Exploring .NET WebAssembly with WASI

Overview

WebAssembly (Wasm) is something that the Cloud Native Advocacy team has been exploring. It has been around for a few years and has mostly been used within browser-based applications. There are many blog posts on what makes WebAssembly an ideal target for running applications (e.g., smaller footprint with .wasm files compared to containers, code isolation, and sandboxing). My colleague Steven Murawski wrote a blog series on getting started with hosting Wasm apps on an emerging PaaS platform called Hippo which is developed by folks at Fermyon. In Part 1 of the series, he introduces topics and define some of the acronyms like “Wagi” and “WASI”. He also introduced a runtime called Wasmtime which implements the WebAssembly System Interface (WASI) standard. This article will walk you through how Steven and I went about getting a .NET console app running as a Wasm app on the Wasmtime runtime in a Dev Container. The .NET console app produced in this article has also been contributed as a csharp template in the yo-wasm repo which is also maintained by Fermyon; so you can quickly test it out for yourself later.