Can you provide a minimal example project which does show your problem? Only from your wording, I can roughly understand the problem you have, but without seeing what you are really doing, one can’t tell what you are doing wrong…

Hmmm… tried to do that, but my sample project seems to work:

[code]defmodule Test do

import Supervisor.Spec

def start do
# static children
children = [
worker(Worker, [0], restart: :permanent, id: :static1),
worker(Worker, [1], restart: :permanent, id: :static2),
worker(Worker, [2], restart: :permanent, id: :static3)
]

Supervisor.start_link(children, strategy: :one_for_one, name: Central.Supervisor)
    Supervisor.start_child(Central.Supervisor,
                           supervisor(Worker.Supervisor, [3], restart: :transient, id: :super))
    test

end

def test do
IO.puts “Central: #{inspect Supervisor.which_children(Central.Supervisor)}”
IO.puts “Worker: #{inspect Supervisor.which_children(Worker.Supervisor)}”

# Supervisor.terminate_child(Central.Supervisor, :super)
    Worker.Supervisor.stop
    IO.puts "Central: #{inspect Supervisor.which_children(Central.Supervisor)}"

end

end

defmodule Worker.Supervisor do

use Supervisor

def start_link(id) do
Supervisor.start_link(MODULE, [id], name: Worker.Supervisor)
end

def init([id]) do
children = [
worker(Worker, [id], restart: :transient, id: 0),
worker(Worker, [id+1], restart: :transient, id: 1),
worker(Worker, [id+2], restart: :transient, id: 2)
]

supervise(children, strategy: :one_for_all)

end

def stop do
Supervisor.stop(Worker.Supervisor)
end

end

defmodule Worker do

use GenServer

def start_link id do
GenServer.start_link(MODULE, [], name: {:global, {:worker, id}})
end

end[/code]

Now I have SASL reports for my app and the following transpires:

2016-04-3011:59:51.496[ERR/connector.ex:43] Received error when listening on TCP port, reason was :closed 2016-04-3011:59:51.496[ERR/SASL] GenServer {:connector, 1} terminating | ** (stop) :error 2016-04-3011:59:51.498[ERR/SASL] Process #PID<0.235.0> terminating ** (exit) :error (stdlib) gen_server.erl:826: :gen_server.terminate/7 (stdlib) proc_lib.erl:240: :proc_lib.init_p_do_apply/3 Initial Call: Connector.init/1 Ancestors: [#PID<0.233.0>, MyMod.Supervisor, #PID<0.181.0>] 2016-04-3011:59:51.498[ERR/SASL] Child {:connection, 1} of Supervisor {:supervisor, 1} shutdown abnormally | ** (exit) :error | Pid: #PID<0.235.0> | Start Call: Connector.start_link(1, #Port<0.7095>) 2016-04-3011:59:51.498[INF/SASL] Application myapp exited: normal

In my application startup I create a TCP listener port:

{ :ok, listenSocket } = :gen_tcp.listen(readUeTcpPort(), [:binary, active: true, packet: :raw, reuseaddr: true])

I then give the listenSocket to each worker child I start:

def addWorker(workerId, listenSocket) do Supervisor.start_child(MyMod.Supervisor, supervisor(Worker.Supervisor, [workerId, listenSocket], restart: :transient, id: {:worker, workerId}, shutdown: :infinity)) end

These workers run their init/1 and send themselves a GenServer.call that makes them wait on :gen_tcp.accept. The first worker is dynamically created during the run of my application’s start/2.

Whenever a new client is accepted, the worker immediately calls MyMod.addWorker to start the next process waiting on the listen port.

Now, when I stop the supervisor of the first group of workers, something odd happens. The 2nd worker suddenly drops out of its :gen_tcp.accept call it is sleeping on with an error. Apparently the listenSocket is somehow closed. And somehow this leads to my whole application to quietly shut down with exit :normal.

Any ideas?

Hello, José.

After rearranging everything under another supervisor I played around with :gen_tcp.controlling_process, and after reading its docs another time and also checking its return value I managed to properly transfer control to the children and also not have this weird exit behavior anymore.

Thank you.

I have a similar problem.

I have a top level dynamic supervisor, say, TopDynSup, whose children are in turn supervisors. The sub supervisors each supervises a fixed number of temporary workers (they should never be restarted even if they died abnormally).

My problem is, I want to let the sub supervisor terminates normally when all of its children terminates. As I played around Supervisor in iex, I saw that a supervisor never ends even when there is no child. How can I make it die?