Asset Price External Adaptor

External Adaptor for Chainlink which aggregates prices of crypto assets from multiple exchanges based on a weighted average of their volume.

This adaptor is built using the bridges framework: https://github.com/linkpoolio/bridges

Currently Supported Exchanges:

• Binance
• Bitfinex
• Bitstamp (highly rate limited)
• Bittrex
• Coinall
• Coinbase Pro
• HitBTC
• Huobi Pro
• Kraken
• Gemini
• ZB

Setup Instructions

Local Install

Make sure Golang is installed.

Build:

make build

Then run the adaptor:

./asset-price-cl-ea -p <port> -t <tickerInterval>

Arguments

Char	Default	Usage
p	8080	Port number to serve
t	1m0s	Ticker interval for the adaptor to refresh supported trading pairs, suggested units: s, m, h

Docker

To run the container:

docker run -it -p 8080:8080 -e PORT=8080 linkpoolio/asset-price-cl-ea

Container also supports passing in CLI arguments.

AWS Lambda

1. Build the executable:

   GO111MODULE=on go build -o asset-price

2. Add the file to a ZIP archive:

   zip asset-price.zip ./asset-price

3. Upload the the zip file into AWS and then use asset-price as the handler.
4. Set the LAMBDA environment variable to true in AWS for the adaptor to be compatible with Lambda.

GCP Functions

1. Change into the app directory:

   cd app

2. Deploy into GCP

   gcloud functions deploy asset-price --runtime go111 --entry-point Handler --trigger-http

Usage

To call the API, you need to send a POST request to http://localhost:<port>/price with the request body being of the ChainLink RunResult type.

For example:

curl -X POST -H 'Content-Type: application/json' -d '{ "jobRunId": "1234", "data": { "base": "BTC", "quote": "USD" }}' http://localhost:8080/price

Should return something similar to:

{
    "jobRunId": "1234",
    "data": {
        "base": "BTC",
        "quote": "USD",
        "id": "BTC-USD",
        "result": 3836.4042305857843,
        "price": "3836.4042305857843",
        "volume": "131747894.87525243",
        "usdPrice": "3836.4042305857843",
        "exchanges": [
            "HitBTC",
            "Bitfinex",
            "Coinbase",
            "COSS"
        ],
        "warnings": null
    },
    "status": "",
    "error": null,
    "pending": false
}

Or:

curl -X POST -H 'Content-Type: application/json' -d '{ "jobRunId": "1234", "data": { "base": "LINK", "quote": "ETH" }}' http://localhost:8080/price

{
    "jobRunId": "1234",
    "data": {
        "base": "LINK",
        "quote": "ETH",
        "id": "LINK-ETH",
        "result": 0.0031786459052877327,
        "price": "0.0031786459052877327",
        "volume": "797.6642187877999",
        "usdPrice": "0.43956635389465454",
        "exchanges": [
            "Binance",
            "Huobi",
            "COSS"
        ],
        "warnings": null
    },
    "status": "",
    "error": null,
    "pending": false
}

ChainLink Node Setup

To integrate this adaptor with your node, follow the official documentation: https://docs.chain.link/docs/node-operators

Solidity Usage

To use this adaptor on-chain, you can create the following Chainlink request:

Chainlink.Request memory req = buildChainlinkRequest(jobId, this, this.fulfill.selector);
req.add("base", "LINK");
req.add("quote", "BTC");
req.add("copyPath", "price");
req.addInt("times", 100000000);

Allowing you to change base and quote to any trading pair.

Contribution

We welcome any contributors. The more exchanges supported, the better. Feel free to raise any PR's or issues.