util/ratelimit.pl

   1 #!/usr/bin/perl -wT
   2
   3 use strict;
   4
   5 BEGIN { pop @INC if $INC[-1] eq '.' };
   6
   7 sub usage () {
   8   print <<END;
   9 usage: ratelimit.pl [options] <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 options:
  17
  18 -d          Show debugging information to stderr
  19 -p          Show progress of parse the log to stderr
  20
  21 <period>    The smoothing period in seconds, as defined by the
  22             documentation for the ratelimit ACL condition.
  23
  24             This script isn't perfectly accurate, because the time
  25             stamps in Exim's log files are only accurate to a second
  26             whereas internally Exim computes sender rates to the
  27             accuracy of your computer's clock (typically 10ms).
  28
  29 <regex>     The second argument is a regular expression.
  30
  31             Each line is matched against the regular expression.
  32             Lines that do not match are ignored. The regex may
  33             contain 0, 1, or 2 () capturing sub-expressions.
  34
  35             If there are no () sub-expressions, then every line that
  36             matches is used to compute a single rate. Its maximum
  37             value is reported when the script finishes.
  38
  39             If there is one () sub-expression, then the text matched
  40             by the sub-expression is used to identify a rate lookup
  41             key, similar to the lookup key used by the ratelimit
  42             ACL condition. For example, you might write a regex
  43             to match the client IP address, or the authenticated
  44             username. Separate rates are computed for each different
  45             client and the maximum rate for each client is reported
  46             when the script finishes.
  47
  48             If there are two () sub-expressions, then the text matched
  49             by the first sub-expression is used to identify a rate
  50             lookup key as above, and the second is used to match the
  51             message size recorded in the log line, e.g. "S=(\\d+)".
  52             In this case the byte rate is computed instead of the
  53             message rate, similar to the per_byte option of the
  54             ratelimit ACL condition.
  55
  56 <logfile>   The log files to be processed can be specified on the
  57             command line after the other arguments; if no filenames
  58             are specified the script will read from stdin.
  59
  60 examples:
  61
  62 ./ratelimit.pl 1 ' <= .*? \[(.*?)\]' <logfile>
  63
  64             Compute burst sending rate like ACL condition
  65             ratelimit = 0 / 1s / strict / \$sender_host_address
  66
  67 ./ratelimit.pl 3600 '<= (.*?) ' <logfile>
  68
  69             Compute sending rate like ACL condition
  70             ratelimit = 0 / 1h / strict / \$sender_address
  71
  72 END
  73   exit 1;
  74 }
  75
  76 sub iso2unix (@) {
  77   my ($y,$m,$d,$H,$M,$S,$zs,$zh,$zm) = @_;
  78   use integer;
  79   $y -= $m < 3;
  80   $m += $m < 3 ? 10 : -2;
  81   my $z = defined $zs ? "${zs}1" * ($zh * 60 + $zm) : 0;
  82   my $t = $y/400 - $y/100 + $y/4 + $y*365
  83         + $m*367/12 + $d - 719499;
  84   return $t * 86400
  85        + $H * 3600
  86        + $M * 60
  87        + $S
  88        - $z;
  89 }
  90
  91 my $debug = 0;
  92 my $progress = 0;
  93 while (@ARGV && $ARGV[0] =~ /^-\w+$/) {
  94   $debug = 1    if $ARGV[0] =~ s/(-\w*)d(\w*)/$1$2/;
  95   $progress = 1 if $ARGV[0] =~ s/(-\w*)p(\w*)/$1$2/;
  96   shift if $ARGV[0] eq "-";
  97 }
  98
  99 usage if @ARGV < 2;
 100
 101 my $progtime = "";
 102
 103 my $period = shift;
 104
 105 my $re_txt = shift;
 106 my $re = qr{$re_txt}o;
 107
 108 my %time;
 109 my %rate;
 110 my %max;
 111
 112 sub debug ($) {
 113   my $key = shift;
 114   printf STDERR "%s\t%12d %8s %5.2f %5.2f\n",
 115     $_, $time{$key}, $key, $max{$key}, $rate{$key};
 116 }
 117
 118 while (<>) {
 119   next unless $_ =~ $re;
 120   my $key = $1 || "";
 121   my $size = $2 || 1.0;
 122   my $time = iso2unix
 123     ($_ =~ m{^(\d{4})-(\d\d)-(\d\d)[ ]
 124               (\d\d):(\d\d):(\d\d)[ ]
 125               (?:([+-])(\d\d)(\d\d)[ ])?
 126             }x);
 127   if ($progress) {
 128     my $prog_now = substr $_, 0, 14;
 129     if ($progtime ne $prog_now) {
 130       $progtime = $prog_now;
 131       print STDERR "$progtime\n";
 132     }
 133   }
 134   if (not defined $time{$key}) {
 135     $time{$key} = $time;
 136     $rate{$key} = 0.0;
 137     $max{$key} = 0.0;
 138     debug $key if $debug;
 139     next;
 140   }
 141   # see acl_ratelimit() for details of the following
 142   my $interval = $time - $time{$key};
 143   $interval = 1e-9 if $interval <= 0.0;
 144   my $i_over_p = $interval / $period;
 145   my $a = exp(-$i_over_p);
 146   $time{$key} = $time;
 147   $rate{$key} = $size * (1.0 - $a) / $i_over_p + $a * $rate{$key};
 148   $max{$key} = $rate{$key} if $rate{$key} > $max{$key};
 149   debug $key if $debug;
 150 }
 151
 152 print map {
 153   " " x (20 - length) .
 154   "$_ : $max{$_}\n"
 155 } sort {
 156   $max{$a} <=> $max{$b}
 157 } keys %max;
 158
 159 # eof