Add function for getting recommended datastore

Add utility function which returns the most recommended datastore from a
datastore cluster where a VM can be cloned to.

Change-Id: Ic532bb9c52270ba34f70d2b7977de49f8753d1d1

oslo_vmware/objects/datastore.py

@@ -55,6 +55,34 @@ def get_datastore_by_ref(session, ds_ref):
                      type=props.get("summary.type"))
 
 
+def get_recommended_datastore_clone(session,
+                                    dsc_ref,
+                                    clone_spec,
+                                    vm_ref,
+                                    folder,
+                                    name,
+                                    resource_pool=None,
+                                    host_ref=None):
+    """Returns a key which identifies the most recommended datastore from the
+    specified datastore cluster where the specified VM can be cloned to.
+    """
+    sp_spec = vim_util.storage_placement_spec(session.vim.client.factory,
+                                              dsc_ref,
+                                              'clone',
+                                              clone_spec=clone_spec,
+                                              vm_ref=vm_ref,
+                                              folder=folder,
+                                              clone_name=name,
+                                              res_pool_ref=resource_pool,
+                                              host_ref=host_ref)
+    spr = session.invoke_api(
+        session.vim,
+        "RecommendDatastores",
+        session.vim.service_content.storageResourceManager,
+        storageSpec=sp_spec)
+    return spr.recommendations[0].key
+
+
 def get_dsc_ref_and_name(session, dsc_val):
     """Return reference and name of the specified datastore cluster.
 

oslo_vmware/vim_util.py

@@ -628,3 +628,31 @@ def propset_dict(propset):
         return {}
 
     return {prop.name: prop.val for prop in propset}
+
+
+def storage_placement_spec(client_factory,
+                           dsc_ref,
+                           type,
+                           clone_spec=None,
+                           config_spec=None,
+                           relocate_spec=None,
+                           vm_ref=None,
+                           folder=None,
+                           clone_name=None,
+                           res_pool_ref=None,
+                           host_ref=None):
+    pod_sel_spec = client_factory.create('ns0:StorageDrsPodSelectionSpec')
+    pod_sel_spec.storagePod = dsc_ref
+
+    spec = client_factory.create('ns0:StoragePlacementSpec')
+    spec.podSelectionSpec = pod_sel_spec
+    spec.type = type
+    spec.vm = vm_ref
+    spec.folder = folder
+    spec.cloneSpec = clone_spec
+    spec.configSpec = config_spec
+    spec.relocateSpec = relocate_spec
+    spec.cloneName = clone_name
+    spec.resourcePool = res_pool_ref
+    spec.host = host_ref
+    return spec