From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:41151) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UTAxz-0003Yv-EU for qemu-devel@nongnu.org; Fri, 19 Apr 2013 09:03:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UTAxy-0008FQ-27 for qemu-devel@nongnu.org; Fri, 19 Apr 2013 09:03:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58955) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UTAxx-0008FI-PD for qemu-devel@nongnu.org; Fri, 19 Apr 2013 09:03:01 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r3JD31gl009222 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 19 Apr 2013 09:03:01 -0400 Message-ID: <51714084.8050907@redhat.com> Date: Fri, 19 Apr 2013 07:03:00 -0600 From: Eric Blake MIME-Version: 1.0 References: <1366275680-15416-1-git-send-email-kraxel@redhat.com> <87ppxq6hmn.fsf@blackfin.pond.sub.org> In-Reply-To: <87ppxq6hmn.fsf@blackfin.pond.sub.org> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="----enig2NRQOQVXOPUHVLEHPQBOO" Subject: Re: [Qemu-devel] [RfC PATCH 0/5] console: qom-ify & extent screendump monitor command List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: lcapitulino@redhat.com, Gerd Hoffmann , qemu-devel@nongnu.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) ------enig2NRQOQVXOPUHVLEHPQBOO Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 04/19/2013 02:37 AM, Markus Armbruster wrote: >> Question for the libvirt guys: Is it ok for libvirt to just extend th= e >> existing screendump command? Can libvirt figure there is a new >> (optional) parameter? See patch #5. >=20 > Nope, QMP can't do that. I argued for such capabilities, but the > "create a new command" philosophy prevailed. >=20 > Go forth and multiply commands! And have fun picking command names tha= t > aren't fugly. Adding optional parameters to an existing command has been done before; drive-mirror gained 'granularity' and 'buf-size' in 1.4 even though the command existed in 1.3. What would make it possible to avoid an explosion of new commands is a way to introspect WHICH options are available for a given command. We don't have that yet, but if we add a command that returns the JSON representation of what the command expects, THAT would make it acceptable to add optional arguments to an existing command in a way that libvirt could query to see whether the qemu it is talking to supports the optional arguments. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org ------enig2NRQOQVXOPUHVLEHPQBOO Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.13 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJRcUCEAAoJEKeha0olJ0NqX8gH/07QvEz1NZ1uDJ6TH3qohiun JiKrPVdHGAWA163V3IlTuLutI5Np8wzXWXWqOKxl0mEvi4Cp8HZ6evPUwObgUpHQ uDJms+xbv8G6XLL2Gxn4tPvawNvwKAMQePBgzu12IhOSqWywyNQvYI0MtETmm4We +hBIrBzleILhQ4/3ZTm4u11NvMJoB+Go9js8Bgr5wR6OvgwfqHOYmaFvACX/+4zr kfVpk8VnAzyH7fASsA3/k37sZ9/zbBdCSJxJX0fz2dlg4mlLgl7s2fBLYsaD5pL3 sGdlO4OGpzl2bh/3PNXUojvN50RKXJeN4upuaAcWuWpZvP1ebZxZo05g+O6Bucw= =TqAp -----END PGP SIGNATURE----- ------enig2NRQOQVXOPUHVLEHPQBOO--