rclonesync-daemon

#!/bin/bash
set -euo pipefail

initfile_name="rclonesync-init.txt"

watch=0
watch_interval=-1
watch_timeout=30
cmd=""
remote=""
syncpoint=""
firstsync=""
user="$(whoami)"
group=""
umask=""
apply_chown=0
apply_chmod=0

timeout=0

sync() {
  [[ -z "$syncpoint" ]] && {
    echo "$0: fatal: no syncpoint specified" >&2
    return 1
  }

  [[ -z "$remote" ]] && {
    echo "$0: fatal: no remote specified" >&2
    return 1
  }

  [[ ! -e "$syncpoint" ]] && mkdir -p "$syncpoint"
  [[ ! -d "$syncpoint" ]] && {
    echo "$0: fatal: not a directory: $syncpoint" >&2
    return 1
  }

  echo "$0: sync '$remote' to '$syncpoint'" >&2
  rccmd="rclonesync -v"
  rccmd+=" --rclone rclonesync-rclone"
  rccmd+=" $firstsync"
  rccmd+=" $remote $syncpoint"

  [[ -n "$firstsync" ]] && {
    firstsync=""
    find "$syncpoint" -mindepth 1 -name '*' | [[ $(wc -l) -eq 0 ]] && {
      echo "touch $syncpoint/$initfile_name" >&2
      echo "This file was created as a placeholder when initializing rclonesync. You may delete it safely." >> "$syncpoint/$initfile_name"
    }
  }

  echo "running $rccmd" >&2
  eval "$rccmd"

  [[ -e "$syncpoint/$initfile_name" ]] && {
    find "$syncpoint" -mindepth 1 -name '*' | [[ $(wc -l) -gt 1 ]] && {
      rm --preserve-root -v "$syncpoint/$initfile_name"
    }
  }

  [[ $apply_chown -eq 1 ]] && {
    local co="chown --preserve-root -chvR $user:$group $syncpoint"
    echo "applying ownership: $co"
    eval "$co"
  }
  [[ $apply_chmod -eq 1 ]] && {
    local cm="chmod --preserve-root -cvR $umask $syncpoint"
    echo "applying umask: $cm"
    eval "$cm"
  }

  return 0
}

main() {
  local OPTIND OPTARG
  while getopts "1wr:s:t:i:u:g:M:" opt; do
    case $opt in
    1)
      firstsync="--first-sync"
      ;;
    w)
      watch=1
      ;;
    r)
      remote="$OPTARG"
      ;;
    s)
      syncpoint="$OPTARG"
      ;;
    t)
      watch_timeout="$OPTARG"
      ;;
    i)
      watch_interval="$OPTARG"
      ;;
    u)
      apply_chown=1
      user="$OPTARG"
      ;;
    g)
      apply_chown=1
      group="$OPTARG"
      ;;
    M)
      apply_chmod=1
      umask="--umask $OPTARG"
      ;;
    \?)
      echo "$0: fatal: unknown option $OPTARG" >&2
      return 1
      ;;
    esac
  done
  shift $((OPTIND - 1))

  cmd="${1:-sync}"

  group="${group:-$(id -gn "$user")}"

  [[ $watch -eq 1 ]] && {
    watch
    return $?
  }
  run_cmd
}

watch_handle_event() {
  read -r evt
  echo "handle event: $evt" >&2
  t=$((timeout - $(date +%s)))
  [[ $timeout -ne 0 && $t -gt 0 ]] && {
    echo "timed out for $t seconds - sleeping..." >&2
    sleep $t
  }
  run_cmd
  timeout=$(($(date +%s) + watch_timeout))
}

watch() {
  watch_handle_event <<< "INIT"
  echo "watching $syncpoint..." >&2
  local e=""
  while true; do
    e="$(inotifywait -qrt "$watch_interval" -e modify,attrib,move,create,delete "$syncpoint")" || {
      e="INTERVAL"
    }
    watch_handle_event <<< "$e"
  done
}

run_cmd() {
  case $cmd in
  sync)
    sync
    ;;
  \?)
    echo "$0: fatal: unknown command '$cmd'" >&2
    return 1
    ;;
  esac
}

main "$@"

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