On Mon, Oct 16, 2000 at 03:28:42PM -0500, [EMAIL PROTECTED]
wrote:
> I am spending most of my time deciphering the terminology and
> corresponding function calls.
>
> Here is my project:
>
> Create a server deamon that waits for a client to connect and
> submit configuration data to fire off a process. There is a limited
> number of resources, so queueing and resource management is
> a must. Once queueing and resource management is handled,
> a job is forked off and the system waits for the child to die to
> know that those resources are now available.
>
> The problem lies in that perl's sigchld handling isn't reliable, due
> to the unavailablity of asyncronous non-blocking I/O. Event.pm
> supposedly can take care of this.
Yes,
use POSIX ":sys_wait_h";
Event->signal(signal => 'CHLD', cb => sub {
my ($e) = @_;
# warn "CHLD ".$e->hits;
for (my $h=0; $h < $e->hits; $h++) {
my $died = waitpid(-1,&WNOHANG);
# process it
}
});
> My understanding so far-
>
> Start an Event loop w/ a watcher and given parameters and when
> a change to the filehandle occurs, the callback is invoked. The
> main routine can interact w/ the Event loop w/ varies functions
> such as: unloop/sweep, etc.
>
> I don't know what Event thingies I should do in this situation. I'll
> gladly write-up an example chapter once I get it figured out.
>
> I think my code will look something like:
>
> use Event qw(loop, unloop)
Remove comma.
> $server = IO::Socket::INET->new ( blah)
Yes, see NetServer::Portal::Top for a code example.
> $w=Event->io(fd=>\$server, poll=>'r' , cb=\&handle_client)
> loop;
>
> $sig_watch=Event->signal(signal=>'chld', async=>1, cb=\&chld_mangler)
Why async=>1?
> loop;
Only loop() once. ;-)
> sub child_mangler
> {
> while(something)
> {
> $pid=waitpid(-1, non-blocking-option)
> delete_pid_from_queue($pid)
> num_kids--;
> }
> }
Yup.
> sub handle_client
> {
> read config info;
> resource_manager;
> create_process;
> }
> sub create_process;
> {
> if # of kids <= $max_num_kids
> {
> add_pid_to_queue
> fork; # do job
> }
> }
>
> I didn't include some of the other sub routines, but this is the main idea.
>
>
> Am I heading in the right direction?
Yes. :-)
--
Never ascribe to malice that which can be explained by stupidity.
(via, but not speaking for Deutsche Bank)
