Boilerplate

Scaffold Eth 2 + Chronicle

info

Please be aware that, as the project currently stands, you should use Hardhat in terms of programming environments, and deploy your contracts to the Sepolia network.

Please refer to the following GitHub repo to take advantage of the boilerplate we have created in conjuction with Scaffold-Eth 2.

To find our OracleReader.sol contract, follow the following path:

- packages
    - hardhat
        - contracts
            - OracleReader.sol

Below is an example of the contract integrated into the repo:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.16;

/**
 * @title OracleReader
 * @notice A simple contract to read from Chronicle oracles
 * @dev Addresses in this contract are hardcoded for the Sepolia testnet.
 * For other supported networks, check https://chroniclelabs.org/dashboard/oracles.
 */
contract OracleReader {
    ///  @notice The Chronicle ETH/USD oracle.
    IChronicle public immutable chronicle;

    /// @notice The SelfKisser granting access to Chronicle oracles.
    ISelfKisser public immutable selfKisser;

    constructor(address chronicle_, address selfKisser_) {
        chronicle = IChronicle(chronicle_);
        selfKisser = ISelfKisser(selfKisser_);

        // Note to add address(this) to chronicle oracle's whitelist.
        // This allows the contract to read from the chronicle oracle.
        selfKisser.selfKiss(address(chronicle));
    }

    /// @notice Function to read the latest data from the Chronicle oracle.
    /// @return val The current value returned by the oracle.
    function read() external view returns (uint256 val) {
        return chronicle.read();
    }
}

// Copied from [chronicle-std](https://github.com/chronicleprotocol/chronicle-std/blob/main/src/IChronicle.sol).
interface IChronicle {
    /**
     * @notice Returns the oracle's current value.
     * @dev Reverts if no value set.
     * @return value The oracle's current value.
     * /
    function read() external view returns (uint256 value);
}

// Copied from [self-kisser](https://github.com/chronicleprotocol/self-kisser/blob/main/src/ISelfKisser.sol).
interface ISelfKisser {
    /// @notice Kisses caller on oracle `oracle`.
    function selfKiss(address oracle) external;
}

Add your environment variables in the .env.example file and rename it to .env:

- packages
    - hardhat
         - .env.example

/* 
* Template for Hardhat environment variables.
* To use this template, copy this file, rename it .env, and fill in the values.
* If not set, we provide default values (check `hardhat.config.ts`) so developers can start prototyping out of the box,
* but we recommend getting your own API Keys for Production Apps.
* The Chronicle ETH/USD oracle on Sepolia.
*/

CHRONICLE_ORACLE=0xdd6D76262Fd7BdDe428dcfCd94386EbAe0151603

// The Chronicle SelfKisser contract on Sepolia.
SELF_KISSER=0x0Dcc19657007713483A5cA76e6A7bbe5f56EA37d

// To access the values stored in this .env file you can use: process.env.VARIABLENAME
ALCHEMY_API_KEY=
DEPLOYER_PRIVATE_KEY=
ETHERSCAN_API_KEY=

The ETH/USD oracle and self-kisser addresses have been added to the .env.example file.

If you would run a Sepolia fork, you can deploy the contract using:

yarn deploy --tags OracleReader

Boilerplate

Scaffold Eth 2 + Chronicle​

Scaffold Eth 2 + Chronicle