[pbs-devel] [PATCH v2 proxmox-backup 3/3] client: reader: signal server before client disconnect

[Christian Ebner]

On 12/5/24 10:40, Fabian Grünbichler wrote:
>>> we could even provide some sort of message via the finish API call that
>>> the server could log if desired, differentiating between:
>>>
>>> - regular finish (no error/warning)
>>> - finish called with a warning message (warning)
>>> - finish not called, reader went away (error)
>>>
>>> ?
>>
>> Not sure about this: What warnings do we even want to tell the server
>> about? I think the reader instance will either work without issues or
>> fail with a hard error? Or do you have some specific use-case in mind here?
> 
> well it would be a way to record on the server that that reader "failed"
> from a client's point of view, which would then be reflected in the task
> lists/warning counts/..
> 
> e.g., if you do a restore, but abort it in the middle for some reason,
> you could tell the server so that an admin looking at the server side
> tasks can tell that this was an "incomplete" read session (this would
> just be warning case, not an error).

Hmm, indeed. An intentional abort might be better handled as warning.
Ideally the same would be possible for the backup writer path as well, 
so signaling this via additional api endpoint `abort` might even be 
better? Since the `finish` is already intended to close and check 
consistency of the backup snapshot for the backup writer case. Just 
adding a flag to differentiate this seems less declarative.

Any thoughts on that?

> not sure it's worth it / makes sense, but wanted to put it out there :)
> 
> if we just want to disambiguate "client vanished" vs "client said good
> bye", then the approach in this patch is probably fine.