wasi-libc VS wasi-sdk

Now there are projects like WASI that allows for interfacing with system resources for WASM code this allows for devs to target WASM runtime for their apps sliding the apps to run locally on any OS without any porting required. This could be a game changer in the future like Docker and containers was in the past decade.

So it doesn’t seem like there has been progress on a pseudo-random number generator function for typst, but there are multiple other ways to solve this: 1. Just don’t. Typst has this functional philosophy, there one input always produces the same output. (not an answer to your question tho) 2. Interface with a webassembly module which has a random number generator. So you could e.g. compile c to wasm and statically link a libc version. You would then just have to export the rand() function. (You could use any lang for this, which has a stdlib with a pseudo random number generator) 3. Implement your own. Random number generators are actually not that hard something like an LCG isn’t to complex. (Id provide an example but im on my phone rn)

Actually WASI[0] will be a better alternative, IIRC extism serialize and deserialize the data that you want to pass every time, adding a lot of overhead.

[0] https://wasi.dev

Actually, it was in wasi-libc: https://github.com/WebAssembly/wasi-libc/blob/main/libc-bott...

Proper isolation in C# is only now becoming a thing, with .Net support for WASI, which is essentially a WebAssembly sandbox which can be given extremely granular privileges (such as access to spefic file system directories, or an effective virtual file system). As an upside, the idea is that it should be possible to write the WASI packages in more or less anything.

Wasm Labs dev here :)

In mod_wasm, there are some differences with a pure CGI implementation. When Apache boots, it loads the configuration and initializes the WasmVM. When a new HTTP request arrives, the VM is ready so you don't need to initialize a different process to manage it.

You still need to process the request and pass the data to the Wasm module. This step is done via STDIN through the WebAssembly System Interface (WASI) implementation [0]. The same happens in the opposite direction, as the module returns the data via STDOUT.

So, the CGI pattern is still there, but it doesn't require new processes and all the code runs in a sandbox.

However this is not the only way you can run a Wasm module. In this specific case, we use CGI via WASI. In other cases, you may compile a module to fulfill a specific API, like ProxyWasm [1] to create HTTP filters for proxies like Envoy.

- [0] https://wasi.dev/

- [1] https://github.com/proxy-wasm/spec

Never done that, but I think you need this: https://wasi.dev/

The Python builds from the WebAssembly language runtimes [0] project target the WebAssembly System Interfaces (WASI) [1]. It allows the Python interpreter to interact with resources like the filesystem.

Many server-side Wasm runtimes supports WASI out of the box. For the browser, you need to provide a polyfill to emulate these resources like the one provided by the WASI team [2].

Regarding SQLite, these builds include libsqlite so you should be able to use it :)

- [0] https://github.com/vmware-labs/webassembly-language-runtimes

- [1] https://wasi.dev/

- [2] https://wasi.dev/polyfill/

Effective debugging results in effective programming; itk-wasm makes effective debugging of WebAssembly possible. In this tutorial, adapted from the itk-wasm documentation, we walk through how to debug a C++ data processing pipeline with the mature, native binary debugging tools that are comfortable for developers. This is a fully featured way to ensure the base correctness of a processing pipeline. Next, we will walk through an interactive debugging experience for WASI WebAssembly. With itk-wasm, we can debug the same source code in either context with an interactive debugger. We also have a convenvient way to pass data from our local filesystem into a WebAssembly (Wasm) processing pipeline.

Communication between the WASM module and the rest of the application needs to be done in very simple types (bytes, ints and floats). No complex types are supported yet. This is why most WASM compilers also provide some glue-code to map between complex types like strings or arrays. The Web Assembly System Interface (WAS) is an on-progress standard aimed to solve this last limitation; once it's mature it will allow easy interoperation with almost every environment. WASI is already available in some WSAM compilers and runtimes.

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...