Catching exit signals in Elixir escript - erlang

Question

I'd like to write an escript that reloads its configuration when it receives a HUP signal. I'm on OS X and searching for any new processes in Activity Monitor when I start the escript. When I do, these pop up: inet_gethost (twice), erl_child_setup, and beam.swp. When I send a SIGHUP to erl_child_setup, it crashes with the message of "erl_child_setup closed". When I send it to beam.swp I get a message of "Hangup: 1", but my trapping code is not called.
Here's some example code that illustrates what I am trying to do:
defmodule TrapHup do
def main(args) do
Process.flag(:trap_exit, true)
main_loop()
end
def main_loop() do
receive do
{ :EXIT, _from, reason } ->
IO.puts "Caught exit!"
IO.inspect reason
main_loop()
end
end
end

Answer 1

I found out this is not possible with just Elixir/Erlang. Apparently it is possible through bash as illustrated in this gist: https://gist.github.com/Djo/bfa9fa75928ce432ec51
Here's the code:
#!/usr/bin/env bash
set -x
term_handler() {
echo "Stopping the server process with PID $PID"
erl -noshell -name "term#127.0.0.1" -eval "rpc:call('app#127.0.0.1', init, stop, [])" -s init stop
echo "Stopped"
}
trap 'term_handler' TERM INT
elixir --name app#127.0.0.1 -S mix run --no-halt &
PID=$!
echo "Started the server process with PID $PID"
wait $PID
# remove the trap if the first signal received or 'mix run' stopped for some reason
trap - TERM INT
# return the exit status of the 'mix run'
wait $PID
EXIT_STATUS=$?
exit $EXIT_STATUS