From 3dd9613b21d78005e1c8f5b3b20b48b686459717 Mon Sep 17 00:00:00 2001
From: Monty Taylor <mordred@inaugust.com>
Date: Mon, 23 Jul 2018 10:19:50 -0500
Subject: [PATCH] Pass volume snapshot size to volume create

When creating a volume from a snapshot, the size parameter is required
and type is checked. Since we have to pass something and it needs to be
a valid data type (None is not acceptable) grab the size from the
snapshot object and pass it.

Change-Id: Ie23e3d23828919234e40336b5c65b22e140d337c
---
 .../tests/unit/volume/v2/test_volume.py          |  2 +-
 openstackclient/volume/v2/volume.py              | 16 +++++++++++++---
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/openstackclient/tests/unit/volume/v2/test_volume.py b/openstackclient/tests/unit/volume/v2/test_volume.py
index 2fa924b8a5..304aa91cbc 100644
--- a/openstackclient/tests/unit/volume/v2/test_volume.py
+++ b/openstackclient/tests/unit/volume/v2/test_volume.py
@@ -430,7 +430,7 @@ class TestVolumeCreate(TestVolume):
         columns, data = self.cmd.take_action(parsed_args)
 
         self.volumes_mock.create.assert_called_once_with(
-            size=None,
+            size=snapshot.size,
             snapshot_id=snapshot.id,
             name=self.new_volume.name,
             description=None,
diff --git a/openstackclient/volume/v2/volume.py b/openstackclient/volume/v2/volume.py
index 61f846b02f..ee3d2f20d3 100644
--- a/openstackclient/volume/v2/volume.py
+++ b/openstackclient/volume/v2/volume.py
@@ -186,11 +186,21 @@ class CreateVolume(command.ShowOne):
                 image_client.images,
                 parsed_args.image).id
 
+        size = parsed_args.size
+
         snapshot = None
         if parsed_args.snapshot:
-            snapshot = utils.find_resource(
+            snapshot_obj = utils.find_resource(
                 volume_client.volume_snapshots,
-                parsed_args.snapshot).id
+                parsed_args.snapshot)
+            snapshot = snapshot_obj.id
+            # Cinder requires a value for size when creating a volume
+            # even if creating from a snapshot. Cinder will create the
+            # volume with at least the same size as the snapshot anyway,
+            # so since we have the object here, just override the size
+            # value if it's either not given or is smaller than the
+            # snapshot size.
+            size = max(size or 0, snapshot_obj.size)
 
         project = None
         if parsed_args.project:
@@ -205,7 +215,7 @@ class CreateVolume(command.ShowOne):
                 parsed_args.user).id
 
         volume = volume_client.volumes.create(
-            size=parsed_args.size,
+            size=size,
             snapshot_id=snapshot,
             name=parsed_args.name,
             description=parsed_args.description,