#! /bin/bash
#
# Manage backup file aging
# received from a remote server by scp

# Full documentation on www.fridu.org -> documentation section (wiki) 

# Author Dominique Le Foll  dominig@fridu.co.uk
# License GNU
# July 2006
# V 1.0
#

#-------------------------------------------------------------------------
#
# Constant and Variables
#
#-------------------------------------------------------------------------
# Site name as printed on reports
readonly SITENAME="www.fridu.org www.agnescreations.co.uk"
# space separated list of receiver of mail report
readonly REPORT_TO="backupadmin@mydomain.eu"
# Number of day to keep archived data
readonly DAYS_ARCHIVED="15"
# path to the backup history to maintain
readonly TAR_PATH="/export/my-large-disk/www.backup"
# Tag for syslog
# NOTE this tag must be present in the archive file name to clean as it is used in the find command later
readonly LOGGER_TAG="Bakup"

# commands Path inclusion is advised to overcome issue with $PATH in cron job
readonly LOGGER="/usr/bin/logger"
readonly MAIL="/usr/bin/mail"
readonly FIND="/usr/bin/find"
readonly RM="/bin/rm"

#---------------------------------------------------------------------
#
# You should NOT have to change anything beyond this point
#
# except if you really know what you do don't change the code
# Validating and debugging complex script is tougher than it seems
#
#---------------------------------------------------------------------

declare PidValue=""
declare FileListToClean=""
declare NumFileToClean=""
#-----------------------------------------------------------------------
#
# Functions
#
#-----------------------------------------------------------------------

# Sanity check

function checkExec() {
  if ! [ -x $1 ]; then
        echo >&2 $0 Error $1 is not a valid check exec path in $0.
        # try to log even if logger may not be available or in the PATH
        logger -p 0 -i $PidValue -t $LOGGER_TAG "$SITENAME backup failled $0 Error $1 is not a valid check exec path in $0"
        exit 5
  fi
}

function checkDir() {
  if ! [ -d $1 ]; then
        echo >&2 $0 Error $1 is not a valid directory check path in $0.
        # log
        logger -p 0 -i $PidValue -t $LOGGER_TAG "$SITENAME backup failled $0 Error $1 is not a valid directory check path in $0"
        exit 5
  fi
}

function sanityCheck() {
  for Exec in "$LOGGER $MAIL  $FIND $RM"
    do
      checkExec $Exec
    done
  for Dirs in "$TAR_PATH"
    do
    for Dir in $Dirs
      do
        checkDir $Dir
      done
    done
}

# Syslog 
function log() {
  $LOGGER -i $PidValue -t $LOGGER_TAG $*
}

# stderr + syslog
function warn() {
  log "-s $*"
}

# clean old backups and logs
function cleanOldBackup() {
  local FileToClean="$TAR_PATH/fileToClean.lst"
  # ATTENTION smart quoting rules required to path all special characters (check bash reference guide)
  # direct user of -exec is problematic because of patern {}
  $FIND $TAR_PATH -atime +$DAYS_ARCHIVED -name \*$LOGGER_TAG\*  > $FileToClean
  NumFileToClean=`wc --lines < $FileToClean`
  if [ $NumFileToClean != "0" ]; then
    FileListToClean=`cat $FileToClean`
    for File in $FileListToClean
      do
         $RM $File
         if [ $? != 0 ]; then
            warn "Error deleting $File"
            break
         fi
      done
  fi
}

#-----------------------------------------------------------------------------
#
# Entry point
#
#-----------------------------------------------------------------------------

PidValue=`pidof $0`

# Sanity check
sanityCheck

# Clean up log and old tar
cleanOldBackup
if [ $? != 0 ]; then
  warn "$SITENAME backup major error : $* mail sent to $REPORT_TO"
  $MAIL -s "$*" $REPORT_TO << END_OF_MAIL_BODY
    Check $REMOTE_DIR files backup received from $SITENAME did not cleaned out
    File list to clean is :  
    $FileListToClean
END_OF_MAIL_BODY
  exit 1
fi

# exit clean
log "$SITENAME file backup clean out done $NumFileToClean file(s) deleted"
exit 0