Code review comment for lp:~chiradeep/nova/msft-hyper-v-support

Hi Chiradeep!

Thanks for the contribution and a start of Windows support in OpenStack! :)

Here are my review notes for you.

1) Documentation is sparse :)

It would be excellent to get some overall design and module documentation for your work. :) This will help those coders in the future who are maintaining and enhancing the hyper-V work. Please see Ewan Mellor's excellent documentation in the xenapi virtualization layer for an example of the kind of documentation that is helpful for maintainers.

This documentation is, IMHO, pretty critical considering the sorry state of python-wmi documentation regarding virtual environments.

Additional code comments would be very useful in places such as the following:

181 + (job, ret_val) = vs_man_svc.DefineVirtualSystem(
182 + [], None, vs_gs_data.GetText_(1))[1:]

What does vs_gs_data.GetText(1) return? What does sv_man_svc.DefineVirtualSystem() return? Without understanding these types of things, maintaining developers have zero chance of successfully fixing bugs that may occur :)

2) Please use Nova's exceptions, which are tested for in the test suites and programs, instead of generic Exception:

402 + raise Exception('instance not present %s' % instance_id)

Should be replaced with:

from nova import exception
...
raise exception.NotFound('instance not found %s' % instance_id)

same for here:

360 + if vm is None:
361 + raise Exception('instance not present %s' % instance.name)

3) Your rewrite of the _fetch_s3_image() function is good, however, it removes the efficiency of using a shared process pool in Linux/BSD environments in favour of cross-platform compatibility. It would be nice to keep the existing code and use your rewrite in an if sys.platform.startswith('win'): block.

============

And here are some style-related things to fix up...

1) Please make sure imports are ordered according to the instructions in the HACKING file. In particular, please make sure system lib imports are first, in alphabetical order, followed by a newline, then imports of 3rd-party libraries (like wmi) in alphabetical order, followed by a newline and imports of nova modules.

2) Something is amiss here:

118 +HYPERV_POWER_STATE = {
119 + 3 : power_state.SHUTDOWN,
120 + 2 : power_state.RUNNING,
121 + 32768 : power_state.PAUSED,
122 + 32768: power_state.PAUSED, # TODO
123 + 3 : power_state.CRASHED
124 +}

The indexes 3 and 32768 are doubled up.

3) Define constants for "magic numbers"

183 + if (ret_val == 4096 ): #WMI job started

Feel free to either create a constant WMI_JOB_STARTED and use that instead of the number 4096 and putting a comment at the end of the line. Self-documenting constants++ :)

Same goes for these locations:

323 + while job.JobState == 4: #job started
327 + if (job.JobState != 7): #job success
385 + if (ret_val == 4096 ): #WMI job started
442 + if (return_val == 4096 ): #WMI job started

4) This looks hacky :)

212 + vcpus = long(str(instance['vcpus']))

I recommend just:

vcpus = long(instance['vcpus'])

5) Please remove extraneous commented-out debugging stuff:

213 + #vcpus = 1

6) Python != C ;)

Please remove outer extraneous parentheses:

286 + if (ret_val != 0):
307 + if (return_val == 4096 ): #WMI job started
320 + if (len(jobs) == 0):
327 + if (job.JobState != 7): #job success
340 + if (len(bound) == 0):
385 + if (ret_val == 4096 ): #WMI job started
387 + elif (ret_val == 0):
442 + if (return_val == 4096 ): #WMI job started
444 + elif (return_val == 0):

7) One newline between methods, 2 newlines between module-level definitions. There are 2 or 3 newlines between method names in a lot of the code.