#!/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
zfsreplicate="/etc/bin/zfs-replicate"
logfile_parser="/etc/bin/zfs-log-parser"
logfile="/var/log/zfs/zfs-replicate.log"
remote="tank.pippins.net"
local_pool=backups
mailto=root@pippins.net
date=`date`
starttime=`date +%s`
zfs=/usr/sbin/zfs

# Specify the list of filesystems to replicate
filesystems_to_replicate='
naspool/www
naspool/git
'

# Specify the maximum run time in minutes that this script can run
maxruntime=240

# This function checks to see if our runtime has exceeded our stoptime
timeexceeded() { 
  currenttime=`date +%s`  
  elapsedtime=$(($currenttime - $starttime))
  stoptime=$(($maxruntime*60))
  if [[ $elapsedtime -gt $stoptime ]]; then
    #echo "$elapsedtime > $stoptime"
    return 1
  fi
  #echo "$elapsedtime < $stoptime"
  return 0
}

# This function cleanup and exit trap
cleanup_and_exit() { 
  #echo "cleanup and exit"
  rm -rf "$lockdir"
  exit 0
}
trap cleanup_and_exit INT

# This function executes the replicate command and checks the stoptime
replicate() { 
  $zfsreplicate $*  >> $logfile 2>&1
  timeexceeded
  if [ $? == 1 ]; then
    cleanup_and_exit
  fi
}

# This function obtains the date a given snapshot was created in epoch seconds
snapshot_age() {
  snapshot=${local_pool}/${1}${previous_backup_marker}
  $zfs list -t snapshot ${snapshot} > /dev/null 2>&1
  if [ $? == 0 ]; then
    $zfs get creation ${snapshot} > /dev/null 2>&1
    if [ $? == 0 ]; then
      snap_creation=`$zfs get creation ${snapshot} | grep $1 | awk '{ print $3" "$4" "$5" "$6" "$7 }'`
      snap_age=`date -d "$snap_creation" +%s` 
      echo "$snap_age"
    else
      echo "0"
    fi
  else
    echo "0"
  fi
}

# Obtain the zpool guid for the local pool
local_pool_guid=`zpool get guid $local_pool 2>&1 | grep $local_pool | awk '{ print $3 }'`
zpool get guid $local_pool > /dev/null 2>&1
if [ $? != 0 ]; then
  echo >&2 "-E- Unable to extract the guid for the local pool: $local_pool"
  exit 1
fi

# Setup our backup marker names
current_backup_marker=@current-backup-${local_pool_guid}
previous_backup_marker=@previous-backup-${local_pool_guid}

# Auto snapshot every zfs filesystem on the system specified below
echo "$date ZFS replicate started" >> $logfile

# Sort the filesystems to replicate by the oldest backup first
tmpfile=`tempfile`
for filesystem in $filesystems_to_replicate; do
  age=`snapshot_age $filesystem`
  echo $filesystem $age >> $tmpfile
done
sorted_filesystems=`cat $tmpfile | sort -n -k 2 | awk '{ print $1 }'`
rm -f $tmpfile

# Replicate the sorted filesystems
for filesystem in $sorted_filesystems; do
  echo "-> Replicating $remote:$filesystem to ${local_pool}/${filesystem}"
  replicate $remote $filesystem
done

# All done
echo `date` ZFS replicate complete >> $logfile

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