Integrating Mutable Data in Elixir Projects with Rust and Rustler

The article begins by highlighting Elixir's immutable data foundation and the challenges it poses when mutable state is needed within a project. The author opts to not create a separate microservice but to find a way to manage mutable data within the same virtual machine as the rest of the service. They present Rustler, a library for creating Erlang NIFs with Rust, as a solution. The author provides a detailed step-by-step guide on integrating Rustler and managing mutable data in Rust, which can be interacted with from Elixir. This includes creating a new type to handle the state of the data store, passing resources between Elixir and Rust, and functions to manipulate and retrieve the data. The example used is wrapping Oxigraph, a Rust graph database library, to enable graph database functionality from Elixir. The article demonstrates storing data outside of the BEAM memory model and efficiently interacting with this data from Elixir. The author concludes by emphasizing the possibilities Rustler brings to the Elixir ecosystem, allowing developers to opt out of the BEAM memory model for specific parts of the code, hence leveraging the strengths of both Elixir and Rust.