parallel/examples/worker-pool.php

#!/usr/bin/env php
<?php

require \dirname(__DIR__) . '/vendor/autoload.php';

use Amp\Loop;
use Amp\Parallel\Worker\CallableTask;
use Amp\Parallel\Worker\DefaultPool;

// A variable to store our fetched results
$results = [];

// We can first define tasks and then run them
$tasks = [
    new CallableTask('file_get_contents', ['http://php.net']),
    new CallableTask('file_get_contents', ['https://amphp.org']),
    new CallableTask('file_get_contents', ['https://github.com']),
];

// Event loop for parallel tasks
Loop::run(function () use (&$results, $tasks) {
    $timer = Loop::repeat(200, function () {
        \printf(".");
    });
    Loop::unreference($timer);

    $pool = new DefaultPool;

    $coroutines = [];

    foreach ($tasks as $index => $task) {
        $coroutines[] = Amp\call(function () use ($pool, $index, $task) {
            $result = yield $pool->enqueue($task);
            \printf("\nRead from task %d: %d bytes\n", $index, \strlen($result));
            return $result;
        });
    }

    $results = yield Amp\Promise\all($coroutines);

    return yield $pool->shutdown();
});

echo "\nResult array keys:\n";
echo \var_export(\array_keys($results), true);