Re: Stopping an HTTP::Server::Simple server

[textual]

I'm facing the same problem, though not in a testing situation.

Following Corion's advice, I'm trying to pass the server's PID (returned by its background() method) to a handler that will be responsible for killing it.

My problem is that I can't find a way to pass the PID to the handler.

I've tried several things which all end up the same way when I access the url associated to the handler: the PID's value has not been passed and Perl "Can't kill a non-numeric process ID".

I've tried this (where the setup is maximally contrived for brevity):

A) Store PID as a global in the main package and access it from the server package.

In test.pl:

use strict;
use warnings;

use MyWebServer;

my  $server = MyWebServer->new(8080);
our $pid    = $server->background();

And in Webserver.pm:

package MyWebServer;

use strict;
use warnings;

use HTTP::Server::Simple::CGI;
use base qw(HTTP::Server::Simple::CGI);

sub handle_request {
    kill 9, $main::pid;
}

1;

B) Store PID as a global in the server package and set it in the main package.

In test.pl:

use strict;
use warnings;

use MyWebServer;

my $server        = MyWebServer->new(8080);
$MyWebServer::pid = $server->background();

And in Webserver.pm:

package MyWebServer;

use strict;
use warnings;

our $pid;

use HTTP::Server::Simple::CGI;
use base qw(HTTP::Server::Simple::CGI);

sub handle_request {
    kill 9, $pid;
}

1;

C) Store the PID in a separate module used by test.pl and webserver.pm.

In test.pl:

use strict;
use warnings;

use Pid;
use MyWebServer;

my $server = MyWebServer->new(8080);
Pid->set($server->background());

In Webserver.pm:

package MyWebServer;

use strict;
use warnings;

use Pid;

use HTTP::Server::Simple::CGI;
use base qw(HTTP::Server::Simple::CGI);

sub handle_request {
    kill 9, Pid->get();
}

1;

And in Pid.pm:

package Pid;

use strict;
use warnings;

my $pid;

sub get {
    my $package = shift;
     return $pid;
}

sub set {
    my $package = shift;
    $pid = shift;
}

1;

I've tried even more esoteric things until I started to feel like Wile E. Coyote, so I think it's time I submit this problem to you.

Any advice would be welcome, and so would any explanation as to what I fail to understand.

[Corion]

Maybe take a look at what you actually get in $pid before trying to kill it? .

[textual]

It's actually not defined.

[Corion]

This is surprising, as HTTP::Server::Simple should then die in the parent with Can't fork: ..., which you should have seen:

sub background {
    my $self  = shift;
    my $child = fork;
    croak "Can't fork: $!" unless defined($child);
    return $child if $child;

    srand(); # after a fork, we need to reset the random seed
             # or we'll get the same numbers in both branches
    if ( $^O !~ /MSWin32/ ) {
        require POSIX;
        POSIX::setsid()
            or croak "Can't start a new session: $!";
    }
    $self->run(@_); # should never return
    exit;           # just to be sure
}

So, either you're looking at a webserver that is not the webserver you launched, or the $pid is not where you store the information.

If you're trying to kill the child from within the child, $pid will also not be defined there (see fork). To kill yourself, use $$ as the pid.