run_rsnapshot_one

#!/bin/bash

cd "$(dirname "$0")"

config_file="$1"
success_file=last_success.d/"$(basename "$config_file")"
tty -s && in_cron=0 || in_cron=1
backup_name="$(basename "$config_file" | sed 's/.conf$//')"

if [[ -z "$config_file" ]]; then
	echo "ERROR: supply the rsnapshot config file as first arg"
	exit 1
fi

root="$(grep ^snapshot_root "$config_file" | sed -r 's/^snapshot_root\s+//g')"

log() {
	# if not in cron
	if [[ $in_cron = 0 ]]; then
		echo "($backup_name) $*"
	else
		logger -t rsnapshot_runner "($config_file) $*"
	fi
}

check_time=$(egrep '^# runner-check: (.*)$' "$config_file" | sed -r 's/.*runner-check: //g')
interval_names=($(egrep '^# runner-interval-names: (.*)$' "$config_file" | sed -r 's/.*runner-interval-names: //g'))
interval_seconds=($(egrep '^# runner-interval-seconds: (.*)$' "$config_file" | sed -r 's/.*runner-interval-seconds: //g'))
egrep -q '^sync_first(.*)1$' "$config_file" && sync_first=1 || sync_first=0

# get the name of the next interval time period from a current name
get_next_interval() {
	next=0
	for name in "${interval_names[@]}"; do
		if [[ $next = 1 ]]; then
			echo "$name"
			return
		fi
		if [[ $name = $1 ]]; then
			next=1
		fi
	done
} # end get_next_interval()

# get representation of internval in seconds
get_interval_seconds() {
	local i=0
	for name in "${interval_names[@]}"; do
		if [[ $name = $1 ]]; then
			echo "${interval_seconds[$i]}"
			return
		fi
		i=$[i+1]
	done
} # end get_interval_seconds()

# rotate through the various intervals
rotate() {
	while read -r ignore interval keep; do
		# if we have enough to rotate
		if [[ -d $root$interval.$[$keep-1] ]]; then
			#log "have enough $interval to rotate, checking for next period"
			next=$(get_next_interval $interval)
			if [[ ! -z $next ]]; then
				next_dir="$root$next.0"
				should_rotate=0
				if [[ ! -d "$next_dir" ]]; then
					log "rotating $next because $next_dir missing"
					rsnapshot_cmd "$next"
				else
					next_mtime="$(date +%s --reference="$next_dir")"
					next_mgap=$[$(date +%s)-$next_mtime]
					next_mgap_wanted=$(get_interval_seconds "$next")
					if [[ $next_mgap -ge $next_mgap_wanted ]]; then
						log "Rotating $next because $next.0 is old ($next_mgap seconds, want $next_mgap_wanted)"
						rsnapshot_cmd "$next"
					fi
				fi
			fi
		fi
	done < <(grep ^interval "$config_file")
} # end rotate()

# check if last valid snapshot older than defined runner-check time
fresh() {
	if [[ ! -f $success_file ]]; then
		return 1
	fi
	last_mtime=$(date +%s --reference="$success_file")
	last_gap=$(($(date +%s)-$last_mtime))
	if [[ $last_gap -ge $check_time ]]; then
		return 1
	fi
} # end fresh()

# execute a single rsnapshot command
rsnapshot_cmd() {
	perl rsnapshot.pl -c "$config_file" "$@"
	return $?
}

# run rsnapshot with whatever the smallest defined period is
take_snapshot() {
	log "Taking a snapshot"
	if [[ $sync_first = 1 ]]; then
		rsnapshot_cmd sync && rsnapshot_cmd "${interval_names[0]}"
		status=$?
	else
		rsnapshot_cmd "${interval_names[0]}"
		status=$?
	fi

	du -sh "${root}"* > "${root}du.out"

	if [[ $status = 0 ]]; then
		log "Snapshot succeeded"
		touch "$success_file"
	else
		log "Snapshot failed"
	fi
} # end take_snapshot()

if ! fresh; then
	rotate
	take_snapshot
	sync
fi