README

$ composer require seankndy/daemon

Usage overview

On each iteration of the main loop, producers are called which should provide a task to fork/run.

Producers can be callables or objects that implement SeanKndy\Daemon\Tasks\Producer. Producers should return null if there is no task to perform otherwise a SeanKndy\Daemon\Tasks\Task or callable. SeanKndy\Daemon\Tasks\Task has 3 methods:

init() - Called from parent process just before child is forked.

run() - Called from within forked process (child work)

finish(int $status) - Called from parent when process exits

So if you need to perform any initialization or teardown of as children are spawned/exiting, then you'll want to make your own task classes implementing SeanKndy\Daemon\Tasks\Task rather than using a simple closure.

There are various events you can listen for (use SeanKndy\Daemon\Daemon::addListener()):

SeanKndy\Daemon\DaemonEvent::START - When daemon starts

SeanKndy\Daemon\DaemonEvent::STOP - When daemon stops

SeanKndy\Daemon\DaemonEvent::DAEMONIZED - When daemonized (backgrounded)

SeanKndy\Daemon\DaemonEvent::LOOP_ITERATION - Called at the end of each loop iteration

SeanKndy\Daemon\Processes\Event::START - New process started

SeanKndy\Daemon\Processes\Event::EXIT - New process exited

SeanKndy\Daemon\Processes\Event::ITERATION - Every main loop iteration this is fired for each running process

<?php
use SeanKndy\Daemon\Daemon;
use SeanKndy\Daemon\Processes\Event as ProcessEvent;

$maxProcesses = 50;
$quietTime = 1000000;
$childTimeout = 30;

$daemon = new Daemon($maxProcesses, $quietTime, $childTimeout);

// $producer can be a callable or an object that implements SeanKndy\Daemon\Tasks\Producer
// it should produce work to do (which is also a callable or an object implementing SeanKndy\Daemon\Tasks\Task)
//
// if multiple producers are added, they will be round-robined
$number = 0;
$producer = function() use (&$number) {
    if ($number >= 10) return null;
    $number++;

    // this is the "task" or the code to run within the forked child
    return function() use ($number) {
        echo "hello from child $number, my pid is " . getmypid() . "\n";
        return 0; // child exit value
    };
};
$daemon->addProducer($producer);

// optional, signal catching
$daemon->addSignal(SIGTERM, function ($signo) {
    // SIGTERM caught, handle it here
});

// optional, example event listeners
$daemon->addListener(ProcessEvent::START, function ($event) {
    // process $event->getProcess() started
});
$daemon->addListener(ProcessEvent::EXIT, function ($event) {
    // process $event->getProcess() exited
});

$daemon->setDaemonize(false); // don't fork to background
$daemon->start();

Inter-process Communication example

You can use \SeanKndy\Daemon\IPC\Socket to send message from child to parent using socket pairs. Here is an example of doing that:

<?php
use SeanKndy\Daemon\Tasks\Task;

class MyTask implements Task
{
    private $ipc;

    /**
     * Initialize task (main thread)
     *
     * @return void
     */
    public function init() : void
    {
        $this->ipc = new \SeanKndy\Daemon\IPC\Socket();
    }

    /**
     * Do the work (child thread)
     *
     * @return int
     */
     public function run() : int
     {
         // do something useful in child and generate $interestingData

         $this->ipc->send($interestingData);
         $this->ipc->close();
     }

     /**
      * Cleanup (main thread)
      *
      * @var int $status Exit status of child thread
      * @return void
      */
     public function finish(int $status) : void
     {
         if ($this->ipc->hasMessage()) {
             $interestingData = $this->ipc->receive();
             // $interestingData now in parent process
         }
         $this->ipc->close();
     }
}