random delay timer in PHP - php

Question

I want to put a php daemon to sleep (with System_Daemon::iterate())
so it runs max 20 times randomly spread over an hour. maybe a min distance would be smart so it doesn't run 20 times in the first half hour and 0 times in the second half.
i'm kinda stuck here and don't know how to start with this one, any help is very apreciated!

Answer 1

You may use cron jobs, to set the script to run ever so often.
http://net.tutsplus.com/tutorials/php/managing-cron-jobs-with-php-2/
... Crontab:
0 9 * * * /path/to/bashscript
and in /path/to/bashscript:
#!/bin/bash
maxdelay=$((1*60)) # every hour, converted to minutes
for ((i=1; i<=20; i++)); do
delay=$(($RANDOM%maxdelay)) # pick an independent random delay, 20 times
(sleep $((delay*60)); /path/to/phpscript.php) & # background a subshell, then run the php script
done

Answer 2

i came up with one possible solution, i didnt try it out yet, so it main contain syntax or logic errors. because it is running as a daemon there is a never ending loop around it.
// 3600 seconds or one hour
$timeframe=3600;
// run max 20 times in $timeframe
$runtimes=20;
// minimum delay between two executions
$mindelay=60;
// maxium delay between two executions
$maxdelay=240;
if ($cnt % $runtimes != 0) {
$delay = rand($mindelay,$maxdelay);
System_Daemon::iterate($delay);
$sum += $delay;
$cnt++;
} else {
//final delay till the $timeframe
if ($sum < $timeframe) {
System_Daemon::iterate($timeframe - $sum);
}
$sum=0;
}
its not perfect and u waste some time but i guess its going to fullfill the job.
any comments?