_call_method should raise exception instead of returning None

[xhzhf]

classic scenario:
def power_on_instance(session, instance, vm_ref=None):
    """Power on the specified instance."""

   if vm_ref is None:
        vm_ref = get_vm_ref(session, instance)

    LOG.debug("Powering on the VM", instance=instance)
    try:
        poweron_task = session._call_method(
                                    session._get_vim(),
                                    "PowerOnVM_Task", vm_ref)
        session._wait_for_task(poweron_task)
        LOG.debug("Powered on the VM", instance=instance)
    except vexc.InvalidPowerStateException:
        LOG.debug("VM already powered on", instance=instance)

if get_vm_ref return None, then PowerOnVM_Task execute with vm_ref None。 After that, _wait_for_task throw exception AttributeError: 'NoneType' object has no attribute 'state'。 It is hard to resolve problem according to the hint。

solution:
    we modify __getattr__() in the oslo.vmware.service.py.
    if not managed_object: return ====> raise ValueError(_('managed object is None'))

[Gary Kotton (garyk)]

Hi,
The get_vm_ref should throw an exception and not return None.
Can you please indicate how I can reproduce this.
Thanks
Gary

[Sabari Murugesan (smurugesan)]

I agree with Gary, get_vm_ref should throw an exception or check the vm_ref before powering on. Either looks fine. I think the bug should belong with Nova.