Skip to content

Latest commit

 

History

History
114 lines (86 loc) · 5.53 KB

README.md

File metadata and controls

114 lines (86 loc) · 5.53 KB
Raw

Subnet EVM Contracts

CONTRACTS HERE ARE ALPHA SOFTWARE AND ARE NOT YET AUDITED. USE AT YOUR OWN RISK!

Introduction

Avalanche is an open-source platform for launching decentralized applications and enterprise blockchain deployments in one interoperable, highly scalable ecosystem. Avalanche gives you complete control on both the network and application layers—helping you build anything you can imagine.

The Avalanche Network is composed of many subnets and chains. Chains in subnets run with customizable virtual machines. One of these virtual machines is Subnet EVM. The Subnet EVM's API is almost identical to an Ethereum node's API. Subnet EVM brings its own features like minting native tokens via contracts, restrincting contract deployer etc. These features are presented with Stateful Precompile Contracts. These contracts are precompiled and deployed when they're activated.

The goal of this guide is to lay out best practices regarding writing, testing and deployment of smart contracts to Avalanche's Subnet EVM. We'll be building smart contracts with development environment Hardhat.

Prerequisites

NodeJS and Yarn

First, install the LTS (long-term support) version of nodejs. This is 16.2.0 at the time of writing. NodeJS bundles npm.

Next, install yarn:

npm install -g yarn

Solidity and Avalanche

It is also helpful to have a basic understanding of Solidity and Avalanche.

Dependencies

Clone the repo and install the necessary packages via yarn.

$ git clone https://github.com/ava-labs/subnet-evm.git
$ cd smart-contract-examples
$ yarn

Write Contracts

ERC20NativeMinter.sol is based on Open Zeppelin ERC20 contract powered by native minting capabilities of Subnet EVM. ERC20 is a popular smart contract interface. It uses INativeMinter interface to interact with NativeMinter precompile.

ExampleDeployerList shows how ContractDeployerAllowList precompile can be used in a smart contract. It uses IAllowList to interact with ContractDeployerAllowList precompile. When the precompile is activated only those allowed can deploy contracts.

Both of these NativeMinter and AllowList should be enabled by a chain config in genesis or as an upgrade. See the example genesis under Tests section.

For more information about precompiles see subnet-evm precompiles.

Hardhat Config

Hardhat uses hardhat.config.js as the configuration file. You can define tasks, networks, compilers and more in that file. For more information see here.

In our repository we use a pre-configured file hardhat.config.ts. This file configures necessary network information to provide smooth interaction with Avalanche. There are also some pre-defined private keys for testing on a local test network. Each chain in subnets has their own RPC URL. Subnet EVM's RPC URL is in form of: "http://{ip}:{port}/ext/bc/{chainID}/rpc. When you create your own subnet and Subnet EVM chain {chainID} will be different. Do not forget to set correct URL under the networks in the configuration file.

Hardhat Tasks

You can define custom hardhat tasks in hardhat.config.ts. Tasks contain helpers for precompiles allowList and minter. Precompiles have their own contract already-deployed when they're activated. So these can be called without deploying any intermediate contract. See npx hardhat --help for more information about available tasks.

Tests

Tests are written for a local network which runs a Subnet-EVM chain. E.g npx hardhat test --network local. Subnet-EVM must activate required precompiles with following genesis:

{
  "config": {
    "chainId": 43214,
    "homesteadBlock": 0,
    "eip150Block": 0,
    "eip150Hash": "0x2086799aeebeae135c246c65021c82b4e15a2c451340993aacfd2751886514f0",
    "eip155Block": 0,
    "eip158Block": 0,
    "byzantiumBlock": 0,
    "constantinopleBlock": 0,
    "petersburgBlock": 0,
    "istanbulBlock": 0,
    "muirGlacierBlock": 0,
    "subnetEVMTimestamp": 0,
    "feeConfig": {
      "gasLimit": 8000000,
      "minBaseFee": 25000000000,
      "targetGas": 15000000,
      "baseFeeChangeDenominator": 36,
      "minBlockGasCost": 0,
      "maxBlockGasCost": 1000000,
      "targetBlockRate": 2,
      "blockGasCostStep": 200000
    },
    "contractDeployerAllowListConfig": {
      "blockTimestamp": 0,
      "adminAddresses": ["0x8db97C7cEcE249c2b98bDC0226Cc4C2A57BF52FC"]
    },
    "contractNativeMinterConfig": {
      "blockTimestamp": 0,
      "adminAddresses": ["0x8db97C7cEcE249c2b98bDC0226Cc4C2A57BF52FC"]
    },
    "allowFeeRecipients": false
  },
  "alloc": {
    "8db97C7cEcE249c2b98bDC0226Cc4C2A57BF52FC": {
      "balance": "0x295BE96E64066972000000"
    }
  },
  "nonce": "0x0",
  "timestamp": "0x0",
  "extraData": "0x00",
  "gasLimit": "0x7A1200",
  "difficulty": "0x0",
  "mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "coinbase": "0x0000000000000000000000000000000000000000",
  "number": "0x0",
  "gasUsed": "0x0",
  "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000"
}