How to use a closed-source Erlang library in an Elixir project?

4
votes

I have a closed-source Erlang library I want to use in my Elixir project. The library has the following directory structure:

  • ebin
    • Contains 1 .app and various .beam files
  • priv
    • Contains shared object files for the part of this library that has been implemented in C

What's the recommended way to use this library from my Elixir project?

1
elixir

1 Answers

4
votes

There is probably more than one way to accomplish having a closed source OTP dependency, but here is one suggested method that should work.

Here is an example closed dependency in a git repository (only the rebar.config and ebin folder are present): https://github.com/potatosalad/erlang-closed-example/tree/closed (the source for the project is on the master branch).

If you were to host the closed sources files from ebin and priv and add a rebar.config file to your own git repository, the following should work the same. Also, make sure your git repository is hosted somewhere private (unless the license for the project says otherwise).

You should be able to add the closed source repository as a dependency to your mix.exs file:

defmodule Example.Mixfile do
  use Mix.Project

  def project do
    [app: :example,
     version: "0.0.1",
     elixir: "~> 1.1",
     build_embedded: Mix.env == :prod,
     start_permanent: Mix.env == :prod,
     deps: deps]
  end

  def application do
    [applications: [:logger, :closed]]
  end

  defp deps do
    [{:closed, git: "https://github.com/potatosalad/erlang-closed-example.git", branch: "closed"}]
  end
end

A full example project is available here: https://github.com/potatosalad/mix-closed-example

After running mix deps.get, I can do the following in a iex -S mix shell:

iex> :closed.secret()
"this is a closed source library"

The shared object files under priv should also work, but will be dependent on the OS and available library versions.