#!/bin/bash

# This script makes a snapshot of several directories using rsync.
# It's based on Rob Bos's snapshot script found at mikerubel.org.

# Version 0.1, Geordy Kitchen, November 26, 2002
# Version 0.2  George A. Nelson, 17 Jul 07  Extensive changes
# Version 0.3  George A. Nelson, 22 Apr 09  -R option
#   Wildcard allowed in source directories; use <wild> in place of *.
#   Uses oldest available backup when promoting, for initial startup
#       and so a missing backup won't continue to gum up the works.
#   Date each operation.
#   All directories processed in one connection.
# This script is released under the terms of the GNU General Public License,
# version 2.0.

# Your crontab will typically look something like this:
# 0 */4 * * * /bin/this_script hourly
# 50 3 * * * /bin/this_script daily
# 40 3 * * 0 /bin/this_script weekly
# 30 3 1 * * /bin/this_script monthly
#
#GAN  My crontab keeps a log and looks like:
#55 3,7,11,15,19,23 * * *    ( nice $HOME/geordy_backup hourly | grep -v ' is uptodate' | grep -v '^[^ ]\+/$' >>$HOME/geordy_backup.out ) 2>&1
#46 3 * * *     ( $HOME/geordy_backup daily   >>$HOME/geordy_backup.out ) 2>&1
#41 3 * * 0     ( $HOME/geordy_backup weekly  >>$HOME/geordy_backup.out ) 2>&1
#36 3 1 * *     ( $HOME/geordy_backup monthly >>$HOME/geordy_backup.out ) 2>&1

# Configuration

  # Destination directory.
dst=/mnt/backups/example.com.d

srcroot="root@example.com"

  # Use a trailing slash for directories, just the filename for files.
src='
/home/
/root/
/var/www/
/var/local/
/var/log/
/var/spool/
/etc/
/boot/
/opt/
/usr/local/
'
src=`echo $src`

  # Rsync filters, usually - (exclude) paths of files or directories to skip.
filter='
'
#-_/home/auser/growing.log
#-_/home/<wild>/.gvfs/
filter=`echo $filter`

  # Number of times to run per day.
hourly=6

# Constants
daily=7
weekly=4
monthly=60
now=1000

# Promote a backup to the next higher time period.
# ex: promote hourly daily
promote ()
{
    local i
    for i in `seq ${!1} -1 1` ; do
        if [ -d /$dst/$1.$i ] ; then
            mv $dst/$1.$i $dst/$2.0
            return
        fi
    done
}

echo
echo "##### Incremental backup $1 $(date)"

if [ "${2:-}" = "warm" ] && /sbin/service httpd status &>/dev/null ; then
    echo "#####    Backup server is active, skipping backup"
    exit 0
fi

case $1 in 
    hourly|now)
        echo
        echo "***** $src"
        [ "$filter" != "" ] &&
            filter=`echo \-\-filter=$filter | sed 's|<wild>|*|g' | sed 's/ / --filter=/'`
        rsync -aHCR --delete -vv --timeout=120          \
            --one-file-system                           \
            --link-dest=$dst/$1.1/                      \
            --link-dest=$dst/daily.1/                   \
            --link-dest=$dst/weekly.1/                  \
            --link-dest=$dst/monthly.1/                 \
            -F -F $filter                               \
            $srcroot:"`echo $src | sed 's|<wild>|*|g'`" $dst/$1.0/
            #Ehh, must remove double quotes above if local backup, sigh.
        ;;
    daily)
        #[ -d $dst/hourly.$hourly ] && mv $dst/hourly.$hourly $dst/daily.0
        promote hourly daily
        ;;
    weekly)
        #[ -d $dst/daily.$daily ] && mv $dst/daily.$daily $dst/weekly.0
        promote daily weekly
        ;;
    monthly)
        #[ -d $dst/weekly.$weekly ] && mv $dst/weekly.$weekly $dst/monthly.0
        promote weekly monthly
        ;;
    *)
        echo "usage: $0 <period> [warm]"
        echo "  period := hourly | daily | weekly | monthly"
        echo "  Run '$0 hourly' $hourly times per day."
        echo "  Keeps $hourly hourly, $daily daily, $weekly weekly, and $monthly monthly backups."
        echo "  Warm only runs if httpd is stopped."
        exit 1
        ;;
esac

# Rotate the current list of backups, if we can.
# ${!1} --> indirection to the number of backups of that period.
if [ -d $dst/$1.0 ]; then
    #oldest=`ls -d $dst/$1.* | tail -n 1 | sed 's/^.*\.//'`
    #for i in `seq $oldest 0`; do
    for i in `seq ${!1} -1 0` ; do
        [ -d $dst/$1.$i ] && mv $dst/$1.$i $dst/$1.$((i+1))
    done

    # if we've rotated the last backup off the stack, remove it.
    [ -d $dst/$1.$((${!1}+1)) ] && rm -rf $dst/$1.$((${!1}+1))

    # finally, let's make the new snapshot reflect the current date.
    [ -d $dst/$1.1 ] && touch $dst/$1.1 && touch $dst/$1.1/"0$1 $(date)"
fi

echo
echo "----- Backup complete $(date)"