We are in the process of re-organizing our applications supervision tree to make it more robustly handle failures and re-starts. However, we have a scenario where we have one parent supervisor that starts four child supervisors. The problem we have is that the first child supervisor starts several children gen_servers that must be started and initialized prior to the second child supervisor starting or it will fail.
So, I need a startup like the following:
test_app.erl -> super_supervisor -> [config_supervisor, auth_supervisor, rest_supervisor]
The trick I'm having trouble with is that config_supervisor must complete all initialization prior to auth_supervisor or rest_supervisor being started. With the rest_for_one startup strategy I get, essentially, this behavior but only by allowing auth_supervisor to fail because the needed config is not there. I would prefer to just request that config_supervisor is completed with it's initialization (which includes starting several gen_servers) prior to moving-on to auth_supervisor.
This seems like a common scenario that would have been conquered previously but, I am having a hard time "googling" a solution. Does anybody have advice or sample code that might exist to handle this scenario?