container_startup_script.sh

#!/bin/sh

# Close container on SIGTERM
# It's a bit hacky but here is the thing
onSIGTERM(){
	# Now pass SIGTERM to application
	kill -15 $applicationPid
	# And wait for it to gracefully close
	wait $applicationPid
	# Now we can close this script and also the running container since this script would be run with PID 1
	exit 0
}

trap "onSIGTERM" 15

# Waiting on some host
WAIT_HOST=localhost
WAIT_PORT=8080
while ! nc --send-only --recv-only $WAIT_HOST $WAIT_PORT  >> /dev/null 2>&1; do
  sleep 1
done

# Starting application
./appplication &
applicationPid=$!

# We cannot close this script because this would stop the container
wait $applicationPid