cmd/jujud: Fix agent openAPIState

cmd/jujud: Fix agent openAPIState

This changes agent.openAPIState to handle better
unauthorized errors, so in case the connection to
state failed or the entity cannot be found after
connecting it'll return worker.ErrTerminateAgent
as expected.

https://code.launchpad.net/~dimitern/juju-core/133-agent-fix-openapistate/+merge/185119

Requires: https://code.launchpad.net/~dimitern/juju-core/133-apiuniter-uses-api/+merge/185091

(do not edit description out of merge proposal)

[dimitern, 2013-09-11 18:01:37]

Please take a look.

[fwereade, 2013-09-12 09:22:07]

Looks fine, but NOT LGTM without a test.

[dimitern, 2013-09-12 13:38:44]

Please take a look.

[fwereade, 2013-09-12 14:08:05]

LGTM with a trivial. Doesn't have to be exactly what I suggest, just a bit
easier to read than it currently is.

https://codereview.appspot.com/13604045/diff/5001/cmd/jujud/agent.go
File cmd/jujud/agent.go (right):

https://codereview.appspot.com/13604045/diff/5001/cmd/jujud/agent.go#newcode157
cmd/jujud/agent.go:157: err == nil && entity.Life() == params.Dead {
Honestly, this is too much for me. The following may be more verbose, but I'd
much prefer it:

unauthorized := params.ErrCode(err) == params.CodeUnauthorized
dead := err == nil && entity.Life() == params.Dead
if unauthorized || dead {
    err = ErrTerminateAgent
}

[dimitern, 2013-09-12 14:15:14]

Please take a look.

https://codereview.appspot.com/13604045/diff/5001/cmd/jujud/agent.go
File cmd/jujud/agent.go (right):

https://codereview.appspot.com/13604045/diff/5001/cmd/jujud/agent.go#newcode157
cmd/jujud/agent.go:157: err == nil && entity.Life() == params.Dead {
On 2013/09/12 14:08:05, fwereade wrote:
> Honestly, this is too much for me. The following may be more verbose, but I'd
> much prefer it:
> 
> unauthorized := params.ErrCode(err) == params.CodeUnauthorized
> dead := err == nil && entity.Life() == params.Dead
> if unauthorized || dead {
>     err = ErrTerminateAgent
> }

Done.