#!/usr/bin/perl -w
#
# watchtokens.pl, v0.34, 2/11/2005
#
# little script to watch for available tokens
# Risto Kotalampi, risto@kotalampi.com
#
# Enhancements: 
# 1) Modify evals to check that variable names are correct
#

use Sys::Syslog;
use Getopt::Long;

# just initialize bunch of variables

$b1 = 0;
$b2 = 0; 
$b3 = 0;
$b4 = 0;
$b5 = 0;
$lproblem = 0;
$maxload = 3.0;
$minload = 1.1;
$lines = 0;
$token_refill = 0;
$io_rate = 0;
$io_tokens = 0;
$token_max = 0;
$delta = 0;
$io_tokens_prev = 0;
$startfile ="/etc/rc.d/start.sh";
$stopfile ="/etc/rc.d/stop.sh";
$sleep = 15;
$filebase = "/var/adm/watchtokens";
$l = 0.2;
$u = 0.5;
$problem = 0;
$ok = 1;
$file_prev = "";

GetOptions("sleep=i", "stop=s", "low=i", "high=i", "startfile=s", 
	   "stopfile=s")
    || die "Wrong option! See the help\n";

if($opt_startfile){
    $startfile = $opt_startfile;
}

if($opt_stopfile){
    $stopfile = $opt_stopfile;
}

if($opt_sleep){
    $sleep = $opt_sleep;
}

if($opt_low){
    $l = $opt_low/100;
}

if($opt_high){
    $u = $opt_high/100;
}

if(!stat("/proc/loadavg") || !stat("/proc/io_status")){
    print STDERR "kernel not compatible\n";
    exit(-1);
}

while ($ok){

    $action = "x";
 
    if($lproblem){
	$action = "L";
    }

    if($problem){
	$action = "P";
    }

    ($sec,$min,$hr,$mday,$mon,$year) = localtime();

    $year += 1900;

    $mon++;

    $file = "$filebase.$mon-$mday-$year.log";

    # open the logfile if date has changed or we don't have it open yet
    if(($file ne $file_prev) && !$fileopen){
	open(FILE, ">>$file");
	$fileopen = 1;
    }

    # close the old logfile and open new if the date has changed
    if(($file ne $file_prev) && $fileopen){
	close(FILE);
	open(FILE, ">>$file");
	$fileopen = 1;
    }

    $file_prev = $file;

    # just pad times to be two digit
    if($sec < 10){
	$sec = "0$sec";
    }

    if($min < 10){
	$min = "0$min";
    }

    if($hr < 10){
	$hr = "0$hr";
    }

    $date = "$hr:$min:$sec";

    # get the critical data
    $load = `cat /proc/loadavg`;
    $out = `cat /proc/io_status`;

    # chomping is fun
    chomp($out);
    chomp($load);

    ($b1, $b2, $b3, $b4, $b5) = split(' ', $load);
    
    $l1 = $b1;

#    print STDERR "$l1\n";
#    exit(0);

    # get the variables from data

    if($out =~ /^(io_count=)(\d+)(\s+)(io_rate=)(\d+)(\s+)(io_tokens=)(\d+)(\s+)(token_refill=)(\d+)(\s+)(token_max=)(\d+)$/){
	$io_rate = $5;
	$io_tokens = $8;
	$token_refill = $11;
	$token_max = $14;
    }
    else
    {
	print STDERR "Invalid /proc/io_status syntax\n";
	exit(-1);
    }

    # this tells if we're going up or down. Positive good, negative bad.
    $rate = $token_refill - $io_rate ;

    # I want to know how much we have changed
    $delta = $io_tokens - $io_tokens_prev;
    $io_tokens_prev = $io_tokens;

    $timeleft = 0;

    # predict the time it will take to hit zero
    if($rate < 0){
	$timeleft = $io_tokens/(-$rate);
	$marker = "-";
    }

    # predict the time it will take to reach token_max again
    if ($rate > 0){
	$diff = $token_max - $io_tokens;
	$timeleft = $diff/$rate;
	$marker = "+";
    }

    $timeleft = abs($timeleft);
    $timeleft = int($timeleft);
    $timeleft = "$marker$timeleft";

    if($marker eq "+"){
	$timel1 = "0";
	$timel2 = abs($timeleft);
    }

    if($marker eq "-"){
	$timel1 = abs($timeleft);
	$timel2 = "0";
    }

    # let's fix the limits
    $llimit = $token_max * $l;
    $ulimit = $token_max * $u;

    # let's see in percents where we are
    $fillrate = int(100*($io_tokens/$token_max));

    # headers are cool
    $hstring =  sprintf ("%8s %2s %5s %10s %7s %7s %7s %7s %10s %7s", 
			 "Time", "A", "%",
			 "io_tokens", "delta", "rate",  "io_rate",
			 "TTL", "Wait", "Load");

    # ... especially every 20 lines (a la vmstat)
    if($lines % 20 == 0) {
	print FILE "$hstring\n";
    }

    # problems!

    if(($l1 > $maxload) && !$problem && !$lproblem){
	if($opt_stop){
	    stop_services();
	}
	$lproblem = 1;
    }

    if($lproblem && ($l1 < $minload)){
	if($opt_stop){
	    start_services();
	}
	$lproblem = 0;
    }

    if((($io_tokens < $llimit) && !$lproblem && !$problem)){
#	print FILE "Problem detected\n";
	if($opt_stop){
	    stop_services();
	}
	$problem = 1;
    }

    # all clear
    if(($io_tokens > $ulimit) && ($problem)){
#	print FILE "Problem cleared\n";
	if($opt_stop){
	    start_services();
	}
	$problem = 0;
    }

    # let's spit it out
    $string = sprintf ("%8s %2s %5d %10d %7d %7s %7d %7d %10d %7s", 
		       $date, $action, $fillrate, 
		       $io_tokens, $delta, $rate, $io_rate, 
		       $timel1, $timel2, $l1);
    
    if($lines){
	print FILE "$string\n";
    }

    $lines++;

    sleep($sleep);
}

# functions

sub stop_services {
    system("sh $stopfile");
    openlog('watchtokens.pl', 'cons,pid', 'user');
    syslog('mail|info', "watchtokens.pl stopped services");
    $action = "-";
    closelog();
}

sub start_services {
    system("sh $startfile");
    openlog('watchtokens.pl', 'cons,pid', 'user');
    syslog('mail|info', "watchtokens.pl started services");
    $action = "+";
    closelog();
}