state: added services watcher for added and removed services

state: added services watcher for added and removed services

Provisioning and firewall need notifications about added and
removed services. The services watcher observes the topology
and returns this information.

https://code.launchpad.net/~themue/juju-core/go-state-service-watcher/+merge/113728

(do not edit description out of merge proposal)

[TheMue, 2012-07-06 11:29:40]

Please take a look.

[niemeyer, 2012-07-09 18:35:46]

LGTM.. doc suggestions only, thanks.

https://codereview.appspot.com/6345072/diff/1/state/state.go
File state/state.go (right):

https://codereview.appspot.com/6345072/diff/1/state/state.go#newcode68
state/state.go:68: // WatchServices watches for new Machines added or removed.
// WatchServices returns a watcher for observing services
// being added or removed.

https://codereview.appspot.com/6345072/diff/1/state/state.go#newcode73
state/state.go:73: // WatchMachines watches for new Machines added or removed.
// WatchMachines returns a watcher for observing machines
// being added or removed.

https://codereview.appspot.com/6345072/diff/1/state/watcher.go
File state/watcher.go (right):

https://codereview.appspot.com/6345072/diff/1/state/watcher.go#newcode68
state/watcher.go:68: // services that have been added to or removed.
// ServicesChange holds services that were added or removed
// from the environment.

https://codereview.appspot.com/6345072/diff/1/state/watcher.go#newcode74
state/watcher.go:74: // ServicesWatcher observes the addition and removal
Please reindent (this fits in a single line easily).

https://codereview.appspot.com/6345072/diff/1/state/watcher.go#newcode84
state/watcher.go:84: // for service changes.
"service changes" is too vague. This comment can either go away entirely or be
replaced with the obvious:

// newServicesWatcher returns a new ServicesWatcher.

https://codereview.appspot.com/6345072/diff/1/state/watcher.go#newcode95
state/watcher.go:95: // Changes returns a channel that will receive changes when
services
s/receive changes/receive a notification/

https://codereview.appspot.com/6345072/diff/1/state/watcher.go#newcode97
state/watcher.go:97: // the first event on the channel holds the initial state
as returned
s/as returned/as would be returned/

[TheMue, 2012-07-10 11:06:35]

*** Submitted:

state: added services watcher for added and removed services

Provisioning and firewall need notifications about added and
removed services. The services watcher observes the topology
and returns this information.

R=niemeyer
CC=
https://codereview.appspot.com/6345072

https://codereview.appspot.com/6345072/diff/1/state/state.go
File state/state.go (right):

https://codereview.appspot.com/6345072/diff/1/state/state.go#newcode68
state/state.go:68: // WatchServices watches for new Machines added or removed.
On 2012/07/09 18:35:46, niemeyer wrote:
> // WatchServices returns a watcher for observing services
> // being added or removed.

Done.

https://codereview.appspot.com/6345072/diff/1/state/state.go#newcode73
state/state.go:73: // WatchMachines watches for new Machines added or removed.
On 2012/07/09 18:35:46, niemeyer wrote:
> // WatchMachines returns a watcher for observing machines
> // being added or removed.

Done.

https://codereview.appspot.com/6345072/diff/1/state/watcher.go
File state/watcher.go (right):

https://codereview.appspot.com/6345072/diff/1/state/watcher.go#newcode68
state/watcher.go:68: // services that have been added to or removed.
On 2012/07/09 18:35:46, niemeyer wrote:
> // ServicesChange holds services that were added or removed
> // from the environment.

Done.

https://codereview.appspot.com/6345072/diff/1/state/watcher.go#newcode74
state/watcher.go:74: // ServicesWatcher observes the addition and removal
On 2012/07/09 18:35:46, niemeyer wrote:
> Please reindent (this fits in a single line easily).

Done.

https://codereview.appspot.com/6345072/diff/1/state/watcher.go#newcode84
state/watcher.go:84: // for service changes.
On 2012/07/09 18:35:46, niemeyer wrote:
> "service changes" is too vague. This comment can either go away entirely or be
> replaced with the obvious:
> 
> // newServicesWatcher returns a new ServicesWatcher.

Done.

https://codereview.appspot.com/6345072/diff/1/state/watcher.go#newcode95
state/watcher.go:95: // Changes returns a channel that will receive changes when
services
On 2012/07/09 18:35:46, niemeyer wrote:
> s/receive changes/receive a notification/

Done.

https://codereview.appspot.com/6345072/diff/1/state/watcher.go#newcode97
state/watcher.go:97: // the first event on the channel holds the initial state
as returned
On 2012/07/09 18:35:46, niemeyer wrote:
> s/as returned/as would be returned/

Done.