Added conjure-up support.

[petevg]

This is basic support for calling out to conjure-up on the command line,
and having it handle the deploy. It requires that you have a version of
conjure-up in your environment that has the patch referenced in
conjure-up/conjure-up#760

Note that this only works if you point matrix at a spell.

@johnsca @seman @abentley This is ready for review!

[petevg]

Bleh. Looks like I don't know how to install snapd on trusty. @johnsca any advice on tweaking .travis.yaml so that it gives me a working conjure-up snap?

[petevg]

Got tests to pass by just adding a conditional skipptest around the conjure-up functional test. It works in my local environment, and it will magically start working when/if we figure out how to install snaps in the travis env.

[johnsca]

Pretty much seems fine to me, but I included a few comments below.

[johnsca]

Could we auto-detect this instead of requiring it to be explicit?

[petevg]

@johnsca The tricky bit about doing it automatically is that a spell is basically just a bundle with a metadata.yaml file in it. Branching just on there being (or not being) a metadata.yaml felt iffy, especially as the conjure-up docs were vague about what exactly needed to be in the file for it to be a legit spell.

I went with the arg, though technically I'd be happier with automagic.

[mikemccracken]

A spell is a directory with a metadata.yaml, and either a 'bundle-location' key in that file, or a separate bundle.yaml file next to it. The only required keys in metadata.yaml are 'friendly-name' and 'version'. I think just checking for a metadata.yaml with a 'friendly-name' key would do for matrix's purposes, but maybe I'm missing something?

Also - line 137 has a typo - "congure-up".

[battlemidget]

Yea every spell at least has to have a metadata.yaml file with a friendly-name attribute so you could check for that automatically

[petevg]

@mikemccracken @battlemidget I added logic (which I will pushed shortly) so that we detect whether or not something is a spell based on it having a metadata.yaml with a friendly-name attribute (version doesn't seem to be required). Thx for the clarification on what is and isn't a spell.

[johnsca]

Might be better to use juju.client.connection.JujuData().controllers() for this?

[petevg]

@johnsca Yes. That's why I was asking about the best way to do it in python-libjuju. You told me there wasn't a way, which I suppose means that I should read the code, rather than trusting you :-p

[johnsca]

I thought you meant a way to do it via the API. The JujuData helper does more or less what you're doing, though I think it reads the yaml files directly.

[johnsca]

This would be easier to read if it used @unittest.skipIf. I'd even recommend decorating the entire class, to avoid any expensive setup.

[petevg]

Hey cool. I didn't know that skipIf was a thing. That makes everything simpler :-)