From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:36135) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UbsfK-0004Y5-1F for qemu-devel@nongnu.org; Mon, 13 May 2013 09:19:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UbsfI-0008BB-Tj for qemu-devel@nongnu.org; Mon, 13 May 2013 09:19:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:8139) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UbsfI-0008Ax-MR for qemu-devel@nongnu.org; Mon, 13 May 2013 09:19:44 -0400 Date: Mon, 13 May 2013 09:18:58 -0400 From: Luiz Capitulino Message-ID: <20130513091858.54c4e4e6@redhat.com> In-Reply-To: <20130513130931.GC6419@dhcp-200-207.str.redhat.com> References: <1367221335-22777-1-git-send-email-stefanha@redhat.com> <1367221335-22777-3-git-send-email-stefanha@redhat.com> <518DC2C6.5030500@redhat.com> <20130513082811.GB6419@dhcp-200-207.str.redhat.com> <5190E30E.40005@redhat.com> <20130513130931.GC6419@dhcp-200-207.str.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 2/3] block: add block-backup QMP command List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: Fam Zheng , qemu-devel@nongnu.org, Wenchao Xia , imain@redhat.com, Stefan Hajnoczi , pbonzini@redhat.com, dietmar@proxmox.com On Mon, 13 May 2013 15:09:31 +0200 Kevin Wolf wrote: > Am 13.05.2013 um 14:56 hat Eric Blake geschrieben: > > On 05/13/2013 02:28 AM, Kevin Wolf wrote: > > > > >>> +{ 'command': 'block-backup', > > >>> + 'data': { 'device': 'str', 'target': 'str', '*format': 'str', > > >> > > >> Hmm - wondering if we should add an enum type for supported disk formats > > >> instead of using free-form strings. The wire representation would be > > >> the same, and now's the time to do it before we add introspection (it's > > >> more than just this command impacted). > > > > > > And ideally we shouldn't make it a static list that contains every > > > format for which qemu has some code, but only those that are actually > > > compiled in. (Hm, and probably not protocols?) > > > > > > Luiz, any idea how to do something like this, a QAPI enum with values > > > that are determined at runtime? Especially with respect to the coming > > > schema introspection? > > > > Or maybe we make the 'enum' list ALL possible types, but then add a > > query-* command that returns an array of only those enum values that are > > supported. Introspection would see all types, but the query command > > would be the useful variant that is runtime-dependent. Agreed. This is a capability, and we're adding query- commands to query capabilities. > Then is there any advantage in making it an enum in the first place? Eric is in a better position to answer this, but the fact that this can be queried isn't a strong pro for having it?