PHP 8.5.0 RC4 available for testing

    La classe parallel\Future

    (0.8.0)

    Futures

    Un Future représente la valeur de retour ou l'exception non attrapée d'une tâche, et expose une API pour l'annulation.

    Exemple #1 Exemple montrant Future comme valeur de retour

    <?php
    $runtime     = new \parallel\Runtime;
    $future = $runtime->run(function(){
    return     "World";
    });
    printf("Hello %s\n", $future->value());
    ?>

    Résultat de l'exemple ci-dessus est similaire à :

    Hello World

    Le comportement d'un Future permet également de l'utiliser comme un simple point de synchronisation même si la tâche ne retourne pas explicitement de valeur.

    Exemple #2 Exemple montrant Future comme point de synchronisation

    <?php
    $runtime     = new \parallel\Runtime;
    $future = $runtime->run(function(){
    echo     "in child ";
    for (    $i = 0; $i < 500; $i++) {
    if (    $i % 10 == 0) {
    echo     ".";
    }
    }
    echo     " leaving child";
    });

    $future->value();
    echo     "\nparent continues\n";
    ?>

    Résultat de l'exemple ci-dessus est similaire à :

    in child .................................................. leaving child
parent continues

    Synopsis de la classe

    final class parallel\Future {
    /* Résolution */
    public value(): mixed
    /* Etats */
    public cancelled(): bool
    public done(): bool
    /* Annulation */
    public cancel(): bool
    }

    Sommaire

    Found A Problem?

    Learn How To Improve This Page • Submit a Pull Request • Report a Bug
    ＋add a note

    User Contributed Notes 1 note

    up
    -2
    Thierry Kauffmann
    3 years ago
    <?php

    /**
    * Sample parallel Runtime/Future processing
    * using a generator to produce the list of items to process
    *
    * Items to process in parallel come from a generator
    * It could be anything : e.g fetch a mysql array, a DirectoryIterator...
    * Thus the number of items to process in parallel is NOT known in advance
    *
    * This algorithm attributes items to each parallel thread dynamically
    * As soon as a thread has finished working
    * It is assigned a new item to process
    * until all items are processed (generator closes)
    *
    * In this example we process 50 items in 5 parallel threads
    * It produces output in this form (output changes at each run) :
    *
    * ThreadId: 1 => Item: 1 (Start)
    * ThreadId: 2 => Item: 2 (Start)
    * ThreadId: 3 => Item: 3 (Start)
    * ThreadId: 4 => Item: 4 (Start)
    * ThreadId: 5 => Item: 5 (Start)
    * ThreadId: 5 => Item: 5 Sleep: 3s (End)
    * ThreadId: 5 => Item: 6 (Start)
    * ThreadId: 3 => Item: 3 Sleep: 4s (End)
    * ThreadId: 3 => Item: 7 (Start)
    * ThreadId: 2 => Item: 2 Sleep: 6s (End)
    * ThreadId: 2 => Item: 8 (Start)
    * ...
    * ThreadId: 4 => Item: 44 Sleep: 6s (End)
    * ThreadId: 4 => Item: 49 (Start)
    * ThreadId: 3 => Item: 46 Sleep: 5s (End)
    * ThreadId: 3 => Item: 50 (Start)
    * ThreadId: 2 => Item: 43 Sleep: 9s (End)
    * Destroy ThreadId: 2
    * ThreadId: 1 => Item: 47 Sleep: 5s (End)
    * Destroy ThreadId: 1
    * ThreadId: 4 => Item: 49 Sleep: 7s (End)
    * Destroy ThreadId: 4
    * ThreadId: 5 => Item: 48 Sleep: 10s (End)
    * Destroy ThreadId: 5
    * ThreadId: 3 => Item: 50 Sleep: 10s (End)
    * Destroy ThreadId: 3
    */

    // Generate list of items to process with a generator
    function generator(int $item_count) {
    echo     "Item count: $item_count\n";
    for (    $i=1; $i <= $item_count; $i++) {
    yield     $i;
    }
    }

    function     testConcurrency(int $concurrency, int $max_item_count) {

    // Set item_count to a random number so that each run is different
    $item_count= rand(1, $max_item_count);
    // Create generator
    $generator = generator($item_count);

    // Function executing in each thread. Have a snap for a random time for example !
    // You could make some calculation here or transfer files or whatever...
    $producer = function (int $item_id) {
    $seconds = rand(1, 10);
    sleep($seconds);
    return [    'item_id' => $item_id, 'sleep_seconds' => $seconds];
    };

    // Fill up threads with a single future initialized to 'false' value
    for ($thread_id = 1; $thread_id <= $concurrency; $thread_id++) {
    $threads[$thread_id] = ['runtime' => new \parallel\Runtime(), 'future' => false];
    }

    // Create infinite loop for the whole processing
    while (true) {
    // Loop through threads until generator closes and all threads are destroyed
    foreach ($threads as $thread_id => &$thread) {
    if (    $thread['future'] === false and $generator->valid()) {
    // Thread is inactive and generator still has values : run something in the thread
    $item_id = $generator->current();
    $thread['future'] = $thread['runtime']->run($producer, [$item_id]);
    echo     "ThreadId: $thread_id => Item: $item_id (Start)\n";
    $generator->next();
    } elseif (    $thread['future'] === false) {
    // Destroy thread in case generator is closed
    echo "Destroy ThreadId: $thread_id\n";
    unset(    $threads[$thread_id]);
    } elseif (    $thread['future']->done()) {
    // Thread finished working. Get result value.
    $item = $thread['future']->value();
    echo     "ThreadId: $thread_id => Item: {$item['item_id']} Sleep: {$item['sleep_seconds']}s (End)\n";
    // Thread is ready to run again
    $thread['future'] = false;
    }
    }

    // Escape infinite loop when all threads are destroyed
    if (empty($threads)) break;
    }
    }

    $concurrency = 5;
    $item_count = 50;

    testConcurrency($concurrency, $item_count);

    ?>
    ＋add a note
    To Top