Daily SVN Incremental Backup

#!/bin/bash

SCRIPT_NAME=`basename $0`

function help() {

    echo
    echo "Incremental dumping for SVN by Ilija Matoski (ilijamt@gmail.com)"
    echo "No command arguments detected, there need to be as following."
    echo "Usage: ${SCRIPT_NAME} <path_to_repo> <path_to_dump> <identifier>"
    echo
    echo "Parameters:"
    echo "  <path_to_repo> - Where is the repository located"
    echo "  <path_to_dump> - Where should we dump the repository"
    echo "  <identifier>   - Used to record the last recorded dump, always stored in the file with the"
    echo "                   dumps from the repo, so we can keep a track of where we at with dumping,"
    echo "                   also identifier is used to generate the dumps names."
    echo "  <compress>     - compress the output dump (default: false)"
    echo
    echo "Examples:"
    echo "  ${SCRIPT_NAME} test /backup/SVN/test test"
    echo "  ${SCRIPT_NAME} test /backup/SVN/test test true"
    echo

    exit -1

}

if [ ! $# -ge 3 ]; then
    help
fi

PATH_TO_REPO=$1
PATH_TO_DUMP=$2
IDENTIFIER=$3
COMPRESS=$4

# Check if they are empty and if they are quit
if [[ -z "$PATH_TO_REPO" || -z "$PATH_TO_DUMP" || -z "$IDENTIFIER" ]]; then
    help
fi

if [ "$COMPRESS" == "true" ]; then
    COMPRESS="true"
else
    COMPRESS="false"
fi

# Check if the repo path exists, and if it's a valid SVN repository
if [ ! -d "$PATH_TO_REPO" ]; then
    echo "Directory ${PATH_TO_REPO} doesn't exist."
    echo "Exiting."
    exit -1
fi

# Check if SVN folder is valid, check for format file in the directory
if [ ! -f "${PATH_TO_REPO}/format" ]; then
    echo "Probably not a valid SVN repository."
    echo "Exiting."
    exit -1
else
    echo "Probably a valid SVN repository detected. Continuing."
fi

# Check if destination exist and if we have writing permissions
# and if it doesn't then create it
if [ ! -d "$PATH_TO_DUMP" ]; then
    echo "Dump directory doesn't exist, creating a new directory: $PATH_TO_DUMP"
    mkdir -p "$PATH_TO_DUMP"
fi

# Check if the directory has writing permissions
if [ ! -w "$PATH_TO_DUMP" ]; then
    echo "No writing permissions."
    echo "Exiting."
    exit -1
fi

# Get the full paths if we have relative paths in the command line
PATH_TO_REPO=`cd $PATH_TO_REPO; pwd`
PATH_TO_DUMP=`cd $PATH_TO_DUMP; pwd`
IDENTIFIER_PATH="$PATH_TO_DUMP/$IDENTIFIER"
DUMP_FILE_MASK="$IDENTIFIER_PATH"
# Check if the identifier exists
if [ ! -f "$IDENTIFIER_PATH" ]; then
    # Doesn't exist, so we create it and set it to revision 0
    echo "-1" > "$IDENTIFIER_PATH"
fi

CYGWIN=`uname -o`

# Check if we are running cygwin, for windows
if [ "$CYGWIN" == "Cygwin" ]; then
    CYGWIN="true"
else
    CYGWIN="false"
fi

# Set up some stuff for cygwin
if [ "$CYGWIN" == "true" ]; then
    repoDrive="${PATH_TO_REPO:10:1}"
    REPO_URL=`echo $PATH_TO_REPO | sed "s/\/cygdrive\/${repoDrive}/${repoDrive}:/g"`
    REPO_DIR="$REPO_URL"
    REPO_URL="file:///${REPO_URL}"
else
    REPO_URL="file:///$PATH_TO_REPO"
    REPO_DIR="$PATH_TO_REPO"
fi

# Get the last revision from the directory repository
REPO_LAST_REVISION=`svn info $REPO_URL | grep "^Revision: " | sed "s/Revision: //g"`
REPO_DUMPED_REVISION=`cat "$PATH_TO_DUMP/$IDENTIFIER"`

# check if the call succeded
if [[ $REPO_LAST_REVISION  != [0-9]* ]]; then
    echo "Cannot fetch information from SVN repository"
    exit -1
fi

# Increment it by one number from the last revision
# so we don't re dump the last one again
REPO_DUMPED_REVISION=$(($REPO_DUMPED_REVISION+1))

echo "Settings"
echo "  Compress: ${COMPRESS}"
echo "  Directory: ${REPO_URL}"
echo "  Dump: ${PATH_TO_DUMP}"
echo "  Identifier: ${IDENTIFIER}"
echo "  Cygwin: ${CYGWIN}"
echo
echo "Repository"
echo "  Revisions: ${REPO_LAST_REVISION}"
echo "  Dumping from: ${REPO_DUMPED_REVISION}"
echo

if [ $REPO_DUMPED_REVISION -gt $REPO_LAST_REVISION ]; then
    echo "ERROR: Dumped revision bigger than the revision in the repository"
    echo "Exiting."
    exit -1
fi

echo "Starting to dump"

list=$(seq "$REPO_DUMPED_REVISION" 1 "$REPO_LAST_REVISION" )

for rev in $list
do

    padding_rev=`printf "%08d" $rev`
    dump_file="$DUMP_FILE_MASK.rev.$padding_rev.svndump"

    if [ "$COMPRESS" == "true" ]; then
        dump_file="${dump_file}.gz"
    fi

    echo "  Dumping revision $rev of $REPO_LAST_REVISION"

    if [ "$COMPRESS" == "true" ]; then
        svnadmin dump "$REPO_DIR" --revision "$rev:$rev" --incremental --deltas -q | gzip > $dump_file
    else
        svnadmin dump "$REPO_DIR" --revision "$rev:$rev" --incremental --deltas -q > $dump_file
    fi

    # put the new dumped revision in the file
    echo $rev > "$IDENTIFIER_PATH"

done

echo "Done."

./incremental_backup.sh