janitor

#!/bin/bash

ideal_free=10 # % of filesystem

video_size=600 # in seconds
nr_cameras=10  # number of cameras

shortest_rm_pause=1 
# delete rate at least 4x of the video recording rate
longest_rm_pause=$(($video_size / $nr_cameras / 4))

remove_old_videos() {
	target_free="$1"
	rm_pause=$shortest_rm_pause
	while true; do
		total=$(($(stat -f --format="%b" .)))
		free=$(($(stat -f --format="%a" .)))
		freepct=$(( $free * 100 / $total ))
		echo "Free ${freepct} target ${target_free}"

		if [ "$freepct" -ge "$target_free" ]; then
			break
		fi

		oldest=$(ls -c *.mkv | tail -1)

		if [ "$oldest" = "" ]; then
			echo "Disk full for other reason than videos!"
			# mail administrator
			break
		fi

		echo "Removing $oldest"
		prermfree=$free
		rm -f $oldest
		sleep $rm_pause
		sync
		free=$(($(stat -f --format="%a" .)))

		if ! [ "$free" -gt "$prermfree" ]; then
			echo "Free block count $free did not increase over $prermfree"
			rm_pause=$(($rm_pause * 2))
			if [ "$rm_pause" -gt "$longest_rm_pause" ]; then
				rm_pause=$longest_rm_pause
			fi
		       	echo "Increasing pause between removals to $rm_pause"
		fi
	done
}

while true; do
	total=$(($(stat -f --format="%b" .)))
	free=$(($(stat -f --format="%a" .)))
	freepct=$(( $free * 100 / $total ))
	date
	echo ${freepct}% free
	if [ "$freepct" -lt "$ideal_free" ]; then
		echo "Free space less than ${ideal_free}%"
		remove_old_videos $(($ideal_free + 1))

	fi
	sleep 3600
done