adding a token service Driver to define the interface

keystone/token/backends/kvs.py

@@ -1,9 +1,10 @@
 # vim: tabstop=4 shiftwidth=4 softtabstop=4
 
+from keystone import token
 from keystone.common import kvs
 
 
-class Token(kvs.Base):
+class Token(kvs.Base, token.Driver):
     # Public interface
     def get_token(self, token_id):
         return self.db.get('token-%s' % token_id)

keystone/token/core.py

@@ -19,3 +19,50 @@ class Manager(manager.Manager):
 
     def __init__(self):
         super(Manager, self).__init__(CONF.token.driver)
+
+
+class Driver(object):
+    """Interface description for a Token driver."""
+
+    def get_token(self, token_id):
+        """Get a token by id.
+
+        :param token_id: identity of the token
+        :type token_id: string
+        :returns: token_ref or None.
+
+        """
+        raise NotImplementedError()
+
+    def create_token(self, token_id, data):
+        """Create a token by id and data.
+
+        :param token_id: identity of the token
+        :type token_id: string
+        :param data: dictionary with additional reference information
+
+        ::
+
+            {
+                expires=''
+                id=token_id,
+                user=user_ref,
+                tenant=tenant_ref,
+                metadata=metadata_ref
+            }
+
+        :type data: dict
+        :returns: token_ref or None.
+
+        """
+        raise NotImplementedError()
+
+    def delete_token(self, token_id):
+        """Deletes a token by id.
+
+        :param token_id: identity of the token
+        :type token_id: string
+        :returns: None.
+
+        """
+        raise NotImplementedError()