GenStateMachine

An idiomatic Elixir wrapper for gen_statem in OTP 19 (and above).

Full documentation is available here.

You can find the package on Hex here.

One important difference between gen_statem and this wrapper is that you declare your callback mode as part of use GenStateMachine in this wrapper, rather than returning it from callback_mode/0 on OTP 19.1 and up, or your init/1 and code_change/4 on versions of OTP prior to 19.1. In versions of OTP prior to 19.1, you can still, however, switch callback modes in code_change/4 by returning a callback mode.

Other than that (and the usual automatically-defined default callbacks as a result of use-ing GenStateMachine), this wrapper does not make any functional alterations.

This wrapper also provides a OTP error translator for Logger, which is automatically added when the :gen_state_machine application is started. Optionally, you may add :gen_state_machine to :included_applications rather than :applications as indicated below if you do not want the translator to be added to Logger.

Installation

1. Add gen_state_machine to your list of dependencies in mix.exs:

def deps do
  [{:gen_state_machine, "~> 2.0"}]
end

2. Ensure gen_state_machine is added to your applications:

def application do
  [applications: [:gen_state_machine]]
end

Special Thanks

I would like to give special thanks to @fishcakez and @michalmuskala, who both provided invaluable feedback on this library!