workers-wasi VS wasi-sdk

The examples seemed clear enough to read (I did not test them), but I felt than even when teaching by example there needs to be more overview and explanation. I.e., I would prefer an overview of WASM structure and use with examples, rather than just the examples. (I have some (but limited) experience using WASM.)

As for the utility of wasm, note also that Cloudflare workers can run WASM on edge servers [1], and that the Swift community has some support for compiling to wasm [2].

I've never really understood how wasm could do better than java bytecode, but I've been impressed with how much people are using lua and BPF. More generally, in a world of federated programming, we need languages client can submit that providers can run safely, without obviously leaking any secret sauce -- perhaps e.g., for model refinement or augmented lookup.

[1] https://github.com/cloudflare/workers-wasi

Those are great questions! I believe Emscripten will be required for some cases as it provides more features for targeting a Web Browser. If WASI is the only requirement for a Wasm module, then there are three possible solutions:

- Use a library that provides the WASI bindings in a browser environments: there are some OSS projects that provides WASI bindings on top of browser technologies. For example, workers-wasi from Cloudflare [1]. It could be even another Wasm module that provides the implementation for the main one. I know the people from Loophole Labs are experimenting with virtual filesystems (VFS) [2].

- Browsers provides a WASI implementation: server-oriented runtimes like NodeJS are already providing these bindings (under a experimental flag). I shouldn't have stated that as a fact, as browsers may provide it or not. However, I saw in the past the Google Chrome team experimenting with WASI and the browser FileSystem API [3]. So, I think it may happen :)

- [1] https://github.com/cloudflare/workers-wasi

- [2] https://www.youtube.com/watch?v=46jZSXVxYPw

- [3] https://github.com/GoogleChromeLabs/wasi-fs-access

Indeed, some people are doing this:

- WASI once had an official polyfill https://wasi.dev/polyfill/, now apparently succeeded by https://github.com/bjorn3/browser_wasi_shim

- wasmer-js provides a JS polyfill for WASI https://docs.wasmer.io/integrations/js/wasi

- Cloudflare has a WIP polyfill https://github.com/cloudflare/workers-wasi

I'm generally leery of non-temporary polyfills, so I'm not sure that any of these feel like a long-term viable option for me.

I think modern C++ could be perfectly viable as well. Maybe https://github.com/cloudflare/workers-wasi would be a good starting point? I'm not too knowledgeable on the subject. Exciting times though, I think WASM might be the great equalizer.

While there is a WASI implementation for Workers: cloudflare/workers-wasi, I prefer to implement each import manually - especially when there are so few and especially while I am still experimenting. This helps me to keep the full picture of what's going on.

I would really love being able to take any POSIX command line tool, compile that to WASI, and run it on (at least) Linux, Windows and macOS like a regular executable without having to install a separate WASI runtime.

I'm a 'WASI convert' since I was able to take an ancient 8-bit assembler written in the mid-90's (http://xi6.com/projects/asmx/), compile that as-is with the WASI SDK (https://github.com/WebAssembly/wasi-sdk), and then integrate it into a VSCode extension (https://marketplace.visualstudio.com/items?itemName=floooh.v...).

A similar problem is I have is a shader cross-compiler (https://github.com/floooh/sokol-tools) which needs to run Linux, macOS and Windows and takes too long to build locally, thus I currently need to distribute that as pre-built binaries. Compiling this to WASI works, but the filesystem access restrictions built into current wasm runtimes are a hassle to manage, and it would require a WASI runtime to be separately installed).

There is the WASI SDK if you want to target WASI from C/C++:

https://github.com/WebAssembly/wasi-sdk

It may not have all the amenities of Emscripten, but it's way less bulky.

The most direct way to debug WebAssembly is through the WebAssembly System Interface (WASI). In itk-wasm, we can build to WASI with the WASI SDK by specifying the itkwasm/wasi toolchain image. A backtrace can quickly be obtained with the itk-wasm CLI. Or, a fully fledged debugger session can be started with LLDB.

We use the add_executable command to build executables with itk-wasm. The Emscripten and WASI toolchains along with itk-wasm build and execution configurations are contained in itk-wasm dockcross Docker images invoked by the itk-wasm command line interface (CLI). Note that the same code can also be built and tested with native operating system toolchains. This is useful for development and debugging.

A more lightweight tool than emscripten is the WASI SDK (https://github.com/WebAssembly/wasi-sdk/releases). However, it doesn't generate JS or HTML.

wget https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-16/wasi-sdk-16.0-macos.tar.gz

First, we’ll download the wasi-sdk. We’ll use wasi-sdk-16.0-linux.tar.gz, the latest version available when writing this article. We’ll move the file to the /opt directory and unpack it as follows:

I'm intrigued. Pretty good write-up about it here. One would need an ebuild for wasi-libc and an ebuild for wasi-sdk.

The previously mentioned PR for wasm32-unknown-unknown compatibility solved this by including libc .c files from OpenBSD. My go to solution is different though. I prefer to build using the wasi-sdk (a WASI-enabled WebAssembly C/C++ toolchain).

There's also the https://github.com/WebAssembly/wasi-sdk repo which is kind of a meta-build-system for all this.

But in FreeBSD we build all the pieces directly, here's our build recipes (with some hacks due to llvm's cmake code being stupid sometimes):

compiler-rt (from llvm): https://github.com/freebsd/freebsd-ports/blob/main/devel/was...

libc (from what you linked): https://github.com/freebsd/freebsd-ports/blob/main/devel/was...

libc++ (from llvm): https://github.com/freebsd/freebsd-ports/blob/main/devel/was...