Allow method handler to decide if operation could be cancelled. If yes,
when connection to the qubesd is terminated (and
protocol.connection_lost get called) the operation is cancelled using
standard asyncio method - in which case asyncio.CancelledError is thrown
inside method handler. This needs to be explicitly enabled, because
cancellable methods are much harder to write, to maintain consistent
system state.
Caveat: protocol.connection_lost is called only when trying to send some
data to it (and it's already terminated). Which makes this whole
mechanism useful only for events. Otherwise, when sending some data (and
possibly detecting that connection is broken), the operation is already
completed.
QubesOS/qubes-issues#2622
* kalkin/device-assignments: (21 commits)
PCI extension cache PCIDevice objects
Make pylint ♥
Fix pylint warning no-else-return
Fix pylint warning len-as-conditional
device-list-attached event returns a dev/options tupples list
DeviceAssignment options are now a dict
Remove WrongAssignment exception
Rename qubes.devices.BlockDevice to qubes.storage.BlockDevice
Update relaxng devices option element
Fix tests broken by the new assignment api
Fix qubes.tests.devices
Fix pci device integration tests
qvm-device add support for assignments
Update ext/pci to new api
BaseVM add DeviceAssignment xml serialization
Migrate DeviceCollection to new API
Add PersistentCollection helper to qubes.devices
Add DeviceAssignment
qvm-device validates device parameters
qvm-device fix handling of non block devices
...
This socket (and commands) are not exposed to untrusted input, so no
need to extensive sanitization. Also, there is no need to provide a
stable API here, as those methods are used internally only.
QubesOS/qubes-issues#853
