sync changes from charms.ceph

Change-Id: I8a83e15a77306cca4baa665c31cb9363f7cbde83
Depends-On: I483ee9dae4ce69c71ae06359d0fb96aaa1c56cbc

lib/ceph/utils.py

@@ -51,6 +51,8 @@ from charmhelpers.core.hookenv import (
     DEBUG,
     ERROR,
     WARNING,
+    storage_get,
+    storage_list,
 )
 from charmhelpers.fetch import (
     apt_cache,
@@ -1353,12 +1355,38 @@ def get_partitions(dev):
         return []
 
 
-def find_least_used_journal(journal_devices):
-    usages = map(lambda a: (len(get_partitions(a)), a), journal_devices)
+def find_least_used_utility_device(utility_devices):
+    """
+    Find a utility device which has the smallest number of partitions
+    among other devices in the supplied list.
+
+    :utility_devices: A list of devices to be used for filestore journal
+    or bluestore wal or db.
+    :return: string device name
+    """
+
+    usages = map(lambda a: (len(get_partitions(a)), a), utility_devices)
     least = min(usages, key=lambda t: t[0])
     return least[1]
 
 
+def get_devices(name):
+    """ Merge config and juju storage based devices
+
+    :name: THe name of the device type, eg: wal, osd, journal
+    :returns: Set(device names), which are strings
+    """
+    if config(name):
+        devices = [l.strip() for l in config(name).split(' ')]
+    else:
+        devices = []
+    storage_ids = storage_list(name)
+    devices.extend((storage_get('location', s) for s in storage_ids))
+    devices = filter(os.path.exists, devices)
+
+    return set(devices)
+
+
 def osdize(dev, osd_format, osd_journal, reformat_osd=False,
            ignore_errors=False, encrypt=False, bluestore=False):
     if dev.startswith('/dev'):
@@ -1405,13 +1433,23 @@ def osdize_dev(dev, osd_format, osd_journal, reformat_osd=False,
         # NOTE(jamespage): enable experimental bluestore support
         if cmp_pkgrevno('ceph', '10.2.0') >= 0 and bluestore:
             cmd.append('--bluestore')
+            wal = get_devices('bluestore-wal')
+            if wal:
+                cmd.append('--block.wal')
+                least_used_wal = find_least_used_utility_device(wal)
+                cmd.append(least_used_wal)
+            db = get_devices('bluestore-db')
+            if db:
+                cmd.append('--block.db')
+                least_used_db = find_least_used_utility_device(db)
+                cmd.append(least_used_db)
         elif cmp_pkgrevno('ceph', '12.1.0') >= 0 and not bluestore:
             cmd.append('--filestore')
 
         cmd.append(dev)
 
         if osd_journal:
-            least_used = find_least_used_journal(osd_journal)
+            least_used = find_least_used_utility_device(osd_journal)
             cmd.append(least_used)
     else:
         # Just provide the device - no other options