minecraft server differential backup

backup.sh

#!/usr/bin/env bash
# Runs a backup of the Hololive Fan Minecraft server and stores it offsite.
# Bits and pieces from https://github.com/nicolaschan/minecraft-backup (MIT License)

ROOT=/home/lae/.hololive-mc
MCROOT=$ROOT/data
WORLD=world
SAVEROOT=$ROOT/backups
OFFSITE_SAVEROOT="lae@10.17.3.10:/mnt/umaru/backups/hololive-mc"
SSH_ARGS="-i $ROOT/backup.key"
# the server should accept an rsync command with the above key, authorized_keys:
# command="rsync --server -vlogDtprCze.iLsfxC --delete . /mnt/umaru/backups/hololive-mc/" ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIJ7zsWDB0f9tJmDnMJnKUCNp79rUuIGMWfi6OAWaalf+ hololive-mc backup key
RCONCMD="docker-compose exec -T minecraft rcon-cli"

execute-command () {
  local COMMAND=$1
  cd $ROOT
  $RCONCMD "$COMMAND"
}

message-players () {
  local MESSAGE=$1
  local HOVER_MESSAGE=$2
  message-players-color "$MESSAGE" "$HOVER_MESSAGE" "gray"
}

message-players-error () {
  local MESSAGE=$1
  local HOVER_MESSAGE=$2
  message-players-color "$MESSAGE" "$HOVER_MESSAGE" "red"
}

message-players-success () {
  local MESSAGE=$1
  local HOVER_MESSAGE=$2
  message-players-color "$MESSAGE" "$HOVER_MESSAGE" "green"
}

message-players-color () {
  local MESSAGE=$1
  local HOVER_MESSAGE=$2
  local COLOR=$3
  if [[ -z "$HOVER_MESSAGE" ]]; then
    echo "$MESSAGE"
    execute-command "tellraw @a [\"\",{\"text\":\"[backup.sh] \",\"color\":\"gray\",\"italic\":true},{\"text\":\"$MESSAGE\",\"color\":\"$COLOR\",\"italic\":true}]"
  else
    echo "$MESSAGE ($HOVER_MESSAGE)"
    execute-command "tellraw @a [\"\",{\"text\":\"[backup.sh] \",\"color\":\"gray\",\"italic\":true},{\"text\":\"$MESSAGE\",\"color\":\"$COLOR\",\"italic\":true,\"hoverEvent\":{\"action\":\"show_text\",\"value\":{\"text\":\"\",\"extra\":[{\"text\":\"$HOVER_MESSAGE\"}]}}}]"
  fi
}

rdiff-backup --compare $MCROOT/$WORLD $SAVEROOT/$WORLD >/dev/null

if [[ $? -eq 0 ]]; then
    echo "No differences found. Not running backup."
    exit
fi

START_TIMESTAMP=$(date +%s)

echo "Creating a backup."

# Disable world autosaving
execute-command "save-off"

# Backup world
START_TIME=$(date +"%s")
rdiff-backup $MCROOT/$WORLD $SAVEROOT/$WORLD
RDIFF_STATUS=$?
rdiff-backup --remove-older-than 2W --force $SAVEROOT/$WORLD
CLEAN_STATUS=$?
sync
rsync -Cazz --info=STATS --delete -e "ssh $SSH_ARGS" $SAVEROOT/ $OFFSITE_SAVEROOT/
RSYNC_STATUS=$?
END_TIME=$(date +"%s")

# Enable world autosaving
execute-command "save-on"

# Save the world
execute-command "save-all"

# Notify players of completion
STATISTICS=$(rdiff-backup-statistics --begin-time $START_TIME $SAVEROOT/$WORLD)
CHANGED_SIZE=$(echo "$STATISTICS" | grep -oP "(?<=^TotalDestinationSizeChange ).*" | grep -oP "(?<=\().*(?=\))")
NEW_FILES=$(echo "$STATISTICS" | grep -oP "(?<=^NewFiles )\d+")
CHANGED_FILES=$(echo "$STATISTICS" | grep -oP "(?<=^ChangedFiles )\d+")
TIME_DELTA=$((END_TIME - START_TIME))

if [[ $RDIFF_STATUS -eq 0 && $CLEAN_STATUS -eq 0 && $RSYNC_STATUS -eq 0 ]]; then
  echo "success: $TIME_DELTAs, $CHANGED_SIZE changed (files: $CHANGED_FILES changed, $NEW_FILES new)"
else
  message-players-error "Backup failed to complete!" "Please notify @lae in #gaming."
  echo -e "rdiff: $RDIFF_STATUS\nclean: $CLEAN_STATUS\nrsync: $RSYNC_STATUS"
fi

holomc-backup.service

[Unit]
Description=Executes a backup of the Hololive Fan Minecraft server
Wants=holomc-backup.timer

[Service]
ExecStart=/home/lae/.hololive-mc/backup.sh
Slice=holomc-backup.slice

holomc-backup.timer

[Unit]
Description=Run Holo-MC backup every 8 hours
Requires=holomc-backup.service

[Timer]
Unit=holomc-backup.service
OnUnitActiveSec=1h

[Install]
WantedBy=timers.target