Submessages
Learn how to use submessages on Secret Network
Introduction
In the CosmWasm SDK, submessages are a powerful feature that allows a contract to execute additional messages within the context of its own execution. They provide a way to perform multiple actions atomically, ensuring that either all actions are successfully executed or none at all. This is particularly useful for complex transactions where multiple steps need to be taken, and any failure in one step should roll back the entire operation.
You can learn more about submessages here!
In this tutorial, you will learn how to use submessages to execute a counter smart contract on Secret Network from another Secret Network smart contract 😊
Getting Started
git clone
the submessages example repository:
Our Multi Contract System
In this tutorial, we will use submessages to execute a counter smart contract that is already deployed to the Secret Network Testnet. Thus, we are working with two smart contracts:
Manager Contract - which executes the Counter Contract using submessages
Counter Contract - which is executed by the Manager Contract
This tutorial follows the same design patterns of the Cross Contract Communication tutorial, but uses submessages in place of Wasm messages
Designing the Manager Contract
We will be designing a Manager Smart Contract which can execute a Counter Contract that is deployed to the Secret testnet. Let's start by examining the message that we want to execute on the counter smart contract. In the src
directory, open msg.rs and review the Increment
msg:
Increment
contains one parameter, the string contract.
This is the contract address of the counter contract, which we will increment.
Where is the code hash?
Unlike other Cosmos chains, Secret Network requires the hash of the smart contract in addition to the address when executing calls to smart contracts.
Contract hashes are what binds a transaction to the specific contract code being called. Otherwise, it would be possible to perform a replay attack in a forked chain with a modified contract that decrypts and prints the input message.
However, there is no need to pass a code_hash
when doing cross contract or sub message calls because we have designed the helper functionget_contract_code_hash
which we call internally when executing the Increment
function.
Notice that we implement HandleCallBack for our ExecuteMsg
enum, which is what allows our submessages to be converted into a CosmosMsg
and executed:
Reply entry point
Submessages offer different options for the other contract to provide a reply. There are four reply options you can choose:
In order to handle the reply from the other contract, the calling contract must implement a new entry point, called reply
:
Here is an example of how to handle the reply:
The submessage returns a Result
containing:
Ok(Response)
if the submessage executed successfully, with an action attribute set to "increment".Err(ContractError)
if the submessage execution failed, with the error encapsulated in a custom contract error.
Executing the Manager contract
Now let's use this manager smart contract to increment a counter smart contract with submessages!
The counter contract we will be executing is deployed here:
Or deploy your own counter contract here :)
cd
into manager/node:
Install the dependencies:
Run node execute to execute the counter contract:
Upon successful execution, you will see a tx
returned in your terminal:
Querying the counter contract
Now, let's query the counter contract to make sure it was executed correctly!
cd
into counter/node:
Install the dependencies:
And run node query
:
You will see that the counter contract has been incremented by 1 :)
Summary
In this tutorial, you learned how to utilize submessages in the CosmWasm SDK to perform complex, atomic operations within smart contracts on the Secret Network. This guide walked you through executing a counter smart contract from another contract, detailing the setup of a Manager Contract that triggered the Counter Contract using submessages, managing replies, and verifying the execution results 🤓
Last updated