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Merge pull request #42 from rsiddall/master

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Added Peter Eisch's load checking plugin, see: http://www.nntp.perl.org/...
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Matt Simerson 2014-03-21 08:46:28 -07:00
commit 8e6ef9385f
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#!/usr/bin/perl
=head1 NAME
loadcheck
=head1 DESCRIPTION
Only takes email transactions if the system load is at or below a
specified level.
If this is running on a system that provides /kern/loadavg or
/proc/loadavg it will be used instead of the 'uptime' command.
Once a load value is determined, it is cached for a period of time.
See the cache_time below.
Since fork/exec is expensive in perl you'll want to use cache_time to avoid increasing your load on every connection by checking system load.
=head1 CONFIG
max_load
This is the 1 minute system load where we won't take transactions
if our load is higher than this value. (Default: 7)
cache_time
A recently determined load value will be cached and used for the
assigned number of seconds. (Default: 10)
uptime
The path to the command 'uptime' if different than the default.
(Default: /usr/bin/uptime)
Example:
loadcheck cache_time 30
loadcheck max_load 7 uptime /usr/bin/uptime
=head1 SEE ALSO
Original version: http://www.nntp.perl.org/group/perl.qpsmtpd/2006/01/msg4422.html
Variant with caching: http://www.nntp.perl.org/group/perl.qpsmtpd/2006/03/msg4710.html
Steve Kemp's announcement of an alternate load limiter: http://www.nntp.perl.org/group/perl.qpsmtpd/2008/03/msg7814.html
=head1 AUTHOR
Written by Peter Eisch <peter@boku.net>.
=cut
my $VERSION = 0.02;
sub register {
my ($self, $qp, @args) = @_;
%{$self->{_args}} = @args;
$self->{_args}->{max_load} = 7
if (! defined $self->{_args}->{max_load});
$self->{_args}->{uptime} = '/usr/bin/uptime'
if (! defined $self->{_args}->{uptime});
$self->{_args}->{cache_time} = 10
if (! defined $self->{_args}->{cache_time});
$self->{_load} = -1;
$self->{_time} = 0;
$self->register_hook("connect", "loadcheck");
}
sub loadcheck {
my ($self, $transaction) = @_;
if (time() > ($self->{_time} + $self->{_args}->{cache_time})) {
# cached value expired
if ( -r '/kern/loadavg' ) { # *BSD
# contains fix-point scaling value
open(LD, "</kern/loadavg");
my $res = <LD>;
close LD;
my @vals = split(/ /, $res);
$self->{_load} = ($val[0] / $val[3]);
$self->{_time} = time();
$self->log(LOGDEBUG, "/kern/loadavg reported: $self->{_load}");
} elsif ( -r '/proc/loadavg' ) { # *inux
# contains decimal value
# contains fix-point scaling value
open(LD, "</proc/loadavg");
my $res = <LD>;
close LD;
$self->{_load} = (split(/ /, $res))[0];
$self->{_time} = time();
$self->log(LOGDEBUG, "/proc/loadavg reported: $self->{_load}");
} else {
# the various formats returned:
#10:33AM up 2:06, 1 user, load averages: 6.55, 3.76, 2.48
# 12:29am 2 users, load average: 0.05, 0.05, 0.06
# 12:30am up 5 days, 12:43, 1 user, load average: 0.00, 0.00, 0.00
my $res = `$self->{_args}->{uptime}`;
if ($res =~ /aver\S+: (\d+\.\d+)/) {
$self->{_load} = $1;
$self->{_time} = time();
$self->log(LOGDEBUG, "$self->{_args}->{uptime} reported: $self->{_load}");
}
}
}
if ($self->{_load} > $self->{_args}->{max_load}) {
$self->log(LOGERROR, "local load too high: $self->{_load}");
return DENYSOFT;
}
return (DECLINED, "continuing with load: $self->{_load}");
}