celery task using wait()

celery task using wait()

def build_document_pdf(document, realtime=False, timeout=None, watermark=True):
    """
    Builds and caches a PDF copy of this document.

    If ``realtime`` is True, returns the URL to the PDF. Otherwise, the PDF is
    generated as asynchronously in the background.
    """
    if not timeout:
        timeout = print_settings.PRINTING_TIMEOUT
    pdf_generator = DocumentPdfGenerator()
    if realtime:
        result = pdf_generator.delay(document, watermark=watermark)
        try:
            result.wait(timeout)
            if not result.successful():
                raise ValueError(result.result)
            return result.result
        except TimeoutError:
            return reverse('printing_wait', kwargs={'task_id': result.task_id})
    else:
        return pdf_generator.delay(document, watermark=watermark)