#!/usr/bin/perl -w

use strict;
use File::Which;
use Getopt::Long;

my $what = 'volume';
my $volume = undef;
my $peer = undef;
my $bricks = undef;

my $gluster = which('gluster');
my $lock = '/var/lock/gluster-zabbix.lock';

unless($gluster){
  # Gluster is not installed, exit with an error
  die "gluster command not found";
}

# Get an exclusive lock
open(LOCK, ">$lock") || die "Can't open $lock";
flock(LOCK, 2);

GetOptions(
  "what=s"   => \$what,
  "volume=s" => \$volume,
  "bricks=i" => \$bricks,
  "peer=s"   => \$peer
);

sub usage(){
  print <<"EOF";

usage: $0 --what=[peer|volume]

If --what=volume you need to pass --volume=<volname>. The optional --bricks arg can be used to pass the number of expected bricks
If --what=peer you need to pass --peer=<host>

EOF
}

sub gluster($){
  my $cmd = shift;
  my $code = 256;
  my @result = ();
  # Loop to run gluster cmd as it can fail if two run at the same time
  for (my $i = 0; ($code != 0 && $i < 3); $i++){
    open (RES, "$cmd 2>/dev/null |")
          || die "error: Could not execute $cmd";
    @result = <RES>;
    close RES;
    $code = $?;
    sleep(1) unless ($code == 0);
  }
  return @result;
}

if (($what eq 'volume' && !$volume) ||
    ($what eq 'peer' && !$peer) ||
    ($what ne 'volume' && $what ne 'peer')){
  usage();
}

if ($what eq 'volume'){
  my $bricksfound = 0;
  my @volinfo = gluster("$gluster vol status $volume");
  unless (scalar @volinfo){
    die "Error occurred while trying to get volume status for $volume";
  }
  foreach my $line (@volinfo){
    # Check that all bricks are online
    if ($line =~ m/^Brick\ ([\w\.]+:\/[\w\.\/]+)\s+\d+(\s+\d+)?\s+([A-Z])/){
      $bricksfound++;
      if ($3 ne 'Y') {
        print "CRITICAL: brick status (reported $3 on $1)";
        exit 1;
      }
    }
    # Check the Self-Heal daemons are up and running
    elsif ($line =~ m/^Self-heal\ Daemon\ on\ ([\w\.]+)\s+N\/A\\s+([A-Z])/ && $2 ne 'Y'){
      print "CRITICAL: self-heal daemon (reported $2 on $1)";
      exit 1;
    }
  }
  # Check the number of bricks is the one we expect
  if ($bricks && $bricks != $bricksfound){
    print "CRITICAL: bricks count mismatch (found $bricksfound while expecting $bricks)";
    exit 1;
  }
  @volinfo = gluster("$gluster vol heal $volume info");
  unless (scalar @volinfo){
    die "Error occurred while trying to get volume heal info for $volume";
  }
  foreach my $line (@volinfo){
    if ($line =~ m/^Number\ of\ entries:\s+(\d+)$/ && $1 gt 0){
      # Lets check a second time to limit false positives
      sleep 1;
      @volinfo = gluster("$gluster vol heal $volume info");
      unless (scalar @volinfo){
        die "Error occurred while trying to get volume heal info for $volume";
      }
      foreach my $line (@volinfo){
        if ($line =~ m/^Number\ of\ entries:\s+(\d+)$/ && $1 gt 0){
          print "CRITICAL: self-heal in progress ($1)";
          exit 1;
        }
      }
    }
  }
  @volinfo = gluster("$gluster vol heal $volume info heal-failed");
  # the heal-failed command isn't supported on all version of GlusterFS
  if (scalar @volinfo){
    foreach my $line (@volinfo){
      # Now, check we don't have any file which the Self-Heal daemon couldn't sync
      if ($line =~ m/^Number\ of\ entries:\s+(\d+)$/ && $1 gt 0){
        print "CRITICAL: self-heal error ($1)";
        exit 1;
      }
    }
  }
  @volinfo = gluster("$gluster vol heal $volume info split-brain");
  unless (scalar @volinfo){
    die "Error occurred while trying to get split-brain info for $volume";
  }
  foreach my $line (@volinfo){
    # Now, check we don't have any file in a split-brain situation
    if ($line =~ m/^Number\ of\ entries:\s+(\d+)$/ && $1 gt 0){
      print "CRITICAL: split-bran ($1)";
      exit 1;
    }
  }
  @volinfo = gluster("$gluster vol info $volume");
  unless (scalar @volinfo){
    die "Error occurred while trying to get volume info for $volume";
  }
  foreach my $line (@volinfo){
    # Check the volume is started
    if ($line =~ m/^Status:\s+(\w+)$/ && $1 ne 'Started'){
      print 'CRITICAL: The volume is not started';
      exit 1;
    }
  }
  print 'OK';
}
elsif ($what eq 'peer'){
  my @peers = gluster("$gluster pool list");
  my $status = 'unknown';
  foreach my $line (@peers){
    if (($line =~ m/^$peer\s+/) ||
        ($line =~ m/^[0-9a-f]{8}-([0-9a-f]{4}-){3}[0-9a-f]{12}\s+$peer\s+/)){
      (undef,undef,$status) = split(/\s+/, $line);
    }
  }
  print $status;
}

close(LOCK);
exit(0);