Re: [Qemu-devel] Should we auto-generate IDs?

[Kevin Wolf <kwolf@redhat.com>]

Am 01.09.2015 um 16:18 hat Programmingkid geschrieben:
> 
> On Sep 1, 2015, at 8:34 AM, Kevin Wolf wrote:
> 
> > Am 27.08.2015 um 14:32 hat Jeff Cody geschrieben:
> >> I'm not married to the ID generation scheme I proposed.  
> >> 
> >> What I am trying to do, however, is have a technical discussion on
> >> generating an ID in a well-formed manner.  And hopefully, in a way
> >> that is useful to all interested subsystems, if possible.
> >> 
> >> Do you disagree with the requirements I listed above?  If so, it would
> >> be useful to begin the discussion around that.  For ease of
> >> discussion, I'll list them again:
> >> 
> >> * Reserved namespaces
> >> * Uniqueness
> >> * Non-predictable (to avoid inadvertently creating a de facto ABI)
> >> 
> >> 
> >> . . .
> >> 
> >> On the generation scheme proposed above:
> >> 
> >> I understand that something you desire is an ID that is easier to
> >> type.
> >> 
> >> If we wanted to make it shorter, perhaps we could have the number
> >> counter be variable length:
> >> 
> >>            qemu#ss#D#XY
> >>              |   | | |
> >> qemu reserved -   | | |
> >>                  | | |
> >> subsystem name ---| | |
> >>                    | |
> >>    counter --------| |
> >>                      |
> >>    2-digit random ---|
> > 
> > Even with keeping all of the information in there we can shorten the ID
> > a bit more: # at the start is enough to mark it as autogenerated, the
> > subsystem seems nice to have in there anyway, and the # separators can
> > be removed without making the ID less unique (assuming that subsystems
> > never end in a digit). This results in an ID that looks like a three (or
> > more) digit number for the subsystem, where the last two digits are
> > random, like this:
> > 
> >    #block150
> >    #block219
> >    #block344
> >    ...
> > 
> > That seems easy to type and still fulfills all of the criteria.
> > 
> > Kevin
> 
> I do know that some really want an indicator that shows that an ID is auto-generated. But we could still do this and keep the ID short. What if the auto-generated ID just started with a character the user could never use at the beginning of the ID. I suggest we use an underscore to indicate machine-generated ID's. Something like this _1. It is very simple and effective. 

That's what I already did. # is a reserved character. I don't think
something like #block150 is unreasonably long, it's a bit more
descriptive than _1, and it fulfills all of Jeff's criteria, which _1
clearly doesn't.

Kevin