Make _discover_extensions public

Heat wants to use
`cinderclient.shell.OpenStackCinderShell._discover_extensions`
function (https://bugs.launchpad.net/heat/+bug/1527071),
which is private currently. It's better to change this method
to public for public use.
This change will do it as novaclient did.

Change-Id: Iaaa4cab530fd495877e15a372fff1354ddbeaa17
Closes-Bug: #1527169

cinderclient/client.py

@@ -20,7 +20,12 @@ OpenStack Client interface. Handles the REST calls and responses.
 
 from __future__ import print_function
 
+import glob
+import imp
+import itertools
 import logging
+import os
+import pkgutil
 import re
 import six
 
@@ -31,6 +36,7 @@ from keystoneclient import discover
 import requests
 
 from cinderclient import exceptions
+import cinderclient.extension
 from cinderclient.openstack.common import importutils
 from cinderclient.openstack.common.gettextutils import _
 from oslo_utils import strutils
@@ -570,6 +576,45 @@ def get_client_class(version):
     return importutils.import_class(client_path)
 
 
+def discover_extensions(version):
+    extensions = []
+    for name, module in itertools.chain(
+            _discover_via_python_path(),
+            _discover_via_contrib_path(version)):
+
+        extension = cinderclient.extension.Extension(name, module)
+        extensions.append(extension)
+
+    return extensions
+
+
+def _discover_via_python_path():
+    for (module_loader, name, ispkg) in pkgutil.iter_modules():
+        if name.endswith('python_cinderclient_ext'):
+            if not hasattr(module_loader, 'load_module'):
+                # Python 2.6 compat: actually get an ImpImporter obj
+                module_loader = module_loader.find_module(name)
+
+            module = module_loader.load_module(name)
+            yield name, module
+
+
+def _discover_via_contrib_path(version):
+    module_path = os.path.dirname(os.path.abspath(__file__))
+    version_str = "v%s" % version.replace('.', '_')
+    ext_path = os.path.join(module_path, version_str, 'contrib')
+    ext_glob = os.path.join(ext_path, "*.py")
+
+    for ext_path in glob.iglob(ext_glob):
+        name = os.path.basename(ext_path)[:-3]
+
+        if name == "__init__":
+            continue
+
+        module = imp.load_source(name, ext_path)
+        yield name, module
+
+
 def Client(version, *args, **kwargs):
     client_class = get_client_class(version)
     return client_class(*args, **kwargs)

cinderclient/shell.py

@@ -22,12 +22,7 @@ from __future__ import print_function
 
 import argparse
 import getpass
-import glob
-import imp
-import itertools
 import logging
-import os
-import pkgutil
 import sys
 
 import requests
@@ -36,7 +31,6 @@ from cinderclient import client
 from cinderclient import exceptions as exc
 from cinderclient import utils
 import cinderclient.auth_plugin
-import cinderclient.extension
 from cinderclient.openstack.common import importutils
 from cinderclient.openstack.common.gettextutils import _
 from cinderclient.v1 import shell as shell_v1
@@ -412,42 +406,6 @@ class OpenStackCinderShell(object):
 
         return parser
 
-    def _discover_extensions(self, version):
-        extensions = []
-        for name, module in itertools.chain(
-                self._discover_via_python_path(version),
-                self._discover_via_contrib_path(version)):
-
-            extension = cinderclient.extension.Extension(name, module)
-            extensions.append(extension)
-
-        return extensions
-
-    def _discover_via_python_path(self, version):
-        for (module_loader, name, ispkg) in pkgutil.iter_modules():
-            if name.endswith('python_cinderclient_ext'):
-                if not hasattr(module_loader, 'load_module'):
-                    # Python 2.6 compat: actually get an ImpImporter obj
-                    module_loader = module_loader.find_module(name)
-
-                module = module_loader.load_module(name)
-                yield name, module
-
-    def _discover_via_contrib_path(self, version):
-        module_path = os.path.dirname(os.path.abspath(__file__))
-        version_str = "v%s" % version.replace('.', '_')
-        ext_path = os.path.join(module_path, version_str, 'contrib')
-        ext_glob = os.path.join(ext_path, "*.py")
-
-        for ext_path in glob.iglob(ext_glob):
-            name = os.path.basename(ext_path)[:-3]
-
-            if name == "__init__":
-                continue
-
-            module = imp.load_source(name, ext_path)
-            yield name, module
-
     def _add_bash_completion_subparser(self, subparsers):
         subparser = subparsers.add_parser(
             'bash_completion',
@@ -540,7 +498,7 @@ class OpenStackCinderShell(object):
             api_version_input = False
 
         # build available subcommands based on version
-        self.extensions = self._discover_extensions(
+        self.extensions = client.discover_extensions(
             options.os_volume_api_version)
         self._run_extension_hooks('__pre_parse_args__')