Power Spawn: Manage forked processes with the pcntl extension

ABOUT
	PowerSpawn is a PCNTL and POSIX wrapper for *nix systems running PHP
	
	It is for managing and running forked process for parrallel computing with PHP

HOW TO USE
	First, be sure to include PowerSpawn in your source: require_once('/path/to/PowerSpawn.class.php')
	
	Then, you'll want to initialize the PowerSpawn Object and setup your config.  See the complete example below

EXAMPLE

<?php
// Include PowerSpawn
require_once('PowerSpawn.class.php');

// Initialize the object
$ps = new PowerSpawn;

// Create a callback function (Not required)
function allChildrenComplete() {
echo "All the children processes have completed\n";
}

function killedChild() {
echo "A child was just killed\n";
}

// Setup PowerSpawn Config
$ps->setCallback('allChildrenComplete'); // Calls the allChildrenComplete() function when all processes have checked in and there is no more work to complete
$ps->setKillCallback('killedChild'); // Calls the killedChild function when a child is executed for exceeding time limit
$ps->maxChildren = 5; // Only allows 5 children to be running at any given time
$ps->timeLimit = 10; // Kills children processes that run longer than 10 seconds

// Build an array with some fake data to proccess
$data = array();
for ($i = 0; $i < 15; $i++) {
$data[] = $i;
}

// Start the parent loop
while ($ps->runParentCode()) {
// Only the parent process will run code inside this loop

// Determine if we still have data to process
if (count($data)) {
// We still have data to process
// Check to see if we have an open slot to spawn a child
if ($ps->spawnReady()) {
// We can spawn a new process
$ps->childData = array_shift($data);

// Echo some text to let the user know that this is the parent and we are spawning a new child
echo "[PARENT] Spawning a new process\n";

// Spawn the process
$ps->spawnChild();
} else {
// All slots are full, just tick for now
$ps->Tick();
}
} else {
// There is no more data to process

// Echo some text to let the user know that the parent process is out of data
echo "[PARENT] Out of data to hand out - Waiting for all children to check in\n";

// Call the shutdown() method - blocks until all chilren have checked in or been killed because of executing too long
$ps->shutdown();

// All child processes have terminated
echo "[PARENT] All child processes have completed\n";
}
}

// Start the children code section
if ($ps->runChildCode()) {
// Only child processes forked by the parent will run this code
// The parent process will not execute this code

// Get the data for this run
$myNumber = $ps->childData;

// Let the user know the thread is running
echo "[CHILD:{$myNumber}] Running with number {$myNumber} - My PID is {$ps->myPID()}\n";

// Now we'll sleep x seconds where x is $myNumber - but we'll loop to show that we are doing work
$x = 0;
while ($x < $myNumber) {
sleep(1);
$x++;
echo "[CHILD:{$myNumber}] Just completed iteration {$x} of {$myNumber}\n";
}

// Let the user know that all work has been completed
// All children that run longer than 10 seconds won't make it this far with the settings above
echo "[CHILD:{$myNumber}] I have completed my work\n";
}


// Send signal 0 to let parent process know we are done
exit(0);

?>


OUPUT FROM EXAMPLE:
dbauer@zent:~/src/PowerSpawn$ php ./example.php 
PHP Deprecated:  Comments starting with '#' are deprecated in /etc/php5/cli/conf.d/mcrypt.ini on line 1 in Unknown on line 0
[PARENT] Spawning a new process
[PARENT] Spawning a new process
[CHILD:0] Running with number 0 - My PID is 22174
[CHILD:0] I have completed my work
[PARENT] Spawning a new process
[CHILD:1] Running with number 1 - My PID is 22175
[PARENT] Spawning a new process
[CHILD:2] Running with number 2 - My PID is 22176
[PARENT] Spawning a new process
[CHILD:3] Running with number 3 - My PID is 22177
[CHILD:4] Running with number 4 - My PID is 22178
[PARENT] Spawning a new process
[CHILD:5] Running with number 5 - My PID is 22179
[CHILD:1] Just completed iteration 1 of 1
[CHILD:1] I have completed my work
[CHILD:2] Just completed iteration 1 of 2
[CHILD:3] Just completed iteration 1 of 3
[CHILD:4] Just completed iteration 1 of 4
[PARENT] Spawning a new process
[CHILD:5] Just completed iteration 1 of 5
[CHILD:6] Running with number 6 - My PID is 22180
[CHILD:2] Just completed iteration 2 of 2
[CHILD:2] I have completed my work
[CHILD:3] Just completed iteration 2 of 3
[CHILD:4] Just completed iteration 2 of 4
[CHILD:5] Just completed iteration 2 of 5
[PARENT] Spawning a new process
[CHILD:6] Just completed iteration 1 of 6
[CHILD:7] Running with number 7 - My PID is 22181
[CHILD:3] Just completed iteration 3 of 3
[CHILD:3] I have completed my work
[CHILD:4] Just completed iteration 3 of 4
[CHILD:5] Just completed iteration 3 of 5
[CHILD:6] Just completed iteration 2 of 6
[CHILD:7] Just completed iteration 1 of 7
[PARENT] Spawning a new process
[CHILD:8] Running with number 8 - My PID is 22182
[CHILD:4] Just completed iteration 4 of 4
[CHILD:4] I have completed my work
[CHILD:5] Just completed iteration 4 of 5
[CHILD:6] Just completed iteration 3 of 6
[CHILD:7] Just completed iteration 2 of 7
[CHILD:8] Just completed iteration 1 of 8
[PARENT] Spawning a new process
[CHILD:9] Running with number 9 - My PID is 22183
[CHILD:5] Just completed iteration 5 of 5
[CHILD:5] I have completed my work
[CHILD:6] Just completed iteration 4 of 6
[CHILD:7] Just completed iteration 3 of 7
[CHILD:8] Just completed iteration 2 of 8
[CHILD:9] Just completed iteration 1 of 9
[PARENT] Spawning a new process
[CHILD:10] Running with number 10 - My PID is 22184
[CHILD:6] Just completed iteration 5 of 6
[CHILD:7] Just completed iteration 4 of 7
[CHILD:8] Just completed iteration 3 of 8
[CHILD:9] Just completed iteration 2 of 9
[CHILD:10] Just completed iteration 1 of 10
[CHILD:6] Just completed iteration 6 of 6
[CHILD:6] I have completed my work
[CHILD:7] Just completed iteration 5 of 7
[CHILD:8] Just completed iteration 4 of 8
[CHILD:9] Just completed iteration 3 of 9
[PARENT] Spawning a new process
[CHILD:10] Just completed iteration 2 of 10
[CHILD:11] Running with number 11 - My PID is 22185
[CHILD:7] Just completed iteration 6 of 7
[CHILD:8] Just completed iteration 5 of 8
[CHILD:9] Just completed iteration 4 of 9
[CHILD:10] Just completed iteration 3 of 10
[CHILD:11] Just completed iteration 1 of 11
[CHILD:7] Just completed iteration 7 of 7
[CHILD:7] I have completed my work
[CHILD:8] Just completed iteration 6 of 8
[CHILD:9] Just completed iteration 5 of 9
[PARENT] Spawning a new process
[CHILD:10] Just completed iteration 4 of 10
[CHILD:11] Just completed iteration 2 of 11
[CHILD:12] Running with number 12 - My PID is 22186
[CHILD:8] Just completed iteration 7 of 8
[CHILD:9] Just completed iteration 6 of 9
[CHILD:10] Just completed iteration 5 of 10
[CHILD:11] Just completed iteration 3 of 11
[CHILD:12] Just completed iteration 1 of 12
[CHILD:8] Just completed iteration 8 of 8
[CHILD:8] I have completed my work
[CHILD:9] Just completed iteration 7 of 9
[CHILD:10] Just completed iteration 6 of 10
[CHILD:11] Just completed iteration 4 of 11
[CHILD:12] Just completed iteration 2 of 12
[PARENT] Spawning a new process
[CHILD:13] Running with number 13 - My PID is 22188
[CHILD:9] Just completed iteration 8 of 9
[CHILD:10] Just completed iteration 7 of 10
[CHILD:11] Just completed iteration 5 of 11
[CHILD:12] Just completed iteration 3 of 12
[CHILD:13] Just completed iteration 1 of 13
[CHILD:9] Just completed iteration 9 of 9
[CHILD:9] I have completed my work
[CHILD:11] Just completed iteration 6 of 11
[CHILD:10] Just completed iteration 8 of 10
[CHILD:12] Just completed iteration 4 of 12
[CHILD:13] Just completed iteration 2 of 13
[PARENT] Spawning a new process
[PARENT] Out of data to hand out - Waiting for all children to check in
[CHILD:14] Running with number 14 - My PID is 22189
[CHILD:10] Just completed iteration 9 of 10
[CHILD:11] Just completed iteration 7 of 11
[CHILD:12] Just completed iteration 5 of 12
[CHILD:13] Just completed iteration 3 of 13
[CHILD:14] Just completed iteration 1 of 14
[CHILD:10] Just completed iteration 10 of 10
[CHILD:11] Just completed iteration 8 of 11
[CHILD:10] I have completed my work
[CHILD:12] Just completed iteration 6 of 12
[CHILD:13] Just completed iteration 4 of 13
A child was just killed
[CHILD:14] Just completed iteration 2 of 14
[CHILD:11] Just completed iteration 9 of 11
[CHILD:12] Just completed iteration 7 of 12
[CHILD:13] Just completed iteration 5 of 13
[CHILD:14] Just completed iteration 3 of 14
[CHILD:11] Just completed iteration 10 of 11
[CHILD:12] Just completed iteration 8 of 12
[CHILD:13] Just completed iteration 6 of 13
[CHILD:14] Just completed iteration 4 of 14
A child was just killed
[CHILD:12] Just completed iteration 9 of 12
[CHILD:13] Just completed iteration 7 of 13
[CHILD:14] Just completed iteration 5 of 14
[CHILD:12] Just completed iteration 10 of 12
[CHILD:13] Just completed iteration 8 of 13
[CHILD:14] Just completed iteration 6 of 14
A child was just killed
[CHILD:13] Just completed iteration 9 of 13
[CHILD:14] Just completed iteration 7 of 14
[CHILD:13] Just completed iteration 10 of 13
[CHILD:14] Just completed iteration 8 of 14
A child was just killed
[CHILD:14] Just completed iteration 9 of 14
[CHILD:14] Just completed iteration 10 of 14
A child was just killed
[PARENT] All child processes have completed
All the children processes have completed