super fabulous backup script

backup.sh

#!/usr/bin/env bash

if [ "${BS_DEBUG}" == "YES" ] ; then
    set -x
fi

# this is a configurable backup script that should run on a cron job.

# declares the arrays we'll be using, don't change these

declare -a backup_folders
declare -a backup_folder_sizes

# configuration

backup_device="/dev/ad8s1d"
backup_device_mountpath="/var/backups" # NO TRAILING SLASH
backup_target_folder="/jenova/"
backup_folders=( "/etc" "/usr/home" "/usr/local/etc" "/var/www" )
backup_folder_sizes=( )
backup_name="`date +%Y-%m-%d`_`hostname | tr . ' ' | awk '{print $1}'`_backup.tar"
backup_logdir="/tmp" # NO TRAILING SLASH
backup_logfile_name="`date +%Y-%m-%d`_`hostname | tr . ' ' | awk '{print $1}'`_backup.log"

# optional config options

tar_path="`which tar`" # default: `which tar`

# bash colors

_green='\033[1;32m'
_yellow='\033[1;33m'
_red='\033[0;31m'
_white='\033[0m'

# path to backup file

backup_file="${backup_device_mountpath}${backup_target_folder}${backup_name}"

# post-op function values

post_umount="NO"

# traps

trap displayBackupSize EXIT
trap clearColours EXIT
trap destroyBackup INT

# functions

function validateBackupLocation() {
    device_actual_mountpath="`df -h | grep "${backup_device}" | awk '{print $6}'`"
    if [ -z "${device_actual_mountpath}" ] ; then
        echo -e "Uh-oh, it appears that ${_yellow}${backup_device}${_white} is not mounted!"
        if [ $EUID == 0 ] ; then
            echo -e "${_yellow}${backup_device}${_white} is being mounted at ${_green}${backup_device_mountpath}${_white}."
            mount -o rw ${backup_device} ${backup_device_mountpath}
            if [ $? != 0 ] ; then
                echo -e "${_red}There was an error while mounting ${_yellow}${backup_device}${_red}!"
                exit 1
            fi
            echo -e "${_yellow}${backup_device}${_white} will be unmounted from ${_yellow}${backup_device_mountpath}${_white} after the operation finishes."
            post_umount="YES"
        else
            echo -e "${_yellow}This script must be run as root to mount ${_green}${backup_device}${_yellow}."
            exit 1
        fi
    fi
    device_actual_mountpath="`df -h | grep "${backup_device}" | awk '{print $6}'`"
    if [ "${backup_device_mountpath}" != "${device_actual_mountpath}" ] ; then
        if [ "${device_actual_mountpath}" == "" || "${device_actual_mountpath}" == " " ] ; then
            echo -e "Uh-oh, it appears that ${_yellow}${backup_device}${_white} is still not mounted!"
            echo -e "${_red}There was an error while mounting ${_yellow}${backup_device}${_red}!"
            exit 1
        fi
        echo -e "Uh-oh, it appears that ${_yellow}${backup_device}${_white} is mounted at ${_red}${device_actual_mountpath}${_white}, not ${_green}${backup_device_mountpath}${_white}."
        echo -e "Ok to adjust my configured path?"
        read -p "[Y/n]: " continue
        if [[ "${continue}" == "Y" || "${continue}" == "y" ]] ; then
            backup_device_mountpath=${device_actual_mountpath}
        else
            exit 0
        fi
    fi
    echo -e "${_green}Your backup path appears ok, continuing.."
}

function getFolderSizes() {
    echo -e "${_yellow}Calculating backup sizes...${_white}"
    for (( i=0; $i < ${#backup_folders[@]}; i++ )) ; do
        folder_size="`du -mhd 0 -B 1M ${backup_folders[${i}]} | awk '{print $1}'`"
        backup_folder_sizes[${i}]=`echo ${folder_size}`
        echo -e "${_white} - ${backup_folders[${i}]} ${_red}=> ${_yellow}${folder_size}${_white}"
    done
}

function createBackupArchive() {
    if test -e ${backup_file} ; then
        echo -e "${_yellow}There is already a backup for today! Aborting!"
        exit 1
    fi
    ${tar_path} -cf ${backup_file} /dev/null 2>/dev/null
    if [ $? != 0 ] ; then
        echo -e "${_red}There was an error while creating the backup archive! Aborting!"
        exit 1
    fi
}

function storeFoldersToArchive() {
    if test ! -e ${backup_file} ; then
        echo -e "${_yellow}Your backup file does not exist! Aborting!"
        exit 1
    fi
    for (( i=0; $i < ${#backup_folders[@]}; i++ )) ; do
        current_folder=${backup_folders[${i}]}
        echo -e "Backing up ${_green}${current_folder}${_white} [ Approx. ${_yellow}${backup_folder_sizes[${i}]}${_white} ]..."
        ${tar_path} -uP --exclude="${backup_device_mountpath}/*" -f ${backup_file} ${current_folder} 2>&1 1>${backup_logdir}/${backup_logfile_name}
        if [ $? != 0 ] ; then
            echo -e "${_red}There was an error while compressing ${_yellow}${current_folder}${_white}! Aborting!"
            exit 1
        fi
    done
}

function compressArchive() {
    if test ! -e ${backup_file} ; then
        echo -e "${_yellow}Your backup file does not exist! Aborting!"
        exit 1
    fi

    backupfile_size=`du -mhd 0 -B 1M ${backup_file} | awk '{print $1}'`

    echo -e "Compressing ${_green}${backup_file} [ Approx. ${_yellow}${backupfile_size}${_white} ].."

    gzip -9v ${backup_file}

    if [ $? != 0 ] ; then
        echo -e "${_red}There was an error while compressing the backup archive! Aborting!${_white}"
        exit 1
    fi

    backup_file="${backup_file}.gz"
}

function runPostActions() {
    if [ "${post_umount}" == "YES" ] ; then
        umount ${backup_device}
        echo -e "Unmounted ${_green}${backup_device}${_white}!"
    fi
}

function displayBackupSize() {
    if [ -e ${backup_file} ] ; then
        echo -e "${_yellow}Calculating total backup size..."
        backup_file_du="`du -mhd 0 -B 1M ${backup_file}`"
        backup_file_size="`echo ${backup_file_du} | awk '{print $1}'`"
        echo -e "${_green}Backup archive is approximately ${backup_file_size}."
    fi
}

function clearColours() {
    echo -e "${_white}"
    tput sgr0
}

function destroyBackup() {
    echo -e "${_red}Received SIGINT, shutting down.."
    if [ -e ${backup_file} ] ; then
        rm -v ${backup_file}
        echo -e "${_red}Partial backup removed, exiting."
    fi
    clearColours
    exit 1
}

# procedure

validateBackupLocation
getFolderSizes
createBackupArchive
storeFoldersToArchive
compressArchive
runPostActions