Malachite

A RubyGem which enables calling Go code from Rails. Probably not production ready.

Installation

Install Go 1.5 or later on relevant machines.

Add this to your Gemfile:

gem 'malachite'

Make a subdirectory of "app" called "go".

Write Some Go Functions

Everything in app/gowill get compiled into one library, so to get it to work with Malachite, you need to:

• name the methods you want exported like: HandleFoo
• the Handle methods can only take one JSON-serializable argument, works best with arrays or structs

For instance, if you wanted to upcase strings, you'd put the following in app/go/upcase.go:

package main

import (
    "strings"
)

func HandleUpcase(things []string) (upperCased []string) {
    for _, thing := range things {
        upperCased = append(upperCased, strings.ToUpper(thing))
    }
    return
}

Then use your function from Rails:

Malachite.upcase(["foo","bar"])
=> ["FOO", "BAR"]

More examples can be found in examples.

Note: This would actually be slower than doing it in Ruby, due to the JSON serialization.

Testing

Check out the wiki on Testing

How Does it Work?

One part code generation, another part pure evil.

• The first time the function is called, Malachite will build a shared library from all the Go code in your app/go folder
• It then uses Ruby's Fiddle to call the shared library
• Arguments are passed back and forth via JSON

Because of the JSON step, you'll only see real performance gains on computationally difficult tasks. Ruby's JSON conversion is a large tax.

Ruby 2.2.4+

It's strongly recommended to use the newest release of Ruby as there was a security issue with older versions of Fiddle.