* rsyncshot
:PROPERTIES:
:COMMENTS: org
:TANGLE:   rsyncshot
:END:
Craig Jennings craigmartinjennings@gmail.com
Inspired by Mike Rubel: http://www.mikerubel.org/computers/rsync_snapshots/
#+begin_SRC sh :tangle yes 
#!/bin/bash
#+end_SRC
** Debugging
#+begin_SRC sh :tangle yes
# uncomment next 4 lines for debugging output
# exec 5> >(logger -t $0)
# BASH_XTRACEFD="5"
# PS4='$LINENO: '
# set -x
#+end_SRC
** Config
*** Default Locations
Default locations for setup
#+begin_SRC sh :tangle yes
SCRIPTLOC=/usr/local/bin/rsyncshot;
DESTINATION=/media/backup;

INSTALLHOME=/etc/rsyncshot
LOGHOME=/var/log/rsyncshot.log;

INCLUDES="$INSTALLHOME/include.txt";
EXCLUDES="$INSTALLHOME/exclude.txt";
#+end_SRC
*** Default Cron Job Entries
Default cron job entries
CRON_H = hourly on minute 0 from 1am to 11pm
CRON_D = daily at midnight, Monday - Saturday
CRON_W = weekly at midnight on Sundays
#+begin_SRC sh :tangle yes
CRON_H="0 1-23 * * * $SCRIPTLOC hourly 22";
CRON_D="0 0 * * 1-6 $SCRIPTLOC daily 6";
CRON_W="0 0 * * 7 $SCRIPTLOC weekly 51";
#+end_SRC
** Functions
*** Help
#+begin_SRC sh :tangle yes
help()
{
    echo ""
    echo "rsyncshot - compact snapshots on Linux using rsync and hard links."
    echo ""
    echo "rsyncshot must be run as root"
    echo ""
    echo "Usage: "
    echo "rsyncshot <name> <number of backups to retain>"
    echo "          setup (installs rsyncshot and cron jobs)"
    echo "          help  (prints this info)"
    echo "Notes:"
    echo "- install and log locations defined in script."

#+end_SRC
*** Error
#+begin_SRC sh :tangle yes
error()
{
    echo "ERROR: $0: $@" 1>&2;
    echo "See \"rsyncshot help\" for usage."
    exit 1;
}
#+end_SRC
*** Setup
#+begin_SRC sh :tangle yes
setup()
{
    # copy this file to directory on path
    cp -f $0 /usr/local/bin
    echo "$0 copied to /usr/local/bin"
    
    # make install home if it doesn't exist;
    if [ ! -d $INSTALLHOME ]; then
	mkdir -p $INSTALLHOME;
	"Created install home at $INSTALLHOME.";
    fi

    # create includes file and add default entries
    if [ -f $INCLUDES ]; then rm $INCLUDES; fi
    printf "/home /etc /usr/local/bin" >> $INCLUDES;
    echo "modify include file at $INCLUDES";

    # create excludes file and add default entries
    if [ -f $EXCLUDES ]; then rm $EXCLUDES; fi
    printf "*.pyc\n*.pyo\n*.class\n*.elc\n*.o\n*.tmp\n.cache*" >>  $EXCLUDES;
    echo "modify exclude file at $EXCLUDES";

    # write out current crontab, append default entries, and install
    crontab -l > crontemp;
    echo "$CRON_H >> $LOGHOME 2>&1" >> crontemp;
    echo "$CRON_D >> $LOGHOME 2>&1" >> crontemp;
    echo "$CRON_W >> $LOGHOME 2>&1">> crontemp;
    crontab crontemp;
    rm crontemp;
    echo "hourly, daily, and weekly cron jobs installed.";
}
#+end_SRC
** Script
*** Check Help Option
If user requested help, display and exit
#+begin_SRC sh :tangle yes
if [ "$TYPE" = "HELP" ]; then help; exit; fi
#+end_SRC
*** Ensure Root
Ensure we're running as root
#+begin_SRC sh :tangle yes
if [ "$EUID" -ne 0 ]; then error "This script must be run as root."; fi
#+end_SRC
*** Display How Script Was Started
Display how the script was started
#+begin_SRC sh :tangle yes
echo "rsyncshot invoked on `date -u` with: $0 $1 $2";
#+end_SRC
*** Parameter Validation
Validate first arg is alpha chars and make it case insensitive. If user requested setup, call function and exit.
#+begin_SRC sh :tangle yes
if ! [[ $1 =~ [a-zA-Z] ]]; then error "snapshot type not recognized."; fi
TYPE=$(tr '[a-z]' '[A-Z]' <<< $1);
if [ "$TYPE" = "SETUP" ]; then setup; exit; fi
#+end_SRC
*** Validate Max Snapshots
Validate second arg (max snapshots) is numeric. 
#+begin_SRC sh :tangle yes
if ! [[ $2 =~ [0-9] ]]; then error "max snapshots not a number."; fi
MAX=$(($2-1));
#+end_SRC
*** Validate Include File
Validate include file (source directories)
#+begin_SRC sh :tangle yes
if [ ! -f "$INCLUDES" ]; then error "include file $INCLUDES not found."; fi
SOURCES=$(<$INCLUDES);
for SOURCE in $SOURCES
do
    if [ ! -d "$SOURCE" ]; then error "source $SOURCE not found"; fi
done
#+end_SRC
*** Validate Exclude File
Validate exclude file (exclusion patterns)
#+begin_SRC sh :tangle yes
if [ ! -f "$EXCLUDES" ]; then error "Exclude file $EXCLUDES not found."; fi
#+end_SRC

*** Sync
Perform the sync, each directory in turn
#+begin_SRC sh :tangle yes
for SOURCE in $SOURCES
do
    rsync -avh -i --times \
    	  --delete  --delete-excluded \
    	  --exclude-from=$EXCLUDES \
    	  --update $SOURCE $DESTINATION/latest ;
done
#+end_SRC
*** Delete Old Snapshot
Delete the snapshot to go over max
#+begin_SRC sh :tangle yes
if [ -d $DESTINATION/$TYPE.$MAX ]; then
    rm -rf $DESTINATION/$TYPE.$MAX;
fi
#+end_SRC
*** Rotate Snapshots
Rotate snapshots descending
#+begin_SRC sh :tangle yes
for (( start=$(($MAX)); start>=0; start--)); do
    end=$(($start+1));
	if [ -d $DESTINATION/$TYPE.$start ]; then
	    mv $DESTINATION/$TYPE.$start $DESTINATION/$TYPE.$end;
	fi
done
#+end_SRC
*** Set Directory Timestamp
Touch the directory for a timestamp 
#+begin_SRC sh :tangle yes
touch $DESTINATION/latest
#+end_SRC
*** Hard Link to Destination
Make a hard-link-only copy into $TYPE.0
#+begin_SRC sh :tangle yes
cp -al $DESTINATION/latest $DESTINATION/$TYPE.0;
#+end_SRC
*** Make Directory Type Read-Only
Make the directory $TYPE.0 read-only
#+begin_SRC sh :tangle yes
chmod -w $DESTINATION/$TYPE.0
#+end_SRC
*** Print Time and Exit
Print end time and exit
#+begin_SRC sh :tangle yes
echo "rsyncshot completed `date -u` ";
exit 0;
#+end_SRC