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Kava Local Development Tutorial

Kava provides tools for easily setting up a local Kava development environment for Solidity smart contract deployment and interaction.

kvtool​

kvtool enables developers to spin up a local Kava development environment. A dockerized local testnet with ethermint EVM can be created with:

kvtool testnet bootstrap --kava.configTemplate master

The faucet Ethereum account is funded with sufficient gas tokens to be used in EVM transactions such as deploying smart contracts. Configuration file hardhat.config.js contains field networks.local.accounts which holds an array of private keys, including the private key for faucet. The private key was exported with:

# Add an alias to the dockerized kava blockchain
alias dkava='docker exec -it generated_kavanode_1 kava'

# Export private key for named account 'faucet'
dkava keys unsafe-export-eth-key faucet --keyring-backend test

For a more detailed overview of running a local network, see Getting Started.

Contract deployment​

kvtool's evm directory contains an integrated Hardhat project for smart contract deployment and interaction.

# Navigate to the evm directory
cd evm

# Install dependencies
yarn

A sample Solidity smart contract located at evm/contracts/token/Token.sol can be easily deployed with:

yarn token-deploy
# TEST token deployed to: 0xff994EcA9074305D353E78a7159fE407537Cf87C

Under the hood yarn token-deploy is running cmd npx hardhat run --network local scripts/deploy/token.js. You can also use the npx hardhat ... syntax to interact with the contracts from the CLI.

Contract interaction​

Basic contract interaction is possible through additional scripts with the full list available in evm/package.json. Each yarn cmd is aliased to one of the Hardhat tasks found in hardhat.config.js.

# Get the deployed TEST token's total supply
yarn token-totalSupply --token [TOKEN_CONTRACT_ADDRESS]
# Total Supply is 100000000

You can get information about any cmd including param options by using the --help flag, for example:

yarn token-totalSupply --help

Using the available scripts, we can transfer tokens:

yarn token-transfer --token [TOKEN_CONTRACT_ADDRESS] --recipient [RECIPIENT_ADDRESS] --amount [AMOUNT]

# We can build a valid cmd by plugging in the relevant params:
yarn token-transfer --token 0xff994EcA9074305D353E78a7159fE407537Cf87C --recipient 0xdd2fd4581271e230360230f9337d5c0430bf44c0 --amount 50
# 0x5452643Ffa7Ab2BE7EF7C376f62FDfA7804Ed1d2 has transferred 50 TEST to 0xdd2fd4581271e230360230f9337d5c0430bf44c0

Deploying your own contracts​

You can easily deploy your own contracts:

  1. Add your Solidity smart contract to evm/contracts.
  2. Add a deployment script to evm/scripts/deploy/[YOUR_SCRIPT].js modeled on evm/scripts/deploy/token.js.
  3. Add Hardhat tasks corresponding to your contract's public methods to the existing tasks in hardhat.config.js.

Done! Now you can deploy and interact with your contract;:

# Deployment
npx hardhat run --network local scripts/deploy/[YOUR_SCRIPT].js

# Interaction
npx hardhat [YOUR_TASK_NAME] --network local

If you want a cleaner CLI experience, you can add some script aliases to evm/package.json as seen in the scripts section.

Next steps​

Verify your newly deployed contract on the Kava explorer.