A few weeks prior to the Grizzly OpenStack Design Summit, I was digging around in various python-*client libraries for OpenStack. Glanceclient had just started to use python-keystoneclient to take care of it’s auth needs, but everyone else was doing it themselves – intertia from having it in the base project from the early days and never refactoring things as clients replicated and split in the Essex release.
Looking at what glanceclient did, and had to do, I got really annoyed and wanted the client to have a much easier to use interface. At the same time, I was also digging around trying to allow the keystoneclient CLI to accept and use an override for the endpoint from the command line. Turns out the various mechanations to make the original client setup work with a system with two distinct URL endpoints was quite a mess under the covers, and that mess just propagated through to anyone trying to use the library.
We just landed some new code updates with keystoneclient to make it much easier to use. So this little article is intended to be a quick guide to using the python keystoneclient library and some of it’s new features. While we’re getting v3 API support installed, we’re still very actively using v2 apis, so we’ll use v2 API examples throughout.
The first is just getting a client object established.
>>> from keystoneclient.v2_0 import client
>>> help(client)
We’ve expanded the documentation extensively to make it easier to use the library. The base client is still working from httplib2 – I didn’t rage-change it into the requests library (although it was damned close).
There’s a couple of common things that you’ll want to do with initializing the client. The first is to authorize the client with the bootstrapping pieces so you can use it to configure keystone. In general, I’m sort of expecting this to be done mostly from the CLI, but you can also do it from the python code directly. To use this setup, you’ll need to initialize the client with two pieces of data:
- token
- endpoint
Token is what you’ll have configured in your keystone.conf file under admin_token and endpoint is the URL to your keystone service. If you were using devstack, it would be http://localhost:35357/v2.0
A bit of example code (making up the admin_token)
from keystone client.v2_0 import client
adminclient = client.Client(token='9fc31e32f61e78f114a40999fbf594c2',
endpoint='http://localhost:35357/v2.0')
Now at this point, you’ll have an instance of the client, and can start interacting with all the internal structures in keystone. adminclient.tenants.list() for example.
You may have spotted the authenticate() method on the client. If you’re using the token/endpoint setup, you do not want to call this method. When you’re using the admin_token setup, you don’t
have a full authorization token as retrieved from keystone, you’re short-cutting the system. This mode is really only intended to be used to bootstrap in projects, users, etc. Once you’ve done that, you’re better using the username/password setup with the client.
To do that, you minimally need to know the username, the password, and the “public” endpoint of Keystone. With the v2 API, the public and administrative endpoints are separate. With devstack, the example public API endpoint is http://localhost:5000/v2.0.
A bit of an example:
from keystoneclient.v2_0 import client
kc = client.Client(username='heckj', password='e2112EFFd3ff',
auth_url='http://localhost:5000/v2.0')
At this point, the client has been initialized, and as a default it will immediately attempt to authenticate() to the endpoint, so it already has some authorization data. With the updated keystoneclient library, this authorization info is stashed into an attribute “auth_ref”. You can check out the code in more detail – the class is keystoneclient.access.AccessInfo, and this represents the token that we retrieved after calling authenticate() to auth against keystone.
With only providing a username and password, the token is really only useful for about two things – getting a list of clients that this user can authorize to (getting a ‘scoped’ token – where the token represents authorization to a project), and then retrieving that token.
>>> kc.username
'heckj'
>>> kc.auth_ref
{u'token': {u'expires': u'2012-11-12T23:28:58Z', u'id': u'97913f8839634946afab2897ac19908d'}, u'serviceCatalog': {}, u'user': {u'username': u'heckj', u'roles_links': [], u'id': u'c8d112a0932a454097dfba0f3b598bdc', u'roles': [], u'name': u'heckj'}}
>>> kc.auth_ref.scoped
False
>>> kc.tenants.list()
[]
>>> kc.authenticate(tenant_name='heckj-project')
True
>>> kc.auth_ref.scoped
True
>>> kc.auth_ref
{u'token': {u'expires': u'2012-11-12T23:37:10Z', u'id': u'6d811d7c39034813b6cab2ad083cdf3e', u'tenant': {u'id': u'7dbf826d086c4580a28cf860a6d13046', u'enabled': True, u'description': u'', u'name': u'heckj-project'}}, u'serviceCatalog': [{u'endpoints_links': [], u'endpoints': [{u'adminURL': u'http://localhost:8776/v1/7dbf826d086c4580a28cf860a6d13046', u'region': u'RegionOne', u'internalURL': u'http://localhost:8776/v1/7dbf826d086c4580a28cf860a6d13046', u'publicURL': u'http://localhost:8776/v1/7dbf826d086c4580a28cf860a6d13046'}], u'type': u'volume', u'name': u'Volume Service'}, {u'endpoints_links': [], u'endpoints': [{u'adminURL': u'http://localhost:9292/v1', u'region': u'RegionOne', u'internalURL': u'http://localhost:9292/v1', u'publicURL': u'http://localhost:9292/v1'}], u'type': u'image', u'name': u'Image Service'}, {u'endpoints_links': [], u'endpoints': [{u'adminURL': u'http://localhost:8774/v2/7dbf826d086c4580a28cf860a6d13046', u'region': u'RegionOne', u'internalURL': u'http://localhost:8774/v2/7dbf826d086c4580a28cf860a6d13046', u'publicURL': u'http://localhost:8774/v2/7dbf826d086c4580a28cf860a6d13046'}], u'type': u'compute', u'name': u'Compute Service'}, {u'endpoints_links': [], u'endpoints': [{u'adminURL': u'http://localhost:8773/services/Admin', u'region': u'RegionOne', u'internalURL': u'http://localhost:8773/services/Cloud', u'publicURL': u'http://localhost:8773/services/Cloud'}], u'type': u'ec2', u'name': u'EC2 Service'}, {u'endpoints_links': [], u'endpoints': [{u'adminURL': u'http://localhost:35357/v2.0', u'region': u'RegionOne', u'internalURL': u'http://localhost:5000/v2.0', u'publicURL': u'http://localhost:5000/v2.0'}], u'type': u'identity', u'name': u'Identity Service'}], u'user': {u'username': u'heckj', u'roles_links': [], u'id': u'c8d112a0932a454097dfba0f3b598bdc', u'roles': [{u'name': u'Member'}], u'name': u'heckj'}, u'metadata': {u'is_admin': 0, u'roles': [u'08ccc339c0074a548104b9050bdf9492']}}
You might have noticed that you can now call authenticate() on the client and just pass in values that are missing from previous authenticate() calls, or you can switch them out entirely. You can change the username, password, project, etc – anything that you’d otherwise normally initialize with the client to do what you need.
Rhonabwy 