Chainlink Hardhat Box

Implementation of the following 3 Chainlink features using the Hardhat development environment:

• Request & Receive data
• Chainlink Price Feeds
• Chainlink VRF

Requirements

• NPM or YARN

Installation

Set your KOVAN_RPC_URL environment variable.. You can get one for free at Infura's site.. You'll also need to set the variable PRIVATE_KEY which is your private key from you wallet, ie metamask.

You can set this in your .env file if you're unfamiliar with how setting environment variables work.

.env example:

KOVAN_RPC_URL='www.infura.io/asdfadsfafdadf'
PRIVATE_KEY='abcdef'
MAINNET_RPC_URL="https://eth-mainnet.alchemyapi.io/v2/your-api-key"

bash example

export KOVAN_RPC_URL='www.infura.io/asdfadsfafdadf'
export MNEMONIC='cat dog frog...'
export MAINNET_RPC_URL="https://eth-mainnet.alchemyapi.io/v2/your-api-key"

If you plan on deploying to a local Hardhat network that's a fork of the Ethereum mainnet instead of a public test network like Kovan, you'll also need to set your MAINNET_RPC_URL environment variable. and uncomment the forking section in hardhat.config.js. You can get one for free at Alchemy's site..

You can also use a PRIVATE_KEY instead of a MNEMONIC environment variable by uncommenting the section in the hardhat.config.js, and commenting out the MNEMONIC line.

Then you can install all the dependencies

git clone https://github.com/smartcontractkit/chainlink-hardhat-box
cd chainlink-hardhat-box

then

npm install

Or

yarn

Deploy

Deployment scripts are in the deploy directory. If required, edit the desired environment specific variables or constructor parameters in each script, then run the hardhat deployment plugin as follows. If no network is specified, it will default to the Kovan network.

This will deploy to a local hardhat network

npx hardhat deploy 

To deploy to testnet:

npx hardhat deploy --network kovan

Test

Tests are located in the test directory and can be modified as required. To run them:

npx hardhat test

Run

The deployment output will give you the contract addresses as they are deployed. You can then use these contract addresses in conjunction with Hardhat tasks to perform operations on each contract

Chainlink Price Feeds

The Price Feeds consumer contract has one task, to read the latest price of a specified price feed contract

npx hardhat read-price-feed --contract insert-contract-address-here --network network

Request & Receive Data

The APIConsumer contract has two tasks, one to request external data based on a set of parameters, and one to check to see what the result of the data request is. This contract needs to be funded with link first:

npx hardhat fund-link --contract insert-contract-address-here --network network

Once it's funded, you can request external data by passing in a number of parameters to the request-data task. The contract parameter is mandatory, the rest are optional

npx hardhat request-data --contract insert-contract-address-here --network network

Once you have successfully made a request for external data, you can see the result via the read-data task

npx hardhat read-data --contract insert-contract-address-here --network network

VRF Get a random number

The VRFConsumer contract has two tasks, one to request a random number, and one to read the result of the random number request. This contract needs to be funded with link first:

npx hardhat fund-link --contract insert-contract-address-here --network network

Once it's funded, you can perform a VRF request with the request-random-number task, passing in the required seed number:

npx hardhat request-random-number --contract insert-contract-address-here --seed '777777' --network network

Once you have successfully made a request for a random number, you can see the result via the read-random-number task:

npx hardhat read-random-number --contract insert-contract-address-here --network network

Verify on Etherscan

You'll need an ETHERSCAN_API_KEY environment variable. You can get one from the Etherscan API site.

npx hardhat verify --network <NETWORK> <CONTRACT_ADDRESS> <CONSTRUCTOR_PARAMETERS>

example:

npx hardhat verify --network kovan 0x9279791897f112a41FfDa267ff7DbBC46b96c296 "0x9326BFA02ADD2366b30bacB125260Af641031331"

Linting

yarn lint:fix