After playing around with this further, here is more functional pseudo-code
... Primary change in the placement and method of the waidpid routine.
I'm still open to comments on this ... Otherwise, I hope this snippet is
useful to someone! : )
// run forever if necessary
set_time_limit(0);
// detatch from the controlling terminal
if (!posix_setsid()) {
die('could not detach from terminal');
}
// setup signal handlers
pcntl_signal(SIGTERM, "sig_handler");
pcntl_signal(SIGHUP, "sig_handler");
// loop forever waiting on jobs
while(1) {
// check queue for pending jobs
// (db lookup omitted, let's assume jobs are waiting)
$jobs_waiting = true;
if($jobs_waiting) {
$pid = pcntl_fork();
if($pid == -1) {
die('could not fork');
} else if ($pid) {
// parent
} else {
// child
// perform task on jobs waiting
// when job(s) complete, quit
exit();
}
}
// call waitpid to collect children that
// have already terminated
$tpid = pcntl_waitpid(-1,$status,WNOHANG);
//verbose output
//if($tpid > 0) echo "Parent collected child $tpid\n";
// wait two seconds before checking queue again
sleep(2);
unset($jobs_waiting);
}
function sig_handler($signo) {
// blah blah
}
-Clay
> From: Clay Loveless <[EMAIL PROTECTED]>
> Date: Sat, 01 Jun 2002 12:38:18 -0700
> To: PHP-General <[EMAIL PROTECTED]>
> Subject: [PHP] pcntl functions for task manager - comments?
>
> I'm experimenting with PHP's pcntl_* functions using the PHP cgi ... I've
> never written a daemon before, and there doesn't seem to be a lot of
> information out there about how to do this with the pcntl functions.
>
> So, I've read what I can find on the subject as it deals with UNIX
> programming. The goal is a script that will run forever, checking a "job
> queue" ... If jobs are waiting, use pcntl_fork() to handle the jobs.
>
> To this end, I've come up with this pseudo-code ... Before going WAY off in
> this direction, I'd like to submit this for comments by those who've had
> more experience with this sort of thing.
>
> ------------------
> // run forever if necessary
> set_time_limit(0);
>
> // detatch from the controlling terminal
> if (!posix_setsid()) {
> die('could not detach from terminal');
> }
>
> // setup signal handlers
> pcntl_signal(SIGTERM, "sig_handler");
> pcntl_signal(SIGHUP, "sig_handler");
>
> // loop forever waiting on jobs
> while(1) {
>
> // check queue for pending jobs
> // (db lookup omitted, let's assume jobs are waiting)
> $jobs_waiting = true;
>
> if($jobs_waiting) {
>
> $pid = pcntl_fork();
> if($pid == -1) {
> die('could not fork');
> } else if ($pid) {
>
> // parent
> // call waitpid to reap children that
> // have already terminated
> do {
> $tpid = pcntl_waitpid(-1,$status,WNOHANG);
> if($tpid == -1)
> die('error occurred while waiting for child');
> } while (!$tpid);
>
> } else {
> // child
> // perform task on jobs waiting
>
> // when job(s) complete, quit
> exit();
> }
>
> }
> // wait two seconds before checking queue again
> sleep(2);
> unset($jobs_waiting);
> }
>
> function sig_handler($signo) {
> // blah blah
> }
> --------------------
>
>
> I am open to suggestions or comments on this approach! Please let me know if
> you think this looks nuts.
>
> Thanks,
> Clay
>
>
> --
> PHP General Mailing List (http://www.php.net/)
> To unsubscribe, visit: http://www.php.net/unsub.php
>
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
