Re: [libvirt] [PATCH v2 3/3] conf: Allow users to define UUID for devices

On Tue, Oct 03, 2017 at 12:58:59PM +0200, Michal Privoznik wrote: I'll be frank with you, I hate the fact that this can only be UUID and there are reasons. Even though other will^Wmight not share my view. I don't want to ACK this patch even though it probably works OK. At the same time I'm not NACKing it since I might get overruled. OK, it's my bad I didn't reply on the previous version, but I don't like this so much I'll reply to it even in this new version. So let me sum it up: 1) UUIDs are more generally useful concept Allowing arbitrary (but sane, e.g. [a-zA-Z0-9\-_.]) also inherently allows UUID is mgmt apps want to use them. This field should never be used by a hypervisor, only by drivers and if necessary. 2) We cannot extend current APIs to support it, it can clash with libvirt's alias in the future. I don't see why not. Searching by IDs (or user aliases, whatever you call it) does not have to be supported at all. Mgmt apps can use is only as a part of domain definition. If we want to add such functionality, then it can be turned on by a flag or flags, e.g.: - VIR_BLAH_BY_ID - VIR_BLAH_PREFER_ID - VIR_BLAH_WHATEVER But there is no requirement for us to provide this. It should not be blocking the inclusion of this feature. 3) We have to add a lot of code that handles duplicates, etc. No. No, we don't. Duplicates can not only be handled by mgmt app itself, it could also be beneficial. Imagine I have bunch of devices that share some source or are similar in a way and I just name them the same. Even if we want to provide a way of specifying devices for APIs by this user supplied string, we can just unplug the first one we'll find. By not requiring that it's an ID, users can take benefit of ti too. And making sure it's an UUID seems like a waste of computing power. Sometimes I feel like we are trying to do too much, even stuff that nobody will effectively use and then we have to support it. The same with solving corner cases in which we could just error out instead of wasting manpower on them. My (way more than) 2 cents. Have a nice day, Martin