#!/usr/bin/perl
# addNagHost.pl creates a new Nagios host configuration file via GUI front end.
# written 05-may-2009 by fgb
#
# NB: 
# 1. You still need to manually add the server(s) to conf.d/hostgroups_nagios2.cfg 
#   in the appropriate hostgroup 'members' list before nagios will monitor them
#   (and recycle nagios).
# 2. Windows servers need agent (service) nsClient++ installed and configured before
#   the check_nt services defined here will work.

use Socket;
use Tk;
use Tk::DialogBox;

my $bDebug = 0;

my $sAppName = 'addNagHost';
my $sAuthor = "Frank Brown";
my $sDate = localtime(time);
my $sToday = substr($sDate,4);
my $sVersion = '0.1';

$sAddress = '';
$sAlias = '';
$sFilename = '';
$sHost = '';
$sIpAddr = '';
$bIis = 0;
$bSql = 0;
$bWin = 1;
$nagiosConfDir = "/etc/nagios2/servers";
$notifyInterval = '30';
$notifyOptions = 'd,u,r';
$notifyPeriod = 'workhours';

$main = MainWindow->new();

$dlg = $main->DialogBox( -title => "Add host to Nagios configuration",
			-buttons => [ "Add", "Cancel" ]);

# add widgets to dialog:

$sDescr = $dlg->add("Text", -wrap => "word", -bd => 2, -height => 3)->pack();
$sDescr->insert('end',"\nCreates a Nagios configuration file for an SFD server.");
$dlg->add("Label", -text => "Server name:")->pack();
$ecName = $dlg->add("Entry", -width => 35, 
	-validate => 'focusout', 
	-validatecommand => sub { if (length($_[0])) { $sHost = $_[0]; &lookupIpAddress(); }; return 1; }, 
	-takefocus => 1)->pack();
$dlg->add("Label", -text => "Description:")->pack();
$ecAlias = $dlg->add("Entry", -width => 35)->pack();
$dlg->add("Label", -text => "IP address:")->pack();
$ecAddr = $dlg->add("Entry", -width => 35 , -textvariable => \$sAddress)->pack();
$chkWin = $dlg->add("Checkbutton", -text => "Windows", -variable => \$bWin)->pack();
$chkWin->select();
$chkIis = $dlg->add("Checkbutton", -text => "IIS server", -variable => \$bIis)->pack();
$chkSql = $dlg->add("Checkbutton", -text => "SQL server", -variable => \$bSql)->pack();

# add buttons to main window:

$main->Button( -text => "Click for form",
		-command => \&addHost) ->pack(-side => "left");
$main->Button( -text => "Quit",
		-command => sub { exit } ) ->pack(-side => "left");

MainLoop;	# start Tk's event handler loop

### here be subs:

sub addHost {
  my $btn;
  my $bDone = 0;

  do {
    &initForm();
    $btn = $dlg->Show;
    if ($btn eq "Add") {
      $sHost = $ecName->get;
      if (defined($sHost) && length($sHost)) { 
	$sAlias = $ecAlias->get;
	if (! defined($sAlias) || ! length($sAlias)) { $sAlias = $sHost; }	# nagios won't accept blank alias
	$sIpAddr = $ecAddr->get;
	&genHostFile();
	if ($bWin) { &addWindowsServices(); }
	print "created file $sFilename\n";
        print "Be sure to add $sHost to windows-servers in hostgroups_nagios2.cfg!\n"; 
	if ($bWin) { print "Also make sure nsClient++ agent is installed on $sHost\n"; }
        $bDone = 1;
        }
      else { print "missing host name\n" }
      }
    elsif ($btn eq "Cancel") { $bDone = 1; } 
    else { print "Unknown button pressed?!"; }
    } until $bDone;
  }

sub addWindowsServices {
  my $sTmp = sprintf(">>%s",$sFilename);
  open(FP,$sTmp) || die "Can't open file $sFilename: $!\n";
  seek(FP,0,2);		# position FP at EOF for append
  print FP "# define services for windows server:\n\n";
  print FP "define service {\n";
  print FP "use\t\t\tgeneric-service\n";
  print FP "host_name\t\t$sHost\n";
  print FP "service_description\tUptime\n";
  print FP "check_command\t\tcheck_nt!UPTIME\n";
  print FP "}\n";
  print FP "define service {\n";
  print FP "use\t\t\tgeneric-service\n";
  print FP "host_name\t\t$sHost\n";
  print FP "service_description\tCPU\n";
  print FP "check_command\t\tcheck_nt!CPULOAD!-l 5,80,90\n";
  print FP "}\n";
  print FP "define service {\n";
  print FP "use\t\t\tgeneric-service\n";
  print FP "host_name\t\t$sHost\n";
  print FP "service_description\tMemory\n";
  print FP "check_command\t\tcheck_nt!MEMUSE!-w 80 -c 90\n";
  print FP "}\n";
  print FP "define service {\n";
  print FP "use\t\t\tgeneric-service\n";
  print FP "host_name\t\t$sHost\n";
  print FP "service_description\tSystem Disk\n";
  print FP "check_command\t\tcheck_nt!USEDDISKSPACE!-l c -w 80 -c 90\n";
  print FP "}\n";
  if ($bIis) {
  print FP "define service {\n";
  print FP "use\t\t\tgeneric-service\n";
  print FP "host_name\t\t$sHost\n";
  print FP "service_description\tW3SVC\n";
  print FP "check_command\t\tcheck_nt!SERVICESTATE!-d SHOWALL -l W3SVC\n";
  print FP "}\n";
    }
  if ($bSql) {
  print FP "define service {\n";
  print FP "use\t\t\tgeneric-service\n";
  print FP "host_name\t\t$sHost\n";
  print FP "service_description\tSQL\n";
  print FP "check_command\t\tcheck_nt!SERVICESTATE!-d SHOWALL -l MSSQLSERVER\n";
  print FP "}\n";
    }
  close(FP);
  }

sub genHostFile {
  my $sBaseFile = "host-$sHost.cfg";
  $sFilename = $nagiosConfDir . '/' . $sBaseFile;
  if ($bDebug) { $sFilename .= '-dbg'; print "dbg: filename = $sFilename\n"; }

  my $sTmp = sprintf(">%s",$sFilename);
  open(FP,$sTmp) || die "Can't open file $sFilename: $!\n";
  print FP "# $sBaseFile - nagios host config file for $sHost\n# Generated by $sAppName $sVersion $sToday\n\n";
  print FP "define host {\n";
  print FP "\tuse\t\t\t\tgeneric-host\n";
  print FP "\thost_name\t\t\t$sHost\n";
  print FP "\talias\t\t\t\t$sAlias\n";
  print FP "\taddress\t\t\t\t$sIpAddr\n";
  print FP "\tcheck_command\t\t\tcheck-host-alive\n";
  print FP "\tmax_check_attempts\t\t5\n";
  print FP "\tcheck_period\t\t\t24x7\n";
  print FP "\tprocess_perf_data\t\t0\n";
  print FP "\tretain_nonstatus_information\t0\n";
  print FP "\tcontact_groups\t\t\tadmins\n";
  print FP "\tnotification_interval\t\t$notifyInterval\n";
  print FP "\tnotification_period\t\t$notifyPeriod\n";
  print FP "\tnotification_options\t\t$notifyOptions\n";
  print FP "\t}\n";
  close(FP);
  }

sub initForm {
  $ecName->delete(0,'end');		# reset entry fields and checkboxes from last call:
  $ecAlias->delete(0,'end');
  $ecAddr->delete(0,'end');
  $chkWin->select();			# default to Windows server
  $chkIis->deselect();
  $chkSql->deselect();
  }

sub lookupIpAddress {
  $s = inet_aton($sHost);
  if (!defined($s)) { print "error: dns lookup failed for $sHost\n"; return 0; }
  if ($bDebug) { print "dbg: host = $sHost, inet_aton = $s\n"; }
  $sAddress = inet_ntoa(inet_aton($sHost));
  #print "dbg: $sHost addr = $sAddress\n";
  }

__END__