Functional Web Development with Elixir, OTP, and Phoenix

A Supervisor for the Game

Now that we have the Game module’s child specification showing the values we want, we’re ready to create a custom supervisor. We’ll explore two ways to do this. One is as simple as starting a supervisor process with the right options. The other involves creating a new module that contains the callbacks we’ll need as well as some helper functions we’ll want.

Each game in Islands is a separate GenServer process. These processes will come and go as players start new games and then end them. We’ll need a supervisor specifically to monitor games, and the :simple_one_for_one strategy is perfect for processes that we need to start and stop at runtime.

Most of the work of creating a custom supervisor comes in starting a new ...