state/apiserver: log API conn setup/teardown

state/apiserver: log API conn setup/teardown

This will make it easier to diagnose certain kinds of issue.

In passing, we also change the error message returned
when an AllWatcher is stopped, and perform some
minor simplifications on API connection-related code.

Both changes were prompted when trying to find out
what was happening in bug #1269519.

https://code.launchpad.net/~rogpeppe/juju-core/484-apiserver-log-connections/+merge/201855

(do not edit description out of merge proposal)

[rog, 2014-01-15 21:47:35]

Please take a look.

[axw, 2014-01-16 09:00:32]

LGTM

https://codereview.appspot.com/52850043/diff/10006/state/apiserver/apiserver.go
File state/apiserver/apiserver.go (right):

https://codereview.appspot.com/52850043/diff/10006/state/apiserver/apiserver....
state/apiserver/apiserver.go:131: logger.Debugf("[%X] API connection from %s",
n.id, req.RemoteAddr)
I wonder if these two don't deserve to be INFO? Dis/connections should be all
that frequent, right? I suppose we don't want the log getting spammed on "juju
deploy service -n 1000" though.

[rog, 2014-01-16 19:28:55]

Please take a look.

[rog, 2014-01-16 19:29:43]

https://codereview.appspot.com/52850043/diff/10006/state/apiserver/apiserver.go
File state/apiserver/apiserver.go (right):

https://codereview.appspot.com/52850043/diff/10006/state/apiserver/apiserver....
state/apiserver/apiserver.go:131: logger.Debugf("[%X] API connection from %s",
n.id, req.RemoteAddr)
On 2014/01/16 09:00:32, axw wrote:
> I wonder if these two don't deserve to be INFO? Dis/connections should be all
> that frequent, right? I suppose we don't want the log getting spammed on "juju
> deploy service -n 1000" though.

Done.

[rog, 2014-01-16 20:57:58]

Please take a look.