Re: [libvirt] Transitioning from HMP to QMP for QEMU

Am 15.12.2011 14:18, schrieb Jan Kiszka: > On 2011-12-15 14:02, Stefan Hajnoczi wrote: >> What is the status of QEMU's transition from HMP to the QMP interface? >> >> My current understanding is that QEMU provides new HMP commands for >> humans, but HMP is being phased out as an API. Management tools >> should rely only on QMP for new commands. That would mean new HMP >> commands are not guaranteed to produce backwards-compatible output >> because tools are not supposed to parse the output. >> >> On the libvirt side, new QEMU features should only be supported via >> the json monitor in the future (i.e. human monitor patches should not >> be sent/merged)? Existing HMP commands will still need the human >> monitor support in order to handle old QEMU versions gracefully, but >> I'm thinking about new commands only. >> >> Does everyone agree on this? I think this is an important discussion >> if we want our management interface to get better and more consistent >> in the future. > > To phase out the classic HMP implementation, we need an internal > HMP-over-JSON wrapper (with tab expansion etc.) so that virtual console > and gdbstub monitors continue to benefit from new commands. Those > interfaces will stay for a long time, I'm sure. I think we're not talking about dropping HMP here, only about how long to support it as a stable API for management tools. I believe that we have been in a transitional phase for long enough now that we can start changing the output format of HMP commands without considering it an API breakage.