#!/usr/bin/perl

# settings
$SnapDir="/snapshots/mysql-data";
$SnapDev="/dev/vg/mysql-data-snapshot";
$MySQLDev="/dev/vg/mysql-data";

system ("touch /root/.backup_start.timestamp");

# determine verbosity settings
if ($ARGV[0] eq "-v") {
  $Verbose="y";
  $RsyncParams="-vaxSH --progress --delete";
  $MountParams="-v -t ext3 -o ro,noatime,nodiratime,noexec,nosuid";
  $UMountParams="-v";
} else {
  $Verbose="n";
  $RsyncParams="-axSH --delete";
  $MountParams="-t ext3 -o ro,noatime,nodiratime,noexec,nosuid";
  $UMountParams="";
}

# connect to the database
use DBI;
$DB=DBI->connect("DBI:mysql:mysql" . ";mysql_read_default_file=/root/.my.cnf", root, $password)
  or die "Could not connect to MySQL\n";

# flush and lock all tables
$DB->do("flush tables with read lock;")
  or die "Can't flush and lock tables: ",$DB->errstr,"\n";

# create the LVM snapshot device
system ("lvcreate -L10G -s -n mysql-data-snapshot $MySQLDev > /dev/null 2>&1") == 0
  or die "Can't create snapshot: $?\n";

# unlock the tables so MySQL can continue serving clients
$DB->do("unlock tables");
$DB->disconnect;

# mount up the snapshot volume
system ("mount $MountParams $SnapDev $SnapDir") == 0
  or die "Unable to mount snapshot: $?\n";

# figure out where we are backing up to
# output currently looks like:
# rmbackup@mysql01.futurequest.net:/backup/mysql/mysql17/
# however the rmbackup user is being deprecated.
$RemPath=`/usr/local/mysql-data/zbin/buddy_rempath.csh`;
chomp $RemPath;
$Rempath =~ s/^rmbackup@//;
# make sure the RemPath is sane...
if ($RemPath !~ /mysql...futurequest.net:\/backup\/mysql\/mysql..\//) {
  system ("umount $UMountParams $SnapDir");
  system ("lvremove -f $SnapDev > /dev/null");
  die "$RemPath does not look sane.\n";
}

# do the actual backup
system ("rsync $RsyncParams $SnapDir/ $RemPath") == 0
  or die "Can't rsync the databases: $?\n";

# Unmount the snapshot
system ("umount $UMountParams $SnapDir") == 0
  or die "Can't unmount snapshot: $?\n";

# Delete the snapshot volume
system ("lvremove -f $SnapDev > /dev/null") == 0
  or die "Can't remove the snapshot volume: $?\n";

if ($Verbose eq "y") {
  print "Backup completed.\n";
}

system ("touch /root/.backup_complete.timestamp");