Update docstring of Channelz function && add default variable initialization

2 files changed, 15 insertions, 5 deletions

diff --git a/src/python/grpcio_channelz/grpc_channelz/v1/channelz.py b/src/python/grpcio_channelz/grpc_channelz/v1/channelz.py
index f03d3b736e..573b9d0d5a 100644
--- a/src/python/grpcio_channelz/grpc_channelz/v1/channelz.py
+++ b/src/python/grpcio_channelz/grpc_channelz/v1/channelz.py
@@ -120,7 +120,19 @@ class ChannelzServicer(_channelz_pb2_grpc.ChannelzServicer):
 
 
 def add_channelz_servicer(server):
-    """Enables Channelz on a server.
+    """Add Channelz servicer to a server. Channelz servicer is in charge of
+    pulling information from C-Core for entire process. It will allow the
+    server to response to Channelz queries.
+
+    The Channelz statistic is enabled by default inside C-Core. Whether the
+    statistic is enabled or not is isolated from adding Channelz servicer.
+    That means you can query Channelz info with a Channelz-disabled channel,
+    and you can add Channelz servicer to a Channelz-disabled server.
+
+    The Channelz statistic can be enabled or disabled by channel option
+    'grpc.enable_channelz'. Set to 1 to enable, set to 0 to disable.
+
+    This is an EXPERIMENTAL API.
 
     Args:
       server: grpc.Server to which Channelz service will be added.
diff --git a/src/python/grpcio_tests/tests/channelz/_channelz_servicer_test.py b/src/python/grpcio_tests/tests/channelz/_channelz_servicer_test.py
index f099a2c8cb..84f8594689 100644
--- a/src/python/grpcio_tests/tests/channelz/_channelz_servicer_test.py
+++ b/src/python/grpcio_tests/tests/channelz/_channelz_servicer_test.py
@@ -130,6 +130,7 @@ class ChannelzServicerTest(unittest.TestCase):
         return resp.channel[idx].ref.channel_id
 
     def setUp(self):
+        self._pairs = []
         # This server is for Channelz info fetching only
         # It self should not enable Channelz
         self._server = grpc.server(
@@ -148,10 +149,7 @@ class ChannelzServicerTest(unittest.TestCase):
     def tearDown(self):
         self._server.__del__()
         self._channel.close()
-        # _pairs may not exist, if the test crashed during setup
-        # In 'invalid query' tests, _pairs may never get set
-        if hasattr(self, '_pairs'):
-            _clean_channel_server_pairs(self._pairs)
+        _clean_channel_server_pairs(self._pairs)
 
     def test_get_top_channels_basic(self):
         self._pairs = _generate_channel_server_pairs(1)