Files
dsnap-sync/bin/snap-sync
Ralf Zerres 4b6a06f885 snap-sync: 0.4.3 version bump (inital posix version)
- use dash as reference shell
- refine all bashism to posix calls
- convert bash arrays to posix "pseudo arrays"
  yes, posix does not support handy arrays
- introduce global/local variables
- using (hopefully) more descriptive variable names
- new function verify_snapper_structure()
  that takes care to construct target snapper file-structure
  as needed
- 0.4.3 bump version

Signed-off-by: Ralf Zerres <ralf.zerres@networkx.de>
2017-11-22 21:59:18 +01:00

692 lines
22 KiB
Bash
Executable File

#!/bin/sh
# snap-sync
# https://github.com/wesbarnett/snap-sync
# Copyright (C) 2016, 2017 James W. Barnett
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# -------------------------------------------------------------------------
# Takes snapshots of each snapper configuration. It then sends the snapshot to
# a location on an external drive. After the initial transfer, it does
# incremental snapshots on later calls. It's important not to delete the
# snapshot created on your system since that will be used to determine the
# difference for the next incremental snapshot.
progname="`basename v$0`"
version="0.4.3"
# The following line is modified by the Makefile or
# find_snapper_config script
SNAPPER_CONFIG=/etc/conf.d/snapper
TMPDIR=$(mktemp -d)
PIPE=$TMPDIR/$progname.out
mkfifo $PIPE
systemd-cat -t "$progname" < $PIPE &
exec 3>$PIPE
# global variables
#disk_uuid_$i
disk_count=-1
disk_uuid_match_count=0
disk_uuid_match=''
selected_uuid='none'
selected_target='none'
selected_subvol='none'
###
# functions
###
check_prerequisites () {
# requested binaries:
which awk >/dev/null 2>&1 || { echo "'awk' is not installed." && exit 1; }
which sed >/dev/null 2>&1 || { echo "'sed' is not installed." && exit 1; }
which tee >/dev/null 2>&1 || { echo "'tee' is not installed." && exit 1; }
which btrfs >/dev/null 2>&1 || { echo "'btrfs' is not installed." && exit 1; }
which findmnt >/dev/null 2>&1 || { echo "'findmnt' is not installed." && exit 1; }
which notify-send >/dev/null 2>&1 || { echo "'notify-send' is not installed." && exit 1; }
if [ $(id -u) -ne 0 ] ; then echo "Script must be run as root" ; exit 1 ; fi
if [ ! -r "$SNAPPER_CONFIG" ]; then
die "$SNAPPER_CONFIG does not exist."
fi
}
die () {
error "$@"
exit 1
}
error () {
printf "==> ERROR: %s\n" "$@"
notify_error 'Error' 'Check journal for more information.'
} >&2
get_disk_infos () {
local disk_uuid
local disk_target
local fs_option
# get mounted BTRFS infos
if [ "$(findmnt --noheadings --nofsroot --target / --output FSTYPE)" = "btrfs" ]; then
exclude_uuid=$(findmnt --noheadings --nofsroot --types btrfs --target / --output UUID)
disk_uuids=$($ssh findmnt --noheadings --nofsroot --types btrfs --output UUID,TARGET --list | grep -v $exclude_uuid | awk '{print $1}')
disk_targets=$($ssh findmnt --noheadings --nofsroot --types btrfs --output UUID,TARGET --list | grep -v $exclude_uuid | awk '{print $2}')
else
disk_uuids=$($ssh findmnt --noheadings --nofsroot --types btrfs --output UUID --list)
disk_targets=$($ssh findmnt --noheadings --nofsroot --types btrfs --output UUID,TARGET --list)
fi
# we need at least one target disk
if [ ${#disk_targets} -eq 0 ]; then die "no suitable target disk found \n"die
fi
# Posix Shells do not support Array. Therefore using ...
# Pseudo-Arrays (assumption: equal number of members)
# Pseudo-Array: disk_uuid_$i
# Pseudo-Array: disk_target_$i
# Pseudo-Array: disk_selected_$y (reference to $i element)
# List: disk_uuid_match (reference to matching preselected uuids)
# initialize our structures
i=0
for disk_uuid in $disk_uuids; do
if [ "$disk_uuid" = "$uuid_cmdline" ]; then
if [ ${#disk_uuid_match} -gt 0 ]; then
disk_uuid_match="${disk_uuid_match} $i"
else
disk_uuid_match="$i"
fi
disk_uuid_match_count=$(($disk_uuid_match_count+1))
fi
eval "disk_uuid_$i='$disk_uuid'"
disk_count=$(($disk_count+1))
i=$((i+1))
done
i=0
for disk_target in $disk_targets; do
eval "disk_target_$i='$disk_target'"
i=$((i+1))
done
}
notify () {
if [ nonotify ]; then
printf "%s %s\n" "$progname" "$2"
else
for u in $(users | sed 's/ /\n/' | sort -u); do
sudo -u $u DISPLAY=:0 \
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$(sudo -u $u id -u)/bus \
notify-send -a $progname "$1" "$2" --icon="dialog-$3"
done
fi
}
notify_info () {
notify "$1" "$2" "information"
}
notify_error() {
notify "$1" "$2" "error"
}
parse_params () {
###
# Evaluate given call parameters
###
while [ $# -gt 0 ]; do
key="$1"
case $key in
-h | --help | \-\? | --usage)
# Call usage() function.
usage
;;
-d|--description)
description="$2"
shift 2
;;
-c|--config)
selected_config="$2"
shift 2
;;
--config=*)
selected_config=${1#*=}
shift
;;
-u|--UUID)
uuid_cmdline="$2"
shift 2
;;
--UUID=*)
uuid_cmdline=${1#*=}
shift
;;
-n|--noconfirm)
noconfirm=1
nonotify=1
shift
;;
--remote)
remote=$2
ssh="ssh $remote"
shift 2
;;
-v|--verbose)
verbose=1
shift 1
;;
--) # End of all options
shift
break
;;
-*)
echo "WARN: Unknown option (ignored): $1" >&2
#shift
exit 1
;;
*)
die "Unknown option: $key\nRun '$progname -h' for valid options.\n"
;;
esac
done
# Set reasonable defaults
. $SNAPPER_CONFIG
selected_configs=${selected_configs:-$SNAPPER_CONFIGS}
description=${description:-"latest incremental backup"}
uuid_cmdline=${uuid_cmdline:-"none"}
target_cmdline=${target_cmdline:-"none"}
if [ -z $remote ]; then
ssh=""
fi
if [ "$verbose" ]; then
echo "Snap UUID : '$uuid_cmdline'"
echo "Snap Description: '$description'"
echo "Snap Config: '$selected_config'"
echo "Snap Remote: '$ssh'"
if [ "$verbose" ]; then snap_sync_options="verbose=true"; fi
if [ "$noconfirm" ]; then snap_sync_options="${snap_sync_options} noconfirm=true"; fi
echo "Options: ${snap_sync_options}"
fi
}
run_config () {
printf "\nVerify configuration...\n" | tee $PIPE
# commandline selection takes precedence
if [ -n "$selected_config" ]; then
selected_configs=$selected_config
fi
# Pseudo Arrays $i -> store associated elements of selected_config
i=0
for selected_config in $selected_configs; do
count=$(eval snapper -c $selected_config list -t single | awk '/uuid='"$selected_uuid"'/, /subvolid'="$selected_subvol"'/ {cnt++} END {print cnt}')
#count=$(eval snapper -c $selected_config list -t single | grep -c -e "subvolid=$selected_subvol" -e 'uuid=$selected_uuid')
if [ -n "$count" ] && [ "$count" -gt 1 ]; then
error "More than one snapper entry found with UUID $selected_uuid for configuration '$selected_config'. Skipping configuration '$selected_config'."
selected_configs=$(echo $selected_configs | sed -e "s/\($selected_config*\)//")
if [ "$verbose" ]; then
printf "Counter=%s" "$count"
fi
continue
fi
# active, non finished snapshot backups are marked with following string
# "$progname backup in progress" (snapper description field)
snapper_failed_ids=$(eval snapper -c $selected_config list -t single | awk '/'"$progname"' backup in progress/ {cnt++} END {print cnt}')
if [ -n "$snapper_failed_ids" ]; then
printf "\nNOTE: Previous failed %s backup snapshots found for '%s'.\n" "$progname" "$selected_config" | tee $PIPE
read -r -p "Delete failed backup snapshots [y/N]? " delete_failed
#get_answer_yes_no
while [ -n "$delete_failed" ] &&
[ "$delete_failed" != "Yes" ] &&
[ "$delete_failed" != "yes" ] &&
[ "$delete_failed" != "Y" ] &&
[ "$delete_failed" != "y" ] &&
[ "$delete_failed" != "No" ] &&
[ "$delete_failed" != "no" ] &&
[ "$delete_failed" != "N" ] &&
[ "$delete_failed" != "n" ]; do
read -r -p "Delete failed backup snapshots [y/N]? " delete_failed
if [ -n "$delete_failed" ] &&
[ "$delete_failed" != "Yes" ] &&
[ "$delete_failed" != "yes" ] &&
[ "$delete_failed" != "Y" ] &&
[ "$delete_failed" != "y" ] &&
[ "$delete_failed" != "No" ] &&
[ "$delete_failed" != "no" ] &&
[ "$delete_failed" != "N" ] &&
[ "$delete_failed" != "n" ]; then
printf "Select 'y' or 'N'.\n"
fi
done
if [ "$delete_failed" = "Yes" ] ||
[ "$delete_failed" = "yes" ] ||
[ "$delete_failed" = "Y" ] ||
[ "$delete_failed" = "y" ]; then
snapper -c $selected_config delete $(snapper -c $selected_config list | awk '/'"$progname"' backup in progress/ {print $3}')
fi
fi
SNAP_SYNC_EXCLUDE=no
if [ -f "/etc/snapper/configs/$selected_config" ]; then
. /etc/snapper/configs/$selected_config
if [ "$SUBVOLUME" = "/" ]; then
SUBVOLUME=''
fi
else
die "Selected snapper configuration $selected_config does not exist."
fi
if [ $SNAP_SYNC_EXCLUDE = "yes" ]; then
continue
fi
printf "\n"
# processed snapshot backup is marked with userdata key/value pairs
# backupdir, uuid
snapper_sync_id=$(eval snapper -c "$selected_config" list -t single | awk '/uuid='"$selected_uuid"'/ {print $1}')
if [ ${#snapper_sync_id} -gt 0 ]; then
snapper_sync_snapshot=$SUBVOLUME/.snapshots/$snapper_sync_id/snapshot
fi
eval "snapper_sync_id_$i='$snapper_sync_id'"
eval "snapper_sync_snapshot_$i='$snapper_sync_snapshot'"
if [ -z "$snapper_sync_id" ]; then
printf "No backups have been performed for snapper config '%s' on target disk.\n" "$selected_config"
if [ $noconfirm ]; then
# go with defaults
if [ "$verbose" ]; then
printf "using defaults\n"
fi
else
read -r -p "Enter name of directory to store backups, relative to $selected_target (to be created if not existing): " backupdir
fi
if [ -z "$backupdir" ]; then
backup_root="$selected_target"
else
backup_root="$selected_target/$backupdir"
fi
### Todo: if interactive, e.g use pv to show progress
printf "Please be pacient, the initial backup could take awhile.\n"
else
if [ "$verbose" ]; then
printf "Last syncronized Snapshot-ID for '%s': %s\n" "$selected_config" "$snapper_sync_id"
printf "Last syncronized Snapshot-Path for '%s': %s\n" "$selected_config" "$snapper_sync_snapshot"
fi
backupdir=$(snapper -c "$selected_config" list -t single | awk -F "|" '/'"$selected_uuid"'/ {print $5}' | awk -F "," '/backupdir/ {print $1}' | awk -F"=" '{print $2}')
backup_root="$selected_target/$backupdir"
$ssh test -d $backup_root || die "%s is not a directory on %s.\n" "$backup_root" "$selected_uuid"
fi
eval "backup_root_$i=$backup_root"
eval "backup_dir_$i=$backupdir"
if [ "$verbose" ]; then
if [ -n "$ssh" ];then
printf "Backup-Path on remote %s: %s/%s\n" "$remote" "$backup_root" "backupdir"
else
printf "Backup-Path: %s/%s\n" "$backup_root" "backupdir"
fi
fi
# acting on source system
printf "Creating new snapshot for snapper config '%s' ...\n" "$selected_config" | tee $PIPE
snapper_new_id=$(snapper -c "$selected_config" create --print-number -d "$progname backup in progress")
snapper_new_snapshot=$SUBVOLUME/.snapshots/$snapper_new_id/snapshot
snapper_new_info=$SUBVOLUME/.snapshots/$snapper_new_id/info.xml
sync
snapper_target_snapshot=$backup_root/$selected_config/$snapper_new_id
if [ -z "$ssh" ]; then
printf "Will backup %s to %s\n" "$snapper_new_snapshot" "$snapper_target_snapshot/snapshot" | tee $PIPE
else
printf "Will backup %s to %s\n" "$snapper_new_snapshot" "$remote":"$snapper_target_snapshot/snapshot" | tee $PIPE
fi
# save in config specific infos in pseudo Arrays
eval "snapper_new_id_$i='$snapper_new_id'"
eval "snapper_new_snapshot_$i='$snapper_new_snapshot'"
eval "snapper_new_info_$i='$snapper_new_info'"
eval "snapper_config_$i='$selected_config'"
eval "snapper_target_subvol_$i='$snapper_target_subvol'"
eval "snapper_target_snapshot_$i='$snapper_target_snapshot'"
cont_backup="K"
eval "snapper_activate_$i=yes"
if [ $noconfirm ]; then
cont_backup="yes"
else
while [ -n "$cont_backup" ] &&
[ "$cont_backup" != "Yes" ] &&
[ "$cont_backup" != "yes" ] &&
[ "$cont_backup" != "Y" ] &&
[ "$cont_backup" != "y" ] &&
[ "$cont_backup" != "No" ] &&
[ "$cont_backup" != "no" ] &&
[ "$cont_backup" != "N" ] &&
[ "$cont_backup" != "n" ]; do
read -r -p "Continue with backup [Y/n]? " cont_backup
if [ -n "$cont_backup" ] &&
[ "$cont_backup" != "Yes" ] &&
[ "$cont_backup" != "yes" ] &&
[ "$cont_backup" != "Y" ] &&
[ "$cont_backup" != "y" ] &&
[ "$cont_backup" != "No" ] &&
[ "$cont_backup" != "no" ] &&
[ "$cont_backup" != "N" ] &&
[ "$cont_backup" != "n" ]; then
printf "Select 'Y' or 'n'.\n"
fi
done
fi
if [ "$cont_backup" != "Yes" ] &&
[ "$cont_backup" != "yes" ] &&
[ "$cont_backup" != "Y" ] &&
[ "$cont_backup" != "y" ] &&
[ -n "$cont_backup" ]; then
eval "snapper_activate_$i=no"
printf "Aborting backup for this configuration.\n"
snapper -c $selected_config delete $snapper_new_id
fi
i=$(($i+1))
done
}
run_backup () {
# Actual backing up
printf "\nPerforming backups...\n" | tee $PIPE
i=-1
for selected_config in $selected_configs; do
i=$(($i+1))
SNAP_SYNC_EXCLUDE=no
if [ -f "/etc/snapper/configs/$selected_config" ]; then
. /etc/snapper/configs/$selected_config
else
die "Selected snapper configuration '$selected_config' does not exist."
fi
cont_backup=$(eval echo \$snapper_activate_$i)
if [ "$cont_backup" = "no" ] || [ "$SNAP_SYNC_EXCLUDE" = "yes" ]; then
notify_info "Backup in progress" "NOTE: Skipping '$selected_config' configuration."
continue
fi
notify_info "Backup in progress" "Backing up data for configuration '$selected_config'."
printf "\n"
# retrieve config specific infos from pseudo Arrays
snapper_config=$(eval echo \$snapper_config_$i)
backup_root=$(eval echo \$backup_root_$i)
backup_dir=$(eval echo \$backup_dir_$i)
snapper_sync_id=$(eval echo \$snapper_sync_id_$i)
snapper_new_id=$(eval echo \$snapper_new_id_$i)
snapper_sync_snapshot=$(eval echo \$snapper_sync_snapshot_$i)
snapper_new_snapshot=$(eval echo \$snapper_new_snapshot_$i)
snapper_new_info=$(eval echo \$snapper_new_info_$i)
snapper_target_snapshot=$(eval echo \$snapper_target_snapshot_$i)
# verify target structure for backupdir
verify_snapper_structure $backup_root $snapper_config $snapper_new_id
if [ -z "$snapper_sync_id" ]; then
cmd="btrfs send $snapper_new_snapshot | $ssh btrfs receive $snapper_target_snapshot"
printf "Sending first snapshot for snapper config '%s'...\n" "$selected_config" | tee $PIPE
if [ "$verbose" ]; then
printf "$cmd"
fi
btrfs send "$snapper_new_snapshot" | $ssh btrfs receive "$snapper_target_snapshot" &>/dev/null
else
printf "Sending incremental snapshot for snapper config '%s'...\n" "$selected_config" | tee $PIPE
# Sends the difference between the new snapshot and old snapshot to the
# backup location. Using the -c flag instead of -p tells it that there
# is an identical subvolume to the old snapshot at the receiving
# location where it can get its data. This helps speed up the transfer.
cmd="btrfs send -c $snapper_sync_snapshot $snapper_new_snapshot | $ssh btrfs receive $snapper_target_snapshot"
$cmd &>/dev/null
if [ "$verbose" ]; then
printf "$cmd"
printf "Deleting sync snapshot for %s...\n" "$selected_config" | tee $PIPE
fi
btrfs send -c "$snapper_sync_snapshot" "$snapper_new_snapshot" | $ssh btrfs receive "$snapper_target_snapshot" &>/dev/null
snapper -c "$selected_config" delete "$snapper_sync_id"
fi
if [ -z "$ssh" ]; then
cp "$snapper_new_info" "$snapper_target_snapshot"
else
rsync -avzq "$snapper_new_info" "$remote":"$snapper_target_snapshot"
fi
# It's important not to change the values of the key/value pairs ($userdata)
# which is stored in snappers info.xml file of the source snapshot.
# This is how we find the parent.
userdata="backupdir=$backup_dir, uuid=$selected_uuid"
# Tag new snapshot as the latest
printf "Tagging new snapshot as latest backup for '%s' ...\n" "$selected_config" | tee $PIPE
snapper -v -c "$selected_config" modify -d "$description" -u "$userdata" "$snapper_new_id"
printf "Backup complete for snapper configuration '%s'.\n" "$selected_config" > $PIPE
done
exec 3>&-
}
select_target_disk () {
local i=0
local disk_id=0
#local disk_selected_ids=''
local disk_selected_count=0
# print selection table
if [ -z "$ssh" ]; then
printf "Selecting a mounted BTRFS device for backups on your local machine.\n"
else
printf "Selecting a mounted BTRFS device for backups on %s.\n" "$remote"
fi
while [ "$disk_id" -eq -1 ] || [ "$disk_id" -le $disk_count ]; do
if [ "$disk_uuid_match_count" -gt 1 ]; then
# got UUID selection from commandline
disk_count=$disk_uuid_match_count
if [ "$verbose" ]; then
printf "%s mount points were found with UUID '%s'.\n" "$disk_uuid_match_count" "$uuid_cmdline"
fi
for disk_uuid in $disk_uuid_match; do
# Pseudo-Array: disk_selected_$i (reference to $disk_uuid element)
eval "disk_selected_$i='$disk_uuid'"
disk=$(eval echo \$disk_uuid_$disk_uuid)
target=$(eval echo \$disk_target_$disk_uuid)
printf "%4s) %s %s\n" "$i" "$disk" "$target"
i=$((i+1))
done
else
while [ "$disk_id" -le $disk_count ]; do
# present all mounted BTRFS filesystems
# Pseudo-Array: disk_selected_$i (reference to $disk_id element)
eval disk_selected_$i="$disk_id"
disk=$(eval echo \$disk_uuid_$disk_id)
target=$(eval echo \$disk_target_$disk_id)
printf "%4s) %s %s\n" "$disk_id" "$disk" "$target"
i=$((i+1))
disk_id=$(($disk_id+1))
done
fi
printf "%4s) Exit\n" "x"
read -r -p "Enter a number: " disk_selected
case $disk_selected in
x)
break
;;
[0-9][0-9]|[0-9])
if [ "$disk_selected" -gt "$disk_count" ]; then
disk_id=0
i=0
else
break
fi
;;
*)
printf "\nNo disk selected. Select a disk to continue.\n"
disk_id=0
i=0
;;
esac
done
if [ "$disk_selected" = x ]; then
exit x
fi
selected_uuid=$(eval echo \$disk_uuid_$disk_selected)
selected_target=$(eval echo \$disk_target_$disk_selected)
}
traperror () {
printf "Exited due to error on line %s.\n" $1
printf "exit status: %s\n" "$2"
printf "command: %s\n" "$3"
printf "bash line: %s\n" "$4"
printf "function name: %s\n" "$5"
exit 1
}
trapkill () {
die "Exited due to user intervention."
}
# bashism
#trap 'traperror ${LINENO} $? "$BASH_COMMAND" $BASH_LINENO "${FUNCNAME[@]}"' ERR
#trap trapkill SIGTERM SIGINT
usage () {
cat <<EOF
$progname $version
Usage: $progname [options]
Options:
-d, --description <desc> Change the snapper description. Default: "latest incremental backup"
-c, --config <config> Specify the snapper configuration to use. Otherwise will perform for each snapper
configuration. Can list multiple configurations within quotes, space-separated
(e.g. -c "root home").
-n, --noconfirm Do not ask for confirmation for each configuration. Will still prompt for backup
directory name on first backup"
-u, --UUID <UUID> Specify the UUID of the mounted BTRFS subvolume to back up to. Otherwise will prompt."
If multiple mount points are found with the same UUID, will prompt user."
--remote <address> Send the snapshot backup to a remote machine. The snapshot will be sent via ssh. You
should specify the remote machine's hostname or ip address. The 'root' user must be
permitted to login on the remote machine.
-v, --verbose Be more verbose on what's going on.
EOF
exit 1
}
verify_snapper_structure () {
local backup_root=$1
local snapper_config=$2
local snapper_id=$3
if [ "$verbose" ]; then
echo "Verify snapper filesystem structure on target ..."
fi
# if not accessible, create backup-path
if $ssh [ ! -d $backup_root/$snapper_config ]; then
if [ "$verbose" ]; then
echo "Create backup-path $backup_root/$snapper_config"
fi
$ssh mkdir --mode=0700 --parents $backup_root/$snapper_config
fi
if $ssh [ ! -d $backup_root/$snapper_config/$snapper_id ]; then
if [ "$verbose" ]; then
echo "Create backup-path $backup_root/$snapper_config/$snapper_id"
fi
$ssh mkdir --mode=0700 $backup_root/$snapper_config/$snapper_id
fi
}
###
# Main
###
cwd=`pwd`
ssh=""
parse_params $@
check_prerequisites
# read mounted BTRFS structures
get_disk_infos
if [ "$uuid_cmdline" != "none" ]; then
if [ -z $ssh ]; then
notify_info "Backup started" "Starting backups to $uuid_cmdline..."
else
notify_info "Backup started" "Starting backups to $uuid_cmdline at $remote..."
fi
else
if [ -z $ssh ]; then
notify_info "Backup started" "Starting backups. Use command line menu to select disk."
else
notify_info "Backup started" "Starting backups. Use command line menu to select disk on $remote."
fi
fi
# select the target BTRFS subvol
select_target_disk
printf "\nYou selected the disk with UUID %s.\n" "$selected_uuid" | tee $PIPE
if [ -z $ssh ]; then
printf "The disk is mounted at %s.\n" "$selected_target" | tee $PIPE
else
printf "The disk is mounted at %s:%s.\n" "$remote" "$selected_target" | tee $PIPE
fi
# create and initialize structures for snapper configs
run_config
# run backups using btrfs-send -> btrfs-receive
run_backup
if [ "$uuid_cmdline" != "none" ]; then
notify_info "Finished" "Backups to $uuid_cmdline complete!"
else
notify_info "Finished" "Backups complete!"
fi