Chainlink External Adapters (JavaScript)

This repository contains the source for Chainlink external adapters. Each adapter must document its own required parameters and output format.

Requirements

• Yarn

Install

yarn

Installs packages for all workspaces.

Test

In order to test adapters locally, you may need to set an $API_KEY environment variable for the given API.

cd $adapter
yarn test

Creating a new external adapter

Run the command below to have the example directory cloned using the name you provide for $adapter:

make new adapter=my-adapter-name

If on a Mac, this requires gnu-sed to be installed and set as the default for the command sed.

Docker

To build a Docker container for a specific $adapter, use the following example:

make docker adapter=bravenewcoin

The naming convention for Docker containers will be $adapter-adapter.

Then run it with:

docker run -p 8080:8080 -e API_KEY='YOUR_API_KEY' -it bravenewcoin-adapter:latest

Serverless

Create the zip:

make zip adapter=bravenewcoin

The zip will be created as ./$adapter/dist/$adapter-adapter.zip.

Install to AWS Lambda

• In Lambda Functions, create function
• On the Create function page:
  • Give the function a name
  • Use Node.js 12.x 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 $adapter-adapter.zip file
• Handler:
  • index.handler (same as index.awsHandlerREST) for REST API Gateways (AWS Lambda default)
  • index.awsHandlerREST for REST API Gateways
  • index.awsHandlerHTTP for HTTP API Gateways
• Add the environment variable (repeat for all environment variables):
  • Key: API_KEY
  • Value: Your_API_key
• Save

By default, Lambda functions time out after 3 seconds. You may want to change that to 60s in case an API takes longer than expected to respond.

To Set Up an API Gateway (HTTP API)

If using a HTTP API Gateway, Lambda's built-in Test will fail, but you will be able to externally call the function successfully.

• Click Add Trigger
• Select API Gateway in Trigger configuration
• Under API, click Create an API
• Choose HTTP API
• Select the security for the API
• Click Add

To Set Up an API Gateway (REST API)

If using a REST API Gateway, you will need to disable the Lambda proxy integration for Lambda-based adapter to function.

• Click Add Trigger
• Select API Gateway in Trigger configuration
• Under API, click Create an API
• Choose REST API
• Select the security for the API
• Click Add
• Click the API Gateway trigger
• Click the name of the trigger (this is a link, a new window opens)
• Click Integration Request
• Uncheck Use Lamba Proxy integration
• Click OK on the two dialogs
• Return to your function
• Remove the API Gateway and Save
• Click Add Trigger and use the same API Gateway
• Select the deployment stage and security
• Click Add

Install to GCP

• In Functions, create a new function, choose to ZIP upload
• Select Node.js 10 for the Runtime
• Click Browse and select the $adapter-adapter.zip file
• Select a Storage Bucket to keep the zip in
• Function to execute: gcpHandler
• Click More, Add variable (repeat for all environment variables)
  • NAME: API_KEY
  • VALUE: Your_API_key