Chainlink Truffle Box

Requirements

• NPM

Installation

1. Install truffle

npm install truffle -g

2. Setup repo

mkdir MyChainlinkProject
cd MyChainlinkProject/

3. Unbox

truffle unbox smartcontractkit/box

4. Install dependencies by running:

npm install

# OR...

yarn install

Test

npm test

Deploy

⚠️ When pushing your code to Github, make sure that your MNEMONIC and RPC_URL are stored in a .env file and it is also in your .gitignore

For deploying to the kovan network, Truffle will use truffle-hdwallet-provider for your mnemonic and an RPC URL. Set your environment variables $RPC_URL and $MNEMONIC before running:

npm run migrate:kovan

You can also run:

truffle migrate --network kovan --reset

If you want to use truffle commands.

Local Blockchain

⚠️ Without a Chainlink node deployed locally, requests from smart contracts will not be responded to. We recommend you deploy to the Kovan network

If needed, edit the truffle-config.js config file to set the desired network to a different port. It assumes any network is running the RPC port on 8545.

npm run migrate:dev

Helper Scripts

There are 3 helper scripts provided with this box in the scripts directory:

• fund-contract.js
• request-data.js
• read-contract.js

In addition, for working with Chainlink Price Feeds and ChainlinkVRF there are folders respectively.

They can be used by calling them from npx truffle exec, for example:

npx truffle exec scripts/fund-contract.js --network kovan

The CLI will output something similar to the following:

Using network 'kovan'.

Funding contract: 0x972DB80842Fdaf6015d80954949dBE0A1700705E
0xd81fcf7bfaf8660149041c823e843f0b2409137a1809a0319d26db9ceaeef650
Truffle v5.0.25 (core: 5.0.25)
Node v10.16.3

In the request-data.js script, example parameters are provided for you. You can change the oracle address, Job ID, and parameters based on the information available on our documentation.

npx truffle exec scripts/request-data.js --network kovan

This creates a request and will return the transaction ID, for example:

Using network 'kovan'.

Creating request on contract: 0x972DB80842Fdaf6015d80954949dBE0A1700705E
0x828f256109f22087b0804a4d1a5c25e8ce9e5ac4bbc777b5715f5f9e5b181a4b
Truffle v5.0.25 (core: 5.0.25)
Node v10.16.3

After creating a request on a kovan network, you will want to wait 3 blocks for the Chainlink node to respond. Then call the read-contract.js script to read the contract's state.

npx truffle exec scripts/read-contract.js --network kovan

Once the oracle has responded, you will receive a value similar to the one below:

Using network 'kovan'.

21568
Truffle v5.0.25 (core: 5.0.25)
Node v10.16.3

TODO

• Add tests for ChainlinkVRF
• Add tests for Chainlink Price Feeds
• Refactor tests to use this instead of defining contracts with let
• Use the Chainlink-published mocks for MockV3Aggregator and VRFCoordinatorMock