Merge ~barryprice/charm-canonical-livepatch/+git/canonical-livepatch-charm:master into ~livepatch-charmers/charm-canonical-livepatch:master

[Barry Price]

Adding an "Effective kernel" message to the unit status message to allow kernel version information to be visible at a glance.

[Barry Price (barryprice)]

Amulet tests all pass

[Stuart Bishop (stub)]

A few style issues inline, but otherwise good.

review: Approve

diff --git a/reactive/canonical_livepatch.py b/reactive/canonical_livepatch.py
index 5ff2774..49f07fb 100644
--- a/reactive/canonical_livepatch.py
+++ b/reactive/canonical_livepatch.py
@@ -1,4 +1,4 @@
-from charms.reactive import when, when_not, set_state
+from charms.reactive import when, when_not, set_state, remove_state
 from charmhelpers.core.host import write_file
 from charmhelpers.core import hookenv
 from charmhelpers.contrib.charmsupport import nrpe
@@ -6,6 +6,7 @@ from subprocess import check_call, check_output, CalledProcessError
 from time import sleep
 from os import path
 from yaml import load, dump
+from platform import release
 
 
 def file_to_units(local_path, unit_path):
@@ -42,6 +43,39 @@ def wait_for_livepatch():
     wait_for_path('/var/snap/canonical-livepatch/current/livepatchd-priv.sock')
 
 
+def unit_update(status=None, message=None):
+    if status and message:
+        hookenv.status_set(status, message)
+    else:
+        hookenv.status_set('active', 'Effective kernel {}'.format(get_equiv_kernel_version()))
+
+
+def get_equiv_kernel_version():
+    # default to actual running kernel
+    version_string = release()
+    livepatch_status = ''
+
+    cmd = ['/snap/bin/canonical-livepatch', 'status']
+    try:
+        livepatch_status = check_output(cmd, universal_newlines=True)
+    except CalledProcessError as e:
+        hookenv.log('Unable to get status: {}'.format(str(e)))
+
+    # status will usually pass YAML (but not always!)
+    try:
+        status_yaml = load(livepatch_status)
+    except:
+        hookenv.log('Unable to parse status yaml')
+
+    # even if we got YAML, be paranoid
+    try:
+        version_string = status_yaml['kernel']
+    except:
+        hookenv.log('Unable to find kernel line in status yaml')
+
+    return version_string
+
+
 def configure_proxies(http_proxy=None, https_proxy=None, no_proxy=None):
     config_path = '/var/snap/canonical-livepatch/common/config'
 
@@ -109,14 +143,13 @@ def canonical_livepatch_connect():
     # Make sure the service is ready for us
     wait_for_livepatch()
 
-    hookenv.status_set('active', 'Ready')
     set_state('canonical-livepatch.connected')
 
 
 @when('canonical-livepatch.connected')
 @when('config.changed.livepatch_key')
 def update_key():
-    hookenv.status_set('maintenance', 'Updating API key')
+    unit_update('maintenance', 'Updating API key')
     config = hookenv.config()
 
     livepatch_key = config.get('livepatch_key')
@@ -135,18 +168,21 @@ def update_key():
             check_output(cmd, universal_newlines=True)
         except CalledProcessError as e:
             hookenv.log('Unable to activate: {}'.format(str(e)))
-            hookenv.status_set('blocked', 'Activation failed')
+            remove_state('canonical-livepatch.active')
+            unit_update('blocked', 'Activation failed')
         else:
-            hookenv.status_set('active', 'Ready')
+            set_state('canonical-livepatch.active')
+            unit_update()
     else:
         hookenv.log('Unable to activate canonical-livepatch as no key has been set')
-        hookenv.status_set('blocked', 'Service disabled, please set livepatch_key to activate')
+        remove_state('canonical-livepatch.active')
+        unit_update('blocked', 'Service disabled, please set livepatch_key to activate')
 
 
 @when('canonical-livepatch.connected')
 @when('config.changed.livepatch_proxy')
 def update_livepatch_proxy():
-    hookenv.status_set('maintenance', 'Configuring proxy servers')
+    unit_update('maintenance', 'Configuring proxy servers')
     config = hookenv.config()
     proxy_url = config.get('livepatch_proxy')
     configure_proxies(http_proxy=proxy_url, https_proxy=proxy_url)
@@ -157,13 +193,13 @@ def update_livepatch_proxy():
     # Make sure the service is ready for us
     wait_for_livepatch()
 
-    hookenv.status_set('active', 'Ready')
+    # force a key update, registration may have been blocked before proxy was set
+    update_key()
 
 
 @when('snap.installed.canonical-livepatch')
 @when('nrpe-external-master.available')
 def init_nagios_checks(nagios):
-    hookenv.status_set('maintenance', 'Configuring Nagios checks')
 
     # Ask charmhelpers.contrib.charmsupport's nrpe to work out our hostname
     hostname = nrpe.get_nagios_hostname()
@@ -192,4 +228,9 @@ def init_nagios_checks(nagios):
                          )
 
     nrpe_setup.write()
-    hookenv.status_set('active', 'Ready')
+
+
+@when('snap.installed.canonical-livepatch')
+@when('canonical-livepatch.active')
+def update_kernel_version():
+    unit_update()