extension: add entry_point_names method1.20.0

This allows to get the list of valid entry points names declared for a
namespace, without loading them.

Change-Id: If9132edc14c2772732fd4ec0dc5dc3ebc4a56b3c

2 files changed, 11 insertions, 0 deletions

diff --git a/stevedore/extension.py b/stevedore/extension.py
index cdd53d2..55cb22c 100644
--- a/stevedore/extension.py
+++ b/stevedore/extension.py
@@ -13,6 +13,7 @@
 """ExtensionManager
 """
 
+import operator
 import pkg_resources
 
 import logging
@@ -168,6 +169,10 @@ class ExtensionManager(object):
             self.ENTRY_POINT_CACHE[self.namespace] = eps
         return self.ENTRY_POINT_CACHE[self.namespace]
 
+    def entry_points_names(self):
+        """Return the list of entry points names for this namespace."""
+        return list(map(operator.attrgetter("name"), self.list_entry_points()))
+
     def _load_plugins(self, invoke_on_load, invoke_args, invoke_kwds,
                       verify_requirements):
         extensions = []
diff --git a/stevedore/tests/test_extension.py b/stevedore/tests/test_extension.py
index a84c2df..4e91429 100644
--- a/stevedore/tests/test_extension.py
+++ b/stevedore/tests/test_extension.py
@@ -58,6 +58,12 @@ class TestCallback(utils.TestCase):
                          set(map(operator.attrgetter("name"), n)))
         self.assertEqual(4, len(n))
 
+    def test_list_entry_points_names(self):
+        em = extension.ExtensionManager('stevedore.test.extension')
+        names = em.entry_points_names()
+        self.assertEqual(set(['e1', 'e2', 't1', 't2']), set(names))
+        self.assertEqual(4, len(names))
+
     def test_contains_by_name(self):
         em = extension.ExtensionManager('stevedore.test.extension')
         self.assertEqual('t1' in em, True)