[Openstack] Common openstack client library

Alessio Ababilov aababilov at griddynamics.com
Mon Aug 13 08:39:24 UTC 2012


Hi!

I have an implementation of blueprint
https://blueprints.launchpad.net/nova/+spec/basic-client-library. The
library is accessible at https://github.com/aababilov/python-openstackclient
-base.

This library is actively used in Grid Dynamics for two month and is quite
stable.

This library can be very useful for python-openstackclient (that started to
build its own client wrapper) and nova server.

Unfortunately, nova, keystone, and glance clients are very inconsistent. A
lot of code is copied between all these clients instead of moving it to a
common library. The code was edited without synchronization between
clients, so, they have different behaviour:

   - all client constructors use different parameters (api_key in nova or
   password in keystone and so on);
   - keystoneclient authenticates immediately in __init__, while novaclient
   does in lazily during first method call;
   - {keystone,nova}client can manage service catalogs and accept
   keystone's auth URI while glanceclient allows endpoints only;
   - keystoneclient can support authorization with an unscoped token but
   novaclient doesn't;
   - novaclient uses class composition while keystoneclient uses
   inheritance.

I have developed a library to unify current clients. The library can be
used as-is, but it would be better if openstack clients dropped their
common code (base.py, exceptions.py and so on) and just began to import
common code.

The library performs file chunking that is necessary for the glance client.
Also, it performs reauthentication if the token is expired.

Here is an example of using unified clients.

from openstackclient_base.base import monkey_patch # optional
monkey_patch()                                     # optional

from openstackclient_base.client import HttpClient
http_client = HttpClient(username="...", password="...",
tenant_name="...", auth_uri="...")

from openstackclient_base.nova.client import ComputeClient
print ComputeClient(http_client).servers.list()

from openstackclient_base.keystone.client import IdentityPublicClient
print IdentityPublicClient(http_client).tenants.list()


-- 
Alessio Ababilov
Software Engineer
Grid Dynamics
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