Fix 500 server error invalid transport key during secret creation

If a user creates a secret and passes in a transport key reference
that does not exist, the server responds to a 500 error. It has
been fixed to return a 400 error with a message that says transport key
not found.

Change-Id: I3c6dd459efc4aec611f88a73b118cd3f36444b63
Closes-Bug: #1554172

barbican/common/exception.py

@@ -424,6 +424,13 @@ class StoredKeyPrivateKeyNotFound(BarbicanException):
                   "key needed for stored key certificate generation.")
 
 
+class ProvidedTransportKeyNotFound(BarbicanHTTPException):
+    message = u._("Provided Transport key %(transport_key_id)s "
+                  "could not be found")
+    client_message = u._("Provided transport key was not found.")
+    status_code = 400
+
+
 class InvalidUUIDInURI(BarbicanHTTPException):
     message = u._("The provided UUID in the URI (%(uuid_string)s) is "
                   "malformed.")

barbican/plugin/resources.py

@@ -11,6 +11,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from barbican.common import exception
 from barbican.common import utils
 from barbican.model import models
 from barbican.model import repositories as repos
@@ -47,10 +48,11 @@ def _get_plugin_name_and_transport_key(transport_key_id):
     transport_key = None
     if transport_key_id is not None:
         transport_key_repo = repos.get_transport_key_repository()
-        transport_key_model = transport_key_repo.get(
-            entity_id=transport_key_id)
-        if transport_key_model is None:
-            raise ValueError("Invalid transport key ID provided")
+        try:
+            transport_key_model = transport_key_repo.get(
+                entity_id=transport_key_id)
+        except exception.NotFound:
+            raise exception.ProvidedTransportKeyNotFound(str(transport_key_id))
 
         plugin_name = transport_key_model.plugin_name
         if plugin_name is None:

barbican/tests/api/controllers/test_secrets.py

@@ -157,6 +157,17 @@ class WhenTestingSecretsResource(utils.BarbicanAPIBaseTestCase):
             transport_key_needed=False
         )
 
+    def test_new_secret_fails_with_invalid_transport_key_ref(self):
+        resp, _ = create_secret(
+            self.app,
+            payload=b'superdupersecret',
+            content_type='text/plain',
+            transport_key_id="non_existing_transport_key_id",
+            transport_key_needed="true",
+            expect_errors=True
+        )
+        self.assertEqual(400, resp.status_int)
+
     def test_new_secret_w_unsupported_content_type_should_fail(self):
         resp, _ = create_secret(
             self.app,