WASI Serial api

Recently, I've been casually involved in the hardware scene and I've realized that programming and interfacing with hardware can be annoying platform-independent. Often software will work, but it's quite complicated to get all the dependencies it requires in exactly the right place. I've noticed some niches start to move towards packaging software as wasm modules that can run on any platform with a compliant wasi runtime (see YoWASP), but this hasn't included the programmers and debuggers themselves. To fully fulfill that role, WASI would need a USB api (akin to WebUSB), but a low-hanging fruit, which would still go a very long way, is a serial api for WASI.

I went ahead and wrote a preliminary witx module (see here) and also implemented a (pretty rough) wasmtime crate for it (see here).

My goal here is to open the conversation about what interfacing with external hardware through WASI could look like. The API I've come up with here does not follow the capability-based security that WASI is based on, so it's obviously not finished.

Applications:

• Programming and debugging microcontrollers (e.g. arduinos, etc) and FPGAs
• Interfacing with MIDI devices(?)
• lots more stuff

Start by reading the linked wasi_ephemeral_serial.witx module and the crates/wasi-serial implementation in wasmtime. The issue is opening a design conversation about external hardware APIs for WASI, so a newcomer can compare the proposed interface and its capability-security concerns, but the payload does not define a settled implementation or completion criteria.