Merge lp://qastaging/~thedac/charms/precise/block-storage-broker/configure-repository into lp://qastaging/charms/block-storage-broker

I'm not massively happy about the default being cloud-archive:havana. This seems like it's going to be a gotcha for anyone using trusty, which before too long will be everyone (I assume). If we know precise requires cloud-archive:havana but trusty doesn't, couldn't we check /etc/lsb-release and act accordingly?

Per Tom's request I have checked for the running series and set the extra repo only when not running trusty.

Also fixed the malformed string error

volume-show had the bare word null as seen below causing the error.
[{"device": "/dev/vdc", "server_id": "6b2d686b-972e-46b8-ba32-db03b6e14ddd", "volume_id":
"a1d3c1e5-3807-4c12-a339-20125c376335", "host_name": null, "id": "a1d3c1e5-3807-4c12-a339-20125c376335"}]

Traceback (most recent call last):
  File "hooks/block-storage-relation-changed", line 144, in <module>
    hooks.execute(sys.argv)
  File
"/var/lib/juju/agents/unit-block-storage-broker-0/charm/hooks/charmhelpers/core/hookenv.py",
line 381, in execute
    self._hooks[hook_name]()
  File "hooks/block-storage-relation-changed", line 128, in
block_storage_relation_changed
    volume_label=volume_label)
  File
"/var/lib/juju/agents/unit-block-storage-broker-0/charm/hooks/util.py",
line 159, in attach_volume
    volume_id = self.get_volume_id(volume_label)
  File
"/var/lib/juju/agents/unit-block-storage-broker-0/charm/hooks/util.py",
line 93, in get_volume_id
    volumes = self.describe_volumes()
  File
"/var/lib/juju/agents/unit-block-storage-broker-0/charm/hooks/util.py",
line 83, in describe_volumes
    return method(volume_id)
  File
"/var/lib/juju/agents/unit-block-storage-broker-0/charm/hooks/util.py",
line 427, in _nova_describe_volumes
    result[volume].update(self._nova_volume_show(volume))
  File
"/var/lib/juju/agents/unit-block-storage-broker-0/charm/hooks/util.py",
line 386, in _nova_volume_show
    attachments = literal_eval(value)
  File "/usr/lib/python2.7/ast.py", line 80, in literal_eval
    return _convert(node_or_string)
  File "/usr/lib/python2.7/ast.py", line 60, in _convert
    return list(map(_convert, node.elts))
  File "/usr/lib/python2.7/ast.py", line 63, in _convert
    in zip(node.keys, node.values))
  File "/usr/lib/python2.7/ast.py", line 62, in <genexpr>
    return dict((_convert(k), _convert(v)) for k, v
  File "/usr/lib/python2.7/ast.py", line 79, in _convert
    raise ValueError('malformed string')
ValueError: malformed string

I've also got conditionals on the series, so the helper should one day end up in charm-helpers (core/host.py probably). I'm also doing something similar in the PG charm, requiring icehouse with precise, and have the same approach. I would like to know the difference between cloud:havana and cloud-archive:havana, and when one should be chosen over the other.

This branch is good to land. I'd like a comment on the 'null' replacement, as this is unobvious, but as the entire helper is uncommented it wouldn't help much.

Oh, and looking back at the original proposal, if there is a next time you can use the standard install_sources() stuff from charmhelpers.fetch rather than your own arbitrary config item.

Jumped the gun sorry. I've identified things that need fixing.

You should be testing for 'if get_running_series() == "precise"', rather than '!= "trusty"', or this charm will break with Utopic and later.

I don't think we should be adding the repo unless hookenv.config('provider') == 'nova'.

test_install_adds_apt_source_and_installs_novaclient() now fails under trusty. This test can be duplicated, with util.get_running_series() mocked, so we test both precise and non-precise behavior.

Fixed the code to be more intelligent about series.

For the life of me I cannot figure out how to mock the get_running_series() function.

lp:~stub/charms/precise/block-storage-broker/configure-repository has tests. I didn't bother to update the test to use the modern standard 'mock' library rather than the dead mocker library. Good to land with the tests.