citadel-core/karen

#!/usr/bin/env bash

# SPDX-FileCopyrightText: 2020 Umbrel. https://getumbrel.com
# SPDX-FileCopyrightText: 2021 Citadel and contributors.
# 
# SPDX-License-Identifier: AGPL-3.0-or-later

# karen watches for signals and executes triggers in the events dir
# karen gets triggered a lot

check_root () {
  if [[ $UID != 0 ]]; then
    echo "Error: This script must be run as root."
    echo "Can I speak to a manager please?"
    exit 1
  fi
}

check_if_not_already_running() {
  if ps ax | grep $0 | grep -v $$ | grep bash | grep -v grep
  then
    echo "karen is already running"
    exit 1
  fi
}

check_dependencies () {
  for cmd in "$@"; do
    if ! command -v $cmd >/dev/null 2>&1; then
      echo "This script requires \"${cmd}\" to be installed"
      exit 1
    fi
  done
}

check_root

check_if_not_already_running

check_dependencies fswatch readlink dirname

if [[ -n "$1" ]]; then
  root_dir="$(readlink -f $1)"
else
  root_dir="$(dirname $(readlink -f ${BASH_SOURCE[0]}))/events"
fi
signal_dir="$root_dir/signals"
trigger_dir="$root_dir/triggers"

if [[ ! -d "$root_dir" ]]; then
  echo "Root dir does not exist '$root_dir'"
  exit 1
fi

echo "karen will start in 30 seconds"
sleep 30
echo "karen is running in $root_dir"
fswatch -0 --event=AttributeModified $signal_dir | while read -d "" event; do
  signal="${event#"$signal_dir"}"
  signal="${signal#"/"}"
  trigger="$trigger_dir/$signal"
  args=""

  echo "Got signal: $signal"

  # If the signal starts wih app-, the trigger is "$trigger_dir/app"
  # and the args are the rest of the signal
  if [[ "$signal" =~ ^app- ]]; then
    trigger="$trigger_dir/app"
    args="${signal#"app-"}"
  fi
  if test -x "$trigger"; then
    echo "karen is getting triggered!"
    if [[ ! -f "statuses/update-in-progress" ]]; then
      "$trigger" $args &
    fi
  else
    echo "No trigger found"
  fi
done