From ad7be843cc87beec1cd1a3ca486963b7f16b7f19 Mon Sep 17 00:00:00 2001
From: Alice Gaudon <alice@gaudon.pro>
Date: Wed, 5 Feb 2020 05:48:37 +0100
Subject: [PATCH] Add zfs_snapshot_cron.sh

---
 zfs_snapshot_cron.sh | 79 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100755 zfs_snapshot_cron.sh

diff --git a/zfs_snapshot_cron.sh b/zfs_snapshot_cron.sh
new file mode 100755
index 0000000..2b454e6
--- /dev/null
+++ b/zfs_snapshot_cron.sh
@@ -0,0 +1,79 @@
+#!/bin/bash
+
+PREFIX="zsc-"
+CONFIG_FILE="$HOME/.zfs_snapshot_cron"
+
+FORMAT='+%Y-%m-%d'
+DATE=$(date $FORMAT)
+
+split_date() {
+	echo "$1" | sed -E 's/([0-9]{4})-([0-9]{2})-([0-9]{2})/\1\n\2\n\3/'
+}
+
+handle_pool() {
+	POOL=$1
+	D=$2
+	W=$3
+	M=$4
+	Y=$5
+	echo "--- $POOL --- $D $W $M $Y"
+
+	SNAPSHOTS=($(zfs list -t snapshot -o name | grep "$POOL@$PREFIX" | sort -r))
+	echo "Snapshots: ${#SNAPSHOTS[@]}"
+
+	EXISTS=0
+	
+	for s in "${SNAPSHOTS[@]}"; do
+		sdate=$(echo "$s" | awk 'match($0, /.+@'"$PREFIX"'(.+)/, a) {print a[1]}')
+
+		if [ "$sdate" = $DATE ]; then
+			EXISTS=1
+		fi
+
+		scomp=($(split_date "$sdate") $(date -d "$sdate" "+%u %W"))
+
+		echo -n "${scomp[3]} ${scomp[4]} | "
+		
+		echo -n "${sdate}: "
+
+		if [ $D -gt 0 ]; then
+			D=$(( D-1 ))
+			echo "KEEP; D: $D"
+		elif [ $W -gt 0 ] && [ ${scomp[3]} -eq 1 ]; then
+			W=$(( W-1 ))
+			echo "KEEP; W: $W"
+		elif [ $M -gt 0 ] && [ ${scomp[3]} -eq 1 ] && [ $(( scomp[4] % 4 )) -eq 0 ]; then
+			M=$(( M-1 ))
+			echo "KEEP; M: $M"
+		elif [ $Y -gt 0 ] && [ ${scomp[3]} -eq 1 ] && [ ${scomp[4]} -eq 4 ]; then
+			Y=$(( Y-1 ))
+			echo "KEEP; Y: $Y"
+		else
+			zfs destroy "$s"
+			echo "DISCARD"
+		fi
+	done
+
+	if [ $EXISTS -eq 0 ]; then
+		echo -e "Creating snapshot $POOL@$PREFIX$DATE"
+		zfs snapshot $POOL@$PREFIX$DATE
+	fi
+}
+
+cat "$CONFIG_FILE" | while IFS=: read pool recursive d w m y; do
+	echo "| ##### Pool: $pool Recursive: $recursive d: $d w: $w m: $m y: $y #####"
+
+	if [ $recursive = "true" ]; then
+		SUBPOOLS=($(zfs list -o name | grep "$pool/"))
+		echo -e "Subpools: ${SUBPOOLS[@]}"
+		echo -e '|'
+		for p in "${SUBPOOLS[@]}"; do
+			handle_pool $p $d $w $m $y | awk '{print "| " $0}'
+			echo -e '|'
+		done
+	fi
+
+	handle_pool $pool $d $w $m $y | awk '{print "| " $0}'
+
+	echo -e "----------------------------------------------------------------------"
+done