   > Saving migration to chain.
   > Saving artifacts
   -------------------------------------
   > Total cost:           0.0032835 ETH


2_deploy_contracts.js
=====================

   Deploying 'ConvertLib'
   ----------------------
   > transaction hash:    0x0644f4e5186e058e18565b13db350ff8f0158c1f5a8f551741b55d11c76fea7d
   > Blocks: 0            Seconds: 0
   > contract address:    0x0Da4E500c4419860688284687efdF743337FE8ab
   > block number:        3
   > block timestamp:     1634129143
   > account:             0x456ad8e2CBF08FCde3C75D169ddF9C20e00F51F4
   > balance:             99.99396028
   > gas used:            95470 (0x174ee)
   > gas price:           20 gwei
   > value sent:          0 ETH
   > total cost:          0.0019094 ETH


   Linking
   -------
   * Contract: MetaCoin <--> Library: ConvertLib (at address: 0x0Da4E500c4419860688284687efdF743337FE8ab)

   Deploying 'MetaCoin'
   --------------------
   > transaction hash:    0xed1abbaf5d5cf4260c69cbec427b9a1b924302cf08b9e7d8e20920b5410bb927
   > Blocks: 0            Seconds: 0
   > contract address:    0x2E2EB10E302b2551C2788baBAe0d5981c18b4DDf
   > block number:        4
   > block timestamp:     1634129144
   > account:             0x456ad8e2CBF08FCde3C75D169ddF9C20e00F51F4
   > balance:             99.98822922
   > gas used:            286553 (0x45f59)
   > gas price:           20 gwei
   > value sent:          0 ETH
   > total cost:          0.00573106 ETH


   > Saving migration to chain.
   > Saving artifacts
   -------------------------------------
   > Total cost:          0.00764046 ETH


Summary
=======
> Total deployments:   3
> Final cost:          0.01092396 ETH

This shows the transaction IDs and addresses of your deployed contracts. It also includes a cost summary and real-time status updates.

Hint

Hint: Your transaction IDs and contract addresses may be different from the above.

In Ganache, click the "Transactions" button to see that the transactions have been processed.

Success

You deployed a smart contract to the Ganache Blockchain!

Migrate to SwapDEX

To deploy the smart contracts to SwapDEX, we need to make some adjustments. First of all we need to install the truffle HDWallet package as follows:

npm install @truffle/hdwallet-provider

HD Wallet is basically an instance of your wallet e.g., MetaMask that has access to the SwapDEX network. Since a contract deployment involves transactions, you need to have your private key or your seed phrase ready.

Open the truffle-config.js file and replace its content with the following code:

const HDWalletProvider = require("@truffle/hdwallet-provider");
const privKey = 'YOUR PRIVATE KEY GOES HERE';

module.exports = {  
    compilers: {    
        solc: {      
            version: "^0.6.0",
        }
    },  
    networks: {
        swapdex: {
            provider: () => new HDWalletProvider({
                privateKeys: [ privKey ],
                providerOrUrl: "https://rpc.swapdex.network",
            }),
            network_id: 142,
        },  
    } 
}

Save the file. You notice a few facts from here, our chainId is 142 and we are using solc version above ^0.6.0.

Hint

Make sure that the wallet which is attached to the private key you provided earlier is funded sufficiently to pay for the gas needed to deploy the smart contracts.

Migrate your Contracts to SwapDEX

To deploy the smart contracts within your project you need to execute the following command:

truffle --network development migrate

You should see the following output:

Compiling your contracts...
===========================
√ Fetching solc version list from solc-bin. Attempt #1
√ Downloading compiler. Attempt #1.
> Compiling .\contracts\ConvertLib.sol
> Compiling .\contracts\MetaCoin.sol
> Compiling .\contracts\Migrations.sol
√ Fetching solc version list from solc-bin. Attempt #1
> Artifacts written to C:\Users\petar\Documents\SwapDex\EVM-Tutorial\build\contracts
> Compiled successfully using:
   - solc: 0.6.12+commit.27d51765.Emscripten.clang



Starting migrations...
======================
> Network name:    'swapdex'
> Network id:      70
> Block gas limit: 30000000 (0x1c9c380)


1_initial_migration.js
======================

   Deploying 'Migrations'
   ----------------------
   > transaction hash:    0x69c148fd82661cafb34a7c3df6d4efa714ed9a4553104def2c26a95cde4e1d6f
   > Blocks: 1            Seconds: 4
   > contract address:    0x37b35EAab7C6a52Fb6cd23CcBadc18CF075F6dF6
   > block number:        113067
   > block timestamp:     1634138652
   > account:             0xd3e849B097f7cFe0fdD381e778012759a972d250
   > balance:             99.99204025
   > gas used:            159195 (0x26ddb)
   > gas price:           50 gwei
   > value sent:          0 ETH
   > total cost:          0.00795975 ETH


   > Saving migration to chain.
   > Saving artifacts
   -------------------------------------
   > Total cost:          0.00795975 ETH


2_deploy_contracts.js
=====================

   Deploying 'ConvertLib'
   ----------------------
   > transaction hash:    0xc5b4688c876ee566e2ae53b76dbbdbb820e3f71faf0360d0a9aabe32d2b9b8a5
   > Blocks: 0            Seconds: 4
   > contract address:    0xBd41c64fB0531ad8579984F521A23c9B27AC25C5
   > block number:        113069
   > block timestamp:     1634138664
   > account:             0xd3e849B097f7cFe0fdD381e778012759a972d250
   > balance:             99.98513905
   > gas used:            95686 (0x175c6)
   > gas price:           50 gwei
   > value sent:          0 ETH
   > total cost:          0.0047843 ETH


   Linking
   -------
   * Contract: MetaCoin <--> Library: ConvertLib (at address: 0xBd41c64fB0531ad8579984F521A23c9B27AC25C5)

   Deploying 'MetaCoin'
   --------------------
   > transaction hash:    0x9dacc10950ae2b6386f0c75a6d86fe88e337442a2adbb7cadceb5fd85a1e763f
   > Blocks: 1            Seconds: 4
   > contract address:    0x32C3681dB7b86852555475D9E91620Dfc51D3A73
   > block number:        113070
   > block timestamp:     1634138670
   > account:             0xd3e849B097f7cFe0fdD381e778012759a972d250
   > balance:             99.970821
   > gas used:            286361 (0x45e99)
   > gas price:           50 gwei
   > value sent:          0 ETH
   > total cost:          0.01431805 ETH


   > Saving migration to chain.
   > Saving artifacts
   -------------------------------------
   > Total cost:          0.01910235 ETH


Summary
=======
> Total deployments:   3
> Final cost:          0.0270621 ETH

Success

Congrats, you deployed your first smart contracts on the SwapDEX Network!

Check Deployment on Network Explorer

To verfiy the successfull deployment head over to the EVM Testnet Explorer and search for your Contract Address.

Interact with the Contract

Since we didn't connect the logic of the smart contracts with a front end we need to interact with our contracts via the console. You can do this in the following ways:

Invoke the truffle console:

truffle console

You will see the following prompt:

truffle(development)>

Begin by establishing both the deployed MetaCoin contract instance and your SwapDEX wallet

Hint

It is normal to get an undefined as response from the console after you executed one command

let instance = await MetaCoin.deployed()
let accounts = await web3.eth.getAccounts()

Check the metacoin balance of the account that deployed the contract:

let balance = await instance.getBalance(accounts[0])
balance.toNumber()

See how much ether that balance is worth (and note that the contract defines a metacoin to be worth 2 ether):

let ether = await instance.getBalanceInEth(accounts[0])
ether.toNumber()

Transfer some metacoin from one account to another:

instance.sendCoin(TARGET ADDRESS, 500)

You should see the following result:

{
  tx: '0x3a81b73b5f9b22ba739b2ba1072ac2b51efa2c5655c4d64f4147937bf5b627ae',
  receipt: {
    blockHash: '0x848addd30c96393e5d1f3dddfd633f0d2ffba0b97b15d2a566eba76d7863f63c',
    blockNumber: 113352,
    contractAddress: null,
    cumulativeGasUsed: 47314,
    from: '0xd3e849b097f7cfe0fdd381e778012759a972d250',
    gasUsed: 47314,
    logs: [ [Object] ],
    logsBloom: '0x00000000000000000000000000000000000000000000000000000008000000000000100001000000000000000000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000400000000000000000000000000000000000000000000000000000010000000000000000000000000004000000000000004000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000202000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000008000000000000',
    status: true,
    to: '0x32c3681db7b86852555475d9e91620dfc51d3a73',
    transactionHash: '0x3a81b73b5f9b22ba739b2ba1072ac2b51efa2c5655c4d64f4147937bf5b627ae',
    transactionIndex: 0,
    rawLogs: [ [Object] ]
  },
  logs: [
    {
      address: '0x32C3681dB7b86852555475D9E91620Dfc51D3A73',
      blockHash: '0x848addd30c96393e5d1f3dddfd633f0d2ffba0b97b15d2a566eba76d7863f63c',
      blockNumber: 113352,
      logIndex: 0,
      removed: false,
      transactionHash: '0x3a81b73b5f9b22ba739b2ba1072ac2b51efa2c5655c4d64f4147937bf5b627ae',
      transactionIndex: 0,
      transactionLogIndex: '0x0',
      id: 'log_cdcbe184',
      event: 'Transfer',
      args: [Result]
    }
  ]
}

Check the balance of the account that received the metacoin:

let received = await instance.getBalance(TARGET ADDRESS)
received.toNumber()

Check the balance of the account that sent the metacoin:

let newBalance = await instance.getBalance(accounts[0])
newBalance.toNumber()

Success

Congrats, you succesfully depolyed 3 smart contracts to SwapDEX via Truffle and Meta Mask!

Continue Learning

Please check Truffle's fantastic docs, guides and tutorials : Truffle

Written by Masterdubs & Petar