DHX fails to pick a unit as of juju 2.0 alpha-2

[chuckbutler]

Looks like DHX was just hit by some of the API nuance changes as of 2.0-alpha2 (verifiable in the latest charmbox:dev, bootstrap a model controller, create a new model, deploy something, then attempt to attach via juju dhx )

ubuntu@dev:~$ juju dhx -r redmine/0
Traceback (most recent call last):
  File "/home/ubuntu/.juju-plugins/juju-dhx", line 328, in <module>
    unit_name, unit = choose_unit(args, opts)
  File "/home/ubuntu/.juju-plugins/juju-dhx", line 296, in choose_unit
    status = get_env(opts).status()
  File "/home/ubuntu/.juju-plugins/juju-dhx", line 182, in get_env
    get_env._env = jujuclient.Environment.connect(opts.env)
  File "/usr/local/lib/python2.7/dist-packages/jujuclient.py", line 534, in connect
    return Connector().run(cls, env_name)
  File "/usr/local/lib/python2.7/dist-packages/jujuclient.py", line 132, in run
    jhome, data = self.parse_env(env_name)
  File "/usr/local/lib/python2.7/dist-packages/jujuclient.py", line 224, in parse_env
    raise EnvironmentNotBootstrapped(env_name)
jujuclient.EnvironmentNotBootstrapped: Environment  is not bootstrapped

[johnsca]

The specific exception listed here is fixed in the newer jujuclient lib, but there were still issues that needed to be addressed in dhx.

There was also an issue with JUJU_ENV no longer being populated that caused this exception. Anyway, the referenced PR should resolve it.