#!/usr/bin/perl -w

use strict;
use vars qw( $DEBUG );
use Getopt::Std;
use FS::Daemon qw(daemonize1 daemonize2 logfile sigint sigterm);
use FS::Yori qw(report);
use Email::Send;

$DEBUG = 0;

&untaint_argv;  #what it sounds like  (eww)

use vars qw(%opt);
getopts('m:p:', \%opt );

my ($machine, @emails) = @ARGV;
die &usage unless @emails;

warn "starting daemonization (forking)\n" if $DEBUG;
daemonize1('freeside-monitor');
#logfile( "%%%FREESIDE_LOG%%%/monitorlog.$machine" );
logfile( "/usr/local/etc/freeside/monitorlog.$machine" );

warn "completing daemonization (detaching))\n" if $DEBUG;
daemonize2();

my $wantfree = $opt{m} || 1048576;
my $wantload = $opt{p} || 5;

die 'bogus memory requirement: $wantfree'
   unless $wantfree && $wantfree =~ /^\d+$/;

die 'bogus load requirement: $wantload'
   unless $wantload && $wantload =~ /^[\d.]+$/;

my $alerts = 0;
my $last = time();
while (1) {

  my(undef, $load, undef) = report('load');
  my($free) = report('freememory');
  
  warn "free is $free and wantfree is $wantfree\n" if $DEBUG > 1;
  warn "load is $load and wantload is $wantload\n" if $DEBUG > 1;
  warn "last is $last\n" if $DEBUG > 1;
  
  unless( defined($load) && $load < $wantload
       && defined($free) && $free > $wantfree
       || ( time() < $last + 1800 && $alerts > 2 ) )
  {
    warn localtime(). ": $machine has load of $load and $free kB free memory\n";
    $alerts++;
    $alerts = 0 if time() > $last + 1800;
    $last = time();
    foreach my $email ( @emails ) {

      my $message = <<"__MESSAGE__";
From: support\@freeside.biz
To: $email
Subject: ALERT - $machine

ALERT: $machine has a load of $load and only $free kB free..

__MESSAGE__

    my $sender = Email::Send->new({mailer => 'SMTP'});
    $sender->mailer_args([Host => 'mail.freeside.biz']);
    $sender->send($message);

    }

  }



  if ( sigterm() ) {
    warn "received TERM signal; exiting\n";
    exit;
  }
  if ( sigint() ) {
    warn "received INT signal; exiting\n";
    exit;
  }

  sleep 30; #too long?  too short?

}

sub untaint_argv {
  foreach $_ ( $[ .. $#ARGV ) { #untaint @ARGV
    $ARGV[$_] =~ /^([\w\-\/\@\.]*)$/ || die "Illegal arguement \"$ARGV[$_]\"";
    $ARGV[$_]=$1;
  }
}

sub usage {
  die "Usage:\n\n  freeside-monitor [ -pm ] machine email\n";
}

=head1 NAME

freeside-monitor - Perform some basic load monitoring

=head1 SYNOPSIS

  freeside-monitor [ -p MAXLOAD ] [ -m REQUIRED_FRERMEM ] machine email [ ... ]

=head1 DESCRIPTION

Load monitoring daemon.  Should be running at all times.

-p: maximum permitted 5 minute load

-m: minimum free vmem in kB

machine: a unique name to be used in alert messages
email: address(es) to which alerts should be sent

=head1 VERSION

=head1 BUGS

=head1 SEE ALSO

=cut