wasm: support new WASI interface

[johanbrandhorst]

Mozilla, Fastly and others have started work on a new standard interface for WASM to interact with system calls, they're calling it WASI, the WebAssembly System Interface.

https://hacks.mozilla.org/2019/03/standardizing-wasi-a-webassembly-system-interface/

I think we should consider supporting this in the Go WASM architecture, possibly under a new OS (GOOS=WASI).

This issue should track the development of such an effort.

Mozilla have invited interested parties to join the #wasi channel on the Mozilla IRC server (https://wiki.mozilla.org/IRC).

[johanbrandhorst]

@neelance @agnivade

[neelance]

I'm already looking into this. Yes, this is likely to become the GOOS/GOARCH wasi/wasm. My current long term plan is to also make js/wasm partially use WASI as soon as a feature can be expressed with WASI without losing any functionality.

[johanbrandhorst]

https://github.com/CraneStation/wasmtime/blob/master/docs/WASI-api.md this looks like a good list to reference.

[neelance]

My WIP for WASI can be found here: https://github.com/neelance/go/tree/wasi

There is no GOOS=wasi yet, use GOARCH=wasm + GOOS=js to target WASI. The fork is thus not compatible with wasm_exec.

This is a very important thing.
Wasi can be a new containerisation approach but running on mobiles, desktops, IOT and servers. It solves is able to solve a fundamental problem of trusting code from someone else with the host deciding what file / network IO the third party code has access to.
Sort of like how android will prompt you when an app wants to access your contacts or file system.

Wasmer git repo has it working for golang, python using a rust wasm / wasi engine currently btw. It's fast too.
https://github.com/wasmerio/go-ext-wasm

It seems that there is not IDL / RPC standard yet for WASI though. I looked but could not find. If anyone knows would be great.

[tiborvass]

@gedw99 you should probably ask on the WASI repo instead. Not sure if WebAssembly/WASI#49 is what you're looking for. Either way WASI is still in active development so it is normal that certain things are lacking.