What happens if you supervise a supervisor as a worker?

blatyo · October 15, 2018, 3:11pm

In this section of the docs, it mentions that you can specify a type in the child spec for either worker or supervisor. As the question in the title implies, what would be the consequences of picking the wrong one?

easco · October 15, 2018, 4:23pm

Looking at the Erlang code:

github.com

erlang/otp/blob/master/lib/stdlib/src/supervisor.erl

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-module(supervisor).

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It appears that the process type is used to define the default “Shutdown Value” if none is given (see “Shutdown Values” in https://hexdocs.pm/elixir/Supervisor.html)

It also appears that the type is used when you call Supervior.count_children which tells you how many of which type of child a supervisor has.

The type is also returned by Supervisor.which_children

rvirding · October 15, 2018, 5:54pm

It also affects code upgrading.