reinstate Unit.principalKey

reinstate Unit.principalKey

...as suggested in https://codereview.appspot.com/6402048/

https://code.launchpad.net/~fwereade/juju-core/unit-principal-key/+merge/115771

(do not edit description out of merge proposal)

[fwereade, 2012-07-19 15:37:39]

Please take a look.

[niemeyer, 2012-07-19 17:51:17]

Looks nice, except for this detail:

https://codereview.appspot.com/6421049/diff/1/state/service.go
File state/service.go (right):

https://codereview.appspot.com/6421049/diff/1/state/service.go#newcode313
state/service.go:313: principalKey = key
I'd prefer to keep the logic in memory closer to the stored logic, to avoid
confusion.

[rog, 2012-07-19 18:25:16]

LGTM except for the detail below.

https://codereview.appspot.com/6421049/diff/1/state/unit.go
File state/unit.go (right):

https://codereview.appspot.com/6421049/diff/1/state/unit.go#newcode73
state/unit.go:73: principalKey string
A comment to say that this might refer to the unit itself might be good here.

https://codereview.appspot.com/6421049/diff/1/state/unit.go#newcode210
state/unit.go:210: return u.key == u.principalKey
it seems slightly odd that topology uses a different method of denoting whether
a unit is principal (principalKey == "").
Is there a particular reason why they're different - can we use the same design
for both?

[fwereade, 2012-07-19 22:02:54]

Please take a look.

https://codereview.appspot.com/6421049/diff/1/state/service.go
File state/service.go (right):

https://codereview.appspot.com/6421049/diff/1/state/service.go#newcode313
state/service.go:313: principalKey = key
On 2012/07/19 17:51:18, niemeyer wrote:
> I'd prefer to keep the logic in memory closer to the stored logic, to avoid
> confusion.

Done.

https://codereview.appspot.com/6421049/diff/1/state/unit.go
File state/unit.go (right):

https://codereview.appspot.com/6421049/diff/1/state/unit.go#newcode73
state/unit.go:73: principalKey string
On 2012/07/19 18:25:16, rog wrote:
> A comment to say that this might refer to the unit itself might be good here.

After consultation with niemeyer, we'll be using principalKey == "" to determine
IsPrincipal -- less code, more obvious, more consistent :).

https://codereview.appspot.com/6421049/diff/1/state/unit.go#newcode210
state/unit.go:210: return u.key == u.principalKey
On 2012/07/19 18:25:16, rog wrote:
> it seems slightly odd that topology uses a different method of denoting
whether
> a unit is principal (principalKey == "").
> Is there a particular reason why they're different - can we use the same
design
> for both?

We will, indeed :).

[niemeyer, 2012-07-19 22:03:43]

LGTM!

[fwereade, 2012-07-19 22:05:24]

*** Submitted:

reinstate Unit.principalKey

...as suggested in https://codereview.appspot.com/6402048/

R=niemeyer, rog
CC=
https://codereview.appspot.com/6421049