第4回 SolidityのUpgradeabilityとOpenZeppelinSDKとは

4.OpenZeppelinSDKの応用

はじめに

OpenZeppelin-contracts-ethereum-packageとは

アップグレーダブルなコントラクトのライブラリの紹介

initilize関数とは

import "@openzeppelin/upgrades/contracts/Initializable.sol";

function initialize(uint256 _rate, IERC20 _token) public initializer {
    rate = _rate;
    token = _token;
  }

アップグレーダブルなコントラクトの運用

アップグレーダブルなERC20のデプロイ

$ npm install --global @openzeppelin/cli

~$ mkdir token-exchange && cd token-exchange
token-exchange$npm init -y
Wrote to /Users/YukinoriHamada/token-exchange/package.json:

{
  "name": "token-exchange",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

token-exchange$ openzeppelin init


? Welcome to the OpenZeppelin SDK! Choose a name for your project token-exchange
? Initial project version 1.0.0
Project initialized. Write a new contract in the contracts folder and run 'openzeppelin create' to deploy it.

token-exchange$openzeppelin link @openzeppelin/contracts-ethereum-package

✓ Dependency @openzeppelin/contracts-ethereum-package installed
Dependency linked to the project. Run 'openzeppelin create' to deploy one of its contracts.

token-exchange$ oz create
No contracts found to compile.
? Pick a contract to instantiate @openzeppelin/contracts-ethereum-package/StandaloneERC20
? Pick a network development
✓ Deploying @openzeppelin/contracts-ethereum-package dependency to network dev-1574386470880
All contracts are up to date
? Call a function to initialize the instance after creating it? Yes
? Select which function * initialize(name: string, symbol: string, decimals: uint8, initialSupply: uint256, initialHolder: address, minters: address[], pauser
s: address[])
? name (string): MyToken
? symbol (string): MYT
? decimals (uint8): 18
? initialSupply (uint256): 100e18
? initialHolder (address): 0x19648B26968Ef0ce385a99412dDBAF3B2F7C0Ea4
? minters (address[]): 0x19648B26968Ef0ce385a99412dDBAF3B2F7C0Ea4
? pausers (address[]): 0x19648B26968Ef0ce385a99412dDBAF3B2F7C0Ea4
✓ Setting everything up to create contract instances
✓ Instance created at 0xd414E2273eA489dD5454b67BCa42D1432Ea2dDE0
0xd414E2273eA489dD5454b67BCa42D1432Ea2dDE0

token-exchange$ oz balance --erc20 0x19648B26968Ef0ce385a99412dDBAF3B2F7C0Ea4
? Enter an address to query its balance 
token-exchange$oz balance --erc20 0xd414E2273eA489dD5454b67BCa42D1432Ea2dDE0
? Enter an address to query its balance 0x19648B26968Ef0ce385a99412dDBAF3B2F7C0Ea4
? Pick a network development
Balance: 100 MYT
100000000000000000000

token-exchange$ oz call
? Pick a network development
? Pick an instance StandaloneERC20 at 0xd414E2273eA489dD5454b67BCa42D1432Ea2dDE0
? Select which function name()
✓ Method 'name()' returned: MyToken
MyToken
token-exchange$oz call
? Pick a network development
? Pick an instance StandaloneERC20 at 0xd414E2273eA489dD5454b67BCa42D1432Ea2dDE0
? Select which function totalSupply()
✓ Method 'totalSupply()' returned: 100000000000000000000
100000000000000000000

token-exchange$ oz send-tx
? Pick a network development
? Pick an instance StandaloneERC20 at 0xd414E2273eA489dD5454b67BCa42D1432Ea2dDE0
? Select which function transfer(to: address, value: uint256)
? to (address): 0xfD19F073E0177fEE72CDDf02eE60e5B5e7C75e0c
? value (uint256): 1e18
✓ Transaction successful. Transaction hash: 0xebcbe8c8f50877249a365e97dbab4049c60b0ec3aa6c0cb89b25e95b1ad3bcc1
Events emitted: 
 - Transfer(0x19648B26968Ef0ce385a99412dDBAF3B2F7C0Ea4, 0xfD19F073E0177fEE72CDDf02eE60e5B5e7C75e0c, 1000000000000000000)


token-exchange$ oz send-tx
? Pick a network development
? Pick an instance StandaloneERC20 at 0xd414E2273eA489dD5454b67BCa42D1432Ea2dDE0
? Select which function approve(spender: address, value: uint256)
? spender (address): 0xfD19F073E0177fEE72CDDf02eE60e5B5e7C75e0c
? value (uint256): 1e18
✓ Transaction successful. Transaction hash: 0x68206ff3f18f1b44460a02cda69afa8b514711f2d8ab4e2ef5cd222490ed0158
Events emitted: 
 - Approval(0x19648B26968Ef0ce385a99412dDBAF3B2F7C0Ea4, 0xfD19F073E0177fEE72CDDf02eE60e5B5e7C75e0c, 1000000000000000000)

アップグレーダブルなexchange contractの作成

$ touch contracts/TokenExchange.sol

pragma solidity ^0.5.0;

// Import base Initializable contract
import "@openzeppelin/upgrades/contracts/Initializable.sol";

// Import interface and library from OpenZeppelin contracts
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol";

contract TokenExchange is Initializable {
  using SafeMath for uint256;

  // Contract state: exchange rate and token
  uint256 public rate;
  IERC20 public token;

  // Initializer function (replaces constructor)
  function initialize(uint256 _rate, IERC20 _token) public initializer {
    rate = _rate;
    token = _token;
  }

  // Send tokens back to the sender using predefined exchange rate
  function() external payable {
    uint256 tokens = msg.value.mul(rate);
    token.transfer(msg.sender, tokens);
  }
}

token-exchange4$ oz create
✓ Compiled contracts with solc 0.5.13 (commit.5b0b510c)
? Pick a contract to instantiate TokenExchange
? Pick a network development
✓ Added contract TokenExchange
✓ Contract TokenExchange deployed
All contracts have been deployed
? Call a function to initialize the instance after creating it? Yes
? Select which function initialize(_rate: uint256, _token: address)
? _rate (uint256): 10
? _token (address): 0x02aDbeF4e8C167e18A005Cd7749dc7615d0138c2
✓ Instance created at 0xEdE0aB69fe6c4Ca6Df767ad19190eF9Fe465c405
0xEdE0aB69fe6c4Ca6Df767ad19190eF9Fe465c405

token-exchange4$ oz send-tx
? Pick a network development
? Pick an instance StandaloneERC20 at 0x02aDbeF4e8C167e18A005Cd7749dc7615d0138c2
? Select which function transfer(to: address, value: uint256)
? to (address): 0xEdE0aB69fe6c4Ca6Df767ad19190eF9Fe465c405
? value (uint256): 10e18
✓ Transaction successful. Transaction hash: 0x1dd0005905e4cb2b94c23dc27555f56e2a806db6aa1cefbd7b0b5313225abef5
Events emitted: 
 - Transfer(0xF987BFe4396FEf1f75488467c6845b74A496e381, 0xEdE0aB69fe6c4Ca6Df767ad19190eF9Fe465c405, 10000000000000000000)

token-exchange4$ oz transfer
? Pick a network development
? Choose the account to send transactions from (1) 0x004925a18aDee88246BE28f020d12E11A1412b5F
? Enter the receiver account 0xEdE0aB69fe6c4Ca6Df767ad19190eF9Fe465c405
? Enter an amount to transfer 0.1 ether
✓ Funds sent. Transaction hash: 0x2b9013a16be4ba3d357d8aa159971a93d5d640d1c7e35dbddf4f0bdd3c26ef9b

token-exchange4$ oz call
? Pick a network development
? Pick an instance StandaloneERC20 at 0x02aDbeF4e8C167e18A005Cd7749dc7615d0138c2
? Select which function balanceOf(account: address)
? account (address): 0xF987BFe4396FEf1f75488467c6845b74A496e381
✓ Method 'balanceOf(address)' returned: 90000000000000000000
90000000000000000000

token-exchange4$ oz call
? Pick a network development
? Pick an instance StandaloneERC20 at 0x02aDbeF4e8C167e18A005Cd7749dc7615d0138c2
? Select which function balanceOf(account: address)
? account (address): 0x004925a18aDee88246BE28f020d12E11A1412b5F
✓ Method 'balanceOf(address)' returned: 1000000000000000000
1000000000000000000

TokenExchange.solのアップグレード

contract TokenExchange is Initializable {
  uint256 public rate;
  IERC20 public token;
  address public owner;

  function withdraw() public {
    //require(msg.sender == owner, "Address not allowed to call this function");
    msg.sender.transfer(address(this).balance);
  }

 // To be run during upgrade, ensuring it can never be called again
   function setOwner(address _owner) public {
     require(owner == address(0), "Owner already set, cannot modify!");
     owner = _owner;
   }

  // (existing functions not shown here for brevity)
}

token-exchange4$ oz upgrade
? Pick a network development
Nothing to compile, all contracts are up to date.
All contracts are up to date
? Which instances would you like to upgrade? Choose by name
? Pick an instance to upgrade TokenExchange
? Call a function on the instance after upgrading it? Yes
? Select which function setOwner(_owner: address)
? _owner (address): 0xF987BFe4396FEf1f75488467c6845b74A496e381
Contract TokenExchange at 0xEdE0aB69fe6c4Ca6Df767ad19190eF9Fe465c405 is up to date.

token-exchange4$ oz send-tx
? Pick a network development
? Pick an instance TokenExchange at 0xEdE0aB69fe6c4Ca6Df767ad19190eF9Fe465c405
? Select which function withdraw()
✓ Transaction successful. Transaction hash: 0x22db891168bb0b72a350bbac1260a3277173828a096daffd162d4ac5c78c2f86

既存のERC20コントラクトをアップグレーダブルなERC20コントラクトにアップグレードする。

アップグレードガバナンスについて

概要

マルチシグウォレットの作成

~$ git clone https://github.com/gnosis/MultiSigWallet.git

~$ cd MultiSigWallet
MultiSigWallet$ npm install

MultiSigWallet$ git submodule update --init --force --recursive --remote

MultiSigWallet$ npm start
Starting up http-server, serving src
Available on:
  http://127.0.0.1:5000
  http://192.168.30.52:5000
Hit CTRL-C to stop the server

まとめ