10-Minute Tutorial

Read time - 10 minutes

Goal

To complete the integration of kOS into your smart contract and to be able to call transactions within a dApp.

This guide covers the instructions for deploying relevant smart contracts and using the KRNL SDK through KRNL Sandbox.

Choosing a kernel is predefined for simplicity and ease of understanding throughout this easy-to-follow guide.

I. Requirements

MetaMask - download MetaMask into your browser here

Etherscan (optional: for verifying smart contracts) - Find the API key here

Sepolia testnet - "Add a custom network" on your MetaMask wallet

Oasis Sapphire testnet - Again, visit "Add a custom network" in your MetaMask wallet. This time, add the network details below (TEST will be used for deploying smart contracts)

Network name:
    Oasis Sapphire Testnet
RPC:
    https://testnet.sapphire.oasis.io
Chain ID:
    23295
Currency symbol:
    TEST

Funds - make sure you have a SepoliaETH and Oasis TEST token balance, by claiming them from faucets here.

[Bonus] 10-Minute Tutorial Walkthrough Video

II. Steps for Smart Contracts

In this section, we will provide you with 2 options for deploying your smart contracts.

Remix (recommended for beginners, no installation required) Remix offers a web-based interface where users can deploy smart contracts without installing extra software.
Hardhat Hardhat offers a variety of features which allow users to deploy, test, and interact with smart contracts on local network, testnet, or mainnet.

Option 1: Remix

For more detailed information on smart contract deployment, please go here.

1. Set up Remix

Go to the Remix website here.

2. Clone our provided example repository by selecting the burger icon in the top-left and clicking "Clone" (see image below)

3. Copy this URL

https://github.com/KRNL-Labs/10-minute-tutorial.git

4. Paste the copied URL into this text field

5. Set up the compiler config

smart-contracts/remix-ide/compiler_config.json

6. Select the Token Authority Solidity file

7. Compile Token Authority

8. Set up MetaMask as your environment in "Deploy & run transactions"

9. Select "Oasis Sapphire Testnet" on MetaMask

10. Deploy Token Authority

11. A successful result will be shown in the terminal

Note down the "contract address" that is shown in the terminal. This is your "Token Authority smart contract address".

12. Install plugin from Remix

13. Verify Token Authority

14. Wait to see if the contract gets verified

15. After verification, visit ABI Playground

https://abi-playground.oasis.io/?network=23295&contractAddress=<CONTRACT_ADDRESS>

16. Copy and save the Token Authority public key

17. Select Sample.sol Solidity file

18. Compile Sample.sol

19. Change network on MetaMask to Sepolia

20. Deploy Sample.sol

21. A successful result will be shown in the terminal (as below)

Note the "contract address" that is shown in the terminal. This is your primary "smart contract address".

22. Verify your smart contract

Etherscan verification (no.6) from the image above will require the Etherscan API key.

If it is your first time verifying smart contract on Etherscan, visit this page to follow steps for getting API key.

23. Wait and see if the contract gets verified

24. Visit the KRNL Platform and continue to "smart contract registration"

Click here to move to the registration section.

Option 2: Hardhat

For more detailed information on smart contract deployment, please go here.

1. Clone the repository to your machine

git clone https://github.com/KRNL-Labs/10-minute-tutorial.git

2. Move into a Hardhat project

cd smart-contracts/hardhat

3. Fill the .env file

4. Install dependencies

npm install

5. Deploy smart contracts

npm run deploy

Wait until the contracts have been deployed and verified successfully. More details can be found in <package.json>.

6. Visit the KRNL Platform for smart contract registration

Click here to move to the registration section.

III. Smart Contract Registration

Find the full KRNL guide to smart contract registration here.

1. Visit the smart contract registration page

2. Click "Register"

3. Fill the required values and click "Activate"

4. Wait until the transaction has finished

5. Visit your registered smart contract page and save your registered "Smart Contract ID"

IV. Steps for dApp registration and KRNL Sandbox

Read the full KRNL guide to dApp registration here.

1. Visit the dApp registration page

2. Click "Register"

3. Fill in the Smart Contract ID

4. Wait until the transaction has finished

5. Go to your registered dApp page and copy both "Entry ID" and "Access Token"

6. Go to the KRNL Sandbox on the KRNL Flow tab

7. Connect your wallet and select the template "10-Minute Tutorial"

8. Fill in the required values from "smart contract deployment" and the KRNL platform

9. Click "Execute Kernels"

10. Fill the required parameter in "Step 3: Submit Your Transaction"

The parameter(s) has to be the same as in "Step 2: Fill Your Parameters".

If you are trying to fill different values on "Step 3: Submit Your Transaction", it means that you are trying to tamper with the transaction after already obtaining the response(s) from kernel(s).