On 19.12.2013 16:15, Eric Blake wrote:
> Several times in the past, qemu has implemented a new event,
> but libvirt has not yet caught up to reporting that event to
> the user applications. While it is possible to track libvirt
> logs to see that an unknown event was received and ignored,
> it would be nicer to copy what 'virsh qemu-monitor-command'
> does, and expose this information to the end developer as
> one of our unsupported qemu-specific commands.
>
> If you find yourself needing to use this API for more than
> just development purposes, please ask on the libvirt list
> for a supported counterpart event to be added in libvirt.so.
>
> While the supported virConnectDomainEventRegisterAny() API
> takes an id which determines the signature of the callback,
> this version takes a string filter and always uses the same
> signature. Furthermore, I chose to expose this as a new API
> instead of trying to add a new eventID at the top level, in
> part because the generic option lacks event name filtering,
> and in part because the normal domain event namespace should
> not be polluted by a qemu-only event. I also added a flags
> argument; unused for now, but we might decide to use it to
> allow a user to request event names by glob or regex instead
> of literal match.
>
> * include/libvirt/libvirt-qemu.h
> (virConnectDomainQemuMonitorEventCallback)
> (virConnectDomainQemuMonitorEventRegister)
> (virConnectDomainQemuMonitorEventDeregister): New prototypes.
> * src/libvirt-qemu.c (virConnectDomainQemuMonitorEventRegister)
> (virConnectDomainQemuMonitorEventDeregister): New functions.
> * src/libvirt_qemu.syms (LIBVIRT_QEMU_1.2.1): Export them.
> * src/driver.h (virDrvConnectDomainQemuMonitorEventRegister)
> (virDrvConnectDomainQemuMonitorEventDeregister): New callbacks.
>
> Signed-off-by: Eric Blake <[email protected]>
> ---
>
> Before I go and implement the guts of this new API, I first
> wanted to get approval from the list that I'm on the right track.
>
> include/libvirt/libvirt-qemu.h | 31 ++++++++++-
> src/driver.h | 15 +++++
> src/libvirt-qemu.c | 123
> +++++++++++++++++++++++++++++++++++++++++
> src/libvirt_qemu.syms | 6 ++
> 4 files changed, 174 insertions(+), 1 deletion(-)
>
> diff --git a/include/libvirt/libvirt-qemu.h b/include/libvirt/libvirt-qemu.h
> index 3e79a8c..5403093 100644
> --- a/include/libvirt/libvirt-qemu.h
> +++ b/include/libvirt/libvirt-qemu.h
> @@ -4,7 +4,7 @@
> * Description: Provides the interfaces of the libvirt library to handle
> * qemu specific methods
> *
> - * Copyright (C) 2010, 2012 Red Hat, Inc.
> + * Copyright (C) 2010, 2012-2013 Red Hat, Inc.
> *
> * This library is free software; you can redistribute it and/or
> * modify it under the terms of the GNU Lesser General Public
> @@ -54,6 +54,35 @@ typedef enum {
> char *virDomainQemuAgentCommand(virDomainPtr domain, const char *cmd,
> int timeout, unsigned int flags);
>
> +/**
> + * virConnectDomainQemuMonitorEventCallback:
> + * @conn: the connection pointer
> + * @dom: the domain pointer
> + * @event: the name of the event
> + * @details: the JSON details of the event
> + * @opaque: application specified data
> + *
> + * The callback signature to use when registering for a qemu monitor
> + * event with virConnectDomainQemuMonitorEventRegister().
> + */
> +typedef void (*virConnectDomainQemuMonitorEventCallback)(virConnectPtr conn,
> + virDomainPtr dom,
> + const char *event,
> + const char *details,
> + void *opaque);
So for instance on this event:
2013-12-19 15:55:05.575+0000: 18630: debug : qemuMonitorJSONIOProcessLine:172 :
QEMU_MONITOR_RECV_EVENT: mon=0x7f8c80008910 event={"timestamp": {"seconds":
1387468505, "microseconds": 574652}, "event": "SPICE_INITIALIZED", "data":
{"server": {"auth": "none", "port": "5900", "family": "ipv4", "host":
"127.0.0.1"}, "client": {"port": "39285", "family": "ipv4", "channel-type": 4,
"connection-id": 375558326, "host": "127.0.0.1", "channel-id": 0, "tls":
false}}}
the callback will be invoked with:
event="SPICE_INITIALIZED"
details="{"server": {"auth": ....}}"?
After all, I don't think we should do anything clever about it. Apps dealing
with monitor/agent code (e.g. command passthru) are dealing with JSON anyway.
Michal
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