Implement udev queue API

[socketpair]

If I use udev monitoring for events, suppose I monitor event 'add'. I use
pyudev.Monitor.from_netlink(context, 'udev')

So, When event occur, I want to look to only .is_initialized devices. In my udev (Ubuntu 12.04) all network devices are NOT is_initialized if checked right in event. Even more, if I perform this:

print device.is_initialized
sleep(5)
print device.is_initialized

I will see that device still not .is_initialized (strace show that no socket syscalls called during this sequence). So, if I perform:

print device.is_initialized
sleep(5)
print Device.from_path(self.context, device.device_path).is_initialized

In this case, will print False and later True, and I am done!. But using blocking sleep with hardcoded value got from sky + call expensive udev function.

So, We need some way to determine when udev event complete before getting device again. AFAIK, udev has no API for monitoring initialization process.

In one hand we have device.sequence_number and udev_queue_get_seqnum_is_finished in other. So, why not to give API to allow polling of udev using udev_queue_get_seqnum_is_finished if udev does not support event-based notification of event completion.

[socketpair]

I looked at udev sources, and saw that it work like:

1. receive netlink message from kernel
2. process queue, writing some info into its DB.
3. notify userspace programs passing original device (without info from DB)

Therefore, I should re-request device from udev DB. So, queue API is not required for me, but it must be done to make python-udev binding complete .

[socketpair]

Is bug fixed?

[mulkieran]

No. See Changelog from new release for changes (https://github.com/pyudev/pyudev/blob/master/CHANGES.rst). python-pyudev has been mostly inactive since you filed this issue. The changes include what looks like completed development from the develop branch, a bunch of housekeeping fixes, and a few bug fixes. There's unlikely to be much progress on this issue unless you open a PR yourself, as this would certainly constitute new development.