Re: [libvirt] [PATCH 03/20] virConnect(Un)RegisterCloseCallback: Throw an error in case the API is not supported
On 03/08/2018 07:20 AM, Marc Hartmayer wrote:
Report an error in case the driver does not support
connect(Un)registerCloseCallback. The commit 'close callback: move it
to driver' (88f09b75eb99) moved the responsibility for the close
callback to the driver. But if the driver doesn't support the
connectRegisterCloseCallback API this function does nothing, even no
unsupported error report. The only case where an error is reported is
when the API is supported but the call fails. The same behavior
applies to virConnectUnregisterCloseCallback.
This behavior is not intended as there are many use cases of this API
where the state of for example allocations depends on the result of
these functions.
To keep the behavior of virsh as before it must silently ignore
unsupported error for virConnectRegisterCloseCallback. For the remote
driver this change wouldn't be needed, but for the byhve driver, for
example. Otherwise the user would see the error message that virsh was
^^^^^^^
I think you forgot to end your sentence for example what about bhyve?
unable to register a disconnect callback.
So the reason to keep the virsh behavior is because failure to do so
could be problematic if connecting to an older server that doesn't
support virConnectRegisterCloseCallback? I almost wonder if we should
blat a vshDebug type message to "inform" the consumer that it's not
possible to catch disconnect...
Since the code path doesn't return -1 anyway (even if "Unable to
register..." is printed), it may not hurt. Your call though - it's not
that important other than the oh, OK so there's something newer in the
newer server that might be useful.
Reviewed-by: John Ferlan <jferlan(a)redhat.com>
John