A demo showing how to use component model with Wasmtime

The component model is a way to build WebAssembly modules that can be composed together to form a larger application. This demo will show how to use the component model to build a simple application that uses multiple WebAssembly modules compiled from various languages, such as Rust, C++, Python and JavaScript.

This demo showcases a web application.

• Rust: Web Server using wasi-http
• Python: String Filtering
• JavaScript: HTML Rendering

JS

For JavaScript, we mainly use the ComponentizeJS to build the WebAssembly module. Note that we will not use jco cause we want to disable all wasi features, which can not be done by jco for now.

We will use marked to render the markdown content. There are two problems we need to handle:

1. We need to bundle the marked module into one JS file.
2. We need to transpile the regex in marked module, and we need marked(v5.0.0).

Python

For Python, we just need componentize-py.

Rust

It is relatively easy to build a WebAssembly module using Rust. We will use wasi-http to build a simple web server.

First we need to download all wits from Wasmtime repository. Then we need to modify the wasmtime crate to support a large wasm file, specifically, we need to modify the wasmtime and set max_core_instances_per_component to 50.