#!/bin/bash

# (c) Wong Hoi Sing Edison <hswong3i@pantarei-design.com>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

set -euxo pipefail

PID_FILE="/var/run/${0##*/}.pid"
LOG_FILE="/var/log/${0##*/}.log"
TIMESTAMP=${TIMESTAMP:-$(date +%s)}

CEPHFS_DIR=${CEPHFS_DIR:-"/mnt/ceph"}
CEPHFS_SNAPSHOT_DIR=${CEPHFS_SNAPSHOT_DIR:-"$CEPHFS_DIR/.snap/$TIMESTAMP"}

RESTIC_OPTS=${RESTIC_OPTS:-"--verbose"}
RESTIC_REPOSITORY=${RESTIC_REPOSITORY:-"/root/backups/restic/ceph"}
RESTIC_PASSWORD_FILE=${RESTIC_PASSWORD_FILE:-"/root/.ssh/id_rsa"}
RESTIC_KEEP_HOURLY=${RESTIC_KEEP_HOURLY:-"24"}
RESTIC_KEEP_DAILY=${RESTIC_KEEP_DAILY:-"7"}
RESTIC_KEEP_WEEKLY=${RESTIC_KEEP_WEEKLY:-"5"}
RESTIC_KEEP_MONTHLY=${RESTIC_KEEP_MONTHLY:-"12"}
RESTIC_KEEP_YEARLY=${RESTIC_KEEP_YEARLY:-"7"}

exec 9>$PID_FILE
flock -n 9 || exit 1
renice 10 -p $$
echo $$ 1>&9

exec 1> >(tee -a $LOG_FILE) 2>&1

# CEPHFS - Mount
! mount $CEPHFS_DIR

# CEPHFS - Snapshot
mkdir -p $CEPHFS_SNAPSHOT_DIR

# RESTIC - Backup
cd $CEPHFS_SNAPSHOT_DIR
restic unlock \
    --repo $RESTIC_REPOSITORY \
    --password-file $RESTIC_PASSWORD_FILE \
    $RESTIC_OPTS
restic backup . \
    --repo $RESTIC_REPOSITORY \
    --password-file $RESTIC_PASSWORD_FILE \
    $RESTIC_OPTS

# CEPHFS - Cleanup
rmdir $CEPHFS_SNAPSHOT_DIR

# RESTIC - Rotation
restic forget \
    --prune \
    --group-by host \
    --keep-hourly $RESTIC_KEEP_HOURLY \
    --keep-daily $RESTIC_KEEP_DAILY \
    --keep-weekly $RESTIC_KEEP_WEEKLY \
    --keep-monthly $RESTIC_KEEP_MONTHLY \
    --keep-yearly $RESTIC_KEEP_YEARLY \
    --repo $RESTIC_REPOSITORY \
    --password-file $RESTIC_PASSWORD_FILE \
    $RESTIC_OPTS

# RESTIC - Snapshots
restic snapshots \
    --repo $RESTIC_REPOSITORY \
    --password-file $RESTIC_PASSWORD_FILE \
    $RESTIC_OPTS
