Foundry Smart Contract Lottery

Welcome to the Foundry Smart Contract Lottery project. This is an agnostic smart contract developed to create provably fair lotteries. This contract can be deployed on any blockchain network that supports EVM-compatible smart contracts, offering a flexible and reliable solution for decentralized lotteries.

Key features include:

• Provably fair lottery system using Chainlink VRF
• Support for deploying the contract on various testnets and mainnets
• Ability to estimate the gas cost for contract operations

Table of Contents

1. Getting Started
   • Requirements
   • Quickstart
   • Optional Gitpod
2. Usage
   • Start a local node
   • Library
   • Deploy
   • Testing
   • Test Coverage
3. Deployment to a Testnet or Mainnet
   • Scripts
   • Estimate Gas
4. Formatting

Getting Started

Requirements

• git
  • You'll know you did it right if you can run git --version and you see a response like git version x.x.x
• foundry
  • You'll know you did it right if you can run forge --version and you see a response like `forge 0.2.0 (816e00b 2023-03-16T00:05:26.396218Z)

Quickstart

git clone https://github.com/abdoMous/foundry-smart-contract-lottery
cd foundry-smart-contract-lottery
forge build

Optional Gitpod

If you can't or don't want to run and install locally, you can work with this repo in Gitpod. If you do this, you can skip the clone this repo part.

Usage

Start a local node

Start a local node with the following command:

make anvil

Library

If you're having a hard time installing the chainlink library, you can optionally run this command.

forge install smartcontractkit/chainlink-brownie-contracts@0.6.1 --no-commit

Deploy

This will default to your local node. You need to have it running in another terminal in order for it to deploy.

make deploy

Testing

Run tests with the following command:

forge test

Or use this command if you want to specify a fork url:

forge test --fork-url $SEPOLIA_RPC_URL

Test Coverage

Generate a test coverage report with this command:

forge coverage

Deployment to a testnet or mainnet

1. Setup environment variables

You'll want to set your SEPOLIA_RPC_URL and PRIVATE_KEY as environment variables. You can add them to a .env file, similar to what you see in .env.example.

• PRIVATE_KEY: The private key of your account (like from metamask). NOTE: FOR DEVELOPMENT, PLEASE USE A KEY THAT DOESN'T HAVE ANY REAL FUNDS ASSOCIATED WITH IT.
  • You can learn how to export it here.
• SEPOLIA_RPC_URL: This is url of the sepolia testnet node you're working with. You can get setup with one for free from Alchemy

Optionally, add your ETHERSCAN_API_KEY if you want to verify your contract on Etherscan.

1. Get testnet ETH

Head over to faucets.chain.link and get some testnet ETH. You should see the ETH show up in your metamask.

2. Deploy

make deploy ARGS="--network sepolia"

This will setup a ChainlinkVRF Subscription for you. If you already have one, update it in the scripts/HelperConfig.s.sol file. It will also automatically add your contract as a consumer.

3. Register a Chainlink Automation Upkeep

You can follow the documentation if you get lost.

Go to automation.chain.link and register a new upkeep. Choose Custom logic as your trigger mechanism for automation.

Scripts

After deploying to a testnet or local net, you can run the scripts.

Using cast deployed locally example:

cast send <RAFFLE_CONTRACT_ADDRESS> "enterRaffle()" --value 0.1ether --private-key <PRIVATE_KEY> --rpc-url $SEPOLIA_RPC_URL

or, to create a ChainlinkVRF Subscription:

make createSubscription ARGS="--network sepolia"

Estimate gas

You can estimate how much gas things cost by running this command:

forge snapshot

And you'll see an output file called .gas-snapshot

Formatting

To run code formatting:

forge fmt

Thank you!

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