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

[Serge Hallyn]

Quoting Alexandru Gheorghe (alghe.global at gmail.com):
> 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?

Yup, that sounds good.  I could just do it I suppose, I've just been
waiting for someone to send a patch :)

> 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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