autosnapshot

#!/bin/bash

# Log the script activity
exec 1> >(logger -s -t $(basename $0)) 2>&1

# Set the variables
# Distro subvolume name to snapshot and backup;
distro="@KDEneon"

# Source and backup parent file system mount points and devices with their UUIDs;
source_mount="/subvol/"
backup1_mount="/backup/"
backup2_mount="/backup2/"
source_device="/dev/sdc3"
backup1_device="/dev/sda4"
backup2_device="/dev/sdb3"
source_UUID=`lsblk -no UUID "$source_device"`
backup1_UUID=`lsblk -no UUID "$backup1_device"`
backup2_UUID=`lsblk -no UUID "$backup2_device"`

# Dates to do things;
today=_`date +%y%m%d`
## Age in days to remove snapshots.
snapremoveday=_`date +%y%m%d --date="-3 day"`
## Age in days to keep backups.
backupkeepday=_`date +%y%m%d --date="-7 day"`
## Age in days to remove backups.
backupremoveday=_`date +%y%m%d --date="-14 day"`

# Assemble the above variables into single variables;
## The source is the full path and distro subvolume name combined;
source="$source_mount""$distro"
## Snapshot name is the source with today's date appended;
newsnap="$source""$today"
## Snapshot to be deleted is the source with the snapshot removal date appended;
oldsnap="$source""$snapremoveday"
## Name for read-only snapshot used for backups is the source with _ro and today's date appended;
newbackup="$distro"_ro"$today"
## Name for the oldest backup is the subvolume name with the backup removal date appended;
oldbackup="$distro""$backupremoveday"

# Verify the parent file system is mounted and mount it if not;
if ! mountpoint -q "$source_mount"
then
    mount "$source_device" "$source_mount"
fi

# Delete the oldest snapshot;
if [ -d "$oldsnap" ]
    then
       btrfs su de -c "$oldsnap"
    fi

# Take a new read-write snapshot;
    btrfs su sn "$source" "$newsnap"
    touch "$newsnap"

# For backups; Take a read-only snapshot and send it to the backup
# locations, make backup snapshots bootable, and delete oldest backups.

# Verify it's backup day;
if [ `date +%w` = 0 ]
then

# Take a read-only snapshot
  btrfs su sn -r "$source" "$source_mount""$newbackup"

# Verify the backup file systems are mounted and mount them it if not;
    if ! mountpoint -q "$backup1_mount"
    then
        mount "$backup1_device" "$backup1_mount"
    fi
    if ! mountpoint -q "$backup2_mount"
    then
        mount "$backup2_device" "$backup2_mount"
    fi

# Delete oldest backups;
    if [ -d "$backup1_mount""$oldbackup" ]
    then
        btrfs su de -c "$backup1_mount""$oldbackup"
    fi
    if [ -d "$backup2_mount""$oldbackup" ]
    then
        btrfs su de -c "$backup2_mount""$oldbackup"
    fi

# Rename previous week's backups by adding backupkeepday;
    mv "$backup1_mount""$distro" "$backup1_mount""$distro""$backupkeepday"
    mv "$backup2_mount""$distro" "$backup2_mount""$distro""$backupkeepday"
## The renaming prepares the oldest backup to be deleted next week and renames
## the current backup so we're ready to receive the newest backup.

# Send the read-only snapshot to the backup locations;
    btrfs send "$source_mount""$newbackup" | btrfs receive "$backup1_mount"
    btrfs send "$source_mount""$newbackup" | btrfs receive "$backup2_mount"

# Take a read-write snapshot of the received backups and using the distro name;
    btrfs su sn "$backup1_mount""$newbackup" "$backup1_mount""$distro"
    btrfs su sn "$backup2_mount""$newbackup" "$backup2_mount""$distro"

# Delete read-only snapshots because they are no longer needed;
    btrfs su de -c "$backup1_mount""$newbackup"
    btrfs su de -c "$backup2_mount""$newbackup"
    btrfs su de -c "$source_mount""$newbackup"

# Edit the UUIDs in grub and fstab so the backups are bootable;
### NOT YET VERIFIED AS WORKING###
    sed -i "s@$source_UUID@$backup1_UUID@" "$backup1_mount""$distro"/etc/fstab
    sed -i "s@$source_UUID@$backup2_UUID@" "$backup2_mount""$distro"/etc/fstab
    sed -i "s@$source_UUID@$backup1_UUID@" "$backup1_mount""$distro"/boot/grub/grub.cfg
    sed -i "s@$source_UUID@$backup2_UUID@" "$backup2_mount""$distro"/boot/grub/grub.cfg
## This sed command is a replace-in-place action to change the UUIDs from the source to
## the backup file systems. The goal here is to make the backups bootable.
fi

# Notify of completion of tasks;
# Verify it's backup day;
if [ `date +%w` = 0 ]
# Notify that backup tasks are complete and the old backups and snapshot are deleted;
then
    su - stuart -c "notify-send -i package-install -t 0 'Desktop backup:' 'Backup made and sent. Old backups and snapshot removed.'"
else
# Notify that a snapshot has been taken and the old one deleted;
    su - stuart -c "notify-send -i package-install -t 0 'Desktop snapshot:' 'Daily snapshot made. Old snapshot removed.'"
fi

# Script complete
exit 0