Chainlink video tutorial walkthrough of the below: https://www.youtube.com/watch?v=Ba1satx_fw0&ab_channel=Chainlink
Note: this repo was built using the Chainlink NodeJS External Adapter Template.
Docker Running: https://www.docker.com
Free Alchemy Account: https://www.alchemy.com/
Postgres: https://postgresapp.com/
Testnet ETH in MetaMask: https://faucets.chain.link/
Testnet LINK in wallet (Kovan): https://faucets.chain.link/
Create a local directory to hold the Chainlink data. Paste the below into your terminal and hit enter:
mkdir ~/.chainlink-kovan
Paste the below into your terminal and hit enter:
echo "ROOT=/chainlink
LOG_LEVEL=debug
ETH_CHAIN_ID=42
MIN_OUTGOING_CONFIRMATIONS=2
LINK_CONTRACT_ADDRESS=0xa36085F69e2889c224210F603D836748e7dC0088
CHAINLINK_TLS_PORT=0
SECURE_COOKIES=false
GAS_UPDATER_ENABLED=true
ALLOW_ORIGINS=*" > ~/.chainlink-kovan/.env
Go to Alchemy: https://www.alchemy.com/ and create a staging App on the Kovan network. View details > view key > copy Websockets address. Paste the below into your terminal, replace CHANGEME with your Websockets address and hit enter:
echo "ETH_URL=CHANGEME" >> ~/.chainlink-kovan/.env
Download and start Postgres: https://postgresapp.com/
Paste the below into your terminal, replace $USERNAME and $DATABASE with the Postgres database that has your username (ie, not the one called Postgres or template1, but your username) and hit enter:
echo "DATABASE_URL=postgresql://$USERNAME:@host.docker.internal:5432/$DATABASE?sslmode=disable" >> ~/.chainlink-kovan/.env
Paste the below into your terminal and hit enter:
cd ~/.chainlink-kovan && docker run -p 6688:6688 -v ~/.chainlink-kovan:/chainlink -it --env-file=.env smartcontract/chainlink:1.0.0 local n
The first time running the image, it will ask you for a password and confirmation. Your password must contain numbers and letters and be more than 12 characters long. This will be your wallet password that you can use to unlock the keystore file generated for you. Then, you'll be prompted to enter an API Email and Password. This will be used to expose the API for the GUI interface, and will be used every time you log into your node.
You can now connect to your Chainlink node's UI interface by navigating to http://localhost:6688
Fund the Ethereum address that your Chainlink node uses. You can find the address in the node Operator GUI under the Keys tab. The address of the node is the Regular type. You can obtain test ETH from several faucets.
I'm able to successfully deploy the Oracle contract to the Kovan testnet using the Remix IDE and run a job with my node per the Chainlink video walkthrough, or here for text version. However, as our ultimate objective is to enable our bnbBridge contract to communicate with our node, we can't use Remix IDE to compile and deploy our contract, but instead use our own frontend. This is where I'm currently stuck.
I've added the Oracle contract (Oracle.sol) into this repo, together with a deploy script in the migrations directory (3_deploy_contracts). In your terminal in the root folder of this project, type truffle compile and hit enter. Then type truffle migrate and hit enter. The Oracle contract should compile and deploy successfully. (Note: I added the Kovan LINK token address "0xa36085F69e2889c224210F603D836748e7dC0088" to the 3_deploy_contracts file in the migrations directory as it's required by the contract's constructor).
Next, I copied the Oracle.json ABI file from the build directory and added it to the bnbbridge-frontend repository (I pushed this to you in a separate git branch). The bnbbridge-frontend repo is a clone from a _buildspace React frontend project that successfully opens MetaMask and mints an NFT in the browser. You can see this by running npm install at the root of the bnbbridge-frontend directory and then npm run start to start the project.
In the App.js, I then try to replace the variables (eg myEpicNFT with SetFulfillmentPermission) and the ABI (eg MyEpicNFT.json with Oracle.json) per the Chainlink video walkthrough above. In particular, I'm unable to replace this line of code with the SetFulFillmentPermission event:
connectedContract.on("NewEpicNFTMinted", (from, tokenId) => {
console.log(from, tokenId.toNumber())
Basically, I'm unable to connect the Oracle contract with the React frontend in order to communicate with our node.