[Truffle] Bank Example

Truffle 과 Ganache를 이용하여 이더리움 은행을 개발

트러플 프로젝트 생성

$ mkdir bank
$ cd bank
$ truffle init

Bank Contract

$ truffle create contract Bank

contracts/Bank.sol

pragma solidity ^0.4.4;

contract Bank {
    address public owner; //계좌의 소유주

    function Bank(address _owner) public {
        owner = _owner;
    }

    //입금
    function deposit() public payable {
        require(msg.value > 0);
    }

    //출금
    function withdraw() public {
        require(msg.sender == owner);
        owner.transfer(address(this).balance);
    }
}

What is a transaction?

The term “transaction” is used in Ethereum to refer to the signed data package that stores a message to be sent from an externally owned account to another account on the blockchain.

Ganache

컴파일

$ truffle compile
Compiling .\contracts\Bank.sol...
Compiling .\contracts\Migrations.sol...

Writing artifacts to .\build\contracts

배포

truffle.js

module.exports = {
  // See <http://truffleframework.com/docs/advanced/configuration>
  // to customize your Truffle configuration!
  networks: {
    development: {
      host: "127.0.0.1",
      port: 7545,
      network_id: "*" // Match any network id
    }
  }
};

배포 스크립트 작성

$ truffle create migration bank

타임스탬프 형식으로 Migration Script가 자동 생성된다.

migrations/1532503784_bank.js

module.exports = function(deployer) {
  // Use deployer to state migration tasks.
};

다음과 같이 작성한다.

var Bank = artifacts.require("Bank");

module.exports = function(deployer) {
  let ownerAddress = web3.eth.accounts[0];
  deployer.deploy(Bank, ownerAddress);
};

$ truffle migrate
Using network 'development'.

Running migration: 1_initial_migration.js
  Deploying Migrations...
  ... 0x217a4c792c920be8e32ed59d16a14205cf81fa77da3100dcb0add8f72ab5c431
  Migrations: 0x13c9f9ac9691ac047e90c253b75d9ec08be13b01
Saving successful migration to network...
  ... 0xcd0404b13daeda92f6f27f40d2559a6905019723fa28f8dc3f8a37a3d8421f8a
Saving artifacts...
Running migration: 1532503784_bank.js
  Deploying Bank...
  ... 0xe02911110604c0986dcf55ff072fb2ffac3a6d1d63ebfdb32a7f83cc02fdf0f7
  Bank: 0xdcbfcb0e112babddbca6af311a75ebb080e4f563
Saving successful migration to network...
  ... 0xb839d9e409c632cf9c5cbec70af02b0a0476ac3ac9178d8ce9c923feb5b58ecb
Saving artifacts...

오류발생 시

truffle migrate --reset

배포 후에 다음과 같이 4개의 트랜잭션 블럭이 추가된 것을 확인 할 수 있다. deposit

테스트

$ truffle console
truffle(development)>

배포한 컨트랙트의 인스턴스를 bank 변수에 저장한다.

truffle(development)> Bank.deployed().then(instance => bank = instance)

truffle(development)> bank.owner()
'0x597193c7db57b66b53f7cea4877f20961a98b0d2'

truffle(development)> bank.deposit({value: web3.toWei(10, 'ether')})
{ tx: '0xbae00009b4a915c8342ceef64b06d307e99e20d3bc72e0e538770d6224111948',
  receipt:
   { transactionHash: '0xbae00009b4a915c8342ceef64b06d307e99e20d3bc72e0e538770d6224111948',
     transactionIndex: 0,
     blockHash: '0x4cdaf5ab1ea8df72ac116484771a360214b1b781fb0cc2d3e1f65fcef70dedad',
     blockNumber: 5,
     gasUsed: 21453,
     cumulativeGasUsed: 21453,
     contractAddress: null,
     logs: [],
     status: '0x1',
     logsBloom: '0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' },
  logs: [] }

Note: deposit() 함수는 payable function 이기 때문에 송금 로직을 작성하지 않고 이더리움을 전송 할 수 있다.

deposit

truffle(development)> bank.withdraw()
{ tx: '0x85d78f1db258514b92c76420332ef04faf9a2bc49b08f43ff722ce0358e20680',
  receipt:
   { transactionHash: '0x85d78f1db258514b92c76420332ef04faf9a2bc49b08f43ff722ce0358e20680',
     transactionIndex: 0,
     blockHash: '0xa2427d52882d9d20b28cb00cae5aed6844cc70c05701014b66c2814a94f234f2',
     blockNumber: 6,
     gasUsed: 29826,
     cumulativeGasUsed: 29826,
     contractAddress: null,
     logs: [],
     status: '0x1',
     logsBloom: '0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' },
  logs: [] }

참조: http://ethdocs.org/en/latest/contracts-and-transactions/account-types-gas-and-transactions.html

withdraw