Return 400 if create volume snapshot force parameter is invalid

Fixes bug #1014689

* Add is_valid_boolstr function in utils.py
* Add force parameter check in SnapshotsController.create()
* Add unittest for invalid force parameter.

Change-Id: Ie6a07a2ac589da76f52a82b126a6d66e5987edc4

1 files changed, 9 insertions, 0 deletions

diff --git a/nova/utils.py b/nova/utils.py
index 31d62a611..41b268c2e 100644
--- a/nova/utils.py
+++ b/nova/utils.py
@@ -941,6 +941,15 @@ def bool_from_str(val):
                val.lower() == 'y'
 
 
+def is_valid_boolstr(val):
+    """Check if the provided string is a valid bool string or not. """
+    val = str(val).lower()
+    return val == 'true' or val == 'false' or \
+           val == 'yes' or val == 'no' or \
+           val == 'y' or val == 'n' or \
+           val == '1' or val == '0'
+
+
 def is_valid_ipv4(address):
     """valid the address strictly as per format xxx.xxx.xxx.xxx.
     where xxx is a value between 0 and 255.