Re: [PATCH] net: vhost-user: add QAPI events to report connection state

[Markus Armbruster <armbru@redhat.com>]

Laurent Vivier <lvivier@redhat.com> writes:

> The netdev reports NETDEV_VHOST_USER_CONNECTED event when
> the chardev is connected, and NETDEV_VHOST_USER_DISCONNECTED
> when it is disconnected.
>
> The NETDEV_VHOST_USER_CONNECTED event includes the ChardevInfo
> (label, filename and frontend_open).
>
> This allows a system manager like libvirt to detect when the server
> fails.
>
> For instance with passt:
>
> { 'execute': 'qmp_capabilities' }
> { "return": { } }
>
> [killing passt here]
>
> { "timestamp": { "seconds": 1739517243, "microseconds": 115081 },
>   "event": "NETDEV_VHOST_USER_DISCONNECTED",
>   "data": { "netdev-id": "netdev0" } }
>
> [automatic reconnection with reconnect-ms]
>
> { "timestamp": { "seconds": 1739517290, "microseconds": 343777 },
>   "event": "NETDEV_VHOST_USER_CONNECTED",
>   "data": { "netdev-id": "netdev0",
>             "info": { "frontend-open": true,
>                       "filename": "unix:",
>                       "label": "chr0" } } }
>
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Standard question for events: if a management application misses an
event, say because it restarts and reconnects, is there a way to obtain
the missed information with a query command?