# Smart Contracts

This article explains the deployment and interaction of CosmWasm Plus CW20 contracts.

Note for non-bash shell (eg, probably most macOS and some Linux) users: for below commands to work correctly without making modification to the environment (eg, check here (opens new window) how zsh does parameter expansion differently for details), please use the bash shell:

% bash

Note 2 outputs of some commands shown below are just for illustration purposes and the output you get might differ.

# Install rustup

First, install rustup (opens new window). Once installed, make sure you have the wasm32 target. This is an important step before running any contract to ensure that you are running Rust 1.51.0+ with wasm32-unknown-unknown target installed.

$ cargo --version

$ rustup --version
$ rustup default stable
$ rustup target add wasm32-unknown-unknown
$ rustup target list --installed

# Deployment and interaction of CW20

CW20 (opens new window) is equivalent to ERC20. CW-20 is similar, in some respects, to bitcoin, Litecoin, and any other cryptocurrency. CW-20 tokens are blockchain-based assets that have value and can be sent and received. The primary difference is that instead of running on their own blockchain, CW-20 tokens are issued on the CosmWasm network.

This section explains how to deploy and interact with CW20 using cudos-noded.

# Functions present in CW20 base standard

The specification of CW20 are represented within the following:

Note that you can find all messages, actions, and queries within the list above.

# Get the binaries and download the CosmWasm Plus contracts

Follow the instructions to Start and build the binaries
Clone the cw-plus (opens new window) repo with release tag of v0.9.0 (opens new window):

$ mkdir -p ~/cudos
$ cd ~/cudos

$ git clone --depth 1 --branch v0.9.0 https://github.com/CosmWasm/cw-plus.git

# Compile the contracts

Navigate to cw-plus folder and run the following commands:

$ cd cw-plus

$ docker run --rm -v "$(pwd)":/code \
  --mount type=volume,source="$(basename "$(pwd)")_cache",target=/code/target \
  --mount type=volume,source=registry_cache,target=/usr/local/cargo/registry \
  cosmwasm/workspace-optimizer:0.12.3

Make sure your binary-builder is on the list of running containers:

$ docker ps --format '{{.Names}}'

Copy the compiled cw20 base contract to binary-builder container:

$ docker cp artifacts/cw20_base.wasm binary-builder:/usr/cudos

# Deployment and instantiation

Set up the environment

$ NODE="https://sentry1.gcp-uscentral1.cudos.org:26657"
$ CHAIN_ID="cudos-testnet-public"
$ KEYRING="os"

$ TXFLAGS="--node $NODE --chain-id $CHAIN_ID --gas auto --gas-adjustment 1.3 --keyring-backend $KEYRING -y"

$ alias CUDOS_NODED='docker exec -it binary-builder cudos-noded'

Where:

NODE should refer to the IP address of your sentry or full/validator node that is running on the Cudos public testnet.
CHAIN_ID is the blockchain network ID, here it is the public testnet ID.
KEYRING uses the operating system's default credentials store (os) to handle keys storage operations securely. The keyring holds the private/public keypairs used to interact with a node and it will request a password each time it is accessed.
TXFLAGS is used as a shorthand for common transaction flags.
CUDOS_NODED is an alias for cudos-noded in binary-builder.

Manage accounts

Create accounts for the owner, Alice and Bob:

Note the first interaction with the keyring will require creation and confirmation of a new keyring passphrase that must be at least 8 characters long

$ CUDOS_NODED keys add owner --keyring-backend "$KEYRING"
$ CUDOS_NODED keys add alice --keyring-backend "$KEYRING"
$ CUDOS_NODED keys add bob --keyring-backend "$KEYRING"

Example of expected output results:

- name: owner
  type: local
  address: cudos16xws8z7zh7yjj69tglyks3jefp7rw38dlq5k0g
  pubkey: '{"@type":"/cosmos.crypto.secp256k1.PubKey","key":"ApRCDX7zSgLqrFSbNpURfMSpb2BEySjRy7ijMvqpBiTO"}'
  mnemonic: ""


**Important** write this mnemonic phrase in a safe place.
It is the only way to recover your account if you ever forget your password.

To view address of an account, use the following format (where <name> should be replaced with an account - eg, owner, alice or bob):

$ CUDOS_NODED keys show -a <name> --keyring-backend "$KEYRING"

Save accounts' addresses for later reuse:

$ OWNER=$( CUDOS_NODED keys show -a owner --keyring-backend "$KEYRING" | tee /dev/tty | tail -1 | tr -d '\r' )
Enter keyring passphrase:
cudos16xws8z7zh7yjj69tglyks3jefp7rw38dlq5k0g

$ ALICE=$( CUDOS_NODED keys show -a alice --keyring-backend "$KEYRING" | tee /dev/tty | tail -1 | tr -d '\r' )
Enter keyring passphrase:
cudos19uudvppffqzqetmeuuux47sgh0xecu07unqwwa

$ BOB=$( CUDOS_NODED keys show -a bob --keyring-backend "$KEYRING" | tee /dev/tty | tail -1 | tr -d '\r' )
Enter keyring passphrase:
cudos15yvgtr5ppu92hx0hu53ygdhnajrhgmjpfe8vdc

Get CUDOS tokens from faucet

To cover transactions fees, add 0.1 or more CUDOS tokens to the owner and Alice accounts' addresses (as shown in the previous step) using the faucet (opens new window).

Deploy the contract

$ RES=$( CUDOS_NODED tx wasm store /usr/cudos/cw20_base.wasm --from owner $TXFLAGS | tee /dev/tty | tail -1 | tr -d '\r' )
$ CODE_ID=$( echo $RES | jq -r '.logs[0].events[-1].attributes[-1].value' | tee /dev/tty )

Instantiate and verify the contract

Let's now instantiate a new CW20 contract, setting the initial balance of owner's address to 1M DIZZ tokens.

Note in this example, the "DIZZ" is used for the token name and symbol, but it can be replaced with any other name.

$ INIT=$( jq -n --arg address $OWNER '{ "name": "DIZZ COIN", "symbol": "DIZZ", "decimals": 6, "initial_balances": [ { "address": $address, "amount": "1000000" } ], "mint": { "minter": $address, "cap": "99900000000" } }' | tee /dev/tty )
$ CUDOS_NODED tx wasm instantiate $CODE_ID "$INIT" --from owner --label "CW20" $TXFLAGS

# check the contract state
$ CUDOS_NODED query wasm list-contract-by-code $CODE_ID --node $NODE --output json | jq -s

# fetch contract address
$ CONTRACT=$( CUDOS_NODED query wasm list-contract-by-code $CODE_ID --node $NODE --output json | jq -r '.contracts[-1]' | tee /dev/tty | tail -1 | tr -d '\r' )

Example of expected output results:

{
  "name": "DIZZ COIN",
  "symbol": "DIZZ",
  "decimals": 6,
  "initial_balances": [
    {
      "address": "cudos16xws8z7zh7yjj69tglyks3jefp7rw38dlq5k0g",
      "amount": "1000000"
    }
  ],
  "mint": {
    "minter": "cudos16xws8z7zh7yjj69tglyks3jefp7rw38dlq5k0g",
    "cap": "99900000000"
  }
}


[
  {
    "contracts": [
      "cudos19mquhvx58jrrk9pklf3uxx624q0f3zqhhmqhws"
    ],
    "pagination": {
      "next_key": null,
      "total": "0"
    }
  }
]

Congrats, you have successfully deployed and instantiated contract.

# Examples of interaction

# Mint CW20 tokens

Mint 1M tokens to Bob:

$ MINT=$( jq -n --arg recipient $BOB '{ "mint": { "recipient": $recipient, "amount": "1000000" } }' | tee /dev/tty )
$ CUDOS_NODED tx wasm execute $CONTRACT "$MINT" --from owner $TXFLAGS

Example of expected output results:

{
  "mint": {
    "recipient": "cudos15yvgtr5ppu92hx0hu53ygdhnajrhgmjpfe8vdc",
    "amount": "1000000"
  }
}

Check the current balance of Bob:

$ BALANCE_OF_BOB=$( jq -n --arg address $BOB '{ "balance": { "address": $address } }' | tee /dev/tty )
$ CUDOS_NODED query wasm contract-state smart $CONTRACT "$BALANCE_OF_BOB" --node $NODE
data:
  balance: "1000000"

# Transfer CW20 tokens

Transfer 10k tokens from owner to Alice:

$ TRANSFER_TO_ALICE=$( jq -n --arg recipient $ALICE '{ "transfer": { "recipient": $recipient, "amount": "10000" } }' | tee /dev/tty )

Example of expected output results:

{
  "transfer": {
    "recipient": "cudos19uudvppffqzqetmeuuux47sgh0xecu07unqwwa",
    "amount": "10000"
  }
}

execute the transfer contract:

$ CUDOS_NODED tx wasm execute $CONTRACT "$TRANSFER_TO_ALICE" --from owner $TXFLAGS

Now check the current balance of owner and Alice:

$ BALANCE_OF_OWNER=$( jq -n --arg address $OWNER '{ "balance": { "address": $address } }' | tee /dev/tty )
$ CUDOS_NODED query wasm contract-state smart $CONTRACT "$BALANCE_OF_OWNER" --node $NODE
data:
  balance: "990000"

$ BALANCE_OF_ALICE=$( jq -n --arg address $ALICE '{ "balance": { "address": $address } }' | tee /dev/tty )
$ CUDOS_NODED query wasm contract-state smart $CONTRACT "$BALANCE_OF_ALICE" --node $NODE
data:
  balance: "10000"

# Increase and check allowance

Increase allowance to 15k tokens for Alice by running this command:

$ INCREASE_ALLOWANCE_FOR_ALICE=$( jq -n --arg spender $ALICE '{ "increase_allowance": { "spender": $spender, "amount": "15000" } }' | tee /dev/tty )
$ CUDOS_NODED tx wasm execute $CONTRACT "$INCREASE_ALLOWANCE_FOR_ALICE" --from owner $TXFLAGS

Check allowance for Alice:

$ ALLOWANCE_FOR_ALICE=$( jq -n --arg owner $OWNER --arg spender $ALICE '{ "allowance": { "owner": $owner, "spender": $spender } }' | tee /dev/tty )
$ CUDOS_NODED query wasm contract-state smart $CONTRACT "$ALLOWANCE_FOR_ALICE" --node $NODE
data:
  allowance: "15000"
  expires:
    never: {}

# Transfer a CW20 tokens (via spender)

Transfer 5k tokens from Alice to Bob using allowance:

$ TRANSFER_FROM_ALICE=$( jq -n --arg owner $OWNER --arg recipient $BOB '{ "transfer_from": { "owner": $owner, "recipient": $recipient, "amount": "5000" } }' | tee /dev/tty )
$ CUDOS_NODED tx wasm execute $CONTRACT "$TRANSFER_FROM_ALICE" --from alice $TXFLAGS

Example of expected output results:

{
  "transfer_from": {
    "owner": "cudos16xws8z7zh7yjj69tglyks3jefp7rw38dlq5k0g",
    "recipient": "cudos15yvgtr5ppu92hx0hu53ygdhnajrhgmjpfe8vdc",
    "amount": "5000"
  }
}

Check all current accounts' balances and allowance for Alice:

$ CUDOS_NODED query wasm contract-state smart $CONTRACT "$BALANCE_OF_OWNER" --node $NODE
data:
  balance: "985000"

$ CUDOS_NODED query wasm contract-state smart $CONTRACT "$BALANCE_OF_BOB" --node $NODE
data:
  balance: "1005000"

$ CUDOS_NODED query wasm contract-state smart $CONTRACT "$BALANCE_OF_ALICE" --node $NODE
data:
  balance: "10000"

$ CUDOS_NODED query wasm contract-state smart $CONTRACT "$ALLOWANCE_FOR_ALICE" --node $NODE
data:
  allowance: "10000"
  expires:
    never: {}

# Decrease allowance

Decrease allowance for Alice by 2k tokens running this command:

$ DECREASE_ALLOWANCE_FOR_ALICE=$( jq -n --arg spender $ALICE '{ "decrease_allowance": { "spender": $spender, "amount": "2000" } }' | tee /dev/tty )
$ CUDOS_NODED tx wasm execute $CONTRACT "$DECREASE_ALLOWANCE_FOR_ALICE" --from owner $TXFLAGS

Check current allowance for Alice:

$ CUDOS_NODED query wasm contract-state smart $CONTRACT "$ALLOWANCE_FOR_ALICE" --node $NODE
data:
  allowance: "8000"
  expires:
    never: {}

# Burn CW20 tokens

Burn 1k tokens by running this command:

$ BURN='{ "burn": { "amount": "1000" } }'
$ CUDOS_NODED tx wasm execute $CONTRACT "$BURN" --from owner $TXFLAGS

Example of expected output results:

gas estimate: 124961
{"height":"719919","txhash":"30440EBD4A1F2102E1E912C31620A2594FDE3755646AC3A204D01295614A9AE6","codespace":"","code":0,"data":"0A260A242F636F736D7761736D2E7761736D2E76312E4D736745786563757465436F6E7472616374","raw_log":"[{\"events\":[{\"type\":\"execute\",\"attributes\":[{\"key\":\"_contract_address\",\"value\":\"cudos19mquhvx58jrrk9pklf3uxx624q0f3zqhhmqhws\"}]},{\"type\":\"message\",\"attributes\":[{\"key\":\"action\",\"value\":\"/cosmwasm.wasm.v1.MsgExecuteContract\"},{\"key\":\"module\",\"value\":\"wasm\"},{\"key\":\"sender\",\"value\":\"cudos16xws8z7zh7yjj69tglyks3jefp7rw38dlq5k0g\"}]},{\"type\":\"wasm\",\"attributes\":[{\"key\":\"_contract_address\",\"value\":\"cudos19mquhvx58jrrk9pklf3uxx624q0f3zqhhmqhws\"},{\"key\":\"action\",\"value\":\"burn\"},{\"key\":\"from\",\"value\":\"cudos16xws8z7zh7yjj69tglyks3jefp7rw38dlq5k0g\"},{\"key\":\"amount\",\"value\":\"1000\"}]}]}]","logs":[{"msg_index":0,"log":"","events":[{"type":"execute","attributes":[{"key":"_contract_address","value":"cudos19mquhvx58jrrk9pklf3uxx624q0f3zqhhmqhws"}]},{"type":"message","attributes":[{"key":"action","value":"/cosmwasm.wasm.v1.MsgExecuteContract"},{"key":"module","value":"wasm"},{"key":"sender","value":"cudos16xws8z7zh7yjj69tglyks3jefp7rw38dlq5k0g"}]},{"type":"wasm","attributes":[{"key":"_contract_address","value":"cudos19mquhvx58jrrk9pklf3uxx624q0f3zqhhmqhws"},{"key":"action","value":"burn"},{"key":"from","value":"cudos16xws8z7zh7yjj69tglyks3jefp7rw38dlq5k0g"},{"key":"amount","value":"1000"}]}]}],"info":"","gas_wanted":"124961","gas_used":"94597","tx":null,"timestamp":""}

You can check the current balance of the owner by running the command:

$ CUDOS_NODED query wasm contract-state smart $CONTRACT "$BALANCE_OF_OWNER" --node $NODE
data:
  balance: "984000"

# Query all allowances

Get all allowances by running this command:

$ ALL_ALLOWANCES=$( jq -n --arg owner $OWNER '{ "all_allowances": { "owner": $owner } }' | tee /dev/tty )
$ CUDOS_NODED query wasm contract-state smart $CONTRACT "$ALL_ALLOWANCES" --node $NODE
data:
  allowances:
  - allowance: "8000"
    expires:
      never: {}
    spender: cudos19uudvppffqzqetmeuuux47sgh0xecu07unqwwa

Example of the expected output results:

{
  "all_allowances": {
    "owner": "cudos16xws8z7zh7yjj69tglyks3jefp7rw38dlq5k0g"
  }
}

# Query all accounts

Get all accounts by running this command:

$ ALL_ACCOUNTS='{ "all_accounts": {} }'
$ CUDOS_NODED query wasm contract-state smart $CONTRACT "$ALL_ACCOUNTS" --node $NODE
data:
  accounts:
  - cudos15yvgtr5ppu92hx0hu53ygdhnajrhgmjpfe8vdc
  - cudos16xws8z7zh7yjj69tglyks3jefp7rw38dlq5k0g
  - cudos19uudvppffqzqetmeuuux47sgh0xecu07unqwwa

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