charm doesn't honor juju-proxy-* settings

[Giuseppe Petralia]

Charm fails to install behind proxy when juju model-config juju-proxy-* are configured.

i.e.

this was failing
def install_ppa(ppa):
    """Install specified ppa"""
    subprocess.check_call(["add-apt-repository", "--yes", ppa)

Workaround was defining an env object and pass to subprocess.check_call doing add-apt-repository and ubuntu-advantage commands like this:

import os

env = dict(os.environ)
proxy = "http://proxy.com:3128/"
env['http_proxy'] = proxy
env['https_proxy'] = proxy

def install_ppa(ppa):
    """Install specified ppa"""
    subprocess.check_call(["add-apt-repository", "--yes", ppa], env=env)

[Bartosz Woronicz (mastier1)]

Proposed bug fix
https://code.launchpad.net/~mastier1/charm-ubuntu-advantage

[Bartosz Woronicz (mastier1)]

Proposed charm:
https://charmhub.io/ubuntu-advantage-with-proxy