Implement new option: filesystem-store-datadir

This change implements a new option in config.yaml that can be used
to change the location of the images store on the filesystem.

Change-Id: I0d8e7409b8eb4e5e403455db03d73020f741afc4
Closes-Bug: #1657165

config.yaml

@@ -337,3 +337,14 @@ options:
     description: |
       A comma-separated list of nagios service groups.
       If left empty, the nagios_context will be used as the servicegroup
+  filesystem-store-datadir:
+    type: string
+    default: "/var/lib/glance/images/"
+    description: |
+      Directory to which the filesystem backend store writes images.
+      Upon start up, Glance creates the directory if it doesn’t already exist
+      and verifies write access to the user under which glance-api runs. If
+      the write access isn’t available, a BadStoreConfiguration exception is
+      raised and the filesystem store may not be available for adding new
+      images. NOTE: This directory is used only when filesystem store is used
+      as a storage backend.

hooks/glance_contexts.py

@@ -53,6 +53,10 @@ class GlanceContext(OSContextGenerator):
         if config('container-formats'):
             ctxt['container_formats'] = config('container-formats')
 
+        if config('filesystem-store-datadir'):
+            ctxt['filesystem_store_datadir'] = (
+                config('filesystem-store-datadir'))
+
         image_size_cap = config('image-size-cap')
         if image_size_cap:
             try:

templates/icehouse/glance-api.conf

@@ -50,7 +50,7 @@ image_size_cap = {{ image_size_cap }}
 notification_driver = rabbit
 {% endif -%}
 
-filesystem_store_datadir = /var/lib/glance/images/
+filesystem_store_datadir = {{ filesystem_store_datadir }}
 
 {% if swift_store -%}
 swift_store_auth_version = 2

templates/juno/glance-api.conf

@@ -53,7 +53,7 @@ image_size_cap = {{ image_size_cap }}
 notification_driver = rabbit
 {% endif -%}
 
-filesystem_store_datadir = /var/lib/glance/images/
+filesystem_store_datadir = {{ filesystem_store_datadir }}
 
 {% if swift_store -%}
 swift_store_auth_version = 2

templates/kilo/glance-api.conf

@@ -50,7 +50,8 @@ image_size_cap = {{ image_size_cap }}
 {% endif -%}
 
 [glance_store]
-filesystem_store_datadir = /var/lib/glance/images/
+filesystem_store_datadir = {{ filesystem_store_datadir }}
+
 stores = {{ known_stores }}
 {% if rbd_pool -%}
 default_store = rbd

templates/mitaka/glance-api.conf

@@ -45,7 +45,9 @@ image_size_cap = {{ image_size_cap }}
 {%- if use_internal_endpoints %}
 catalog_info = {{ volume_catalog_info }}
 {%- endif %}
-filesystem_store_datadir = /var/lib/glance/images/
+
+filesystem_store_datadir = {{ filesystem_store_datadir }}
+
 stores = {{ known_stores }}
 {% if rbd_pool -%}
 default_store = rbd

unit_tests/test_glance_contexts.py

@@ -42,29 +42,38 @@ class TestGlanceContexts(CharmTestCase):
         config = {
             'disk-formats': 'dfmt1',
             'container-formats': '',
+            'filesystem-store-datadir': "/var/lib/glance/images/",
             'image-size-cap': ''}
         self.config.side_effect = lambda x: config[x]
-        self.assertEqual(contexts.GlanceContext()(), {'disk_formats': 'dfmt1'})
+        self.assertEqual(contexts.GlanceContext()(), {
+            'disk_formats': 'dfmt1',
+            'filesystem_store_datadir': "/var/lib/glance/images/"})
 
     def test_glance_context_container_fmt(self):
         config = {
             'disk-formats': 'dfmt1',
             'container-formats': 'cmft1',
+            'filesystem-store-datadir': "/var/lib/glance/images/",
             'image-size-cap': ''}
         self.config.side_effect = lambda x: config[x]
         self.assertEqual(contexts.GlanceContext()(),
                          {'disk_formats': 'dfmt1',
+                          'filesystem_store_datadir':
+                             "/var/lib/glance/images/",
                           'container_formats': 'cmft1'})
 
     def test_glance_context_image_size_cap(self):
         config = {
             'disk-formats': 'dfmt1',
             'container-formats': 'cmft1',
+            'filesystem-store-datadir': "/var/lib/glance/images/",
             'image-size-cap': '1TB'}
         self.config.side_effect = lambda x: config[x]
         self.assertEqual(contexts.GlanceContext()(),
                          {'disk_formats': 'dfmt1',
                           'container_formats': 'cmft1',
+                          'filesystem_store_datadir':
+                             "/var/lib/glance/images/",
                           'image_size_cap': 1099511627776})
 
     def test_swift_not_related(self):