Handling of UNIX-signals in Erlang/Elixir is not supported, this script provides start-stop management with handling TERM signal for Docker installation.

run.sh

#!/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

if you are using docker-compose make sure to use the entrypoint config variable and not command. command runs the file under /bin/sh -c and doesn't pass through signals.

Is this for Erlang or Elixir? I see both above. Do you have a trimmed down one for Erlang?

Nice! FWIW, OTP 19.3 in Oct 2018 added handling of SIGTERM:

A received SIGTERM signal to beam will generate a 'stop' message to the init process and terminate the Erlang VM nicely. This is equivalent to calling init:stop/0
https://www.erlang.org/downloads/19.3