Question

Is there a way to tell a gen_server: “supervisor has initialised all gen_servers, now you can send then messages”?

I have a worker gen_server whose job is to set up states of other gen_servers in his supervision tree. If I just start sending messages in init function of my configuration server, sometimes it gets {noproc, _}. I suppose that means that config server was to fast: he sent messages before supervisor had enough time to start all workers. I fixed that by putting timer:sleep(500) in config_server:init(), which ensures all gen_server had enough time to initialise, but this seems like a inelegant solution.

Is there a proper way to do this?

Answer 1

Return tuple with timeout 0 from init. Then immediately after it returns, handle_info(timeout, State) will be called. In handle_info make some call which won’t return until the supervisor finishes initialization (e.g. supervisor:which_children).