Decentralized oracle for requesting cryptocurrency market prices

Used technologies

• Docker and Docker Compose
• Node (v10.20.1)
• Ethereum and Solidity
• Chainlink and LinkPool
• React (Truffle Box)
• Web3.js

Install

Install dependencies with yarn/npm.

General Usage

To first use this on Ropsten, you can update truffle.js with your private key and RPC host for deployment. This could be Infura or your own node for example.

This repository includes the ropsten contract build files, so once you set up truffle.js you can use the scripts on the Ropsten network.

You can also deploy this locally using ganache-cli, but you need to deploy the Oracle.sol contract for your Chainlink node and create a new job spec as per the example you want to use in specs.

Setup

In truffle.js enter your mnemonic and Ethereum URL, eg Infura.

Deployment

To deploy contract, run a standard Truffle migration (uses Truffle from local deps):

npm run migrate

or

truffle migrate --network ropsten --reset

API Aggregator

To run the external adapter:

docker run -d -p 8080:8080 linkpool/apiaggregator-bridge:latest

Request the current price of ETH aggregated from Coinbase & Bitstamp:

npm run exec scripts/consumer/fund-contract.js -- --network ropsten
npm run exec scripts/consumer/request-data.js eth usd -- --network ropsten
npm run exec scripts/consumer/read-contract.js eth usd -- --network ropsten

Chainlink node setup

To deploy Chainlink node, setup credentials in chainlink.env and run:

cd deploy
./start.sh

• Navigate to http://localhost:6688
• Create a bridge called api-aggregator with your host IP address and port 8080
• Create a new job with JSON specification from specs/api_aggregator.json
• Call setFulfillmentPermission on Oracle contract for your Oracle node as described in https://docs.chain.link/docs/fulfilling-requests#add-your-node-to-the-oracle-contract

Client

Run the dApp:

cd client
npm start