wit-bindgen-cs

This is the start of C# bindings for wit.

This is a project started at "Componentize The World" – a hackathon hosted by the Bytecode Alliance, and was continued at Microsoft's internal hackathon for the period of one week. With that, it's very much a work in progress and, for now, only works with very specific WIT files (i.e., 1 interface exposing 1 function).

How to use it?

One of our main focuses was the developer experience, where we hoped to integrate with existing dotnet tooling and abstract away direct interactions w/ wit-bindgen, and wasm-tools.

Prerequisites

• .NET 8 Preview 4 or later
  • This can be downloaded from Download .NET 8.0 (Linux, macOS, and Windows)
  • Verify that dotnet --version tells you it's .NET 8 Preview 4 or later
• WASI SDK
  • Download from wasi-sdk releases page. If you're using Windows, you need the one with mingw in its name.
    • curl -LO https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-20/wasi-sdk-20.0-linux.tar.gz
  • Create an environment variable called WASI_SDK_PATH giving the path where you extracted the WASI SDK download, i.e., the directory containing bin/lib/share.
• Rust tooling (i.e., cargo, cargo component, etc.) for demo. purposes.
  • Install from rustup.rs
  • Install from cargo-component
    • `cargo install --git https://github.com/bytecodealliance/cargo-component --rev 36c221e4 --locked cargo-component``
• wasmtime 13.0.0
  • Install from 1234dddc commit by running cargo install --git https://github.com/bytecodealliance/wasmtime --rev 134dddc wasmtime-cli --features component-model

Note:

• wit-bindgen, and wasm-tools are automatically installed with dotnet component init.
• preview reactor files can be found here, but are already included in this repo..

Running the demo

This demo. utilizes the work upstream from the component-model tutorial, but replaces one of the components w/ a C# one.

(cd ./csharp-component-generator && ./install-tool.sh)
# ^^^ install the dotnet plugin
rm -rf MyProject
# ^^^ remove any existing project directory
mkdir MyProject
# ^^^ create a new project directory
(cd ./MyProject && dotnet new console)
# ^^^ create a new console project
(cd ./MyProject && dotnet component init)
# ^^^ initialize the project for use with wasm-tools
(cp ./Program.cs ./MyProject/Program.cs)
# ^^^ copy the Program.cs with Add impl. into the project directory
(cd ./MyProject && dotnet component generate --wit ../adder.wit)
# ^^^ generate the C# bindings for the WIT file
(cd ./MyProject &&  dotnet component build --world adder --wit ../adder.wit --preview ../wasi_snapshot_preview1.reactor.wasm)
# ^^^ build the project
./build.sh
# ^^^ build the Rust components to be composed with the C# component
wasmtime run --wasm-features component-model final.wasm 1 2 add
# ^^^ run the composed component

Video demo