[moVirt] when connection fails, user does not know the data are old

[Martin Betak]

----- Original Message -----
> From: "Michal Skrivanek" <michal.skrivanek at redhat.com>
> To: "Tomas Jelinek" <tjelinek at redhat.com>
> Cc: "Martin Betak" <mbetak at redhat.com>, "Martin Beták" <matobet at gmail.com>, bolya2003 at bk.ru, "Yixin Zhang"
> <yixin_1992_cia at 126.com>, movirt at ovirt.org
> Sent: Tuesday, May 26, 2015 11:06:46 AM
> Subject: Re: [moVirt] when connection fails, user does not know the data are old
> 
> 
> On May 26, 2015, at 11:04 , Tomas Jelinek <tjelinek at redhat.com> wrote:
> 
> > Hey All,
> > 
> > we have an interesting bug report from Sandro [1] which says that after the
> > connection between engine and moVirt goes down, moVirt does not notify the
> > user about this and keeps showing the
> > old data in the UI as if nothing happened even they are weeks old. This is
> > obviously not correct but not exactly clear how should it behave. I see
> > this options:
> > 
> > - if the connection fails during the refresh, set all the statuses of
> > everything to "unknown"
> >  (I would not do this since this would generate the notifications and may
> >  be temporal (e.g. phone in tunnel or something))
> > 
> > - leave the data as they are and have some top bar or something saying how
> > old the data are. This would be updated at every poll
> >  (Not sure, would occupy place and would make it hard for partial updates.
> >  And track this for each entity is costy)
> > 
> > - leave the data as they are and if some server communication fails add a
> > top bar with a warning that the connection to server is lost and the data
> > are old - maybe with some note when was the last successful connection.
> >  (this seems simple enough and my favorite but still not convinced I like
> >  it…)
> 
> how about greying out the outdated data a little, after some period?

This would require tracking of "last updated" timestamp for each tracked entity
and as Tomas mentioned this would be somewhat costly (but maybe not prohibitively).

My suggestion would probably be a single global timestamp (last successful request)
and have this displayed *always* as a little non-obtrusive footer in each activity.
In case a request fails we can make it more prominent (bigger and with cause of last 
error) so the user knows what is going on. 

Having always readily available how old the data is will also serve as a simple 
check that the periodic refresh is working.
> 
> > 
> > Any more ideas?
> > 
> > Thanx,
> > Tomas
> > 
> > 
> > [1]: https://github.com/matobet/moVirt/issues/66
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>