Dais-Neon

Dais interceptor chain in Rust+Node.js with ClojureScript support.

There is also C++ support via node-gyp and Native Abstractions for Node.js.

The Dais Interceptor Chain is a simple, synchronous-only interceptor chain, inspired by Pedestal. Dais was first written in Java and designed to be used in Java and Clojure.

Getting Started

You can compile the Rust, C++, and ClojureScript with npm install.

From there you can enter Node.js REPL with node:

$ node
> const dais = require('.')
> dais.hello()
'hello node - from JavaScript'
> dais.hellorust()
'hello node - from Rust'
> dais.hellocljs()
'hello node - from ClojureScript'
> dais.hellocpp()
'hello node - from C++'

And you can also use the ClojureScript/Lumo REPL (without access to index.js)

$ make cljs-repl
cljs.user=> (require '[daisneon.bridge :as bridge])
nil
cljs.user=> (.hello bridge/rust)
"hello node - from Rust"
cljs.user=> (.Hello bridge/cpp)
"hello node - from C++"

Hacking

• This project uses npm for build tasks. For convenience, these are plumbed into a Makefile
• The ClojureScript REPL has socketrepl support, all via Lumo
• You may want to modify target/main.js and add goog.require("daisneon.example"); if you're working at the node shell via index.js
• You can directly require JS files from the CLJS REPL eg: (require '[dais :as dais]) for JavaScript Dais chain

Basic benchmarks

This project is mostly about exploring the integration possibilities and understanding runtime overhead. The native code never migrates to typed arrays, it only does interop and works directly in the v8 types.

"The machine code that V8 emits for your JS code can specialize and take shortcuts but every element Get/Set call in your [native] code goes through a lot of layers to implement the proper JS semantics." see issue

To see the general numbers, modify target/main.js and add goog.require("daisneon.example"); Then you can examine chain executions:

$ node
> const dais = require('.')
> dais.testChains()

• rust: 0.073ms
  • Static processing only (no dynamic chains, and no error handling)
• cpp: 0.042ms
  • Static processing only (no dynamic chains, and no error handling)
• js: 0.051ms
• cljs-static: 0.287ms
• cljs: 0.346ms
• cljs-js-interop: 1.737ms
  • Involves converting JS objects to maps and then back to objects at the end

For reference, the Java Dais chain runs between 0.02ms - 0.20ms. The Pedestal Chain runs between 1-3ms. The Pedestal chain includes logging, runtime metrics, is thread-safe, and has full async capabilities (ie: it includes extra signaling and thread-pool migration)

TODO

• Consider adding Nan::TryCatch and tc.HasCaught() to the C++ code