Drupal 7 dompdf нет данных в цикле foreach

Question

Я пытаюсь отправить электронное письмо с приложением PDF, созданного с помощью dompdf. Я создал функцию для отправки одного за другим, чтобы отправить их всех сразу. Проблема в том, что при функции их одновременной отправки вложения не имеют данных из базы данных.

Ниже приведен код моей функции:

function cust_finance_send_invoice_callback(&$context){
  $batch_limit = 10;
  global $language;

  if (empty($context['sandbox'])) {
    $query_rs = db_select("my_invoices", "i");
    $query_rs->join("node", "n", "i.nid = n.nid");
    $query_rs->join("field_email_invoice", "e", "n.nid = e.entity_id AND e.entity_type = 'node'");
    $query_rs->fields("i", array("nid"));
    $query_rs->condition("i.sent", 0, "=");
    $query_rs->condition("e.field_email_invoice", "", "!=");
    $query_rs->condition("e.bundle", "page", "=");
    $total_results = $query_rs->countQuery()->execute()->fetchField();

    $context['sandbox']['progress'] = 0;
    $context['sandbox']['max'] = $total_results;
  }
  if( !is_array($context["results"]) ) {
    $context["results"] = array();
  }

  if ( $context['sandbox']['max'] > 0 ) {
    $invoices_rs = db_select("finance_invoices", "i");
    $invoices_rs->join("node", "n", "i.nid = n.nid");
    $invoices_rs->join("field_email_invoice", "e", "n.nid = e.entity_id AND e.entity_type = 'node'");
    $invoices_rs->fields("i", array("id", "nid"));
    $invoices_rs->fields("n", array("title"));
    $invoices_rs->fields("e", array("field_email_invoice"));
    $invoices_rs->condition("i.sent", 0, "=");
    $invoices_rs->condition("e.field_email_invoice", "", "!=");
    $invoices_rs->condition("e.bundle", "prd", "=");
    $invoices_rs->orderBy("i.id", "desc");
    $invoices_rs->range(0, $batch_limit);
    $invoices = $invoices_rs->execute()->fetchAll();

    foreach( $invoices as $invoice ) {
      $txn = db_transaction();
      try {
        $send_invoice_id = db_update("my_invoices")->condition("id", $invoice->id)->fields(array("sent" => 1))->execute();

        $context['results'][] = $invoice->title;
        $context['message'] = t("Sent invoices so far: @nr_invoices.", array("@nr_invoices" => count($context['results'])) );
        $context['message'] .= "<br />" . t("Last sent invoice was to @someone", array("@someone" => $invoice->title) );

        $params = array(
          "subject" => variable_get("cust_mail_invoice_generated_sent_title", "My subject"),
          "body" => variable_get("cust_mail_invoice_generated_sent_body", t("Body with the link: \n\n[invoice_link].\n\nThanks,\nTest Team")),
          "to" => "my-email@hotmail.com"
        );
        $salt = "fsdfsdge4456546467"; //test salt
        $hash = md5($invoice->nid . $invoice->id . $salt);
        $invoice_link = " " . url("node/" . $invoice->nid . "/finance/pdf/" . $invoice->id . "/" . $hash, array("absolute" => true)) . " ";
        $params["body"] = str_replace("[invoice_link]", $invoice_link, $params["body"]);
        $prd = node_load($invoice->nid);
        if ($dompdf = cust_finance_render_invoice_pdf($prd, $invoice)) {
          $params['attachment'] = array('filename' => "invoice-$invoice->id.pdf", 'filecontent' => $dompdf->output(), 'filemime' => 'application/pdf');
        }
        drupal_mail("cust_function", "cust_function_invoice_generated_sent_mail", $params["to"], $language, $params);
      } catch (Exception $e) {
        $txn->rollback();
        $context['message'] = t("Sent invoices so far: @nr_invoices.", array("@nr_invoices" => count($context['results'])) );
        $context['message'] .= "<br />" . t("Last processed item: Failed to send invoice to @someone", array("@someone" => $invoice->title) );
      }
      $context['sandbox']['progress']++;
    }
    if ($context['sandbox']['progress'] != $context['sandbox']['max']) {
      $context['finished'] = $context['sandbox']['progress'] / $context['sandbox']['max'];
    } else {
      $context['finished'] = 1;
    }
  } else {
    $context['finished'] = 1;
  }
}