Add `fsid` to RBD store properties

Currently the RBD store/backend doesn't report the FSID field.
To include the FSID field, we need a connection to the RBD cluster.
Luckily, while initializing the RBD store, we fetch the FSID and
put it in the _url_prefix field (given fsid and pool info are available).

We just need to fetch it from the _url_prefix field and return it
in the response.
If FSID is not set in the RBD store, we return NULL value.

This is required for the effort of optimizing the upload volume to
image operation from cinder RBD to glance RBD backend.

Partial-Implements: blueprint optimize-upload-volume-to-rbd-store
Change-Id: I3e7dc11bc632ca0f3e134e0bca7eb2442bf797ca

api-ref/source/v2/samples/stores-list-detail-response.json

@@ -9,7 +9,8 @@
             "properties": {
                 "pool": "pool1",
                 "chunk_size": 65536,
-                "thin_provisioning": false
+                "thin_provisioning": false,
+                "fsid": "ddf1b25f-1907-449e-89f6-cd30a679c8dc",
             }
         },
         {

glance/api/v2/discovery.py

@@ -92,12 +92,34 @@ class InfoController(object):
 
         return {'stores': backends}
 
+    @staticmethod
+    def _get_fsid_from_url(store_detail):
+        fsid = None
+        prefix = 'rbd://'
+        url_prefix = store_detail.url_prefix
+        # When fsid and pool info are not available,
+        # url_prefix is same as prefix
+        if url_prefix and url_prefix.startswith(
+                prefix) and len(url_prefix) > len(prefix):
+            # Remove last trailing forward slash
+            url_prefix = (
+                url_prefix[:-1] if url_prefix.endswith('/') else url_prefix)
+            pieces = url_prefix[len(prefix):].split('/')
+            # We expect the rbd store's url format to look like 'rbd://%s/%s/'
+            # where the fsid is in the first position; if there are more than
+            # 2 pieces, then something has changed in the driver code, so we
+            # won't set the fsid
+            if len(pieces) == 2:
+                fsid = pieces[0]
+        return fsid
+
     @staticmethod
     def _get_rbd_properties(store_detail):
         return {
             'chunk_size': store_detail.chunk_size,
             'pool': store_detail.pool,
-            'thin_provisioning': store_detail.thin_provisioning
+            'thin_provisioning': store_detail.thin_provisioning,
+            'fsid': InfoController._get_fsid_from_url(store_detail),
         }
 
     @staticmethod

glance/tests/unit/base.py

@@ -73,9 +73,12 @@ class MultiStoreClearingUnitTest(test_utils.BaseTestCase):
         :param passing_config: making store driver passes basic configurations.
         :returns: the number of how many store drivers been loaded.
         """
+        fake_fsid = "db437934-7e1c-445b-a4f5-7cc5bc44ba1b"
         rbd_store.rados = mock.MagicMock()
         rbd_store.rbd = mock.MagicMock()
-        rbd_store.Store._set_url_prefix = mock.MagicMock()
+        rbd_store.Store.get_connection = mock.MagicMock()
+        conn_mock = rbd_store.Store.get_connection.return_value.__enter__()
+        conn_mock.get_fsid.return_value = fake_fsid
         cinder.cinderclient = mock.MagicMock()
         cinder.Store.get_cinderclient = mock.MagicMock()
         swift.swiftclient = mock.MagicMock()

glance/tests/unit/v2/test_discovery_stores.py

@@ -93,7 +93,8 @@ class TestInfoControllers(base.MultiStoreClearingUnitTest):
             self.assertIsNotNone(stores['properties'])
 
     def test_get_stores_detail_properties(self):
-        store_attributes = {'rbd': ['chunk_size', 'pool', 'thin_provisioning'],
+        store_attributes = {'rbd': ['chunk_size', 'pool', 'thin_provisioning',
+                                    'fsid'],
                             'file': ['data_dir', 'chunk_size',
                                      'thin_provisioning'],
                             'cinder': ['volume_type', 'use_multipath'],

releasenotes/notes/add-fsid-in-rbd-store-detail-9c611684c7f59c32.yaml

@@ -0,0 +1,5 @@
+---
+other:
+  - |
+    Updated the stores detail API response to include
+    ``fsid`` field in RBD store properties.