Merge lp:~kubernetes/charms/trusty/etcd/trunk into lp:charms/trusty/etcd

[Charles Butler]

is_leader requires juju 1.23.2 or better

The ETCD charm fails with a non committal error message when probing for
is_leader, and will cause some headaches if users of older Juju
versions attempt to use this charm as its leveraging the leader election
components.

[Matt Bruzek (mbruzek)]

-1 You have merge conflict stuff in there.

review: Needs Fixing

[lp:~kubernetes/charms/trusty/etcd/trunk]

17. By Charles Butler on 2015-08-11

Backport of store edits and minor typo correction
Marco Ceppi 2015-08-07 [merge] [lazypower] Working fix for #1478121
Matthew Bruzek 2015-07-17 Changing the deploy syntax to use the promulgated namespace.

[Matt Bruzek (mbruzek)]

+1 this looks right, sorry for my part in the confusion on the merge.

review: Approve

=== modified file 'README.md'
--- README.md	2015-07-17 14:48:11 +0000
+++ README.md	2015-08-11 17:56:53 +0000
@@ -51,11 +51,17 @@
     juju action fetch <uuid>
 
 
+## Usage Caveats
+
+This charm requires Leader Election, which is a feature of Juju >= 1.23.2. The
+charm will panic and refuse to continue if the leader_election binary is not
+found. Please take care when deploying this charm on older versions of Juju.
+
 ## Credits
 
 The etcd charm was originally written by Kapil Thangavelu ([@kapilt](https://github.com/kapilt)).
 
-#### Mantainers:
+#### Maintainers:
 
 The kubernetes team maintains this charm:
   - Whit Morriss &lt;[e-mail]&gt;

=== modified file 'hooks/hooks.py'
--- hooks/hooks.py	2015-07-24 19:30:09 +0000
+++ hooks/hooks.py	2015-08-11 17:56:53 +0000
@@ -16,11 +16,18 @@
 hook_data = unitdata.HookData()
 db = unitdata.kv()
 
-leader_status = check_output(['is-leader']).rstrip() != "False"
 private_address = hookenv.unit_get('private-address')
 public_address = hookenv.unit_get('private-address')
 unit_name = environ['JUJU_UNIT_NAME'].replace('/', '')
 
+try:
+    leader_status = hookenv.is_leader()
+except NotImplementedError:
+    hookenv.log('This charm requires Leader Election. Juju >= 1.23.2.'
+                ' Leader election binary not found, Panic and exit!',
+                'CRITICAL')
+    sys.exit(1)
+
 
 @hooks.hook('config-changed')
 def config_changed():