Chronicle | Avalanche Builder Hub

Overview

Chronicle Protocol is a novel Oracle solution that overcomes the current limitations of transferring data onchain by developing scalable, cost-efficient, decentralized, and verifiable Oracles. For the data feeds addresses, please check out the Chronicle Dashboard under Oracles section. Select either Mainnets or Testnets, then Avalanche C-Chain Oracles.

Data Feeds Types

Chronicle provides two categories of Oracles: DeFi Oracles and Verified Asset Oracles (VAO).

DeFi Oracles include:

Cryptocurrency Oracles
Fiat Currency Oracles
Yield Rate Oracles

The Verified Asset Oracle (VAO) — formerly known as the RWA Oracle — securely and transparently verifies the integrity and quality of any offchain asset, transports the resulting data onchain, and makes it directly available to smart contracts and onchain products.

Check the Chronicle Oracles on the Chronicle Dashboard

Using Chronicle DeFi Oracles on Avalanche Fuji Testnet

The following example showcases how to integrate the AVAX/USD oracle on Avalanche Fuji Testnet.

Chronicle contracts are read-protected by a whitelist, meaning you won't be able to read them onchain without your address being added to the whitelist. On the Testnet networks, users can add themselves to the whitelist through the SelfKisser contract; a process playfully referred to as "kissing" themselves. To get access to production Oracles on the Mainnet, please open a support ticket in Discord in the 🆘 ｜ support channel.

For oracle addresses, please check out the Dashboard.

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

/**
 * @title OracleReader
 * @notice A simple contract to read from Chronicle oracles
 * @dev To see the full repository, visit https://github.com/chronicleprotocol/OracleReader-Example.
 * @dev Addresses in this contract are hardcoded for Avalanche Fuji Testnet.
 * For other supported networks, check the https://chroniclelabs.org/dashboard/oracles.
 */
contract OracleReader {
    /**
    * @notice The Chronicle oracle to read from.
    * Chronicle_AVAX_USD - 0x8b3328b27436263e0BfE7597a0D97B1BEE9cC576
    * Network: Avalanche Fuji Testnet
    */

    IChronicle public chronicle = IChronicle(address(0x8b3328b27436263e0BfE7597a0D97B1BEE9cC576));

    /**
    * @notice The SelfKisser granting access to Chronicle oracles.
    * SelfKisser_1:0x371A53bB4203Ad5D7e60e220BaC1876FF3Ddda5B
    * Network: Avalanche Fuji Testnet
    */
    ISelfKisser public selfKisser = ISelfKisser(address(0x371A53bB4203Ad5D7e60e220BaC1876FF3Ddda5B));

    constructor() {
        // 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.
    * @return age The timestamp of the last update from the oracle.
    */
    function read() external view returns (uint256 val, uint256 age) {
        (val, age) = chronicle.readWithAge();
    }
}

// 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);

    /**
    * @notice Returns the oracle's current value and its age.
    * @dev Reverts if no value set.
    * @return value The oracle's current value using 18 decimals places.
    * @return age The value's age as a Unix Timestamp .
    * */
    function readWithAge() external view returns (uint256 value, uint256 age);
}

// 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;
}

Documentation Link

For more examples, check out the Chronicle Documentation.

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