Merge "Use eventlet.patcher.original to get Python select module in get_hub" into stable/rocky

swift/common/utils.py

@@ -2163,9 +2163,18 @@ def get_hub():
 
     In contrast, both poll() and select() specify the set of interesting
     file descriptors with each call, so there's no problem with forking.
+
+    As eventlet monkey patching is now done before call get_hub() in wsgi.py
+    if we use 'import select' we get the eventlet version, but since version
+    0.20.0 eventlet removed select.poll() function in patched select (see:
+    http://eventlet.net/doc/changelog.html and
+    https://github.com/eventlet/eventlet/commit/614a20462).
+
+    We use eventlet.patcher.original function to get python select module
+    to test if poll() is available on platform.
     """
     try:
-        import select
+        select = eventlet.patcher.original('select')
         if hasattr(select, "poll"):
             return "poll"
         return "selects"

test/unit/common/test_utils.py

@@ -4939,6 +4939,38 @@ class TestFileLikeIter(unittest.TestCase):
         iter_file.close()
         self.assertTrue(iter_file.closed)
 
+    def test_get_hub(self):
+        # This test mock the eventlet.green.select module without poll
+        # as in eventlet > 0.20
+        # https://github.com/eventlet/eventlet/commit/614a20462
+        # We add __original_module_select to sys.modules to mock usage
+        # of eventlet.patcher.original
+
+        class SelectWithPoll(object):
+            def poll():
+                pass
+
+        class SelectWithoutPoll(object):
+            pass
+
+        # Platform with poll() that call get_hub before eventlet patching
+        with mock.patch.dict('sys.modules',
+                             {'select': SelectWithPoll,
+                              '__original_module_select': SelectWithPoll}):
+            self.assertEqual(utils.get_hub(), 'poll')
+
+        # Platform with poll() that call get_hub after eventlet patching
+        with mock.patch.dict('sys.modules',
+                             {'select': SelectWithoutPoll,
+                              '__original_module_select': SelectWithPoll}):
+            self.assertEqual(utils.get_hub(), 'poll')
+
+        # Platform without poll() -- before or after patching doesn't matter
+        with mock.patch.dict('sys.modules',
+                             {'select': SelectWithoutPoll,
+                              '__original_module_select': SelectWithoutPoll}):
+            self.assertEqual(utils.get_hub(), 'selects')
+
 
 class TestStatsdLogging(unittest.TestCase):
     def setUp(self):