azielinski/simple-process

Simple wrapper for PHP pcntl fork functions

dev-master 2015-05-09 13:22 UTC

Requires

• ext-pcntl: *

MIT

README

This small library makes it simple to use the pcntl extension; Also, I strongly encourage you to take a look at the PThreads library (http://pthreads.org) which is more powerful than this tiny wrapper; I wrote it just because using PThreads was not an option in my use-case.

Installation

Requirements

PHP >= 5.3
pcntl extension installed

Composer

Just add the following line to your "require": section:

"azielinski/simple-process": "dev-master"

You do not use composer?

Then just clone the repo :) You will also have to manually include all four files.

Basic usage

Basic usage looks like this:

declare(ticks=1); // This part is critical, be sure to include it
$manager = new SimpleProcess\ProcessManager();
$manager->fork(new SimpleProcess\Process(function() { sleep(5); }, "My super cool process"));
    
do
{
    foreach($manager->getChildren() as $process)
    {
        $iid = $process->getInternalId();
        if($process->isAlive())
        {
            echo sprintf('Process %s is running', $iid);
        } else if($process->isFinished()) {
            echo sprintf('Process %s is finished', $iid);
        }
        echo "\n";
    }
    sleep(1);
} while($manager->countAliveChildren());

And that's it! Child processes will execute only the provided callable, so there is no need to worry about "Am I in the right process in this line?"; Parent process continues execution normally after the ->fork() was called; ProcessManager class also takes care of reaping children processes, so you may focus on your application's logic instead of dark corners of pcntl_* functions usage.

parent<->child communication

ProcessManager may allocate some shared memory for each child process - then you may access it from the parent process:

declare(ticks=1); // This part is critical, be sure to include it
$manager = new SimpleProcess\ProcessManager();
$manager->allocateSHMPerChildren(1000); // allocate 1000 bytes for each forked process
for($i=0;$i<4;$i++)
{
    $manager->fork(new SimpleProcess\Process(function(SimpleProcess\Process $currentProcess) {
        $currentProcess->getShmSegment()->save('status', 'Processing data...');
        sleep(5);
        $currentProcess->getShmSegment()->save('status', 'Connecting to the satellite...');
        sleep(5);
    }, $i));
}
$manager->cleanupOnShutdown(); // Register shutdown function that will release allocated shared memory;
                               // It is important to call this after all fork() calls, as we don't want
                               // to release it when child process exits

do
{
    foreach($manager->getChildren() as $process)
    {
        $iid = $process->getInternalId();
        if($process->isAlive())
        {
            echo sprintf('Process %s is running with status "%s"', $iid, $process->getShmSegment()->fetch('status'));
        } else if($process->isFinished()) {
            echo sprintf('Process %s finished execution', $iid);
        }
        echo "\n";
    }
    sleep(1);
} while($manager->countAliveChildren());

$manager->cleanup(); // You can also call cleanup() manually if you want to

Other things

This library comes also with the Semaphore class in case you'd need to use semaphores somewhere in your code; Use it like this:

$s = SimpleProcess\Semaphore::create('critical_section');
$s->acquire();
$s->release();