#!/bin/bash

# Author: Alan J. Pippin
# Description: This script calls zfs-replicate for each filesystem needing
#              to be backed up, or replicated, to another ZFS pool.

# Setup some default values
replicate="/usr/local/etc/bin/zfs-replicate"
logfile_parser="/usr/local/etc/bin/zfs-log-parser"
logfile="/var/log/zfs/zfs-replicate.log"
lockdir="/tmp/zfs-admin-lock"
mailto=root
destpool="backups"
maxsleeptime=60
maxattempts=600
released_lock_date=0
date=`date`

# Setup our cleanup and exit trap
cleanup() { 
  rm -rf "$lockdir"
  if [ $released_lock_date == 0 ]; then 
    zpool export $destpool
    /usr/local/etc/bin/ext-drive-power off
    echo `date` ZFS admin lock released >> $logfile
  fi
  exit
}
trap cleanup INT

# Auto snapshot every zfs filesystem on the system specified below
echo "$date Polling for ZFS admin lock" >> $logfile

# Poll for a lock on the zfs subsystem, and make the lock once we can do so
attempts=0
while true; do
  if ! mkdir "$lockdir" >/dev/null 2>&1; then
    # Another zfs admin tool is running.
    # Wait a random amount of time and try again
    ransleep=$(($RANDOM % $maxsleeptime))
    sleep $ransleep
    ((attempts=attempts+1))
  else 
    # No other zfs admin tool is running, we can now.
    break
  fi
  if [[ $attempts -gt $maxattempts ]]; then
    # We've exceeded our maximum while loop count
    ls -ld $lockdir | /usr/bin/mailx -s "zfs-replicate-all unable to obtain zfs admin lock" $mailto
    exit 1
  fi
done
date=`date`;
echo "$date ZFS admin lock obtained" >> $logfile

# Poweron the destpool and import it
/usr/local/etc/bin/ext-drive-power on >> $logfile
zpool import $destpool

# List the filesystems to replicate
# The parent filesystems MUST be listed ahead
# of the children filesystems.
# Pool root filesystems must end with a slash.
$replicate tank/ $destpool
$replicate tank/var $destpool
$replicate tank/usr $destpool
$replicate tank/usr/home $destpool
$replicate tank/usr/videos $destpool
$replicate tank/usr/local $destpool
$replicate tank/usr/local/etc $destpool
$replicate tank/usr/local/var $destpool
$replicate tank/backup $destpool

# Export the destpool and power it down
zpool export $destpool
/usr/local/etc/bin/ext-drive-power off >> $logfile

# Release our lock
released_lock_date=1
echo `date` ZFS admin lock released >> $logfile

# Parse the log file and extract our backup stats
$logfile_parser "$logfile" "$date" >> $logfile

# clean things up and exit
cleanup