retention.bash

1 files changed, 71 insertions, 0 deletions

diff --git a/retention.bash b/retention.bash
new file mode 100755
index 0000000..149bc7a
--- /dev/null
+++ b/retention.bash
@@ -0,0 +1,71 @@
+#!/bin/bash
+
+datetime_regexp='[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]T[0-9][0-9]:[0-9][0-9]:[0-9][0-9],[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]-[0-9][0-9]:[0-9][0-9]'
+
+main()
+{
+        [ $# = 1 ] || exit
+        case "$1" in
+                /*) ;;
+                *) exit 1 ;;
+        esac
+
+        find "$1" -maxdepth 1 -type d -name '.snapshot~'"$datetime_regexp" | sort -n | retain
+}
+
+is_readonly_subvolume()
+{
+        return 0
+        btrfs subvolume show -- "$1" | egrep -q '^      Flags:.*\breadonly\b'
+}
+
+retain()
+{
+        _year= _month= _day= _hour= _minute= _second= _nanosecond=
+        now=$(date +%s)
+        while read line
+        do
+                dateline=${line#*/.snapshot~}
+                before=$(date -d "$dateline" +%s)
+                age=$((now - before))
+
+                IFS='~-T:,' read year month day hour minute second nanosecond <<< "$dateline"
+
+                keep=
+                if [ "$year" != "$_year" ]
+                then
+                        keep="$year -> $line"
+                elif [ "$month" != "$_month" ] && [ "$age" -lt $((365 * 24 * 60 * 60)) ]
+                then
+                        keep="$year-$month -> $line"
+                elif [ "$day" != "$_day" ] && [ "$age" -lt $((7 * 24 * 60 * 60)) ]
+                then
+                        keep="$year-$month-$day -> $line"
+                elif [ "$hour" != "$_hour" ] && [ "$age" -lt $((24 * 60 * 60)) ]
+                then
+                        keep="$year-$month-${day}T$hour -> $line"
+                elif [ "$minute" != "$_minute" ] && [ "$age" -lt $((60 * 60)) ]
+                then
+                        keep="$year-$month-${day}T$hour:$minute -> $line"
+                elif [ "$age" -lt 60 ]
+                then
+                        keep="recent -> $line"
+                fi
+
+                if [ "$keep" ]
+                then
+                        echo "$keep" >&2
+                else
+                        btrfs subvolume delete "$line"
+                fi
+
+                _year=$year
+                _month=$month
+                _day=$day
+                _hour=$hour
+                _minute=$minute
+                _second=$second
+        done
+}
+
+main "$@"