cw-simulate

This package combines cosmwasm-vm-js with additional abstractions and state management to more accurately simulate the effects of CosmWasm contracts on the blockchain environments on which they are hosted.

Features

• configure multiple host chain environments with chain-specific settings / state
• multiple simultaneous contract instances can exist per chain
• chain modules can be simulated through custom user code
• extensible for further instrumentation via custom middlewares

Getting Started

Import the cw-simulate library from NPM in your package.json.

$ npm install -S @terran-one/cw-simulate

If you're using Yarn:

$ yarn add @terran-one/cw-simulate

Usage

1. Create a CWSimulateApp object - this is a simulation environment describing a single chain.
2. As needed, per chain:
   • Upload the WASM bytecode using App.wasm.create. This will register a new codeId to reference the uploaded contract code.
   • Create a new contract instance using App.wasm.instantiateContract, passing in the codeId generated in the previous step.
   • From the response, retrieve the contractAddress to refer to the contract instance.

• You can now run execute and query messages against the instance, and they should work as expected.

Example

The following example creates a chain, instantiates a contract on it, and performs an execute and query.

import{CWSimulateApp}from'@terran-one/cw-simulate';import{readFileSync}from'fs';constsender='terra1hgm0p7khfk85zpz5v0j8wnej3a90w709vhkdfu';constfunds=[];constwasmBytecode=readFileSync('cw-template.wasm');constapp=newCWSimulateApp({chainId: 'phoenix-1',bech32Prefix: 'terra'});// import the wasm bytecodeconstcodeId=app.wasm.create(sender,wasmBytecode);// instantiate the contractletresult=awaitapp.wasm.instantiateContract(sender,funds,codeId,{count: 0});console.log('instantiateContract:',result.constructor.name,JSON.stringify(result,null,2));// pull out the contract addressconstcontractAddress=result.val.events[0].attributes[0].value;// execute the contractresult=awaitapp.wasm.executeContract(sender,funds,contractAddress,{increment: {}});console.log('executeContract:',result.constructor.name,JSON.stringify(result,null,2));// query the contractresult=awaitapp.wasm.query(contractAddress,{get_count: {}});console.log('query:',result.constructor.name,JSON.stringify(result,null,2));

Using with Vue.js and vite

Vite doesn't include shims for Node variables like Webpack 4 does, and cw-simulate currently relies on these. The following workaround exists:

1. Add the buffer package (npm add buffer)
2. Add the following to your index.html (inside the body tag, before your other js imports):

<script>window.global=window;</script><scripttype="module">import{Buffer}from"buffer";window.Buffer=Buffer;</script>

See this github issue for more details.