Безопасная интеграция
Robokassa «под ключ»
для высоконагруженных проектов

async def _try_acquire_lock(inv_id: str) -> bool:
    """
    Atomically checks and marks InvId as processed.
    Returns True if first time, False if already locked.
    Prevents race conditions from gateway retries.
    """
    r = await aioredis.from_url(settings.redis_url)
    was_set = await r.set(
        f"robokassa:processed:{inv_id}",
        "processing",
        ex=2592000, # 30 days TTL
        nx=True,    # Strict SET if Not eXists
    )
    return bool(was_set)

@shared_task(bind=True, max_retries=3)
def process_robokassa_payment(self, inv_id: str):
    """
    Background worker: heavy lifting decoupled from HTTP response.
    Retry logic with exponential backoff on DB locks.
    """
    try:
        with transaction.atomic():
            order = Order.objects.select_for_update().get(id=inv_id)
            if order.is_paid:
                return "Already processed"
            
            order.mark_as_paid()
            fiscal_client.issue_receipt(order) # 54-FZ Check
            provision_digital_goods(order.user)
            
    except DatabaseError as exc:
        raise self.retry(exc=exc, countdown=2 ** self.request.retries)