Termux service management script, because convenience, and also because I wanna have fewer runit watchers running all the time

service

#!/bin/sh

# This script 100% requires termux-services to be installed
if ! dpkg -L termux-services 2>&1 >/dev/null; then
  echo "Requires termux-services package to be installed." >&2
  read -r -p "Would you like me to install that now? (y/n) " INSTALL >&2

  if [ "$INSTALL" != "y" ]; then
    echo "Aborting..." >&2
    exit 1
  fi

  apt update && apt install termux-services

  if [ $? -eq "0" ]; then
    echo 'Failed to install package! Quitting.' >&2
    exit 1
  fi
fi

if [ -z "$SVDIR" ]; then
  echo 'Warning! $SVDIR not set! Assuming default termux location.' >&2
  export SVDIR="$PREFIX/var/service"
fi

# Where the real service folders will live
SVREPO="$SVDIR/../services-available"

# To verify and start the services daemon if it isn't already.
# That way we don't need to rely on an existing terminal session
# existing to run the services we want
ensure_sv_started() {
  if ! ps aux | grep -v grep | grep runsvdir 2>&1 >/dev/null; then
    export LOGDIR="$PREFIX/var/log"
    (service-daemon start >/dev/null 2>&1 & )
  fi
}

# Checks if the service dir, "$1" exists
dir_exists(){
  [ -d "$SVREPO/$1" -o -d "$SVDIR/$1" ]
  return $?
}

# Checks if the service passed in:
# 1) Exists
# 2) Is valid
# It also outright exits the script with a status of 1 if either are untrue
check_service(){
  if [ -z "$1" ]; then
    echo Needs service name too >&2
    exit 1
  elif ! dir_exists "$1"; then
    echo Service not found: "$1" >&2
    exit 1
  fi

  return 0
}

# Checks if a service is enabled in the "has a folder in the service
# directory" sense
service_enabled(){
  [ -d "$SVDIR/$1" ]
  return $?
}

# Lists all available services, all enabled services, and the status
# of all the enabled services out to stdout
services_overview(){
  echo "Available services:"
  ls "$SVREPO"
  echo
  echo "Enabled services:"
  ls "$SVDIR"
  echo
  echo "Details:"

  for service in `ls "$SVDIR"`; do
    sv status "$service"
  done
}

# Uninstaller option has priority over everything else
if [ "$1" = "uninstall" -a -z "$2" ]; then
  if dir_exists "uninstall"; then
    cat <<-EOF
	Note: "uninstall" is a service. If you are attempting to get the status
	of that, please run "$0 status uninstall" instead.

	EOF
  fi

  cat <<-EOF
	This will attempt to remove the changes made by this script that allow
	it to manage your services so you can go back to how it was before
	using it.

	In order to do this, it will run the following commands:

	  rm -f "$SVDIR"/*
	  mv "$SVREPO"/* "$SVDIR"/
	  rmdir "$SVREPO"

	EOF

  read -r -p "Allow? (y/n) " ALLOWED

  if [ "$ALLOWED" = "y" ]; then
    echo "rm -f \"$SVDIR\"/*"
    rm -f "$SVDIR"/* && echo 'Succeeded!' || echo 'Failed...'
    echo "mv \"$SVREPO\"/* \"$SVDIR\"/"
    mv "$SVREPO"/* "$SVDIR"/ && echo 'Succeeded!' || echo 'Failed...'
    echo "rmdir \"$SVREPO\""
    rmdir "$SVREPO" && echo 'Succeeded!' || echo 'Failed...'

    cat <<-EOF

	Uninstall complete!

	If anything above failed, your service files should all still be in one
	of the following places:
	- $SVREPO
	- $SVDIR

	To complete the uninstall, you want to:
	1) Move all of the folders into	$SVDIR
	2) Remove the $SVREPO folder once it's empty

	If all is well though? Good luck! And seeya 'round!
	EOF

    exit 0
  else
    echo "Exiting..."
    exit 1
  fi
fi

# If we have this, we are definintely being called wrong, act like we
# have no parameters whatsoever to show usage, summary, and quit
if [ -n "$3" ]; then
  $0
fi

# No service repo? Run initial setup
if [ ! -d "$SVREPO" ]; then
  cat <<-EOF
	Services are not currently managed by this script.

	To do this, it needs to make another folder where it can move your
	existing services, this will allow this script to manage them using
	symlinks. (Which is important because it will let us disable and enable
	your services instead of always having runit processes watching their
	folders)

	To do this, this script will run these commands:

	  mkdir -p "$SVREPO"
	  mv "$SVDIR"/* "$SVREPO"
	  ln -s "$SVREPO"/* "$SVDIR"

	EOF

  read -r -p "Allow? (y/n) " ALLOWED

  if [ "$ALLOWED" = "y" ]; then
    echo "mkdir -p \"$SVREPO\""
    mkdir -p "$SVREPO" && echo 'Succeeded!' || echo 'Failed...'
    echo "mv \"$SVDIR\"/* \"$SVREPO\""
    mv "$SVDIR"/* "$SVREPO" && echo 'Succeeded!' || echo 'Failed...'
    echo "ln -s \"$SVREPO\"/* \"$SVDIR\""
    ln -s "$SVREPO"/* "$SVDIR" && echo 'Succeeded!' || echo 'Failed...'

    cat <<-EOF

	Initialization steps performed, try running me again!

	If anything failed, or you wish to go back to how the services used to
	be managed, you can run "$0 uninstall" to attempt to revert the above.
	EOF
  else
    echo "Exiting..."
    exit 1
  fi
fi

case "$1" in
  start)
    check_service "$2" && sv up "$2" && ensure_sv_started
    ;;

  stop)
    check_service "$2" && sv down "$2"
    ;;

  restart)
    check_service "$2" && sv down "$2" && sv up "$2" && ensure_sv_started
    ;;

  status)
    if [ -n "$2" ]; then
      if service_enabled "$2"; then
	sv status "$2"
	exit $?
      elif dir_exists "$2"; then
	echo "Status: disabled"
	exit 1
      else
        echo "Invalid service: $2"
        exit 1
      fi
    fi

    services_overview
    ;;

  enable)
    if check_service "$2"; then
      echo "Enabling $2!"
      ln -s "$SVREPO/$2" "$SVDIR/"
      rm -f "$SVDIR/$2/down" 2>/dev/null
      sv up "$2"
      ensure_sv_started
    fi
    ;;

  disable)
    if check_service "$2"; then
      echo "Disabling $2!"
      touch "$SVDIR/$2/down"
      sv down "$2"
      rm "$SVDIR/$2"
    fi
    ;;

  edit)
    check_service "$2" && editor "$SVREPO/$2/run"
    ;;

  list)
    # In case there is a "list" service to manage
    if [ -n "$2" ]; then
      $0 "$2" "$1" "$3"
      return $?
    fi

    ls "$SVREPO"
    ;;

  *)
    if [ -n "$1" ]; then
      # Is the first argument a service name?
      if dir_exists "$1"; then
        # Likely called in the form $0 <service> <command>, swap operands
        if [ -n "$2" ]; then
	  $0 "$2" "$1"
        else # Just a service name, get the status of the service and exit
	  $0 status "$1"
        fi

        exit $?
      else
        echo "Unrecognized option: $1" >&2
      fi
    fi

    # No operands will still give us a summary, because that's pleasant!
    echo "Usage: $0 <service> {start|stop|restart|enable|disable|status|edit}"
    echo "or $0 {start|stop|restart|enable|disable|status|edit} <service>"
    echo "or $0 {status|list|uninstall}"
    echo
    $0 status

    exit 1
esac

exit $?