Add a new command for returning the api endpoints.

Add a new command for returning the api endpoints.

Utilities that build on top of juju-core's api need a simple discovery mechanism 
for the api endpoints available. Currently that involves retrieving the entire
tstatus of the environment and then parsing out implicitly the api servers 
(machine 0). This command (api-endpoints) adds an alternative mechanism that 
directly returns exactly the information needed without the additional 
computation or roundtrips needed by status and is forward compatible to HA API
servers.

https://code.launchpad.net/~hazmat/juju-core/endpoint-cli/+merge/179063

(do not edit description out of merge proposal)

[hazmat, 2013-08-07 23:00:45]

Please take a look.

[dimitern, 2013-08-08 15:30:56]

LGTM with a few suggestions below

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint.go
File cmd/juju/endpoint.go (right):

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint.go#newcode1
cmd/juju/endpoint.go:1: // Copyright 2012, 2013 Canonical Ltd.
This should be 2013 only (in all such headers).

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint.go#newcode8
cmd/juju/endpoint.go:8: "launchpad.net/juju-core/cmd"

Blank line after fmt please.

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint.go#newcode12
cmd/juju/endpoint.go:12: // EndpointCommand returns the api endpoint
s/api endpoint/API endpoint./

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint.go#newcode21
cmd/juju/endpoint.go:21: Purpose: "Print the api server address",
s/api/API/

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint_test.go
File cmd/juju/endpoint_test.go (right):

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint_test.go#newc...
cmd/juju/endpoint_test.go:9: . "launchpad.net/gocheck"
Blank lines before and after gocheck, and please do it like this: gc
"launchpad.net/gocheck" - then change the rest of the file to use the gc. prefix
where needed (look for similar test modules).

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint_test.go#newc...
cmd/juju/endpoint_test.go:15: type EndpointSuite struct {
s/EndpointSuite/endpointSuite/ - no need to be exported.

https://codereview.appspot.com/12633043/diff/1/cmd/juju/main_test.go
File cmd/juju/main_test.go (right):

https://codereview.appspot.com/12633043/diff/1/cmd/juju/main_test.go#newcode229
cmd/juju/main_test.go:229: "endpoint",
Not sure if you should call this "endpoint" or perhaps "api-endpoint". There are
a few places where "endpoint" means something very different.

[fwereade, 2013-08-09 14:23:35]

LGTM modulo suggestions below.

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint.go
File cmd/juju/endpoint.go (right):

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint.go#newcode12
cmd/juju/endpoint.go:12: // EndpointCommand returns the api endpoint
On 2013/08/08 15:30:56, dimitern wrote:
> s/api endpoint/API endpoint./

endpoints?

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint_test.go
File cmd/juju/endpoint_test.go (right):

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint_test.go#newc...
cmd/juju/endpoint_test.go:15: type EndpointSuite struct {
On 2013/08/08 15:30:56, dimitern wrote:
> s/EndpointSuite/endpointSuite/ - no need to be exported.

Why *not* export it? It's in a _test package, so it doesn't really matter, but
it's a bit surprising... did this become policy at some point?

https://codereview.appspot.com/12633043/diff/1/cmd/juju/main_test.go
File cmd/juju/main_test.go (right):

https://codereview.appspot.com/12633043/diff/1/cmd/juju/main_test.go#newcode229
cmd/juju/main_test.go:229: "endpoint",
On 2013/08/08 15:30:56, dimitern wrote:
> Not sure if you should call this "endpoint" or perhaps "api-endpoint". There
are
> a few places where "endpoint" means something very different.

+1 to api-endpoint... possibly even endpoint*s* to be clear, even if it only
returns one today

[jameinel, 2013-08-13 13:35:57]

I think you might be missing the long help for "juju help endpoint" and I'd like
to see it called at least "juju endpoints" so callers are prepared for when we
have multiple API servers.

otherwise, LGTM

https://codereview.appspot.com/12633043/diff/1/cmd/juju/main_test.go
File cmd/juju/main_test.go (right):

https://codereview.appspot.com/12633043/diff/1/cmd/juju/main_test.go#newcode229
cmd/juju/main_test.go:229: "endpoint",

> 
> +1 to api-endpoint... possibly even endpoint*s* to be clear, even if it only
> returns one today

I was going to comment on calling it "endpoints" as well. "api-endpoints" is
fine with me.

Mostly, we want to be clear that this will be returning more than one line on
any HA system, so people parsing it don't get surprised.

[fwereade, 2013-08-13 15:08:02]

On 2013/08/13 13:35:57, jameinel wrote:
> I think you might be missing the long help for "juju help endpoint" and I'd
like
> to see it called at least "juju endpoints" so callers are prepared for when we
> have multiple API servers.
> 
> otherwise, LGTM
> 
> https://codereview.appspot.com/12633043/diff/1/cmd/juju/main_test.go
> File cmd/juju/main_test.go (right):
> 
>
https://codereview.appspot.com/12633043/diff/1/cmd/juju/main_test.go#newcode229
> cmd/juju/main_test.go:229: "endpoint",
> 
> > 
> > +1 to api-endpoint... possibly even endpoint*s* to be clear, even if it only
> > returns one today
> 
> I was going to comment on calling it "endpoints" as well. "api-endpoints" is
> fine with me.
> 
> Mostly, we want to be clear that this will be returning more than one line on
> any HA system, so people parsing it don't get surprised.

Hey, a thought: an output formatter would be nice, the "smart" one handles lists
of strings already IIRC, and json/yaml would be nice too.

[hazmat, 2013-08-15 14:59:36]

On 2013/08/13 15:08:02, fwereade wrote:
> On 2013/08/13 13:35:57, jameinel wrote:
> > I think you might be missing the long help for "juju help endpoint" and I'd
> like
> > to see it called at least "juju endpoints" so callers are prepared for when
we
> > have multiple API servers.
> > 
> > otherwise, LGTM
> > 
> > https://codereview.appspot.com/12633043/diff/1/cmd/juju/main_test.go
> > File cmd/juju/main_test.go (right):
> > 
> >
>
https://codereview.appspot.com/12633043/diff/1/cmd/juju/main_test.go#newcode229
> > cmd/juju/main_test.go:229: "endpoint",
> > 
> > > 
> > > +1 to api-endpoint... possibly even endpoint*s* to be clear, even if it
only
> > > returns one today
> > 
> > I was going to comment on calling it "endpoints" as well. "api-endpoints" is
> > fine with me.
> > 
> > Mostly, we want to be clear that this will be returning more than one line
on
> > any HA system, so people parsing it don't get surprised.
> 
> Hey, a thought: an output formatter would be nice, the "smart" one handles
lists
> of strings already IIRC, and json/yaml would be nice too.

done, using smart by default

[hazmat, 2013-08-15 15:00:12]

review comments addressed.

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint.go
File cmd/juju/endpoint.go (right):

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint.go#newcode1
cmd/juju/endpoint.go:1: // Copyright 2012, 2013 Canonical Ltd.
On 2013/08/08 15:30:56, dimitern wrote:
> This should be 2013 only (in all such headers).
done

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint.go#newcode8
cmd/juju/endpoint.go:8: "launchpad.net/juju-core/cmd"
On 2013/08/08 15:30:56, dimitern wrote:
> 
> Blank line after fmt please.
done

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint.go#newcode12
cmd/juju/endpoint.go:12: // EndpointCommand returns the api endpoint
On 2013/08/08 15:30:56, dimitern wrote:
> s/api endpoint/API endpoint./

Done.

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint.go#newcode12
cmd/juju/endpoint.go:12: // EndpointCommand returns the api endpoint
On 2013/08/09 14:23:35, fwereade wrote:
> On 2013/08/08 15:30:56, dimitern wrote:
> > s/api endpoint/API endpoint./
> 
> endpoints?

Done.

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint.go#newcode21
cmd/juju/endpoint.go:21: Purpose: "Print the api server address",
On 2013/08/08 15:30:56, dimitern wrote:
> s/api/API/

Done.

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint_test.go
File cmd/juju/endpoint_test.go (right):

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint_test.go#newc...
cmd/juju/endpoint_test.go:9: . "launchpad.net/gocheck"
On 2013/08/08 15:30:56, dimitern wrote:
> Blank lines before and after gocheck, and please do it like this: gc
> "launchpad.net/gocheck" - then change the rest of the file to use the gc.
prefix
> where needed (look for similar test modules).

done. although prefixing various checks (Equal) etc with gc feels rather silly
compared to directly using gocheck assertions.

https://codereview.appspot.com/12633043/diff/1/cmd/juju/endpoint_test.go#newc...
cmd/juju/endpoint_test.go:15: type EndpointSuite struct {
On 2013/08/09 14:23:35, fwereade wrote:
> On 2013/08/08 15:30:56, dimitern wrote:
> > s/EndpointSuite/endpointSuite/ - no need to be exported.
> 
> Why *not* export it? It's in a _test package, so it doesn't really matter, but
> it's a bit surprising... did this become policy at some point?

i'm leaving this exported for now, all the other cli tests do so as well.

https://codereview.appspot.com/12633043/diff/1/cmd/juju/main_test.go
File cmd/juju/main_test.go (right):

https://codereview.appspot.com/12633043/diff/1/cmd/juju/main_test.go#newcode229
cmd/juju/main_test.go:229: "endpoint",
On 2013/08/13 13:35:57, jameinel wrote:
> 
> > 
> > +1 to api-endpoint... possibly even endpoint*s* to be clear, even if it only
> > returns one today
> 
> I was going to comment on calling it "endpoints" as well. "api-endpoints" is
> fine with me.
> 
> Mostly, we want to be clear that this will be returning more than one line on
> any HA system, so people parsing it don't get surprised.

switched to api-endpoints.

[hazmat, 2013-08-15 15:03:14]

Please take a look.

[hazmat, 2013-08-15 15:11:17]

Please take a look.

[hazmat, 2013-08-15 15:11:38]

On 2013/08/13 13:35:57, jameinel wrote:
> I think you might be missing the long help for "juju help endpoint" and I'd
like
> to see it called at least "juju endpoints" so callers are prepared for when we
> have multiple API servers.
> 

added long form doc documenting the default format of one per line (along with
rename to api-endpoints)