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erlangelixirerlang-otperlang-supervisor

In Elixir, are dependent applications supervised?

So far, I know that when I start my Elixir application, a bunch of dependent applications also get started.

Are these dependent applications started inside my app supervision tree somehow?

What happens if a dependent application crashes? Is it restarted?

Solution

  • I guess that Elixir works like Erlang for application.

    • In Erlang each application have an independent supervision tree
    • If an application crashes, this means that the topmost supervisor did crash, and that all the restart strategy failed. There is few chance that simply adding a new layer of supervision will solve the problem.
    • it is possible to start all the dependencies using application:ensure_all_started(Application[,StartType]), StartType can be either
      • temporary : (default value): nothing occurs if a temporary application stops for any reason
      • permanent : all other applications terminate if a permanent application stops for any reason
      • transient : all other applications terminate is a transient application stops for any reason but normal
    • it is also possible to call application:ensure_started(Application[,StartType]) for each dependencies. Note that in both cases, the StartType only controls the effect of one application termination on the others, but there is no restart strategy applied.
    • it is possible to know which applications are running using application:which_applications()