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Neon: Node plus Rust (calculist.org)
338 points by aturon on Dec 24, 2015 | hide | past | web | favorite | 69 comments

Wow! The integration with rayon for data parallelism is especially interesting, and I imagine that could be a killer feature for some people looking to accelerate compute-heavy node.js code without having to deal with the nastiness of parallelism in C++, or C++ at all.

I don't believe the blog post announcing Rayon ever made it to HN, so here's a convenient link: http://smallcultfollowing.com/babysteps/blog/2015/12/18/rayo...

Only a handful of comments but it was posted a few days ago: https://news.ycombinator.com/item?id=10759434

I can see this being useful in combination with Piston[1] to achieve scripting for game engines, in the same way Lua is normally used. Rust as a core for a game engine seems like a really great idea, considering the speed and safety benefits it provides.

[1] https://github.com/PistonDevelopers/piston

Javascript seems like a great contender in this space to me. Btw, as well as using nodejs / v8, there are also Rust bindings for SpiderMonkey (Mozilla's JS engine): https://github.com/servo/rust-mozjs

(not super user-friendly yet, as this mainly exists for Servo - but there's enough here to embed Javascript scripts in your Rust projects!)

I've been very excited to see this project develop. I think it really speaks to what we can do with Rust in the future: once we get some nice abstractions, "FFI" barely even feels like it.

Node is actually the worst case here: V8 being in C++ makes this harder than Ruby or Python, being implemented in C.

Did Yehuda ever open source or complete a similar abstraction like this but for Ruby? I remember someone mentioning to me he was working on it. I have a longstanding todo (though I have no motivation because I currently have no use for Rust or Ruby) to try something similar though I remember my initial attempts having trouble with how Ruby's C API expresses some values.

I'm actively working on it (https://github.com/tildeio/turboruby) and in fact was racing @dherman to finish. He beat me by a mile :( but I hope to wrap up a usable first version soon.

Eat my dust! :P

I'm looking forward to it! I really want to flex some Rust muscle at work for our performance critical stuff.

There's an API thing from the JS side I don't understand, and I didn't find anything documentation-wise (maybe it's just because I haven't had my coffee yet):

So this loads... which rs file, exactly? Where do I specify the Rust file to be loaded? Or is there just a single entry point and you're supposed to have one singular Rust module that is named by convention?

Rust is a compiled language, so the JS files don't directly load a .rs file but instead they load a native Node extension, i.e. a .node file, which is generated by compiling and linking the Rust sources. (The node-cli tooling automates the whole build process.)

The line you cited is automatically locating the .node file, loading it, and returning the module object associated with it.

On IRC a couple people have been questioning this part of the API, suggesting that just using the standard npm module `bindings` might be better. It's a reasonable idea and I'll probably open a discussion in a GitHub issue.

I realize that Rust is a compiled language, that's not the issue. The syntax somehow suggested to me the modules could be compiled on demand, but that is not the issue either.

My question is/was, given two or more modules written in Rust, how do I address and require them by name? Due to its naming I assumed "neon-bridge" would be the glue that handles this. Given the fact that you can require .node files directly, it was not clear to me that "neon-bridge" is just the name of an example module (or is it?).

Ah, I see!

So neon-bridge is a utility npm package I published that automates loading your Neon project (so it's not the name of an example module). And the expectation is that you only have one Rust package ("crate" in Rust parlance) per Node package, which is why you don't need to pass it the name of anything -- it's looking for _the_ native module in the package, as opposed to _a_ native module.

However, that single Rust crate may have multiple modules in its implementation. They live in the src/ directory of your Neon project and are picked up by the Rust compiler and build tool.

And yes, deeeeefinitely need to get some docs going... :P

Cool, thanks for clearing that up. And thanks for working on this, I know with the questions it can sometimes seem like it's not appreciated... :)

Not at all -- my goal is simplicity and clarity so a confused (potential) user is a bug report!

Looks like `neon-bridge`, in this case, is an NPM module.

Yes, it is, but the point is its load() function apparently takes no parameters.

Honest question: Why would someone use Node instead of a Rust web framework when writing part of the code in Rust anyway?

- Node has full garbage collection. Rust has some very clever memory-handling, but it's not quite the same.

- Node is javascript. You may want to run the same code on client and server, and it's simpler than compiling Rust to JS.

- There may be JS libraries you want to use.

I could go on.

> Node is javascript. You may want to run the same code on client and server, and it's simpler than compiling Rust to JS.

What would be the reason to do that?

You need to do the same thing on the client and the server.

- DOM manipulation for AJAX states so they can be reached directly from the server without needing client side JS to do anything

- Calculate discounts for products (obviously clients just POST the product they want, but the discounts should be applied on the server consistently to how they were shown to the user)

- Your code is something generic, like recursively checking for a keypath on an object, and totally useful for JS anywhere it runs.

All kinds of other reasons.

I found it rather pleasant to have the same libs on client and server. Learn one lib API and use it everywhere :)

It also enabled me to move functionality freely around.

Calculating report data on the front-end, so it gets ready tomorrow and later moving it into the back-end, for performance reasons.

The reason that I'm using Rust and Node together is Lambda. It supports Java, Python and Node and my (admittedly perfunctory) tests showed that Node had the smallest overhead of the three in getting to Rust. However, this library seems to offer a richer interaction between the two platforms, which would imply using Node as something beyond a bridge to Rust, so there's likely an answer beyond mine that the author has in mind.

Because rust isn't web yet: http://arewewebyet.com.

That site is very out of date. We've been trying to get it fixed (as none of us control it), but we haven't been able to so far. :(

To clarify, are you saying that Rust is web (i.e. that the tools necessary for modern web server development and deployment are available to the Rust ecosystem)?

Depends on what your needs are. I think Rust is ready for certain Web apps. crates.io runs on Rust, for example, and it's a modern Ember-based web app running right now.

I think that the situation is a lot better than that site indicates.

This is fantastic! Great idea and job so far! One of the biggest disadvantages with node is any type of complex manipulations / processing due to the single threaded, scheduler paradigm but combining node with native modules makes it much easier to pass off more complex pieces directly to C++.

Passing off to rust? Count me in! I'll be taking a look at this when linux is supported (would also love windows support but mac os x and linux are necessary for me).

  >  I'll be taking a look at this when linux is supported 


I just saw :D

Damn people work fast. I hadn't even looked into what it would take to support Linux (and honestly my rust knowledge at the moment is so limited I probably wouldn't have figured it out in a reasonable time frame).

Could be killer if combined with electron.

If the goal is having a fast "business-rules engine" coupled to a pretty HTML5-based app-wrapper, one of my own projects is to combine Electron with the Erlang VM.

Rather than trying to go whole-hog on linking the two worlds together at a process level, I've just embedded an Erlang release into the Electron package, which decompresses itself to the user's Library/APPDATA dir on Electron startup, transparently registers as a service (so it can continue to run for things like server sync when the app is quit), and then communicates with the app using Unix domain sockets.

It's a bit like the feeling of having a Service Worker, but one that just happens to be able to embed things like physics engines inside of it.

Using Erlang in a desktop application sounds great, do you have any code online somewhere? Or could you make a gist? I would love to see how you made that work.

You might want to look into BERT [0], I think there is a JavaScript library. We used it a few years ago to call Ruby from Erlang, it wasn't fast at the time, but it did what we needed it to do.

[0] https://github.com/blog/531-introducing-bert-and-bert-rpc

I'm doing the same thing with a JVM. I had to fix the bug where named pipes on Windows were totally busted in Electron before I could make any progress.

Ah, I ran into that problem (I think?) and had been just using regular IP sockets as a stop-gap, planning to switch back over after it was fixed. I'm glad to hear someone with knowledge of Electron internals ran into it as well; I feel bad that I didn't file it as a bug, though.

If you're curious, the fix was here: https://github.com/atom/electron/issues/1968

It made it out into the regular release and I think it's fixed but TBH I haven't tested for a few months.

My work is all on GH here as well: https://github.com/orbitaljs There might be some synergy here between the projects.

Give me this but with Elixir and Im sold.

why elixir over rust? I'd assume rust makes more sense because you don't need gc

What is electron in this context? (The ex-atom maybe?)


Great idea. Also wonder if using Neon to speed up Electron could give a noticeable performance boost to Atom.

Why particularly with Electron?

Presumably because Electron needs to be hackable/customizable for lots of devs and performant for lots of workloads.

I wonder what makes it osx only? very cool project though, hope it takes off. I wish there was a way on github to watch a project at a level where you could just get notified of new releases.

Only that Dave only has access to OS X. I plan on contributing Linux support if nobody else beats me to it.

Yeah, that's all, just crawling before I walk. Lots of work to do, and very excited to welcome contributors and collaborators!

I'll be very happy to test on Linux (don't think I have the skill to create it just yet:)

Watching Christmas movies with the family right now but I'll file a bug with some hints later. :)

This is a nice Christmas present to the Node.js+Rust community. Thank you.

Or even better

line.split(' ').filter(|word| matches(word, search)).count()

I love the functional programming style embraced by Rust.

That's really, really slick.

Does anyone know what is the difference between using this neon vs using node-ffi[1]?


Neon is for creating native Node modules in rust, which are libraries that use the Node addon API [1].

node-ffi seems to be for adding a bridge between an existing non-Node module dynamic library and node, which at the very least seems to incur some non-negligible overhead; see the "Call Overhead" section of your link.

[1]: https://nodejs.org/api/addons.html

Since both node and Rust use libuv for parallelism. Is it possible to provide the node libuv pool to rust so that they share a single bound on parallel operations?

Also, can I use Neon for async callbacks?

Rusts std lib does not utilize any longer. It only used in in some pre 1.0 versions when green threads were still a thing.

This is really cool. I'd love to see a system whereby pure computation modules were also supported in the browser via web assembly.

Me too! :)

The possibilities of rustc (which has an LLVM backend) and Emscripten (which consumes LLVM IR) are really interesting.

Agreed! In fact it would also be useful in Node: you could build an almost-full-performance but portable version of a native module as a fallback for clients who don't have the requisite software to build a Neon library (say, one they only indirectly depend on) on their machine.

And, before you know it, we'll have realized the dream of Urbit, in JS ;)

Always bet on JS!

nice to have access to rust libs from node.

Would this allow Rust to be run on AWS Lambda?

I don't know the answer to how Neon would affect that, but AFAIK, you can already do this:


But that uses a shell command. There's also this way to do so using FFI (article is about C++, but I'm pretty sure you could do the same with Rust):


Many thanks for writing this.

Node + Rust ~= Go

Not even close. The expressiveness of rust alone far outclasses go in my opinion. Add in the node ecosystem and it's in a different ballpark altogether.

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