start

#!/bin/bash
RSYNC_INTERVAL=${RSYNC_INTERVAL:-0}
RSYNC_VOL="${RSYNC_VOL:-/vol}"
RSYNC_PID_FILE="$RSYNC_VOL/.rsync.pid"
RSYNC_ARGV=$@
RSYNC_ARGC=$#

function do_rsync() {
  if [ $RSYNC_ARGC -gt 0 ]; then
    echo "Performing rsync $RSYNC_ARGV"
    rsync $RSYNC_ARGV
  else
    echo "Skipping rsync; no arguments passed"
  fi
}

function do_cleanup() {
  if [ -f $RSYNC_PID_FILE ]; then
    rm -f $RSYNC_PID_FILE;
  fi
}

function do_shutdown() {
 kill -SIGINT $RSYNC_PID
}

function do_main() {
  (
  do_cleanup
  while true; do
    echo "$$" > "$RSYNC_PID_FILE"
    if [ "$RSYNC_INTERVAL" == "on-exit" ]; then
      sleep infinity
    elif [ "$RSYNC_INTERVAL" == "infinity" ] || [ "$RSYNC_INTERVAL" -gt 0 ]; then
      do_rsync;
      sleep "$RSYNC_INTERVAL"
    else
      do_rsync;
      break
    fi
  done
  )&
  RSYNC_PID=$!
}


do_main

# trap interrupts, do final rsync and quit
trap "echo -e '\nInterrupted'; do_shutdown" SIGINT SIGTERM
wait

if [ "$RSYNC_INTERVAL" == "on-exit" ] || [ "$RSYNC_INTERVAL" == "infinity" ] || [ "$RSYNC_INTERVAL" -gt 0 ]; then
  # do one final rsync
  do_rsync
fi

# cleanup before we exit
do_cleanup