From acf82c432d1e8b75ef163ddac6501dcfb245ca43 Mon Sep 17 00:00:00 2001
From: Alice Gaudon <alice@gaudon.pro>
Date: Tue, 27 Oct 2020 15:15:22 +0100
Subject: [PATCH] Add zfs_backup.sh and zfs_backup_dataset.sh

---
 zfs_backup.sh         | 60 +++++++++++++++++++++++++++++++++++++
 zfs_backup_dataset.sh | 70 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 130 insertions(+)
 create mode 100755 zfs_backup.sh
 create mode 100755 zfs_backup_dataset.sh

diff --git a/zfs_backup.sh b/zfs_backup.sh
new file mode 100755
index 0000000..c97191d
--- /dev/null
+++ b/zfs_backup.sh
@@ -0,0 +1,60 @@
+#!/bin/sh
+
+if ! lockfile-create -p -r 2 $0; then
+	echo "Another backup is running, aborting"
+	exit 49
+fi
+
+
+### Arguments ###
+DATASET=$1
+if test -z "$DATASET"; then
+	echo "Missing dataset argument"
+	exit 1
+fi
+
+NAME=$2
+if test -z "$NAME"; then
+	echo "Missing snapshot name argument"
+	exit 1
+fi
+
+PREVIOUS_NAME=$3
+if test -z "$NAME"; then
+	echo "Missing previous snapshot name argument"
+	exit 1
+fi
+
+TARGET=$4
+if test -z "$TARGET"; then
+	echo "Missing target"
+	exit 1
+fi
+
+TARGET_PATH=$5
+if test -z "$TARGET_PATH"; then
+	echo "Missing target path"
+	exit 1
+fi
+
+SNAPSHOT="$DATASET@$NAME"
+PREVIOUS_SNAPSHOT="$DATASET@$PREVIOUS_NAME"
+REMOTE_NAME="$TARGET_PATH/"$(echo -e $DATASET | sed -r "s/\//_/g")
+
+
+# Take snapshot
+echo "Creating $SNAPSHOT snapshot..."
+zfs snapshot $SNAPSHOT || exit 1
+echo "Snapshot created."
+
+# Send snapshot
+echo "Sending snapshot ($PREVIOUS_SNAPSHOT --- $SNAPSHOT) to $REMOTE_NAME ..."
+if test ! -z "$PREVIOUS_NAME"; then
+	incr="-I $PREVIOUS_SNAPSHOT"
+fi
+zfs send -v -p $incr $SNAPSHOT | ssh $TARGET zfs receive -F $REMOTE_NAME || exit 1
+echo "Snapshot sent."
+
+# Remove lock
+echo "Backup finished. Removing lock..."
+lockfile-remove $0
diff --git a/zfs_backup_dataset.sh b/zfs_backup_dataset.sh
new file mode 100755
index 0000000..d538d26
--- /dev/null
+++ b/zfs_backup_dataset.sh
@@ -0,0 +1,70 @@
+#!/bin/sh
+
+DATASET=$1
+if test -z "$DATASET"; then
+	echo "Missing dataset argument"
+	exit 1
+fi
+
+TARGET=$2
+if test -z "$TARGET"; then
+	echo "Missing target"
+	exit 1
+fi
+
+TARGET_PATH=$3
+if test -z "$TARGET_PATH"; then
+	echo "Missing target path"
+	exit 1
+fi
+
+### New snapshot ###
+NAME=$(date +%Y-%m-%d_%H-%M-%S)
+SNAPSHOT="$DATASET@$NAME"
+
+echo "New snapshot name is: $NAME"
+echo "New snapshot is: $SNAPSHOT"
+
+
+### Default last snapshot ###
+DEFAULT_LAST_SNAPSHOT=$(zfs list -t snapshot -o name -s creation -H $DATASET | tail -n 1)
+DEFAULT_LAST_NAME=$(echo -e $DEFAULT_LAST_SNAPSHOT | rev | cut -d"@" -f1 | rev)
+echo "Default last snapshot is: $DEFAULT_LAST_SNAPSHOT"
+echo "Default last snapshot name is: $DEFAULT_LAST_NAME"
+
+
+### Tracking folder ###
+tracking_folder="$HOME/.local/share/zfs_backup"
+if test ! -d $tracking_folder; then
+	echo "Creating backup tracking files directory"
+	mkdir -p $tracking_folder
+fi
+
+
+### Last snapshot ###
+LAST_SNAPSHOT=$DEFAULT_LAST_SNAPSHOT
+
+last_snapshot_file="$tracking_folder/last_snapshot_"$(echo -e $DATASET | sed -r "s/\//_/g")
+if test -f $last_snapshot_file; then
+	LAST_SNAPSHOT=$(cat $last_snapshot_file)
+	echo "Found $last_snapshot_file"
+else
+	echo "No $last_snapshot_file, resolving to default"
+fi
+
+LAST_SNAPSHOT_NAME=$(echo -e $LAST_SNAPSHOT | rev | cut -d"@" -f1 | rev)
+
+echo "Last snapshot is: $LAST_SNAPSHOT"
+echo "Last snapshot name is: $LAST_SNAPSHOT_NAME"
+
+echo "Starting backup with args $DATASET $NAME $LAST_SNAPSHOT_NAME"
+$HOME/scripts/zfs_backup.sh $DATASET $NAME $LAST_SNAPSHOT_NAME $TARGET $TARGET_PATH || exit 1
+
+echo "Saving new snapshot in tracking folder..."
+echo -e $SNAPSHOT > $last_snapshot_file
+
+echo "Destroying last snapshot..."
+# zfs destroy $LAST_SNAPSHOT
+echo "(dry)"
+
+echo "Backup finished."