Re: [libvirt] [PATCH] qemu: hotplug: unify "not found" logs when detaching device
On 12/15/2017 09:50 PM, Chen Hanxiao wrote:
At 2017-12-16 09:26:32, "John Ferlan" <jferlan(a)redhat.com> wrote:
>
>
> On 12/14/2017 06:16 AM, Chen Hanxiao wrote:
>> From: Chen Hanxiao <chenhanxiao(a)gmail.com>
>>
>> Some services, such as Nova, check whether device was not found
>> by errror messages "not found". [1]
>
> error
>
>>
>> This patch unify logs of qemuDomainDetachDeviceLive, which will be helpful.
>>
>> [1]
https://github.com/openstack/nova/blob/master/nova/virt/libvirt/guest.py#...
>>
>> Signed-off-by: Chen Hanxiao <chenhanxiao(a)gmail.com>
>> ---
>> src/qemu/qemu_hotplug.c | 18 +++++++++++-------
>> 1 file changed, 11 insertions(+), 7 deletions(-)
>>
>
> Something about a tool that parses the error message(s) looking for a
> specific message string in English and needing to alter libvirt sources
> to match that tools' needs strikes me as incorrect and a "slippery
> slope" to follow.
>
> I'm not in favor of this because we'll be constantly chasing these types
> of bugs to match some other tools' (what I think is) incorrect means to
> handle errors.
>
Agree.
But we don't have enough error code to cover all of scenario.
Then there'd be a "different" fix required - adding an error code...
Perhaps VIR_ERR_NO_DEVICE which would have error text "device %s not found"?
Of course that would require up the stack source code changes as well.
Still better than scanning the error message which only works for a
specific language set. IOW: how would this work for non "English" languages?
For qemuDomainDetachDeviceDiskLive, VIR_ERR_OPERATION_FAILED can be
"disk not found", also can be "cannot hot unplug multifunction PCI
device"
in the following call of qemuDomainDetachVirtioDiskDevice.
So it's "OK" to have a different operational failure? I assume that'll
cause a failure elsewhere in the code. I didn't go digging on the source
code - just a quick look at the _try_detach_device method from the above
nova link.
So the tools powered by libvirt had to find a workaround by
analyzing error messages...
Again, wouldn't those tools be broken without the right language set
being used?
John
Regards,
- Chen