New feature for 1.26 (master), $(JUJU_HOME)/aliases

[Tim Penhey]

On 23/10/15 21:28, roger peppe wrote:
> On 23 October 2015 at 05:12, Tim Penhey <tim.penhey at canonical.com> wrote:
>> Hi folks,
>>
>> I scratched a personal itch yesterday and added the ability for users to
>> specify their own aliases for juju commands.
>>
>> There are two primary use cases that I was trying to address.
>>
>> Firstly, the ability to specify default flags for commands:
>>   status = status --format=tabular
> 
> This sounds useful, thanks. Presumably additional arguments are
> just tacked onto the end?

No... not exactly, an infix replacement.

For example, lets say I had the above status alias. If I really wanted
json output I'd go:

  juju status --format=json

The alias mechanism turns this into:

 juju status --format=tabular --format=json

And the default flag behaviour is for the last to win, so format is set
to json.

>> I could never remember the right environment variable to set to get
>> tabular by default.
>>
>> The second was to allow quicker iteration around playing with new CLI
>> structure.  As most people are aware, the 2.0 CLI is going to be
>> somewhat different to the current one, and I thought it would be good to
>> provide a way in which we could "test drive" the new CLI with the
>> existing codebase without having to actually code anything.
> 
> Unless the new CLI is non-hierarchical I'm thinking that may
> not work unless you can specify multi-level aliases;
> For example:
> 
>     model destroy = environment destroy
> 
> which might be a little harder.

Exactly. We tried with hierarchical sub-menus, but the experiment is
considered a successful way to not do it :-)

Juju 2.0 will transition back to a flat command namespace with a
predictable set of <verb>-<object> commands along with another set that
make more sense by themselves, i.e. "deploy", "relate".

Tim