How do I test if provider credentials are valid in apache libcloud? - apache

Question

I was trying to create a driver for openstack using apache libcloud. It doesn't raise any error even if the user credentials are wrong. So When i checked the faq i found an answer as given in the link
Apache libcloud FAQ
But it doesn't seem to be effective since querying each time to check whether the user is authenticated will reduce the performance if the query returns a bulk of data.
When i checked the response i got from the api there is a field called driver.connection.auth_user_info and i found that the field is empty if the user is not authenticated. So can i use this method as a standard? Any help is appreciated

Answer 1

An openstack driver for libcloud is already available:
from libcloud.compute.types import Provider
from libcloud.compute.providers import get_driver
os = get_driver(Provider.OPENSTACK)
params = {'key': 'username', 'ex_force_service_region':'regionOne',
'ex_force_service_name':'nova', 'ex_force_auth_version':'2.0_password',
'ex_force_auth_url':'http://127.0.0.1:5000',
'ex_force_service_type':'compute', 'secret':'password',
'ex_tenant_name':'tenant'}
driver = os(**params)
But libcloud does not check the credentials by just creating the driver object. Instead, the creds will be validated only when a request is sent. If the internal exception InvalidCredsError is thrown the credentials are invalid, and an own variable could be set:
from libcloud.common.types import InvalidCredsError
validcreds = False
try:
nodes = driver.list_nodes()
if nodes.count >= 0:
validcreds = True
except InvalidCredsError:
print "Invalid credentials"
except Exception as e:
print str(e)
I would not rely on the internal variable auth_user_info because it could change over time.