openstack: load all available authentication plugins

Instead of only loading the v3password authentication plugin, lets load
all the available keystoneauth plugins so that the user is able to use
their preferred authentication method.

Fixes #86

cloud_info/providers/openstack.py

@@ -364,34 +364,40 @@ def occify(term_name):
 
     @staticmethod
     def populate_parser(parser):
+        plugins = loading_base.get_available_plugin_names()
         default_auth = "v3password"
+
         parser.add_argument('--os-auth-type',
                             '--os-auth-plugin',
                             metavar='<name>',
-                            default=default_auth,
-                            help='Authentication type to use')
-
-        plugin = loading_base.get_plugin_loader(default_auth)
-
-        for opt in plugin.get_options():
-            # FIXME(aloga): the code below has been commented. This commit has
-            # been cherry picked from another branch that took into account the
-            # VOs and configured projects. The code below needs to be
-            # uncommented whenever Glue2.1 is in place.
-
-            # NOTE(aloga): we do not want a project to be passed from the CLI,
-            # as we will iterate over it for each configured VO and project.
-            # However, as the plugin is expecting them when parsing the
-            # arguments we need to set them to None before calling the
-            # load_auth_from_argparse_arguments method in the __init__ method
-            # of this class.
-            # if opt.name in ("project-name", "project-id"):
-            #    continue
-            parser.add_argument(*opt.argparse_args,
-                                default=opt.argparse_default,
-                                metavar=opt.metavar,
-                                help=opt.help,
-                                dest='os_%s' % opt.dest)
+                            default=utils.env('OS_AUTH_TYPE', default=default_auth),
+                            choices=plugins,
+                            help='Authentication type to use, available '
+                                 'types are: %s' % ", ".join(plugins))
+
+        for plugin_name in plugins:
+
+            plugin = loading_base.get_plugin_loader(plugin_name)
+
+            for opt in plugin.get_options():
+                # FIXME(aloga): the code below has been commented. This commit has
+                # been cherry picked from another branch that took into account the
+                # VOs and configured projects. The code below needs to be
+                # uncommented whenever Glue2.1 is in place.
+
+                # NOTE(aloga): we do not want a project to be passed from the CLI,
+                # as we will iterate over it for each configured VO and project.
+                # However, as the plugin is expecting them when parsing the
+                # arguments we need to set them to None before calling the
+                # load_auth_from_argparse_arguments method in the __init__ method
+                # of this class.
+                # if opt.name in ("project-name", "project-id"):
+                #    continue
+                parser.add_argument(*opt.argparse_args,
+                                    default=opt.argparse_default,
+                                    metavar='<auth-%s>' % opt.name,
+                                    help=opt.help,
+                                    dest='os_%s' % opt.dest.replace("-", "_"))
 
         parser.add_argument(
             '--insecure',