iotstack_backup_general

#!/bin/bash

# should not run as root
[ "$EUID" -eq 0 ] && echo "This script should NOT be run using sudo" && exit -1

# support user renaming of script
SCRIPT=$(basename "$0")

# the default name and correct extension type is
DEFAULTFILENAME="general-backup.tar.gz"

# $1 is required and is either path to a .tar.gz or path to a folder
# $2 is optional and is the runtag (yyyy-mm-dd_hhmm.host-name)
# $3 is optional and overrides the default file name

case "$#" in

  1)
    BACKUP_TAR_GZ=$(realpath "$1")
    ;;

  2 | 3)
    BACKUP_TAR_GZ=$(realpath "$1/$2.${3:-"$DEFAULTFILENAME"}")
    ;;

  *)
    echo "Usage 1: $SCRIPT path/to/$DEFAULTFILENAME"
    echo "Usage 2: $SCRIPT path/to/backupdir runtag {override}"
    echo "         (override defaults to $DEFAULTFILENAME)"
    exit -1
    ;;

esac

# fail safe if the file already exists - no accidental overwrites
if [ -e "$BACKUP_TAR_GZ" ] ; then
   echo "Error: $BACKUP_TAR_GZ already exists - will not be overwritten"
   exit -1
fi

# assumptions
IOTSTACK="$HOME/IOTstack"
COMPOSEPREFIX="docker-compose"
COMPOSE="$IOTSTACK/$COMPOSEPREFIX.yml"

# check the key assumptions
if ! [ -d "$IOTSTACK" -a -e "$COMPOSE" ] ; then
   echo "Error: One of the following does not exist:"
   echo "   $IOTSTACK"
   echo "   $COMPOSE"
   echo "This may indicate a problem with your installation."
   exit -1
fi

# define files/folders to be included in the backup
# (note - temporary file created in RAM)
BACKUP_INCLUDE="$(mktemp -p /dev/shm/)"
cat <<-INCLUSIONS >"$BACKUP_INCLUDE"
./services/
./volumes/
INCLUSIONS

# check that the items to be included exist
for INCLUDE in $(cat $BACKUP_INCLUDE); do
   I=$(realpath "$IOTSTACK/$INCLUDE")
   if [ ! -e "$I" ]; then
      echo "Error: $I does not exist. This may indicate a problem with your installation."
      exit -1
   fi
done

# add all docker-compose files in directory-relative form
for INCLUDE in "$IOTSTACK/$COMPOSEPREFIX".* ; do
   echo "."/$(basename "$INCLUDE") >> "$BACKUP_INCLUDE"
done

# define files/folders to be excluded from the backup
# (note - temporary file created in RAM)
BACKUP_EXCLUDE="$(mktemp -p /dev/shm/)"
cat <<-EXCLUSIONS >"$BACKUP_EXCLUDE"
./volumes/influxdb/*
./volumes/nextcloud/*
./volumes/postgres/*
./volumes/pihole.restored
EXCLUSIONS

# now we can begin
echo "----- Starting $SCRIPT at $(date) -----"

# create the file (sets ownership correctly)
touch "$BACKUP_TAR_GZ"

# perform the backup (relative to ~/IOTstack)
sudo tar \
	-czf "$BACKUP_TAR_GZ" \
	-C "$IOTSTACK" \
	-X "$BACKUP_EXCLUDE" \
	-T "$BACKUP_INCLUDE"

# report size of archive
du -h "$BACKUP_TAR_GZ"

# clean up the working files
rm $BACKUP_INCLUDE
rm $BACKUP_EXCLUDE

echo "----- Finished $SCRIPT at $(date) -----"