namespace can be set via environment variable

namespace can be set via environment variable

This infers default values for scheme, user, series from the an env var for
assembling a charm url based on what's provided on the cli for a charm name.

Based on clint's namespace-from-env branch. Refactored the defaults extraction
to a helper function.

https://code.launchpad.net/~hazmat/juju/ns-from-env/+merge/101381

(do not edit description out of merge proposal)

[hazmat, 2012-04-10 14:18:23]

Please take a look.

[niemeyer, 2012-04-10 14:35:29]

https://codereview.appspot.com/5990067/diff/1/juju/charm/tests/test_url.py
File juju/charm/tests/test_url.py (right):

https://codereview.appspot.com/5990067/diff/1/juju/charm/tests/test_url.py#ne...
juju/charm/tests/test_url.py:129: "name", "local", None, "default", "name",
None, 'local')
As discussed in the thread in the mailing list, can we please support these
forms only:

1) scheme: (not "scheme" without colon.. that's potentially ambiguous with
series)
2) scheme:series or scheme:series/ (e.g. local:oneiric, or cs:oneiric/)
3) scheme:~user/series, or scheme:~user/series/ (e.g. cs:~spamaps/oneiric/)

[hazmat, 2012-04-10 14:39:13]

On Tue, Apr 10, 2012 at 10:35 AM, <n13m3y3r@gmail.com> wrote:

>
> https://codereview.appspot.**com/5990067/diff/1/juju/charm/**
>
tests/test_url.py<https://codereview.appspot.com/5990067/diff/1/juju/charm/tests/test_url.py>
> File juju/charm/tests/test_url.py (right):
>
> https://codereview.appspot.**com/5990067/diff/1/juju/charm/**
>
tests/test_url.py#newcode129<https://codereview.appspot.com/5990067/diff/1/juju/charm/tests/test_url.py#newcode129>
> juju/charm/tests/test_url.py:**129: "name", "local", None, "default",
> "name", None, 'local')
> As discussed in the thread in the mailing list, can we please support
> these forms only:
>
> 1) scheme: (not "scheme" without colon.. that's potentially ambiguous
> with series)
>

why is scheme without a colon ambigious, scheme is required here, series is
optional and must be specified with a preceding scheme:


> 2) scheme:series or scheme:series/ (e.g. local:oneiric, or cs:oneiric/)

3) scheme:~user/series, or scheme:~user/series/ (e.g.
> cs:~spamaps/oneiric/)
>
>
i'll add the trailing slash support.

thanks for the review.

[niemeyer, 2012-04-10 14:49:13]

On 2012/04/10 14:39:13, hazmat wrote:
> > 1) scheme: (not "scheme" without colon.. that's potentially ambiguous
> > with series)
> 
> why is scheme without a colon ambigious, scheme is required here, series is
> optional and must be specified with a preceding scheme:

Because people are allowed to provide it in the command line. They type "juju
deploy series/foo". It sounds very plausible to do "A=series juju deploy foo" as
well, but that's incorrect, and should be flagged as such. Requiring the colon
is a cheap way to make that obvious.

Btw, if you disagree with the discussed design, would you mind to bring it up so
that we have a chance to talk about it? I'm getting a bit concerned that we
haven't really been talking about all those features, and I've been catching up
disagreements just by chance in notes passing by.