Add API versioning support

* Specific versions supported are managed in XXXXXX.client.py with a
  mapping from version to client class.  This is based on the scheme
  that is included in novaclient; none of the other client libs have
  that capability.

Change-Id: I930b197f1189e7f52c3b0096e73e0773cf925542

openstackclient/common/clientmanager.py

@@ -54,9 +54,7 @@ class ClientManager(object):
                  tenant_name=None, tenant_id=None,
                  username=None, password=None,
                  region_name=None,
-                 identity_api_version=None,
-                 compute_api_version=None,
-                 image_api_version=None,
+                 api_version=None,
                  ):
         self._token = token
         self._url = url
@@ -66,9 +64,7 @@ class ClientManager(object):
         self._username = username
         self._password = password
         self._region_name = region_name
-        self._identity_api_version = identity_api_version
-        self._compute_api_version = compute_api_version
-        self._image_api_version = image_api_version
+        self._api_version = api_version
         self._service_catalog = None
 
         if not self._url:

openstackclient/common/exceptions.py

@@ -39,6 +39,12 @@ class EndpointNotFound(Exception):
     pass
 
 
+class UnsupportedVersion(Exception):
+    """Indicates that the user is trying to use an unsupported
+       version of the API"""
+    pass
+
+
 class ClientException(Exception):
     """
     The base exception class for all exceptions this library raises.

openstackclient/common/utils.py

@@ -20,6 +20,7 @@ Common client utilities
 """
 
 import os
+import sys
 import uuid
 
 import prettytable
@@ -67,3 +68,10 @@ def env(*vars, **kwargs):
         if value:
             return value
     return kwargs.get('default', '')
+
+
+def import_class(import_str):
+    """Returns a class from a string including module and class."""
+    mod_str, _sep, class_str = import_str.rpartition('.')
+    __import__(mod_str)
+    return getattr(sys.modules[mod_str], class_str)

openstackclient/compute/client.py

@@ -27,7 +27,7 @@ def make_client(instance):
     """
     LOG.debug('instantiating compute client')
     client = nova_client.Client(
-        version=instance._compute_api_version,
+        version=instance._api_version['compute'],
         username=instance._username,
         api_key=instance._password,
         project_id=instance._tenant_name,

openstackclient/identity/client.py

@@ -17,23 +17,42 @@
 
 import logging
 
-from keystoneclient.v2_0 import client as identity_client
+from openstackclient.common import exceptions as exc
+from openstackclient.common import utils
 
 LOG = logging.getLogger(__name__)
 
+API_VERSIONS = {
+    '2.0': 'keystoneclient.v2_0.client.Client',
+}
+
+
+def get_client_class(version):
+    """Returns the client class for the requested API version
+    """
+    try:
+        client_path = API_VERSIONS[str(version)]
+    except (KeyError, ValueError):
+        msg = "Invalid client version '%s'. must be one of: %s" % (
+              (version, ', '.join(API_VERSIONS.keys())))
+        raise exc.UnsupportedVersion(msg)
+
+    return utils.import_class(client_path)
+
 
 def make_client(instance):
     """Returns an identity service client.
     """
+    identity_client = get_client_class(instance._api_version['identity'])
     if instance._url:
         LOG.debug('instantiating identity client: token flow')
-        client = identity_client.Client(
+        client = identity_client(
             endpoint=instance._url,
             token=instance._token,
         )
     else:
         LOG.debug('instantiating identity client: password flow')
-        client = identity_client.Client(
+        client = identity_client(
             username=instance._username,
             password=instance._password,
             tenant_name=instance._tenant_name,

openstackclient/shell.py

@@ -172,9 +172,7 @@ class OpenStackShell(App):
             username=self.options.os_username,
             password=self.options.os_password,
             region_name=self.options.os_region_name,
-            identity_api_version=self.options.os_identity_api_version,
-            compute_api_version=self.options.os_compute_api_version,
-            image_api_version=self.options.os_image_api_version,
+            api_version=self.api_version,
             )
         return