Designing Elixir Systems With OTP

Start Per-User Processes with a Dynamic Supervisor

Now we need to start a process per user. Since we don’t have a fixed number of processes to start, and since we’ll also need to be able to look them up based on a user’s attributes, we will need a structure that is a little more sophisticated. We will use a dynamic supervisor.

Most supervisors create processes when an application starts or restarts. That’s normally what you want, but not always. A dynamic supervisor is a supervisor that starts children dynamically. Since we have no way of knowing who will take quizzes and when, that sounds like exactly what we need. To use a dynamic supervisor, you need many of the same pieces of information:

• You must provide a child spec, the description for ...