From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:52472) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sexpa-00027i-H7 for qemu-devel@nongnu.org; Wed, 13 Jun 2012 20:22:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SexpY-0000Gu-Ss for qemu-devel@nongnu.org; Wed, 13 Jun 2012 20:22:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38331) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SexpY-0000Gg-KC for qemu-devel@nongnu.org; Wed, 13 Jun 2012 20:22:32 -0400 Date: Wed, 13 Jun 2012 14:49:10 -0300 From: Luiz Capitulino Message-ID: <20120613144910.598bfe24@doriath.home> In-Reply-To: <4FC78637.4040605@redhat.com> References: <1338387301-10074-1-git-send-email-lcapitulino@redhat.com> <1338387301-10074-3-git-send-email-lcapitulino@redhat.com> <4FC74B1A.8080700@redhat.com> <20120531110608.4dc3fe22@doriath.home> <4FC77F6C.8000008@redhat.com> <20120531113127.1c8aa213@doriath.home> <4FC78637.4040605@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Adding errno to QMP errors List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: aliguori@us.ibm.com Cc: Kevin Wolf , Paolo Bonzini , qemu-devel@nongnu.org, armbru@redhat.com On Thu, 31 May 2012 16:54:47 +0200 Paolo Bonzini wrote: > Wait, I think you're conflating two things. > > One is "do not shoehorn errors into errno values". So for QOM invalid values we > have PropertyValueBad, not a generic InvalidArgument value. We convert everything > to Error rather than returning negative errno values and then returning generic > error codes, because those would be ugly and non-descriptive. I agree with that. > > The other is "when errors come straight from the OS, _do_ use errno values". > This is for OpenFileFailed, for the new socket errors and so on. This is what > I am proposing. [...] > $ echo | sed p > /dev/full > sed: couldn't flush stdout: No space left on device > ^^^^^^^^^^^^^^ error type > ^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^ arguments > > That would become, in JSON: > > { 'error': 'FlushFailed', > 'file': 'stdout', > 'os_error': 'enospc' } This is not a new discussion and what we're doing today is to return errno as a QError class name. So, for the example above we'd return something like: { 'error': 'NoSpace' } It's possible to add new optional values if you need more information, but I know that that's not what you're asking. I mostly agree that your version would be better, the only problem I see is that this is probably going to mess a bit more our API as we have been doing like my example above for some time. Anthony, the current design was mostly influenced by you and you had objections on doing what Paolo and Kevin are suggesting. What do you think?