On Tue, Dec 11, 2007 at 08:51:32AM -0600, Anthony Liguori wrote: > Dor Laor wrote: > >Laurent Vivier wrote: > >>Le mardi 11 décembre 2007 à 10:10 +0100, Fabrice Bellard a écrit : > >> > >>>Hi, > >>> > >> > >>Hi, > >> > >> > >>>At this point I am not interested in integrating it into QEMU as it is > >>>one more API level to maintain in addition to the command line monitor. > >>>However, I can change my mind if several projects insists to have a > >>>similar interface. > >>> > >> > >>perhaps the DBUS interface can replace the command line monitor ? > >>We have just to move the command line interface to a client speaking to > >>qemu through the DBUS interface. > >> > >> > >This is a valid option but the problem is that local user will have to > >use another tool (client) to > >send commands. Another option is to have a common backend with machine > >& user interfaces. > >For example, if we use dbus as the backend, monitor commands will just > >be translated into dbus. > >The opposite option is also valid. > > > >Anyway, the motivation behind a new interface is that the monitor > >interface is not good enough for automation: > >There are not return status for commands, no option for async > >notifications, no option for parallel actions in case > >a command takes long time to complete (like snapshot). > > All of these are valid, and addressable. Return statuses can just be > added to the beginning of the output of each command (similar to how > POP3 works). Async notification can be made to work by add support to > the monitor for a "select" command. Semantically, select would block > the monitor and then output events. For this to work really well, you > would have to support multiple simultaneous monitor sessions. The > parallel options for long running commands is already address in KVM > with the migration command. We just have to rework the snapshotting to > be properly asynchronous.
Or have 2 monitor interaction modes. One mode uses the command line style suitable for people / scripting languages. The other umode ses a binary XDR protocol for serializing the args & returns values for formal control APIs to use in a easy manner. It ought to be reasonably straightforward to add a binary serialization format for all existing commands Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|
