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.
- 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.
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're already using
serde
, consider usingserde_rustler
to easily encode and decode your data types into and from Elixir terms.
NOTE: If you have previously used Rustler, you need to run mix archive.uninstall rustler_installer.ez
to remove it before generating the NIF.
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", [add]);
Rustler uses erlang:system_info(nif_version)
to detect the supported NIF version of the Erlang/OTP
system for which the NIF is to be compiled. It is possible to restrict the NIF version to an older
version if the NIF is to be compiled for an older version of Erlang. For example, if the target NIF
version should be 2.7
(Erlang/OTP 17.3), this can be defined using an environment variable:
RUSTLER_NIF_VERSION=2.7 mix compile
You can find us in #rustler
on freenode or the elixir-lang slack.
Licensed under either of
- Apache License, Version 2.0, (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)
at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.