DeFiChain Oracle Adapters (The Salmon Project)

Mono-repo for DeFiChain Oracle Adapters. Next generation implementation replacing existing JellyfishSDK/salmon.

Technical Design

DeFiChain Oracle Adapters follows a mono-repo design with two distinct sections: salmon packages, and adapters. Packages represent each module component of the oracle system with a runner. Adapters are a data-only, price feed fetcher that conforms to the specification of packages/salmon-fetch.

@defichain/oracle-adapters

Featuring a collection of Oracle Price Feed adapters. Powered with @defichain/salmon-fetch it fetches data and transforms it into a list of AssetPrice for publishing.

The Salmon Framework

A runner agnostic ephemeral oracle publishing framework. Each module component represent a modular subsystem of salmon.

@defichain/salmon

A modular PriceFeed publisher to push prices through a filter and publish it into SalmonWallet.

0. Prior - fetch the price feed from an adapter and pushes it to a Salmon instance.
1. Setup - reads the env configs, initialize the instances and client.
2. Filter - reads the price feed data and decide whether to alter, accept or reject it.
3. Publish - finally broadcast the accepted prices' data.

@defichain/salmon-fetch

Helper utility to fetch form URL with Response as JSON with all numbers parsed as BigNumber. Providing an AssetPrice interface that contains the token-amount pair and the currency that represent the pair. This format is used for SalmonRunner downstream.

@defichain/salmon-filter

SalmonFilter orchestrates all Filter configured, it is run in the given order set in the constructor. Using a chain of responsibility design pattern, it is configured with the network, whale client, and oracleId. This filter pattern receives a list of prices for filtering. Once filtered, it can accept, warn, reject partial by filtering or rejecting all.

This approach allows all filtering and data manipulation to be carried out in a separate manner within a singular scope. Using the chain of responsibility design pattern, the filter only needs to be responsible for its filtering logic.

This filter logic can be greatly expanded to many categories for more data pruning and cleaning processes with all sorts of integration capabilities.

@defichain/salmon-testing

Providing the e2e testing capability for salmon framework. This package is a Whale + Ain Masternode RegTest Container that automatically setup a network and connects ain and whale together providing a WhaleApiClient for testing.

@defichain/salmon-wallet

SalmonWallet is a serverless first lightweight wallet setup that is easy to configure. Powered by the jellyfish ecosystem, this wallet uses Ocean APIs and requires all transactions to be signed in Bech32 format.

Requiring just the PrivateKey (WIF), NetworkName, and WhaleApiClient for its entirety. This wallet will construct an oracle price feed for submission and sign the oracle price feed with the given private key. Lastly, submit the price feed into the connected network.

Usage

import { Salmon, SalmonWallet, WhaleApiClient } from '@defichain/salmon'
import coingecko from 'coingecko'

/**
 * As simple as coingecko() to get prices and push to publish.
 */
async function main (): Promise<void> {
  const client = new WhaleApiClient()
  const wallet = new SalmonWallet()
  const salmon = new Salmon('oracleId', 'mainnet', client, wallet)
  await salmon.publish(await coingecko())
}

Security issues

If you discover a security vulnerability in @defichain/salmon, please see submit it privately.

License & Disclaimer

By using @defichain/salmon (this repo), you (the user) agree to be bound by the terms of this license.