src/util/ratelimit.pl

   1 #!/usr/bin/perl -wT
   2 #
   3 # $Cambridge: exim/src/util/ratelimit.pl,v 1.3 2006/04/12 13:37:29 fanf2 Exp $
   4
   5 use strict;
   6
   7 sub usage () {
   8   print <<END;
   9 usage: ratelimit.pl <period> <regex> logfile
  10
  11 The aim of this script is to compute clients' peak sending rates
  12 from an Exim log file, using the same formula as Exim's ratelimit
  13 ACL condition. This is so that you can get an idea of a reasonable
  14 limit setting before you deploy the restrictions.
  15
  16 This script isn't perfectly accurate, because the time stamps in
  17 Exim's log files are only accurate to a second whereas internally
  18 Exim computes sender rates to the accuracy of your computer's clock
  19 (typically 10ms).
  20
  21 The log files to be processed can be specified on the command line
  22 after the other arguments; if no filenames are specified the script
  23 will read from stdin.
  24
  25 The first command line argument is the smoothing period, as defined by
  26 the documentation for the ratelimit ACL condition. The second argumetn
  27 is a regular expression.
  28
  29 Each line is matched against the regular expression. Lines that do not
  30 match are ignored. The regex may contain 0, 1, or 2 () capturing
  31 sub-expressions.
  32
  33 If there are no () sub-expressions, then every line that matches is
  34 used to compute a single rate. Its maximum value is reported when the
  35 script finishes.
  36
  37 If there is one () sub-expression, then the text matched by the
  38 sub-expression is used to identify a rate lookup key, similar to the
  39 lookup key used by the ratelimit ACL condition. For example, you might
  40 write a regex to match the client IP address, or the authenticated
  41 username. Separate rates are computed for each different client and
  42 the maximum rate for each client is reported when the script finishes.
  43
  44 If there are two () sub-expressions, then the text matched by the
  45 first sub-expression is used to identify a rate lookup key as above,
  46 and the second is used to match the message size recorded in the log
  47 line, e.g. " S=(\\d+) ". In this case the byte rate is computed instead
  48 of the message rate, similar to the per_byte option of the ratelimit
  49 ACL condition.
  50 END
  51   exit 1;
  52 }
  53
  54 sub iso2unix (@) {
  55   my ($y,$m,$d,$H,$M,$S,$zs,$zh,$zm) = @_;
  56   use integer;
  57   $y -= $m < 3;
  58   $m += $m < 3 ? 10 : -2;
  59   my $z = defined $zs ? "${zs}1" * ($zh * 60 + $zm) : 0;
  60   my $t = $y/400 - $y/100 + $y/4 + $y*365
  61         + $m*367/12 + $d - 719499;
  62   return $t * 86400
  63        + $H * 3600
  64        + $M * 60
  65        + $S
  66        - $z;
  67 }
  68
  69 my $debug = 0;
  70 my $progress = 0;
  71 while (@ARGV && $ARGV[0] =~ /^-\w+$/) {
  72   $debug = 1    if $ARGV[0] =~ s/(-\w*)d(\w*)/$1$2/;
  73   $progress = 1 if $ARGV[0] =~ s/(-\w*)p(\w*)/$1$2/;
  74   shift if $ARGV[0] eq "-";
  75 }
  76
  77 usage if @ARGV < 2;
  78
  79 my $progtime = "";
  80
  81 my $period = shift;
  82
  83 my $re_txt = shift;
  84 my $re = qr{$re_txt}o;
  85
  86 my %time;
  87 my %rate;
  88 my %max;
  89
  90 sub debug ($) {
  91   my $key = shift;
  92   printf "%s\t%12d %8s %5.2f %5.2f\n",
  93     $_, $time{$key}, $key, $max{$key}, $rate{$key};
  94 }
  95
  96 while (<>) {
  97   next unless $_ =~ $re;
  98   my $key = $1 || "";
  99   my $size = $2 || 1.0;
 100   my $time = iso2unix
 101     ($_ =~ m{^(\d{4})-(\d\d)-(\d\d)[ ]
 102               (\d\d):(\d\d):(\d\d)[ ]
 103               (?:([+-])(\d\d)(\d\d)[ ])?
 104             }x);
 105   if ($progress) {
 106     my $prog_now = substr $_, 0, 14;
 107     if ($progtime ne $prog_now) {
 108       $progtime = $prog_now;
 109       print "$progtime\n";
 110     }
 111   }
 112   if (not defined $time{$key}) {
 113     $time{$key} = $time;
 114     $rate{$key} = 0.0;
 115     $max{$key} = 0.0;
 116     debug $key if $debug;
 117     next;
 118   }
 119   # see acl_ratelimit() for details of the following
 120   my $interval = $time - $time{$key};
 121   $interval = 1e-9 if $interval <= 0.0;
 122   my $i_over_p = $interval / $period;
 123   my $a = exp(-$i_over_p);
 124   $time{$key} = $time;
 125   $rate{$key} = $size * (1.0 - $a) / $i_over_p + $a * $rate{$key};
 126   $max{$key} = $rate{$key} if $rate{$key} > $max{$key};
 127   debug $key if $debug;
 128 }
 129
 130 print map {
 131   " " x (20 - length) .
 132   "$_ : $max{$_}\n"
 133 } sort {
 134   $max{$a} <=> $max{$b}
 135 } keys %max;
 136
 137 # eof