Add gce_img module for utilizing GCE image resources

[tanpeter]

No description provided.

[sivel]

These module snippets should actually appear as the line directly before the call to main()

[sivel]

cc @erjohnso

[erjohnso]

Please add version_added: "1.9" here and remove it from the options below.

[erjohnso]

Thanks for contributing this @tanpeter! And thanks for the quick review @sivel.

[tanpeter]

Ok, I got your idea now. My only concern is when gce.ex_create_image() returns successfully, I can't effectively know is it a new image or an existing image, then how do I flip the changed flag?

[erjohnso]

I usually set changed = False early on and then only flip it to true if something has changed. In this case, when you call gce.ex_create_image() and the call succeeds, you can set changed = True. If the call errors out because the resource already exists, you can leave changed = False, but not throw a module error. That gives us the idempotency that ansible strives to follow.

[tanpeter]

This looks like a libcloud bug: when I pass in string parameter to gce.ex_delete_image() and the image doesn't exist, I got:

File ".ansible_module_generated", line 151, in delete_image return gce.ex_delete_image("fedora1")
File "/usr/local/lib/python2.7/dist-packages/libcloud/compute/drivers/gce.py", line 2172, in ex_delete_image
    request = '/global/images/%s' % (image.name)
AttributeError: 'NoneType' object has no attribute 'name'

And libcloud does the following when the parameter is not a GCENodeImage:

if not hasattr(image, 'name'):
            image = self.ex_get_image(image)

So there will be an ex_get_image() call in either cases.

[erjohnso]

Hmm... what version of libcloud are you using? It looks like trunk handles string and object OK unless I'm missing something: https://github.com/apache/libcloud/blob/trunk/libcloud/compute/drivers/gce.py#L3294

FWIW, the plan is to release libcloud 0.17.0 this weekend, so if there is a bug I can get it merged in today.

[tanpeter]

Please look at line 3307, if the image does not exist, self.ex_get_image() would return None; then referencing None.name will crash.

[erjohnso]

Ah, gotcha! Thanks, I'll wrap that with a try/except NotFound error. I'll /cc you on the PR.

Then you'll be able to do something like,

def delete_image(gce, image, module):
  """Delete a specific image resource."""
  try:
     image = gce.ex_get_image(image)
     image.delete()
  except ResourceNotFoundError:
     pass
  except GoogleBaseError, e:
     module.fail_json(msg=str(e), changed=False)

[erjohnso]

@tanpeter - ok, merged apache/libcloud#441

[erjohnso]

@bcoca - Hi Brian, new GCE module ready for merge (unless you want to review). With the recent org change, I wanted an ACK before just hitting the merge button. Are you (in general) OK with me helping maintain GCE modules?

[bcoca]

looks good to me. It is fine if you continue in charge of the GCE modules as you have up to now.

[erjohnso]

Thanks Brian.