Problem: I want to implement several php-worker processes who are listening on a MQ-server queue for asynchronous jobs. The problem now is that simply running this processes as daemons on a server doesn't really give me any level of control over the instances (Load, Status, locked up)...except maybe for dumping ps -aux. Because of that I'm looking for a runtime environment of some kind that lets me monitor and control the instances, either on system (process) level or on a higher layer (some kind of Java-style appserver)
Any pointers?
Here's some code that may be useful.
<?
define('WANT_PROCESSORS', 5);
define('PROCESSOR_EXECUTABLE', '/path/to/your/processor');
set_time_limit(0);
$cycles = 0;
$run = true;
$reload = false;
declare(ticks = 30);
function signal_handler($signal) {
switch($signal) {
case SIGTERM :
global $run;
$run = false;
break;
case SIGHUP :
global $reload;
$reload = true;
break;
}
}
pcntl_signal(SIGTERM, 'signal_handler');
pcntl_signal(SIGHUP, 'signal_handler');
function spawn_processor() {
$pid = pcntl_fork();
if($pid) {
global $processors;
$processors[] = $pid;
} else {
if(posix_setsid() == -1)
die("Forked process could not detach from terminal\n");
fclose(stdin);
fclose(stdout);
fclose(stderr);
pcntl_exec(PROCESSOR_EXECUTABLE);
die('Failed to fork ' . PROCESSOR_EXECUTABLE . "\n");
}
}
function spawn_processors() {
global $processors;
if($processors)
kill_processors();
$processors = array();
for($ix = 0; $ix < WANT_PROCESSORS; $ix++)
spawn_processor();
}
function kill_processors() {
global $processors;
foreach($processors as $processor)
posix_kill($processor, SIGTERM);
foreach($processors as $processor)
pcntl_waitpid($processor);
unset($processors);
}
function check_processors() {
global $processors;
$valid = array();
foreach($processors as $processor) {
pcntl_waitpid($processor, $status, WNOHANG);
if(posix_getsid($processor))
$valid[] = $processor;
}
$processors = $valid;
if(count($processors) > WANT_PROCESSORS) {
for($ix = count($processors) - 1; $ix >= WANT_PROCESSORS; $ix--)
posix_kill($processors[$ix], SIGTERM);
for($ix = count($processors) - 1; $ix >= WANT_PROCESSORS; $ix--)
pcntl_waitpid($processors[$ix]);
} elseif(count($processors) < WANT_PROCESSORS) {
for($ix = count($processors); $ix < WANT_PROCESSORS; $ix++)
spawn_processor();
}
}
spawn_processors();
while($run) {
$cycles++;
if($reload) {
$reload = false;
kill_processors();
spawn_processors();
} else {
check_processors();
}
usleep(150000);
}
kill_processors();
pcntl_wait();
?>