Quick S3 bulk downloader

downloader.php

<?php // requires aws/aws-php-dsk

// reads s3://bucket/key.ext lines from STDIN, saves them to ../files

require __DIR__ . '/vendor/autoload.php';

ini_set("memory_limit", "2G"); // impacted by concurrency + file sizes, since we aren't streaming

$s3 = new Aws\S3\S3Client(['credentials' => [
    'key' => 'KEY_HERE', 'secret' => 'SECRET_HERE'
], 'version' => '2006-03-01', 'region' => 'us-tirefire-1']);

for ($i = 0, $promises = []; $line = trim(fgets(STDIN)); $i++) {
    $line = str_replace('s3://', '', $line);
    [$bucket, $key] = explode('/', $line, 2);
    fputs(STDERR, "Starting to download " . $key . "\n");

    $promises[] = $s3->getObjectAsync([
        'Bucket' => $bucket,
        'Key' => $key
    ])->then(function (\Aws\Result $result) use ($key) {
        fputs(STDOUT, 'Downloaded: ' . $key . ', size: ' . $result->get('ContentLength') . "\n");
        file_put_contents(__DIR__ . '/../files/' . $key, $result->get('Body'));
    }, function() use ($key) {
        fputs(STDOUT, 'Failed: ' . $key);
        var_dump(func_get_args());
    });

    if (count($promises) == 100) /* concurrency level */ {
        \GuzzleHttp\Promise\all($promises)->wait();
        $promises = [];
    }
}
\GuzzleHttp\Promise\all($promises)->wait();
fputs(STDOUT, "Downloaded $i files\n");