Rustler

Documentation | Getting Started | Example

Rustler is a library for writing Erlang NIFs in safe Rust code. That means there should be no ways to crash the BEAM (Erlang VM). The library provides facilities for generating the boilerplate for interacting with the BEAM, handles encoding and decoding of Erlang terms, and catches rust panics before they unwind into C.

The library provides functionality for both Erlang and Elixir, however Elixir is favored as of now.

Features

Safety

The code you write in a Rust NIF should never be able to crash the BEAM.

Interop

Decoding and encoding rust values into Erlang terms is as easy as a function

call.

Type composition

Making a Rust struct encodable and decodable to Erlang or Elixir can be done

with a single attribute.

Resource objects

Enables you to safely pass a reference to a Rust struct into Erlang code. The

struct will be automatically dropped when it’s no longer referenced.

Getting started

The easiest way of getting started is the rustler Elixir library.

• Add the rustler Elixir library as a dependency of your project.
• Run mix rustler.new to generate a new NIF in your project. Follow the instructions.
• If you are already using serde and/or have been using serde_rustler before, please enable the serde feature in your NIF crate’s Cargo.toml on the rustler dependency.

What it looks like

This is the code for a minimal NIF that adds two numbers and returns the result.

#[rustler::nif]
fn add(a: i64, b: i64) -> i64 {
    a + b
}

rustler::init!("Elixir.Math");

Community

You can find us in the #rustler:matrix.org channel on Matrix or in the #rustler channel in the Elixir lang Slack.