[lxc-devel] [PATCH 3/9] lxc_start: ERROR if container is already running.

[Alexandru Gheorghe]

On 10/21/2014 07:54 PM, Serge Hallyn wrote:
> Quoting Dwight Engen (dwight.engen at oracle.com):
>> On Tue, 21 Oct 2014 09:58:29 -0500
>> Tycho Andersen <tycho.andersen at canonical.com> wrote:
>>
>>> On Tue, Oct 21, 2014 at 02:54:34PM +0000, Serge Hallyn wrote:
>>>> Quoting Tycho Andersen (tycho.andersen at canonical.com):
>>>>> On Tue, Oct 21, 2014 at 02:29:28PM +0000, Serge Hallyn wrote:
>>>>>> Quoting Tycho Andersen (tycho.andersen at canonical.com):
>>>>>>> On Fri, Oct 10, 2014 at 11:16:54AM +0800, Dongsheng Yang
>>>>>>> wrote:
>>>>>>>> We should exit with a error when starting a running
>>>>>>>> container.
>>>>>>>
>>>>>>> Is this intentional? I just noticed it when pulling from
>>>>>>> master that it breaks some of my scripts. Are we sure it
>>>>>>> doesn't break anything else?
>>>>>>
>>>>>> Which scripts does it break?
>>>>>
>>>>> No public ones, just some that I wrote myself. Just curious if the
>>>>> behavior change was intentional or not (I prefer the previous
>>>>> behavior :)
>>>>
>>>> What exactly is the change?  Did it used to return true instead of
>>>> false?  The intent was simply to shortcut a bunch of extra work in
>>>> the case where the container was already running.
>>>
>>> Yes, sorry. It used to exit 0 instead of 1 when the container was
>>> already running (and didn't print any ERROR or anything).
>>
>> I also find this a bit inconsistent, we purposefully don't report an
>> error when doing stop on an already stopped container (see the early
>> return 0 in lxc_cmd_stop()). I think it can be argued that its not an
>> error since the command did what the caller wanted (ensure the
>> container is started/stopped).
> 
> Ok - I don't want to revert the patch, but am happy to have it return 0.

Why not return a different code, like 5, when is already running (and
trying to start)/stopped (and trying to stop it), so wrappers can detect
this and use the information further?

Could this be useful? At least it will allow some more handling by
knowing if it's an error (1) or it really succeeded (0), and that is
already in the state wanted (5) when tried so.

--
; Alexandru Gheorghe
; alghe.global {at} gmail {dot} com
; OpenPGP key ID 0xCAF985D2

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