#!/bin/bash

# s3putsecurefolder
#
# Synchronise a folder with Amazon s3 securely (s3putsecurefolder --help)
# Note that you should install s3cmd before using this script, and configure it
# using "s3cmd --configure". 
# In particular you need to configure GPG encryption via the 'Encryption
# password' option during the configure process; this means that your data is 
# not readable on S3 by anyone who doesn't have the password.
# I'm aware that s3cmd has a 'sync' option, but this synchronises in both 
# directions, and also performs a remote operations to sync. This tool only ever
# uploads, giving you the certainty that you will never accidentally download
# any data and overwrite local files, and requires no remote access to determine
# whether any files need uploading (local timestamps are used).
#
# I personally use this script to upload my backup volumes to Amazon S3 as an 
# offsite storage. The files are re-used (pseudo tape volume cycling) so that
# I only use a finite amount of space on S3.

# Copyright (c) 2009 Steve Streeting

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

TIMESTAMPFILENAME=.s3lastupload

function usage {
        echo "Usage: "
        echo "  $0 [-n] <source_folder> <dest_bucket>"
        echo "Options:"
        echo "  -n       : Just list actions, don't perform them."
	echo "  -c FILE  : Use FILE as S3 config instead of ~/.s3cfg"
}

function help {
	usage
	echo
	echo "s3putsecurefolder is a tool for synchronising a folder with Amazon S3"
	echo "in a single direction (upload) and always using encryption."
	
}

function checkAndUploadFile {
	filename=$1
	prefix=$2
	bucket=$3
	dryrun=$4
        cfg=$5

	lenprefix=${#prefix}
	targetpath=${filename:$lenprefix}

	if [[ "$cfg" != "" ]]
	then
		cfgopt="-c $cfg"
	fi

	if [[ `basename $filename` != $TIMESTAMPFILENAME ]]
	then
		# Hmm, s3cmd -n still seems to create files of 0 size in bucket!
		# do our own dry run
		if [[ $dryrun = 1 ]]
		then
			echo "Would execute: s3cmd -e $cfgopt put $filename s3://$bucket/$targetpath"
		else
			# upload (encrypted)
			s3cmd -e $cfgopt put $filename s3://$bucket/$targetpath
		fi
	fi
}

if [[ "$1" == "--help" ]]
then
	help
	exit
fi

# Deal with optional named arguments
DRYRUN=0
CFGFILE=""
while getopts "nc:" Opt
do
        case $Opt in
                n) DRYRUN=1;;
		c) CFGFILE=$OPTARG;;
        esac
done
shift $(($OPTIND - 1))

if [[ $# < 2 ]]
then
	usage
        exit
fi

if [[ ! -e "$1" ]]
then
        echo "First parameter needs to be source folder"
        exit
fi

if [[ "$CFGFILE" != "" && ! -e "$CFGFILE" ]]
then
        echo "Configuration file $CFGFILE not found."
        exit
fi

BACKUP_FOLDER=$1
TARGET_BUCKET=$2
INFOFILE=$BACKUP_FOLDER/$TIMESTAMPFILENAME


echo "Synchronising $BACKUP_FOLDER to s3://$TARGET_BUCKET"
if [[ $DRYRUN = 1 ]]
then
	echo "Simulation only, not uploading"
fi

# Timestamp at start
TMPINFOFILE=`tempfile`
touch $TMPINFOFILE

if [[ -e $INFOFILE ]]
then
	# All files since last time
	for filename in `find $BACKUP_FOLDER -type f -cnewer $INFOFILE`
	do
		checkAndUploadFile $filename $BACKUP_FOLDER $TARGET_BUCKET $DRYRUN $CFGFILE
	done

else
	# Do all files
	for filename in `find $BACKUP_FOLDER -type f`
	do
		checkAndUploadFile $filename $BACKUP_FOLDER $TARGET_BUCKET $DRYRUN $CFGFILE
	done

fi

if [[ $DRYRUN == 0 ]]
then
	# Update final info file, preserve timestamp
	cp -p $TMPINFOFILE $INFOFILE
fi
rm $TMPINFOFILE