Chainlink External Adapter for CryptoCompare VWAP

This external adapter calculates the market weighted average for a given coin, converting all non-USD markets to USD in order to return a VWAP.

Input Params

• coin: The symbol of the asset to query

Environment variables

Variable		Description	Example
API_KEY	Required	Your CryptoCompare API Key	ABCDEFGHJIKLMo64FtaRLRR5BdHEESmha49TM

To get CryptoCompare API credentials, check out https://min-api.cryptocompare.com/.

Install

npm install

Test

npm test

Create the zip

zip -r cl-cryptocompare-vwap.zip .

Install to AWS Lambda

• In Lambda Functions, create function
• On the Create function page:
  • Give the function a name
  • Use Node.js 8.10 for the runtime
  • Choose an existing role or create a new one
  • Click Create Function
• Under Function code, select "Upload a .zip file" from the Code entry type drop-down
• Click Upload and select the cl-cryptocompare-vwap.zip file
• Handler should remain index.handler
• Add the environment variable (repeat for all environment variables):
  • Key: API_KEY
  • Value: Your_API_key
• Save

Install to GCP

• In Functions, create a new function, choose to ZIP upload
• Click Browse and select the cl-cryptocompare-vwap.zip file
• Select a Storage Bucket to keep the zip in
• Function to execute: gcpservice
• Click More, Add variable (repeat for all environment variables)
  • NAME: API_KEY
  • VALUE: Your_API_key

Run with Docker

docker build . -t cryptocompare-vwap-adapter
docker run -d \
    -p 8080:8080 \
    -e EA_PORT=8080 \
    -e API_KEY="Your_cryptocompare_API_key" \
    cryptocompare-vwap-adapter

Testing

Once the docker container is deployed, run the following curl request to test that the adapter is querying the API correctly and outputting a valid response.

curl -H "Content-Type: application/json" -d '{"id":"1234","data":{"coin":"AMPL"}}' http://localhost:8080/

Sample Response

{
  "jobRunID":"1234",
  "data":{
    "markets":[
      {"exchange":"Bitfinex","exchange_fsym":"AMP","exchange_tsym":"USD","fsym":"AMPL","tsym":"USD","last_update":1561732980},
      {"exchange":"Bitfinex","exchange_fsym":"AMP","exchange_tsym":"UST","fsym":"AMPL","tsym":"USDT","last_update":1561732985}
    ],
    "results":{
      "AMPL":{
        "USD":1.041,
        "USDT":1.124
      }
    },
    "conversions":[{
      "USDT":{
        "USD":1.001
      }
    }],
    "result":1.083062
  },
  "result":1.083062,
  "statusCode":200
}