Delivery Link

This is a workshop project that uses Chainlink to implement secure, decentralized payment-on-delivery. This project is built on top of Chainlink Dev.

The goal of this project is to allow the user to go from a bare development setup (Docker, Ganache, etc) to deploying a fully sandboxed, fully functional Chainlink network in a single command. Run the npm start command to achieve the following:

1. Migrate a LINK token, Chainlink oracle and Chainlink client smart contract to Ganache with Truffle.
2. Deploy a local, pre-configured Chainlink node with Docker. The Chainlink node will be connected to Ganache.
3. Deploy a Chainlink external adapter locally with Docker.
4. Perform the following tasks with Truffle scripts:
   1. Fund the Chainlink client smart contract with 100 LINK tokens.
   2. Set fulfillment permission to true for your Chainlink node on your oracle smart contract.
   3. Fund the Chainlink node with 1 ETH.
   4. Add jobs to the Chainlink node, including one that exercises the external adapter.
   5. Configure the Chainlink client smart contract to use the jobs on the Chainlink node.

Disclaimers

This project is intended for development purposes only. A number of the configuration settings used by this project should never be deployed in a production setting.

As of 2019-11-18 this project is still in a rather unpolished state and has only been tested on Linux.

Dependencies

In addition to the dependencies described in the package.json file, this project is also dependent upon Docker/Docker Compose, Ganache and possibly others.

In order to exercise the external adapter capabilities, you will need to provide an API key for the EasyPost API.

Usage

1. Run npm i to install dependencies.
2. Update the API_KEY key value in the adapters/easypost/.env file to reflect the value of your EasyPost API key.
3. Create a new workspace in Ganache:
   1. On the Workspace tab, add truffle/truffle-config.js from this project.
   2. On the server tab, select the 0.0.0.0 - All Interfaces hostname.
   3. Save the workspace.
4. Run npm start to perform the steps described above.
5. Run npm run chainlink:logs to view the Chainlink node logs and ensure it started successfully.
6. Sign in to the Chainlink node's web UI:
   1. Use your web browser to navigate to http://localhost:6688.
   2. Login with the following credentials:
      • Email: user@example.com
      • Password: password
7. Use the Chainlink node web UI to inspect the bridge and jobs that were created when you ran npm start.
8. Use Remix to interact with the deployed Chainlink client smart contract:
   1. Run npm run remix to invoke the remixd command. remixd will allow you to use the Remix web IDE to interact with Solidity smart contracts on your local file system.
   2. Use your web browser to navigate to https://remix.ethereum.org and follow the steps to connect Remix to localhost.
   3. Use the Remix file explorer to open the truffle/contracts/DeliveryLink.sol contract from this project.
   4. Use the Remix Solidity compiler to compile the DeliveryLink contract.
   5. Use the Remix UI to configure Ganache as your Web3 provider.
   6. Use Ganache to get the address of the deployed DeliveryLink contract.
   7. Use Remix to load the deployed instance of DeliveryLink.
   8. Use Remix to inspect the DeliveryLink contract and view the values of some of its state variables; correlate these with values found on the Chainlink node web UI:
      • getChainlinkOracle
      • getChainlinkToken
      • getDeliveryStatusJobId
      • getTimestampJobId
   9. Use Remix to inspect the value of the timestamp state variable; you should note that the value has not been set.
   10. Use Remix to inspect the definition of the requestCurrentTimestamp function on the DeliveryLink contract and then execute it.
   11. Use the Chainlink node web UI to view the completed job run that was executed as a result of calling the function on the DeliveryLink contract.
   12. Use Remix to inspect the updated value of the timestamp state variable.
   13. Use Remix to inspect the value of the deliveryStatus state variable; you should note that the value has not been set.
   14. Use Remix to execute the following functions with the provided parameters in order to prepare the DeliveryLink contract to exercise the external adapter that was deployed using Docker. The parameter values are test values provided by EasyPost for the purpose of developing with their API:
       • setPackageCarrier: USPS
       • setPackageCode: EZ1000000001
   15. Use Remix to inspect the definition of the requestDeliveryStatus function on the DeliveryLink contract and then execute it.
   16. Use the Chainlink node web UI to view the completed job run that was executed as a result of calling the function on the DeliveryLink contract.
   17. Use Remix to inspect the updated value of the deliveryStatus state variable.

Features and Capabilities for Further Development

This project is meant to expose a host of features and capabilities that can be reused for further development.

Chainlink Node REST API

The chainlink/cl-utils.js file implements a minimal client for the Chainlink node REST API as well as some helper functions to assist in exercising the REST API's capabilities.

createBridge(name, url)

This helper function is meant to be used in conjunction with postBridge(bridge).

Return value:

{
   "name": name,
   "url": url
}

createJob(initiatorType)

This helper function is meant to be used in conjunction with postJob(job).

Return value:

{
    "initiators": [
      {
        "type": initiatorType,
        "params": {}
      }
    ],
    "tasks": []
  }

createTask(type)

This helper function is meant to be used to add elements to the tasks array of the object returned by createJob.

Return value:

{
   "type": type,
   "params": {}
}

getAcctAddr()

Retrieves the account address of the Chainlink node from the Chainlink node's REST API.

postBridge(bridge)

Create a bridge on the Chainlink node using the Chainlink node REST API.

postJob(job)

Create a job on the Chainlink node using the Chainlink node REST API.

External Adapters

A key feature of this project is the ease with which external adapters can be deployed and consumed.

To deploy a new external adapter, simply add it as a service to the docker-compose.yml file found in this project. The included EasyPost adapter is deployed from source by referring to the provided Dockerfile.

To see an example of how the features and capabilities of this project can be used to configure a Chainlinked smart contract to consume an external adapter, please refer to the provided add-jobs.js script and the usage steps described above.