CosmWasm Multisend Contract on Terra Blockchain

This is a multisend smart contracts in Rust built to run on Cosmos SDK module on all chains that enable it. The project was built and tested for the Terra network.

What it does

This project covers all that is required to build, deploy and interact with the smart contract on the Terra blockchain. The main parts of the project are:

• The contract (this page)
• The deployment scripts in scripts
• A basic CLI client application to send and receive Terra/Luna as well as interact with the deployed contract: multisender-client

Each part has its own README and instructions

Multisend Contract

The contract is written in Rust and is compiled to wasm. The contract receives a list of addresses and amounts, and distributes the passed coins to these addresses. The amount sent to the contract must be enough to cover the outgoing payments.

The contract also includes a possible fee, set on contract initialization. The fee is paid to the contract owner and must be added to the total payment received by the contract when creating a transaction. The script in multisender-client queries the contract and adds the required fee to the transaction.

Prerequisites

Building the contract requires an up-to-date Rust version with wasm support.

rustup default stable
rustup target add wasm32-unknown-unknown

For further details, consult the official Terra documentation for setting up the environment.

As a live test environment, it is recommended to use LocalTerra. Follow the installation process of LocalTerra in the link

Building the contract

Clone the contract to a new environment.

Make sure the project compiles by running

```sh
cargo wasm

This will build an unoptimized version of the contract, just to make sure the compilation works. To build an optimized version that can be uploaded to the blockchain, run

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/rust-optimizer:0.10.3

More instructions on building and developing the contract in Developing

Once the contract is compiled, go to scripts to deploy the contract using Terra.js

Contract use cases and limitations

The Terra blockchain supports sending multiple payments simultaneously via a MsgMultiSend. Still, the contract could be useful for several use cases:

• Integration with other smart contracts
• Sending ERC20/CW20 tokens (in future versions)
• Collecting payment for the provided service

The contract can be also easily extended to perform additional tasks, such as swapping tokens to the required coin etc.

Contract Demo

In the demo, the contract sends a batch of transactors to the addresses specified in the CSV. The The address of sending address gets funds removed, and added to the specified addresses. This is easy to practice in LocalTerra, as it several addresses with funds for testing. Do not use these addresses in production

Misc

Publishing contains useful information on how to publish your the contract, once you are ready to deploy it on a running blockchain. Importing contains information about pulling in other contracts or crates that have been published.