Merge lp:~wgrant/charms/trusty/turnip/storage-really into lp:~canonical-launchpad-branches/charms/trusty/turnip/devel

[William Grant]

Rework storage support: the storage_external config option now requests a volume and waits until the volume is mounted.

Redesign storage subordinate support, ignoring the services framework even harder.

Previously we'd request a volume (setting the relation's mountpoint value) after service startup, and not wait until it was mounted. Now, instead, if the storage_external option is set we emit the request and wait until it's mounted (ie. the mountpoint value is set from the other end). If the option is not set, we assume local storage and ignore the data relation entirely.

[Colin Watson (cjwatson)]

review: Approve

=== modified file 'config.yaml'
--- config.yaml	2015-03-19 02:49:15 +0000
+++ config.yaml	2015-03-27 10:53:18 +0000
@@ -45,10 +45,13 @@
     type: string
     default: '/srv/turnip'
     description: Root checkout/srv directory.
-  data_dir:
-    type: string
-    default: '/srv/data'
-    description: Block storage mountpoint.
+  storage_external:
+    type: boolean
+    default: false
+    description: |
+      Connect to the storage subordinate charm for repo storage.
+      A volume will be requested and mounted at ${base_dir}/data/repos.
+      The service will not start until the volume is attached.
   code_user:
     type: string
     default: webops_deploy

=== modified file 'hooks/actions.py'
--- hooks/actions.py	2015-03-27 07:43:45 +0000
+++ hooks/actions.py	2015-03-27 10:53:18 +0000
@@ -111,7 +111,13 @@
         '-e', CODE_DIR])
 
 
-def publish_wsgi_relations(self):
+def ensure_repo_store_writable(service_name):
+    repo_dir = os.path.join(hookenv.config()['base_dir'], 'data', 'repos')
+    os.chown(repo_dir, pwd.getpwnam(USER).pw_uid, grp.getgrnam(GROUP).gr_gid)
+    os.chmod(repo_dir, 0o755)
+
+
+def publish_wsgi_relations(service_name):
     # Publish the wsgi-file relation so the gunicorn subordinate can
     # serve us. Other WSGI containers could be made to work, as the most
     # gunicorn-specific thing is the --paste hack.

=== modified file 'hooks/services.py'
--- hooks/services.py	2015-03-27 07:43:45 +0000
+++ hooks/services.py	2015-03-27 10:53:18 +0000
@@ -37,15 +37,25 @@
         actions.unpack_source('turnip')
         actions.install_python_packages('turnip')
 
+    extra_requirements = []
+
+    if hookenv.config()['storage_external']:
+        # Request a volume from the storage subordinate, and ensure the
+        # service doesn't try to start until it's present.
+        repo_dir = os.path.join(hookenv.config()['base_dir'], 'data', 'repos')
+        for relid in hookenv.relation_ids('data'):
+            hookenv.relation_set(relid, mountpoint=repo_dir)
+        extra_requirements.append(turnip_helpers.TurnipStorageRelation())
+
     config = hookenv.config()
     manager = ServiceManager([
         {
             'service': 'turnip',
             'ports': actions.get_ports(),
-            'provided_data': [turnip_helpers.TurnipApiRelation(),
-                              turnip_helpers.TurnipStorageRelation()],
-            'required_data': [config],
+            'provided_data': [turnip_helpers.TurnipApiRelation()],
+            'required_data': [config] + extra_requirements,
             'data_ready': [
+                actions.ensure_repo_store_writable,
                 helpers.render_template(
                     source='turnip.conf.j2',
                     target='/etc/init/turnip.conf',

=== modified file 'hooks/turnip_helpers.py'
--- hooks/turnip_helpers.py	2015-03-19 02:49:15 +0000
+++ hooks/turnip_helpers.py	2015-03-27 10:53:18 +0000
@@ -18,13 +18,4 @@
 class TurnipStorageRelation(helpers.RelationContext):
     name = 'data'
     interface = 'block-storage'
-
-    def provide_data(self):
-        config = hookenv.config()
-        mount_point = config['data_dir']
-        data = {
-            'mountpoint': mount_point
-        }
-        hookenv.log('Allocating block storage volume at mountpoint: {}.'.format(
-            mount_point))
-        return data
+    required_keys = ['mountpoint']