Restore compatibility with MaaS 1.0 in provider

Restore compatibility with MaaS 1.0 in provider

For supporting the new constraints in MaaS, two changes to the maas
provider were needed. Passing extra parameters to acquire is okay, as
they just get ignored. However, listing tags is a new api call, so
returns 404 in the old version.

To work around this, any http errors when listing tags are now
treated as meaning there are no valid tags, rather than raising.

https://code.launchpad.net/~gz/juju/maas_tagless_compat_1068566/+merge/131724

(do not edit description out of merge proposal)

[gz, 2012-10-27 07:52:14]

Please take a look.

[jimbaker, 2012-10-29 11:34:40]

+1, LGTM.

https://codereview.appspot.com/6777067/diff/1/juju/providers/maas/maas.py
File juju/providers/maas/maas.py (right):

https://codereview.appspot.com/6777067/diff/1/juju/providers/maas/maas.py#new...
juju/providers/maas/maas.py:193: return self.get("api/1.0/tags/",
params).addErrback(
Reasonable, but why not use @inlineCallbacks and simplify error processing:

         try:
             tags = yield self.get("api/1.0/tags/",  {"op": "list"})
         except ProviderError:
             log.exception("Listing valid maas-tags failed")
             tags = []
         returnValue(tags)

[gzlist, 2012-10-29 15:28:46]

On 2012/10/29 11:34:40, jimbaker wrote:
> +1, LGTM.
> 
> https://codereview.appspot.com/6777067/diff/1/juju/providers/maas/maas.py
> File juju/providers/maas/maas.py (right):
> 
>
https://codereview.appspot.com/6777067/diff/1/juju/providers/maas/maas.py#new...
> juju/providers/maas/maas.py:193: return self.get("api/1.0/tags/",
> params).addErrback(
> Reasonable, but why not use @inlineCallbacks and simplify error processing:
> 
>          try:
>              tags = yield self.get("api/1.0/tags/",  {"op": "list"})
>          except ProviderError:
>              log.exception("Listing valid maas-tags failed")
>              tags = []
>          returnValue(tags)

Yes, that's a reasonable change, I just developed a phobia a inlineCallbacks
when writing the test before the bug fix.