Merge lp:~jacekn/charms/trusty/prometheus/storage-fixes into lp:~canonical-is-sa/charms/trusty/prometheus/layer-prometheus

[Jacek Nykis]

Remove redundant metrics-block storge from metadata.yaml and rename metrics-filesystem to metrics. Fix and storage support

[Chris Stratford (chris-gondolin)]

Failures in subprocess.check_call() aren't caught, but I guess a stacktrace may be enough, so +1

review: Approve

=== modified file 'README.md'
--- README.md	2016-02-17 11:51:35 +0000
+++ README.md	2016-06-15 15:23:18 +0000
@@ -5,6 +5,10 @@
 
 ## How to deploy the charm
 
+To deploy with storage support and use 13GB volume for metrics:
+
+juju deploy --storage metrics=13G local:xenial/prometheus prometheus
+
 ## Development
 
 Explicitly set `JUJU_REPOSITORY`:
 
=== modified file 'metadata.yaml'
--- metadata.yaml	2016-04-13 16:13:22 +0000
+++ metadata.yaml	2016-06-15 15:23:18 +0000
@@ -23,14 +23,9 @@
   alertmanager-service:
     interface: http
 storage:
-  metrics-filesystem:
+  metrics:
     type: filesystem
     description: Storage for prometheus data
     location: /srv/prometheus
     multiple:
       range: 0-1
-  metrics-block:
-    type: block
-    description: Storage for prometheus data
-    multiple:
-      range: 0-1
 
=== modified file 'reactive/prometheus.py'
--- reactive/prometheus.py	2016-04-13 15:58:16 +0000
+++ reactive/prometheus.py	2016-06-15 15:23:18 +0000
@@ -32,25 +32,22 @@
 
 
 # TODO: once there's reactive support for storage hooks, convert off @hook()
-@hook('metrics-{filesystem,block}-storage-attached')
+@hook('metrics-storage-attached')
 def configure_storage():
+    # Storage hooks always run before install so we don't have to worry
+    # about states here
     storage_path = subprocess.check_output(
         ['storage-get', 'location']).decode().strip()
     kv = unitdata.kv()
     kv.set('storage-path', storage_path)
     runtime_args('-storage.local.path', storage_path)
-    set_state('storage.configured')
-    set_state('prometheus.do-check-reconfig')
-
-
-def set_datadir_perms():
-    datadir = unitdata.kv().get('storage-path', False)
-    if not datadir:
-        # No juju storage attached, use defaults from package
-        return
-    users = [i for i in pwd.getpwall() if i.pw_name == 'nobody']
-    if len(users) == 1:
-        os.lchown(datadir, users[0].pw_uid, users[0].pw_gid)
+
+    subprocess.check_call(['addgroup', '--system', 'prometheus'])
+    subprocess.check_call(['adduser', '--system', '--home', storage_path, '--ingroup', 'prometheus',
+                           '--shell', '/bin/false', '--no-create-home',
+                           '--gecos', 'Prometheus daemon', 'prometheus'])
+    users = [i for i in pwd.getpwall() if i.pw_name == 'prometheus']
+    os.lchown(storage_path, users[0].pw_uid, users[0].pw_gid)
 
 
 @when('prometheus.do-install')
@@ -154,7 +151,6 @@
         hookenv.status_set('maintenance', 'Waiting for basenode to run')
         return
     hookenv.status_set('maintenance', 'Configuring software')
-    set_datadir_perms()
     install_packages()
     set_state('prometheus.do-check-reconfig')