#!/bin/bash
# Usage: ./docker_volume_backup.sh $SAVE_DIR
# Or: curl -s https://git.immiles.com/miles/scripts/raw/master/docker_volume_backup.sh | bash -s $SAVE_DIR

#set -ex

SAVE_DIR=$1
LOG_FILE=$HOME/logs/docker_volume_backup.log
DATE=`date +"%Y%m%d_%H%M%S"`

RETENTION=$((14*24*60))  # 2 weeks
KEEP=7

mkdir -p $HOME/logs

echo "--------------------------$DATE------------------------" >> $LOG_FILE
echo "[BEGIN] Backup docker volume" >> $LOG_FILE

# list and iterate volume 
volumes=( `docker volume ls | awk '{print $2}' | tail -n +2` )

for x in "${volumes[@]}"; do
  cmd="docker run --rm -v $x:/src -v $SAVE_DIR:/backup ubuntu tar --ignore-failed-read -jpcf /backup/${x}_${DATE}.tar.bz2 /src"
  echo $cmd >> $LOG_FILE
  eval $cmd >> $LOG_FILE 2>&1
done

# Clean up
find $SAVE_DIR -name "*.tar.bz2" -type f -printf '%T@ %p\n' -mmin +$RETENTION | sort -nr | tail -n +$KEEP | awk '{ print $2 }' | xargs -r rm >> $LOG_FILE 2>&1

echo "[Finish] Backup docker volume" >> $LOG_FILE
echo "--------------------------$DATE------------------------" >> $LOG_FILE

exit 0