Hello,
I am using Cache::FastMmap 1.34 with mod_perl 2.0.4 (Debian packaged) to help with configuration. I am using the PerlTransHandler hook to determine where on the filesystem a particular virtual host resides, by looking it up in a database then caching the results.
It mostly works, but every now and then it stops working. When it's not working Apache seems to hang on every page load, and I see this in the log:
[Thu Nov 12 23:30:56 2009] [notice] child pid 21117 exit signal Alarm
+clock (14)
[Fri Nov 13 00:14:54 2009] [notice] child pid 21309 exit signal Alarm
+clock (14)
[Fri Nov 13 00:49:55 2009] [error] [client 66.249.71.244] cache old sl
+ots mistmatch at /usr/local/lib/perl/5.10.0/Cache/FastMmap.pm line 65
+6.\n
[Fri Nov 13 01:46:04 2009] [error] [client 68.40.244.40] cache old slo
+ts mistmatch at /usr/local/lib/perl/5.10.0/Cache/FastMmap.pm line 656
+.\n
Google doesn't turn up any obvious solutions for this.
My Apache configuration looks like this:
PerlModule My::VirtualHost
PerlTransHandler My::VirtualHost::TransHandler
My code looks basically like this (in reality it is a bit more complicated):
package My::VirtualHost::TransHandler;
use strict;
use warnings;
use Apache2::Const -compile => qw(OK DECLINED);
use Apache2::RequestRec ();
use My::Config;
use DBI;
use Cache::FastMmap;
# This happens globally in the parent process
our $cache = Cache::FastMmap->new(
read_cb => \&get_virthost,
expire_time => '1m',
init_file => 1,
cache_not_found => 1,
);
our($dbh,$sth);
sub get_sth {
if (!$dbh) {
$dbh = DBI->connect(My::Config::DB_DSN, My::Config::DB_USER, M
+y::Config::DB_PASS)
or die "Couldn't connect to database\n";
$sth = $dbh->prepare('SELECT virthost_id FROM virtual_hosts WH
+ERE url = lower(?)')
or die "Couldn't prepare statement\n";
}
return $sth;
}
sub get_virthost {
my($ctx,$hn)=@_;
my $ret;
eval {
my $url = 'http://'.$hn;
my $sth = get_sth();
$sth->execute($url);
my $row = $sth->fetchrow_arrayref();
if ($row && defined($row->[0])) {
$ret = $row->[0];
} else {
$ret = undef;
}
$sth->finish();
return $ret;
};
if ($@) {
# TODO: Some kind of error handling
warn "Error getting virtual host: $@";
$ret = undef;
}
$ret;
}
sub handler {
my $r = shift;
my $hn = $r->hostname();
if (!$hn) {
# TODO: Return some kind of error
return Apache2::Const::DECLINED;
}
my $id = $cache->get($hn);
if (defined($id)) {
my $newfn = My::Config::BASE_PATH . "/virthosts/$id".$r->uri()
+;
$r->filename($newfn);
return Apache2::Const::OK;
} else {
return Apache2::Const::DECLINED;
}
}
My questions are:
- Does anybody see anything obviously wrong with what I'm doing?
- Has anybody done something similar before, successfully or unsuccessfully?
Thanks!
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