Magento: Generate Inventory File Csv By Script

<?php
    define('MAGENTO', realpath(dirname(__FILE__)));
    require_once 'app/Mage.php';
    umask(0);
    Mage::app();
    Mage::app()->getCacheInstance()->flush();
    $products = Mage::getModel("catalog/product")->getCollection()->addAttributeToFilter('type_id', array('eq' => 'simple'));
    $fileName = 'InventorySnapshot_' . date("YmdHis") . '.csv';
    $file = fopen(MAGENTO . '/var/export/Inventory/'. $fileName, 'w');
    $csvHeader = array("sku", "qty"); // Add the fields you need to export
    fputcsv( $file , $csvHeader,",");
    foreach ($products as $product){
        $stock = Mage::getModel('cataloginventory/stock_item')->loadByProduct($product);
        //echo "<pre>"; print_r($product->getData('sku'));
        //echo $stock->getQty();
        $sku = $product->getData('sku');
        $qty = $stock->getQty();
        fputcsv($file, array($sku,$qty), ","); //Add the fields you added in csv header
        echo "<br />". $sku ." == ". (int)$stock->getQty();
    }
    echo "<br /><br />Inventory Csv Created Successfully";
    fclose($file );