*** Submitted:

Avoid installing from PPA if not required.

No longer add the juju-gui PPA by default:
the external repository is added only if required,
i.e. if the legacy server is used or if a branch
is passed to juju-gui-source.

The only missing bit to make the charm work well
from behind a firewall AFAICT is avoiding the release
to be downloaded from Launchpad.

Also included the shelltoolbox file in the charm:
unfortunately the python-shelltoolbox package is
not available on precise. On the other hand, this
allows for getting rid of the bootstrap_utils.py
file, and the install hook now feels cleaner.

Refactoring + some magic removal on the backend
framework. Now it should be less surprising, and
also allows for more customizations, e.g. what
I did in the install method.

Also added missing tests for the backend framework:
those were required in order to increase our control
over what's really happening in the backend "hooks".

Switched to the builtin Tornado server by default.

This diff is very big, I am sorry, but:
- you can ignore the bootstrap_utils removal;
- you can ignore the shelltoolbox.py file: it is
   just a copy of the one present in the raring
   python-shelltoolbox package;
- a lot of code is tests, the rest of the code
   should be quite easy to follow.

QA:
     `make deploy` and watch the logs:
     - no PPA should be installed by default;
     - the deployment succeeds and the GUI works well;
     switch to builtin-server=false and watch the logs:
     - the PPA is installed (and then haproxy, apache...);
     - the config-change hook exits without errors and
       the GUI works well.

Tests:
     `make unittest`
     (I ran the functional tests myself).


Thank you!

R=gary.poster, rharding
CC=
https://codereview.appspot.com/14433049



https://codereview.appspot.com/14433049/diff/1/hooks/backend.py
File hooks/backend.py (right):

https://codereview.appspot.com/14433049/diff/1/hooks/backend.py#newcode116
hooks/backend.py:116: debs = ('curl',)
On 2013/10/07 17:01:08, gary.poster wrote:
> Does this belong somewhere else now? Or can it be deleted?

Yeah, I was curious about that dependency too. I found that curl is used
by fetch_gui_release to download a release tarball from Launchpad. So,
formally it belongs here: added a comment describing what curl is used
for.

https://codereview.appspot.com/14433049/diff/1/hooks/backend.py#newcode229
hooks/backend.py:229: If reverse is True, the method is called on the
reversed list of objects.
On 2013/10/07 17:01:08, gary.poster wrote:
> Delete this line? (functionality is gone)

Done thank you, and yes, my first implementation included that kwarg,
but then I realized it was unnecessary.

https://codereview.appspot.com/14433049/diff/1/hooks/backend.py#newcode310
hooks/backend.py:310: """Execute the charm starting steps."""
On 2013/10/07 17:01:08, gary.poster wrote:
> A subtle thing, but any one of these would read a bit better to me, as
ranked
> from my personal highest to lowest preference.

> Execute the charm's "start" steps.
> Execute the charm's starting steps.
> Execute the charm-starting steps.

Done.

https://codereview.appspot.com/14433049/diff/1/hooks/backend.py#newcode314
hooks/backend.py:314: """Execute the charm stopping steps."""
On 2013/10/07 17:01:08, gary.poster wrote:
> Perhaps the following?
> ----
> Execute the charm's "stop" steps.

> Iterates through the mixins in reverse order.

Done.

https://codereview.appspot.com/14433049/diff/1/hooks/backend.py#newcode318
hooks/backend.py:318: """Execute the charm removal steps."""
On 2013/10/07 17:01:08, gary.poster wrote:
> WDYT?
> ---
> Execute the charm removal steps.

> Iterates through the mixins in reverse order.

Done.

https://codereview.appspot.com/14433049/diff/1/hooks/shelltoolbox.py
File hooks/shelltoolbox.py (right):

https://codereview.appspot.com/14433049/diff/1/hooks/shelltoolbox.py#newcode3
hooks/shelltoolbox.py:3: # This file is part of python-shell-toolbox.
On 2013/10/07 17:01:08, gary.poster wrote:
> I included comments about the source in hooks/charmhelpers.py.  Check
what I did
> there.  If you like it, include it here; otherwise, feel free to
ignore it.

Good idea, done.

https://codereview.appspot.com/14433049/