wit-bindgen VS interface-types

The component model is already shipping in Wasmtime, and will be stable for use in Node.js and in browsers via jco (https://github.com/bytecodealliance/jco) soon. WASI Preview 2 will be done in December or January, giving component model users a stable set of interfaces to use for scheduling, streams, and higher level functionality like stdio, filesystem, sockets, and http on an opt-in basis. You should look at wit-bindgen (https://github.com/bytecodealliance/wit-bindgen) to see some of the languages currently supported, and more that will be mature enough to use very soon (https://github.com/bytecodealliance/componentize-py)

Right now jco will automatically generate the JS glue code which implements a Component Model runtime on top of the JS engine's existing WebAssembly implementation. So, yes, Components are a composition of Wasm Modules and JS code is handling passing values from one module/instance to another. You still get the performance benefits of running computation in Wasm.

One day further down the standardization road, we would like to see Web engines ship a native implementation of the Component Model, which might be able to make certain optimizations that the JS implementation cannot. Until then you can consider jco a polyfill for a native implementation, and it still gives you the power to compose isolated programs written in many languages and run them in many different contexts, including the Web.

(Disclosure: I am co-chair of WASI, Wasmtime maintainer, implemented many parts of WASI/CM)

Thank you!

To your point, the primary consideration for choosing the languages is their support for WebAssembly, and WASI in particular.

Due to Spin's heavy use of WASI and the component model, languages that have first party support in the WIT bindings generator (https://github.com/bytecodealliance/wit-bindgen) are the easiest to implement, followed by languages that can be built on top of the support for those with first party support.

For example, the JavaScript support is built by embedding QuickJS (in particular, Shopify's Javy project — https://github.com/fermyon/spin-js-sdk), which then uses the Rust SDK.

There are many options, but what worked best for me is compiling with cargo-wasi and loading the resulting Wasm file with browser_wasi_shim. Using wasm32-wasi instead of wasm32-unknown-unknown requires a bit more work (the communication with JS has to be set up manually), but gives the flexibility of having just a Wasm file that can be dropped in and loaded dynamically. (There's wit-bindgen for generating wrapping code according to an interface definition but I didn't have much success with it.)

I've been playing with creating a go version of the abi for use with wit-bindgen because the current one uses cgo https://github.com/bytecodealliance/wit-bindgen

wit-bindgen - Language Binding Generator for WASM Interface Type

wit-bindgen-rust = { git = "https://github.com/bytecodealliance/wit-bindgen.git", rev = "60e3c5b41e616fee239304d92128e117dd9be0a7" }

Yep, you're right. For this, there are a few options. The ones most relevant to you are fp-bindgen, which targets Wasmer, and wit-bindgen, which targets wasmtime.

Are you evaluating if WebAssembly Component Model, its WIT format and related tooling like wit-bindgen could be a good fit for your multiple languages support?

[package] name = "sentiment" version = "0.1.0" edition = "2021" # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html [dependencies] wit-bindgen-rust = { git = "https://github.com/bytecodealliance/wit-bindgen.git", rev = "60e3c5b41e616fee239304d92128e117dd9be0a7" } vader_sentiment = { git = "https://github.com/ckw017/vader-sentiment-rust" } lazy_static = "1.4.0" [lib] crate-type = ["cdylib"]

Some things that might greatly increase wasm usage and overall tooling:

1) Tools that run docker containers and serverless function services (like AWS lambda) to support providing a .wasm files instead

2) Garbage collection in the runtime to make GC languages easier to port to wasm

3) Dynamically typed languages (NodeJS, Python, Ruby) being able to compile to webassembly directly instead of porting the runtime to webassembly and then running the code through the runtime. This is a big ask though, basically needs to redesign the runtime completely

4) wasm-DOM bindings will enable other languages to do HTML rendering which will require new web frameworks for every language that wants to take over the space from JS. This will lead to (even more) fragmentation of the web ecosystem

5) A new wasm-first SDK (unrelated to the DOM) for building cross platform applications. I can see this taking off only if it is built-into the browsers and backed by some standards committee, so not very likely I think

6) Something like the Interface Types proposal ( https://github.com/WebAssembly/interface-types/blob/main/pro... ) becomes a thing allowing wasm programs to be consisted of modules written in several different languages and being able to call said modules with low or 0 runtime performance hit (and of course, no compilation to multiple CPU archs). So much of programming ecosystems are locked to specific languages (like data science with python) when there is little technical reason for it be like that.

AFAIK GC is irrelevant for "direct DOM access", you would rather want to hop into the following rabbit hole:

- reference types: https://github.com/WebAssembly/reference-types/blob/master/p...

- interface types (inactive): https://github.com/WebAssembly/interface-types/blob/main/pro...

- component model: https://github.com/WebAssembly/component-model

If this looks like a mess, that's because it is. Compared to that, the current solution to go through a Javascript shim doesn't look too bad IMHO.

I'm not really optimistic that particular aspect will get much improvement. Many people expected interface types to come save the day, but after a looong stagnation that proposal has been archived (for now) in favour of component types, which has much less potential for performance gains.

Really good questions. Unfortunately, most of the issues I found back then were fundamental ones. I've seen that Wasm has deprecated "Interface Types" and is now working on the "Component Model". But even then, as far as I understand that would only avoid the serialization and deserialization steps, and you would still need to copy complex types. It will be more performant, but I don't think it would be enough for Tremor either.

wasm doesn't know anything about the outside world on purpose. This allows it to be used in other domains. For direct access to the DOM et al, interface types are being developed. It's a non-trivial problem to interoperate with a dynamically typed GC'd language from any statically typed no-GC language that can compile to wasm.

You may want to look into WASM interface types, which is defining what amounts to am IDL for WASM and different languages have common calling conventions: https://hacks.mozilla.org/2019/08/webassembly-interface-type...

I don’t know if there’s a better intro article. I believe this is the current iteration of the proposal: https://github.com/WebAssembly/interface-types/blob/main/pro...

Yes, and if I'm not mistaken, this is the RFC

I see no reason why not. See the interface types proposal for a proposed solution.

Wanted to get thoughts from the Rust experts on this - the author of the Yew framework seems to think that Web Assembly Interface Types (https://github.com/WebAssembly/interface-types/blob/master/proposals/interface-types/Explainer.md) will allow Yew to eventually become faster than Vue, React, Angular, etc. Is there general consensus on this in the Rust community? The prospect of mixing Rust (for the performance critical pieces) with TS on the front end doesn't seem super appealing to me.