backUP

#!/usr/bin/bash

source /usr/local/lib/backUP/logging
source /usr/local/lib/backUP/args2array

CONFIGURATION_FILE='/usr/local/etc/backUP/backUP.conf'
MIN_BASH_VER='4.0'
MIN_BORG_VER='1.2.3'
MIN_COREUTIL_VER='7.0'
DATE="$(date +%m-%d-%Y-%I:%M:%S-%p)"
FILENAME="$(basename $0)"
IS_NUM_REGEX='^[1-9][0-9]*$'
REPO_STR='This is a Borg Backup repository.'
SMOL_OPTS='a:e!r:hblLcs!v!'
LONG_OPTS='dest!,repo!,pass,dupe:,conf!'
declare -a dupe_paths

usage(){
>&2 cat << EOF
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

This program is used to manage the backup 'database' defined in '$CONFIGURATION_FILE'

It is probably inefficient, buggy, and prone to explode or worse.

Usage: 
 $FILENAME option [<path>]
 
Options:
     -a <path> : Add <path> to the 'database'
     -b        : Backup all 'database' entries with BORG backup
     -c        : Prune and then cleanup BORG backups
 --conf <path> : Specify an alternate $FILENAME config file to use
 --dupe <path> : Duplicate to <path> ( No limit to number of calls )
     -e        : Extract a BORG backup ( Defaults to ~/temp )
 --dest <path> : Set extraction directory ( Only applies to -e flag )
     -l        : List all BORG backups
     -L        : List all paths monitored by $FILENAME
     -h        : Display usage information
     -r <path> : Remove <path> from the 'database'
     -s <name> : Search archives for <name>
 --pass        : Prompts for the BORG Backup passphrase
 --repo <path> : Sets the BORG repo to <path>

Configuration options are loaded from '$CONFIGURATION_FILE'

A Borg repository must be setup prior to using '$FILENAME'. Use:
	borg init /path/to/borg/repository

EOF
exit 1
}

parse_config() {
	# don't allow multiple configuration files to pollute each other
	unset __LOG_STOUT__ __LOG_LEVEL__ __LOGPATH__ BORG_PASSPHRASE 
	unset BORG_REPO BACKUP_DB SOME_USER EXTRACT_TO dupe_paths
	export BORG_RELOCATED_REPO_ACCESS_IS_OK=yes
	local -A config verb

	config=(
		[BORG_PASSPHRASE]=""
		[BORG_REPO]=""
		[BACKUP_DB]=""
		[SOME_USER]="$SUDO_USER"
		[EXTRACT_TO]=""
	)
	verb=( [STOUT]=0 [CRIT]=1 [ERROR]=2	[DEBUG]=3 [TRACE]=4	)

	while read line; do
		# skip processing lines that begin with '#'
		[[ "$line" =~ ^#.*$ ]] && continue
		
		if echo "$line" | grep -F = &>/dev/null; then
			grab_key "$line" varname
			grab_value "$line" value
			edumpvar varname value
			case "$varname" in
				DUPLICATE_REPO_PATH )
					tval="$(realpath -mq "$value")"
					validate_duplicate "$tval" && dupe_paths+=("$tval")
					;;
				BORG_REPO )
					validate_repo "$value" && config["$varname"]="$value"
					;;
				* )
					config["$varname"]="$value"
					;;
			esac
		fi

	done < "$CONFIGURATION_FILE"

	if [[ "${config[LOGSTOUT]}" == "true" || "${config[LOGSTOUT]}" == "1"  ]]; then
		export __LOG_STOUT__=1
	fi

	if [[ "${config[LOGSTERR]}" == "true" || "${config[LOGSTERR]}" == "1" ]]; then
		export __LOG_STERR__=1
	fi

	if [[ -n "${config[LOGLEVEL]}" ]]; then
		if [[ "${verb[${config[LOGLEVEL]}]+1}" ]]; then
			export __LOG_LEVEL__=${verb[${config[LOGLEVEL]}]}
		else
			ewarn "$FILENAME does not recognize configuration option LOGLEVEL = ${config[LOGLEVEL]}"
		fi
	fi
	if [[ -n "${config[LOGPATH]}" ]]; then
		export __LOGPATH__="${config[LOGPATH]}"
		__open_logfile__
	fi

	export BORG_PASSPHRASE="${config[BORG_PASSPHRASE]}"
	export BORG_REPO="${config[BORG_REPO]}"
	export BACKUP_DB="${config[BACKUP_DB]}"
	export SOME_USER="${config[SOME_USER]}"
	
	if [[ -z "${config[EXTRACT_TO]}" ]]; then
		export EXTRACT_TO="$(getent passwd "$SOME_USER" | cut -d: -f6)/temp"
	else
		export EXTRACT_TO="${config[EXTRACT_TO]}"
	fi
}

append_to_backup_list() {
	local argument
	for argument in "$@"; do 
		if [[ ! -f "$argument" && ! -d "$argument" ]]; then
			ecrit "Path '$argument' doesn't seem to exist. Exiting."
			exit 1
		fi
	done
	for argument in "$@"; do
		# normalize the input
		file="$(readlink -e "$argument")"
		if ! grep -Fxq "$file" "$BACKUP_DB"; then
			eprint "Appending '$file' to '$BACKUP_DB'"
			echo "$file" >> "$BACKUP_DB"
		else
			ewarn "Entry for '$file' already exists in '$BACKUP_DB'"
		fi
	done
	sort -o "$BACKUP_DB" "$BACKUP_DB"
}

remove_from_backup_list() {
	local -i db_entry_line_num num_lines=$(wc -l "$BACKUP_DB" | awk '{print $1}')
	local -A lines_passed
	local argument db_entry

	for argument in "$@"; do
		if [[ $argument =~ $IS_NUM_REGEX && $argument -le $num_lines ]]; then
			# function received a number less than or equal to the number of borg backups
			db_entry=$(sed -n "$argument{p;q}" "$BACKUP_DB")
			db_entry_line_num="$argument"
		else
			file="$(readlink -e "$argument")"
			if grep -Fxq "$file" "$BACKUP_DB"; then
			# function received an entry tracked by the database
				db_entry="$file"
				db_entry_line_num="$(grep -nFx "$file" "$BACKUP_DB" | cut -f1 -d:)"
			else
				# function does not recognize the argument received
				ecrit  "No match to '$file' found in '$BACKUP_DB'"
				exit 1
			fi
		fi
		lines_passed["$db_entry_line_num"]="$db_entry"
	done
	
	local sed_string=""
	for key in "${!lines_passed[@]}"; do
		eprint "Removing '${lines_passed[$key]}' from '$BACKUP_DB'"
		sed_string+="${key}d;"
	done
	
	sed -i "${sed_string%;}" "$BACKUP_DB"
}

parse_parents() {
	local line
	while read line; do
		printf '%s\n' "$line"
	done < "$BACKUP_DB" | \

	# The commands below (recursively?) creates a unique entry for the full *parent* directory structure 
	# pointing to the file/folder we want backed up,
	# Stolen from: https://serverfault.com/questions/877254/tar-does-not-retain-directory-permissions
	awk -F/ '{ d=$1; for (i=2; i <= NF; i++) { print d; d=d "/" $i }; print d }' | \
	awk '{ if (index(old,$0 "/") != 1) { old=$0; print } }' | \
	sed -e '/^[[:space:]]*$/d' -e '/\/$/d'
}

recurse_directories() {
	while read line; do
		if [[ -d $line ]]; then
			# this recursively prints all files and subdirectories of the folder we wish to backup
			find "$line" -print
		fi
	done < "$BACKUP_DB"
}

create_borg_backup() {
	eprint "Creating new backup '$DATE' in '$BORG_REPO'"

	{ parse_parents && recurse_directories; } | sort -u | \
		borg create --paths-from-stdin "$BORG_REPO::$DATE" 
}

list_borg_backups() {
	local -i counter
	borg list "$BORG_REPO" | \
		while read line; do
			((counter+=1))
			if [[ $counter -eq 1 ]]; then
				printf "\n%-8s%s\n" "#" "ARCHIVE NAME"
				printf "%s%s\n" "------  ------------"
			fi
			archive_name=$(echo $line | awk '{print $1}')
			if [[ $# -eq 0 ]]; then
				printf "%-8s%s\n" "$counter" "$archive_name"
			elif [[ $counter -eq $1 ]]; then
				printf "%-8s%s\n" "[*$counter]" "$archive_name"
			else
				printf "%-8s%s\n" "$counter" "$archive_name"
			fi
		done 
		printf "\n"
}

restore_borg_backup() {
	local -i num_archives=$(borg list "$BORG_REPO" | wc -l)
	local borg_archive
	# Don't change permissions of /
	if [[ ! -d "$EXTRACT_TO" ]]; then
		install -d -m 0755 -o "$SOME_USER" -g "$SOME_USER" "$EXTRACT_TO"
	fi

	if [[ $1 =~ $IS_NUM_REGEX && $1 -le $num_archives ]]; then
		# function received a number that is less than or equal to the number of borg backups
		borg_archive=$(borg list "$BORG_REPO" | sed -n "$1{p;q}" | awk '{print $1}')
	else	
		borg_archive=$1
	fi

	eprint "Extracting '$borg_archive' to '$EXTRACT_TO'."
	local workingdir=$(pwd)
	cd "$EXTRACT_TO"
	borg extract "$BORG_REPO::$borg_archive" 
	if [[ $? -ne 0 ]]; then
		eerror "Borg Backup reports that archive '$1' does not exist in '$BORG_REPO'"
		eerror "Use '$FILENAME -l' to display a list of all valid archives."
	else
		eprint "Success! Files extracted to $EXTRACT_TO."
	fi
	cd "$workingdir"
}

search() {
	local a
	borg list --short "$BORG_REPO"	| \
		while read -r a; do
			printf "%s\n%s\n" "${a}" "----------------------"
			borg list --short "${BORG_REPO}::$a"  | grep "$1"
			echo
		done   | \
			awk 'BEGIN { empty = 0 } {
			if ($0 == "") {
				if (NR - empty == 3) {
					start = 0
				} else {
					print data
				}
				empty = NR
				data = ""
			} else {
				if (start == 0) {
					start = NR
				}
				data = data "\n" $0
			}
		 }
		 END { print data }'
}

borg_compact_and_prune() {
	borg prune --list --keep-daily=7 --keep-weekly=3 --keep-monthly=11 --keep-yearly=1 "$BORG_REPO"		
	borg compact "$BORG_REPO" 
}

duplicate_borg_repo() {
	local primary_repo="$(realpath -mq "$BORG_REPO")/"	# strip excessive trailing slashes

	if validate_repo "$primary_repo"; then
		if [[ ${#dupe_paths[@]} -gt 0 ]]; then
			for secondary_repo in "${dupe_paths[@]}"; do
				rsync -au --delete --timeout=1 "$primary_repo" "$secondary_repo"  > /dev/null
				if [[ $? -ne 0 ]]; then
					ewarn "rsync encountered an error duplicating '$primary_repo' to '$secondary_repo'"
				else
					edebug "Successfully duplicated to '$secondary_repo'"
				fi
			done
		else
			ewarn "No duplication paths specified. '$primary_repo' will not be duplicated"
		fi
	else
		ecrit "BORG repo '$primary_repo' is not valid. This shouldn't have happened"
		exit 1
	fi
}

print_database() {
	printf "\n%-8s%-8s%s\n" "#" "TYPE" "PATH"
	printf "%s%s%s\n" "------  ------  ------"
	local -i counter
		while read line; do
			if [[ -d $line ]]; then
				entry_type="Folder"
			elif [[ -f $line ]]; then
				entry_type="File"
			fi

			((counter+=1))
			if [[ $# -eq 0 ]]; then
				printf "%-8s%-8s%s\n" "$counter" "$entry_type" "$line"
			elif [[ $counter -eq $1 ]]; then
				printf "%-8s%-8s%s\n" "[*$counter]" "$entry_type" "$line"
			else
				printf "%-8s%-8s%s\n" "$counter" "$entry_type" "$line"
			fi
		done < "$BACKUP_DB"
}

get_password() {
	local first_entry second_entry
	read -s -p "Enter Password: " first_entry
	echo
	read -s -p "Re-Enter Password: " second_entry
	echo

	if [[ "$first_entry" == "$second_entry" ]]; then
		export BORG_PASSPHRASE="$first_entry"
	else
		eerror "Passwords don't match. Please try again."
		get_password
	fi

	borg info "$BORG_REPO" > /dev/null 2>&1
	if [[ $? -ne 0 ]]; then
		ecrit "Your password for '$BORG_REPO' is incorrect. Exiting."
		exit 1
	fi
}

validate_repo() {
	if ! [[ -f "${1}/README" && "$(head -n 1 "${1}/README")" == "$REPO_STR" ]]; then
		# according to https://borgbackup.readthedocs.io/en/stable/internals/data-structures.html#repository
		# all BORG repositories contain a "README" file with the string "This is a Borg Backup repository."
		ecrit "The path, '$1' does not contain a valid BORG repository. Exiting."
		exit 2
	else
		return 0
	fi
}

validate_duplicate() {
	# Duplication is performed with rsync --delete so anything in the destination will be wiped
	# This script runs as root and we don't want to accidentally erase any important directories!

	local duplicate_repo_path="$1"

	if [[ ! -d "$duplicate_repo_path" ]]; then
		# argument is not a valid directory
		ewarn "Duplication path '$duplicate_repo_path' is not a valid directory and will be skipped."
		return 1
	elif awk '$1 !~ /^#/ && $2 ~ /^[/]/ {print $2}' /etc/fstab | grep -Fxq "$duplicate_repo_path"; then
		# mountpoint command provided by util-linux - checks if duplicate_repo_path is mounted
		if ! mountpoint -q "$duplicate_repo_path"; then
			ewarn "'$duplicate_repo_path' isn't mounted and will be skipped."
			return 1
		fi
	elif [[ $(ls -A "$duplicate_repo_path" | wc -l) -eq 0 ]]; then
		# empty directories are OK
		return 0
	elif [[ -f "${duplicate_repo_path}/README" && "$(head -n 1 "${duplicate_repo_path}/README")" == "$REPO_STR" ]]; then
		# according to https://borgbackup.readthedocs.io/en/stable/internals/data-structures.html#repository
		# all BORG repositories contain a "README" file with the string "This is a Borg Backup repository."
		return 0
	else
		# duplication directory is probably not a BORG repo, and we don't want to delete everything inside of it
		ewarn "Duplication path '$duplicate_repo_path' is either non-empty or not a BORG repo and will be skipped."
		return 1
	fi
}

grab_key() {
	# parameter $1 contains the config file line
	declare -n gk_kref=$2 # gk_kref is a reference to the variable passed as parameter 2
	gk_kref=${1#"${1%%[![:space:]]*}"} # remove leading whitespace
	gk_kref=${gk_kref%%=*} # extract key before the first equal sign
	gk_kref=${gk_kref%"${gk_kref##*[![:space:]]}"}
}

grab_value() {
	# paraemter $1 contains the config file line
	local -n gv_vref=$2 # gv_vref is a reference to the variable passed as parameter 2 
	gv_vref="${1#*=}" # remove everything up to and including first '=' from head of input
	gv_vref="${gv_vref#"${gv_vref%%[![:space:]]*}"}" # removes leading whitespace
	gv_vref="${gv_vref%"${gv_vref##*[![:space:]]}"}" # remove trailing whitespace
	gv_vref="${gv_vref#"${gv_vref%%[![:space:]\"]*}"}" # remove first " and any white space between it and the next character
	gv_vref="${gv_vref%"${gv_vref##*[![:space:]\"]}"}" 
}

__init_messages__ "$@"

if [[ ${__ARGS_LOADED__} -ne 1 ]]; then
	ecrit "$FILENAME depends on args2array."
	exit 1
fi

if [[ ${__LOGS_LOADED__} -ne 1 ]]; then
	ecrit "$FILENAME depends on logging."
	exit 1
fi

{ printf '%s\n%s' "$MIN_BASH_VER" "$BASH_VERSION" | sort -C -V; } > /dev/null 2>&1	
if [[ $? -ne 0 ]]; then
	ecrit "$FILENAME depends on coreutils v${MIN_COREUTIL_VER}+ and Bash v${MIN_BASH_VER}+. Your system is configured with"
	printf '%-11s%s\n' "Coreutils:" "$(whoami --version | head -n 1 | awk '{print $NF}')"
	printf '%-11s%s\n\n' "Bash:" "$BASH_VERSION"
	exit 1
fi

borg -V > /dev/null 2>&1
	borg_install_check=$?
{ printf '%s\n%s' "$MIN_BORG_VER" "$(borg -V | awk '{print $NF}')" | sort -C -V; } > /dev/null 2>&1
	borg_version_check=$?

if [[ $borg_install_check -ne 0 || $borg_version_check -ne 0 ]]; then
	ecrit "$FILENAME depends on BORG Backup v${MIN_BORG_VER}+. Your system is configured with"
	printf '%-13s%s\n\n' "BORG Backup:" "$(borg -V | awk '{print $NF}')"
	exit 1
fi

if [[ $# -eq 0 ]]; then
	usage
	exit 1
fi

if [[ $EUID -ne 0 ]]; then
	ecrit "$FILENAME requires sudo privileges."
	exit 1
fi

parse_config
declare -A ARGS
args2array ARGS "$@"

for arg in "${!ARGS[@]}"; do
	case "$arg" in
		a ) unpack_args ADD_ARGS "${ARGS[a]}"
			;;
		repo )
			REPO_ARG="$(readlink -e "${ARGS[repo]}")"
			;;
		dupe ) unpack_args dupes "${ARGS[dupe]}"
			for i in "${dupes[@]}"; do
				tval="$(realpath -mq "$i")"
				validate_duplicate "$tval" && dupe_paths+=("$tval")
			done
			;;
		conf )
			CONF_ARG="$(realpath -mq "${ARGS[conf]}")"
			;;
		r ) unpack_args REM_ARGS "${ARGS[r]}"
			;;
	esac
done

if [[ -v ARGS[h] ]]; then
	usage
	exit 0
else
	[[ -v ARGS[conf] ]] && CONFIGURATION_FILE="$CONF_ARG" && parse_config
	[[ -v ARGS[repo] ]] && validate_repo "$REPO_ARG" && export BORG_REPO="$REPO_ARG"
	[[ -v ARGS[pass] ]] && get_password
	[[ -v ARGS[dest] ]] && export EXTRACT_TO="${ARGS[dest]}"
	[[ -v ARGS[r] ]] && remove_from_backup_list "${REM_ARGS[@]}"
	[[ -v ARGS[a] ]] && append_to_backup_list "${ADD_ARGS[@]}"
	[[ -v ARGS[b] ]] && create_borg_backup
	[[ -v ARGS[c] ]] && borg_compact_and_prune
	[[ -v ARGS[e] ]] && restore_borg_backup "${ARGS[e]}"
	[[ -v ARGS[s] ]] && search "${ARGS[s]}"
	[[ -v ARGS[l] ]] && list_borg_backups
	[[ -v ARGS[L] ]] && print_database

	duplicate_borg_repo
	__end_messages__
fi

exit 0