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From: Luiz Capitulino <lcapitulino@redhat.com>
To: aliguori@us.ibm.com
Cc: Kevin Wolf <kwolf@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	qemu-devel@nongnu.org, armbru@redhat.com
Subject: [Qemu-devel] Adding errno to QMP errors
Date: Wed, 13 Jun 2012 14:49:10 -0300	[thread overview]
Message-ID: <20120613144910.598bfe24@doriath.home> (raw)
In-Reply-To: <4FC78637.4040605@redhat.com>

On Thu, 31 May 2012 16:54:47 +0200
Paolo Bonzini <pbonzini@redhat.com> 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?

  parent reply	other threads:[~2012-06-14  0:22 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1338387301-10074-1-git-send-email-lcapitulino@redhat.com>
     [not found] ` <1338387301-10074-3-git-send-email-lcapitulino@redhat.com>
     [not found]   ` <4FC74B1A.8080700@redhat.com>
     [not found]     ` <20120531110608.4dc3fe22@doriath.home>
     [not found]       ` <4FC77F6C.8000008@redhat.com>
     [not found]         ` <20120531113127.1c8aa213@doriath.home>
     [not found]           ` <4FC78637.4040605@redhat.com>
     [not found]             ` <20120531124411.659ed161@doriath.home>
     [not found]               ` <4FC79316.6080603@redhat.com>
     [not found]                 ` <20120531130814.5779aae9@doriath.home>
2012-06-01 12:40                   ` [Qemu-devel] [PATCH 02/14] qerror: add new errors Kevin Wolf
2012-06-13 17:49             ` Luiz Capitulino [this message]
2012-06-15 14:46               ` [Qemu-devel] Adding errno to QMP errors Luiz Capitulino
2012-06-15 16:52               ` Anthony Liguori
2012-06-15 16:55                 ` Paolo Bonzini
2012-06-15 17:48                   ` Anthony Liguori
2012-06-15 19:11                     ` Paolo Bonzini
2012-06-15 17:02                 ` Luiz Capitulino
2012-06-15 17:23                   ` Kevin Wolf
2012-06-15 17:03                 ` Daniel P. Berrange
2012-06-18 15:41                   ` Markus Armbruster
2012-06-18 18:31                     ` Anthony Liguori
2012-06-19  7:39                       ` Kevin Wolf
2012-06-19  9:20                         ` Daniel P. Berrange
2012-06-19  9:31                           ` Kevin Wolf
2012-06-19 13:12                       ` Luiz Capitulino
2012-06-20 17:48                         ` [Qemu-devel] [RFC] Fixing the error failure Luiz Capitulino
2012-06-20 18:46                           ` Anthony Liguori
2012-06-20 19:40                             ` Luiz Capitulino
2012-06-20 19:47                               ` Anthony Liguori
2012-06-20 20:13                                 ` Luiz Capitulino
2012-06-21 12:42                           ` Daniel P. Berrange
     [not found]                             ` <20120625165651.31f9e0bd@doriath.home>
     [not found]                               ` <m34npyld8y.fsf@blackfin.pond.sub.org>
     [not found]                                 ` <20120626093511.GD14451@redhat.com>
     [not found]                                   ` <m3hatyco9g.fsf@blackfin.pond.sub.org>
     [not found]                                     ` <4FE9E275.40303@codemonkey.ws>
     [not found]                                       ` <m3txxvq3i3.fsf@blackfin.pond.sub.org>
2012-07-02 12:47                                         ` Anthony Liguori
2012-07-02 13:47                                           ` Luiz Capitulino
2012-07-02  8:03                           ` Paolo Bonzini

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