src/util/ratelimit.pl

   1 #!/usr/bin/perl -wT
   2
   3 use strict;
   4
   5 sub usage () {
   6   print <<END;
   7 usage: ratelimit.pl [options] <period> <regex> <logfile>
   8
   9 The aim of this script is to compute clients' peak sending rates
  10 from an Exim log file, using the same formula as Exim's ratelimit
  11 ACL condition. This is so that you can get an idea of a reasonable
  12 limit setting before you deploy the restrictions.
  13
  14 options:
  15
  16 -d          Show debugging information to stderr
  17 -p          Show progress of parse the log to stderr
  18
  19 <period>    The smoothing period in seconds, as defined by the
  20             documentation for the ratelimit ACL condition.
  21
  22             This script isn't perfectly accurate, because the time
  23             stamps in Exim's log files are only accurate to a second
  24             whereas internally Exim computes sender rates to the
  25             accuracy of your computer's clock (typically 10ms).
  26
  27 <regex>     The second argumetnis is a regular expression.
  28
  29             Each line is matched against the regular expression.
  30             Lines that do not match are ignored. The regex may
  31             contain 0, 1, or 2 () capturing sub-expressions.
  32
  33             If there are no () sub-expressions, then every line that
  34             matches is used to compute a single rate. Its maximum
  35             value is reported when the script finishes.
  36
  37             If there is one () sub-expression, then the text matched
  38             by the sub-expression is used to identify a rate lookup
  39             key, similar to the lookup key used by the ratelimit
  40             ACL condition. For example, you might write a regex
  41             to match the client IP address, or the authenticated
  42             username. Separate rates are computed for each different
  43             client and the maximum rate for each client is reported
  44             when the script finishes.
  45
  46             If there are two () sub-expressions, then the text matched
  47             by the first sub-expression is used to identify a rate
  48             lookup key as above, and the second is used to match the
  49             message size recorded in the log line, e.g. "S=(\\d+)".
  50             In this case the byte rate is computed instead of the
  51             message rate, similar to the per_byte option of the
  52             ratelimit ACL condition.
  53
  54 <logfile>   The log files to be processed can be specified on the
  55             command line after the other arguments; if no filenames
  56             are specified the script will read from stdin.
  57
  58 examples:
  59
  60 ./ratelimit.pl 1 ' <= .*? \[(.*?)\]' <logfile>
  61
  62             Compute burst sending rate like ACL condition
  63             ratelimit = 0 / 1s / strict / \$sender_host_address
  64
  65 ./ratelimit.pl 3600 '<= (.*?) ' <logfile>
  66
  67             Compute sending rate like ACL condition
  68             ratelimit = 0 / 1h / strict / \$sender_address
  69
  70 END
  71   exit 1;
  72 }
  73
  74 sub iso2unix (@) {
  75   my ($y,$m,$d,$H,$M,$S,$zs,$zh,$zm) = @_;
  76   use integer;
  77   $y -= $m < 3;
  78   $m += $m < 3 ? 10 : -2;
  79   my $z = defined $zs ? "${zs}1" * ($zh * 60 + $zm) : 0;
  80   my $t = $y/400 - $y/100 + $y/4 + $y*365
  81         + $m*367/12 + $d - 719499;
  82   return $t * 86400
  83        + $H * 3600
  84        + $M * 60
  85        + $S
  86        - $z;
  87 }
  88
  89 my $debug = 0;
  90 my $progress = 0;
  91 while (@ARGV && $ARGV[0] =~ /^-\w+$/) {
  92   $debug = 1    if $ARGV[0] =~ s/(-\w*)d(\w*)/$1$2/;
  93   $progress = 1 if $ARGV[0] =~ s/(-\w*)p(\w*)/$1$2/;
  94   shift if $ARGV[0] eq "-";
  95 }
  96
  97 usage if @ARGV < 2;
  98
  99 my $progtime = "";
 100
 101 my $period = shift;
 102
 103 my $re_txt = shift;
 104 my $re = qr{$re_txt}o;
 105
 106 my %time;
 107 my %rate;
 108 my %max;
 109
 110 sub debug ($) {
 111   my $key = shift;
 112   printf STDERR "%s\t%12d %8s %5.2f %5.2f\n",
 113     $_, $time{$key}, $key, $max{$key}, $rate{$key};
 114 }
 115
 116 while (<>) {
 117   next unless $_ =~ $re;
 118   my $key = $1 || "";
 119   my $size = $2 || 1.0;
 120   my $time = iso2unix
 121     ($_ =~ m{^(\d{4})-(\d\d)-(\d\d)[ ]
 122               (\d\d):(\d\d):(\d\d)[ ]
 123               (?:([+-])(\d\d)(\d\d)[ ])?
 124             }x);
 125   if ($progress) {
 126     my $prog_now = substr $_, 0, 14;
 127     if ($progtime ne $prog_now) {
 128       $progtime = $prog_now;
 129       print STDERR "$progtime\n";
 130     }
 131   }
 132   if (not defined $time{$key}) {
 133     $time{$key} = $time;
 134     $rate{$key} = 0.0;
 135     $max{$key} = 0.0;
 136     debug $key if $debug;
 137     next;
 138   }
 139   # see acl_ratelimit() for details of the following
 140   my $interval = $time - $time{$key};
 141   $interval = 1e-9 if $interval <= 0.0;
 142   my $i_over_p = $interval / $period;
 143   my $a = exp(-$i_over_p);
 144   $time{$key} = $time;
 145   $rate{$key} = $size * (1.0 - $a) / $i_over_p + $a * $rate{$key};
 146   $max{$key} = $rate{$key} if $rate{$key} > $max{$key};
 147   debug $key if $debug;
 148 }
 149
 150 print map {
 151   " " x (20 - length) .
 152   "$_ : $max{$_}\n"
 153 } sort {
 154   $max{$a} <=> $max{$b}
 155 } keys %max;
 156
 157 # eof