This is my implementation of the scheduler,i need only to launch it if isn't active and add all jobs on the mysql job table(i already have one for my main script),this script will launch all jobs ready to be executed(the sql table have a datetime field).
What i call "Mutex" is a class that tells if one or more than one copy of the script is running and can even send commands to the running script throught a pipe(you simply have to create a new mutex with the same name for all the scripts)so you can even stop a running script from another script.
<?php
//---logging---
$logfile = dirname(dirname(__FILE__)).'/scheduler.log';
$ob_file = fopen($logfile,'a');
function ob_file_callback($buffer)
{
global $ob_file;
fwrite($ob_file,$buffer);
}
//--includes---
$inc=dirname(dirname(__FILE__)).'/.include/';
require_once($inc.'Mutex.php');
require_once($inc.'jobdb.php');
//--mutex---
//i call it mutex but it's nothing like POSIX mutex,it's a way to synchronyze scripts
$m=new Mutex('jscheduler');
if(!$m->lock())//if this script is already running
exit();//only one scheduler at time
//---check loop---
set_time_limit(-1);//remove script time limit
for(;;){
ob_start('ob_file_callback');//logging
$j=jobdb_get_ready_jobs(true);//gets all ready jobs,works with mysql
if($j!=null)//found some jobs
foreach($j as $val){//run all jobs
$ex='*SCRIPT NAME AND PARAMETERS HERE*';
if(!run_script($ex))
echo "UNABLE TO LAUNCH THE JOB!\n";
}
$n=($j!=null)?count($j).'JOBS LAUNCHED':'NO JOBS';
sleep(60);
if($m->has_to_stop())//yeah,i can stop this script from other scripts,it works with a file pipeline
exit("# STOPPING SCHEDULER\n");
ob_end_flush();//LOGGING
}
?>
My "run_script" function works the same way as the Sciberras "run" function.
To activate the scheduler you should simply use this command
run_script('scheduler.php');
to check if it's active
$m=new Mutex('jscheduler');
if(!$m->test_lock())
echo 'SCHEDULER IS ACTIVE';
else
echo 'SCHEDULER IS INACTIVE';
and to stop the scheduler
$m=new Mutex('jscheduler');
$m->ask_to_stop();//simply sent throught the pipe the command,now has_to_stop()will return true on the process that have gain the lock of the mutex
echo 'STOPPING SCHEDULER...';
i may have gone way too far on his implementation,anyway there may be a problem of "lag",for example if the scheduler starts at 0:00.00 and i have two scripts at 0:01.01 and 0:01.59 both are launched at 0:02.0 .
To fix this "lag" i'll may retreive all the jobs scheduled in the next minute and schedule them like in the Sciberras code using time_sleep_until.
This will not create too many running threads(i may want to test if there's a limit or a performance drop on launching a HUDGE amount of threads but i'm sure there will be some problems)and ensures perfect timing requiring only to check if the scheduler is active.
