Cw-20 Smart Contract Implementation

cwtools is an alternative to Rust-optimizer. It is developed by Oraichain, source code here: https://github.com/oraichain/cosmwasm-tools (I did NOT develop this tool, the source code belongs to Oraichain - though in this version, there are minor changes within the code). This file only serves as a reminder of the steps and brief functionalities to 'deploy' a Cosmos smart contract.

---

Configuration

Configure .env and package.json to allow Node.js and NPM servers (samples of these files are in this respository) to manage your crate. Specifically, the env should include:

• the encrypted mnemonic
• the server's RPC and LCD URLs
• the token's denom, the blockchain's ID (important, in our case we'll use a testnet)
• the derivation path
• and the gas price.

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Instantiate

Normally, you'd deploy your smart contract, which you can do with cwtools. That said, deployment is expensive, so if your contract is reusing a code base from some other contract already existed on the network, it is better to instantiate it without uploading (the latter can therefore be optional). This is where CosmWasm differs from EVM - you don't actually have to deploy a source code for a smart contract with existing logic!

# Instantiate
cwtools wasm instantiate --env .env --input '{
  "name": "Eames", "symbol": "EAM", "decimals": 10, 
  "initial_balances": [{
    "amount: "20000", "address": "your_addr"
  }], 
  "mint": {"minter": "your_addr"}
}' --code-id 6082 --label "basic" --admin "your_addr"

• This process is so that you instantiate a copied wasm file from another existing contract with its specified code id.
• --env option should precede the path to your environment file.
• --input is the json schema for deploying the smart contract, or it can also be in base-16 format. Note that if this were for atomic swap instantiation, then the input would be an empty {} (see instantiate function in contract.rs).
• --code-id is a source code's ID (true ID is a complicated hashed value, so they simplify this process by adding another mapping to an ever-incrementing integer identifier).
  • In simplier terms, though, it is the simplified id of the smart contract that you referred to, where said contract shares the same Cw20 base as yours.
  • Sharing the same underlying standard allows this instantiation without having to upload your source code to the network.
• --label is required, though arbitrary.
• --admin is used specifically for operations that require some form of authorization. It could be an existing contract's, or a wallet's address. In this case, we've used "your_addr", which is referring to the wallet's address.

---

Upload / Deploy

# Compile
cwtools wasm build contracts/atomic-swap -o path/to/compiled

• The first step to upload or deploy is to compile your contract (at top level of smart contract crate) into a compressed .wasm file. This is the file that can be deployed / uploaded onto the blockchain network. (In this example, we use atomic-swap contract.)
• cwtools will automatically optimize the file size for you with its build wasm operation. Full-size file is often large and unsuitable for the blockchain.

# Upload
cwtools wasm upload path/to/compiled/atomic-swap.wasm --env .env --input '{
  "name": "Eames", "symbol": "EAM", "decimals": 10, 
  "initial_balances": [{
    "amount: "20000", "address": "your_addr"
  }]
}'

# Deploy
cwtools wasm deploy path/to/compiled/atomic-swap.wasm --env .env --input '{
  "name": "Eames", "symbol": "EAM", "decimals": 10, 
  "initial_balances": [{
    "amount: "20000", "address": "your_addr"
  }]
}'

• The upload process is to upload your smart contract and obtain the .wasm file to run on the network. As disucssed, you won't be required to upload the source code unless you make internal logic changes to the Cw20 base.
• After uploading, a new smart contract ID (the simplified code-id discussed above) will be returned. You will use this id to instantiate your smart contract on the chain. This means that instead of borrowing some other contract's id, you are instead using your own true, new provided one from the uploaded source code.
• Deploy is simply upload and instantiate in one. Just as the process above, it will first upload the .wasm file, use the returned code-id to pass it to instantiate the contract.

---

Execute & Query

We can query, for example, the balance of our address. Otherwise, we can also execute. The following is a mint execution for basic smart contract example:

cwtools wasm execute hashed_ref --env .env --input '{
  "mint": {"recipient": "your_addr", "amount": "1500"}
}'

• hashed_ref is the hashed reference to the instantiation smart contract you had borrowed.
• Specifically, in instantitation, you called a --code-id, and that id is the smart contract whose underlying standard you borrowed so that you don't have to upload your source code to the network. When instantiation of your new smart contract succeeds, you will receive a successful MsgInstantiation on the blockchain, where it will specify a new hashed reference. Use that value here.
• In our instantiate operation above, we specified a minter, which is our address. This is why this mint operation will work.

For details of atomic swap, read README of atomic-swap directory in contracts.