Minimal implementation of CW20 token on CosmWasm. Supported functionalities:

• Transfer tokens
• Mint tokens (from only fixed address)
• Burn tokens

This guideline is based on official CosmWasm doc.

1. Requirement: Step-by-step
   • wasmd
   • Rust with wasm32 build target
   • jq (tool to parse json response when execute smart contract)
2. Create your wallet (should create more than 1 wallet for testing transfer)

   wasmd keys add {your-wallet-name}

3. Export those variables to use later

   # We gonna use malaga testnet
   export CHAIN_ID="malaga-420"  
   export TESTNET_NAME="malaga-420"
   export RPC="https://rpc.malaga-420.cosmwasm.com:443"
   export API="https://api.malaga-420.cosmwasm.com"
   export FAUCET="https://faucet.malaga-420.cosmwasm.com"
   
   export FEE_DENOM="umlg"
   export STAKE_DENOM="uand"
   export BECH32_HRP="wasm"
   export WASMD_VERSION="v0.27.0"
   export CONFIG_DIR=".wasmd"
   export BINARY="wasmd"
   
   export NODE=(--node $RPC)
   export TXFLAG=($NODE --chain-id $CHAIN_ID --gas-prices 0.25$FEE_DENOM --gas auto --gas-adjustment 1.3)

4. Add fund to your wallet (to deploy and run smart contract, called gas in Ethereuum)

   JSON=$(jq -n --arg addr $(wasmd keys show -a {your-wallet-name}) '{"denom":"umlg","address":$addr}') && curl -X POST --header "Content-Type: application/json" --data "$JSON" https://faucet.malaga-420.cosmwasm.com/credit
   
   # Quick check your balance
   wasmd query bank balances $(wasmd keys show -a {your-wallet-name}) $NODE

1. Update minter address in src/state.rs to yours
2. Compile to .wasm file (You can also use docker for more optimized here)

   RUSTFLAGS='-C link-arg=-s' cargo wasm

3. Deploy

   # Upload your smart contract
   RES=$(wasmd tx wasm store {your-path-to-wasm-file} --from wallet $TXFLAG -y --output json -b block)
   
   # Get code_id of your smart contract
   CODE_ID=$(echo $RES | jq -r '.logs[0].events[-1].attributes[0].value')

4. Initialize

   # InstantiateMsg (change this on your preference)
   INIT_MSG='{"name": "THONG COIN","symbol": "CUCMO","cap": "1000000","total_supply": "500000"}'
   
   # Initialize contract with InstantiateMsg
   wasmd tx wasm instantiate $CODE_ID "$INIT_MSG" --from {your-wallet-name} --label {your-contract-label} $TXFLAG -y --no-admin
   
   # Check list of contract that initialized before
   wasmd query wasm list-contract-by-code $CODE_ID $NODE --output json
   
   # Extract the contract address to use later
   CONTRACT=$(wasmd query wasm list-contract-by-code $CODE_ID $NODE --output json | jq -r '.contracts[-1]')
   

5. Interact

   # Wallet name that have tokens
   WALLET_FROM={your-wallet-name}
   
   # Wallet name that you want to transfer to
   WALLET_TO={another-wallet-name}
   
   # TransferMsg (change this on your preference)
   TRANSFER='{"transfer":{"recipient":"'$(wasmd keys show -a $WALLET_TO)'","amount":"55"}}'
   echo $TRANSFER
   
   # Execute TRANSFER command on smart contract
   wasmd tx wasm execute $CONTRACT "$TRANSFER" --from $WALLET_FROM $TXFLAG -y
   
   # QueryBalanceMsg (change this on your preference)
   BALANCE='{"balance": {"address": "'$(wasmd keys show -a $WALLET_FROM)'"}}'
   
   # Execute QUERY balance command on smart contract
   wasmd query wasm contract-state smart $CONTRACT "$BALANCE" $NODE --output json