Merge pull request #22860 from lidizheng/fix-metadata-flags-test-flake

Fix the metadata flags test flake

src/python/grpcio_tests/tests/unit/_metadata_flags_test.py

@@ -17,6 +17,7 @@ import time
 import weakref
 import unittest
 import threading
+import logging
 import socket
 from six.moves import queue
 
@@ -25,7 +26,7 @@ import grpc
 from tests.unit import test_common
 from tests.unit.framework.common import test_constants
 import tests.unit.framework.common
-from tests.unit.framework.common import bound_socket
+from tests.unit.framework.common import get_socket
 
 _UNARY_UNARY = '/test/UnaryUnary'
 _UNARY_STREAM = '/test/UnaryStream'
@@ -101,7 +102,8 @@ class _GenericHandler(grpc.GenericRpcHandler):
 
 def create_dummy_channel():
     """Creating dummy channels is a workaround for retries"""
-    with bound_socket() as (host, port):
+    host, port, sock = get_socket()
+    sock.close()
     return grpc.insecure_channel('{}:{}'.format(host, port))
 
 
@@ -203,7 +205,11 @@ class MetadataFlagsTest(unittest.TestCase):
         #   main thread. So, it need another method to store the
         #   exceptions and raise them again in main thread.
         unhandled_exceptions = queue.Queue()
-        with bound_socket(listen=False) as (host, port):
+
+        # We just need an unused TCP port
+        host, port, sock = get_socket()
+        sock.close()
+
         addr = '{}:{}'.format(host, port)
         wg = test_common.WaitGroup(len(_ALL_CALL_CASES))
 
@@ -227,6 +233,7 @@ class MetadataFlagsTest(unittest.TestCase):
         for perform_call in _ALL_CALL_CASES:
             test_thread = threading.Thread(target=test_call,
                                            args=(perform_call,))
+            test_thread.daemon = True
             test_thread.exception = None
             test_thread.start()
             test_threads.append(test_thread)
@@ -234,8 +241,7 @@ class MetadataFlagsTest(unittest.TestCase):
         # Start the server after the connections are waiting
         wg.wait()
         server = test_common.test_server(reuse_port=True)
-            server.add_generic_rpc_handlers(
-                (_GenericHandler(weakref.proxy(self)),))
+        server.add_generic_rpc_handlers((_GenericHandler(weakref.proxy(self)),))
         server.add_insecure_port(addr)
         server.start()
 
@@ -250,4 +256,5 @@ class MetadataFlagsTest(unittest.TestCase):
 
 
 if __name__ == '__main__':
+    logging.basicConfig(level=logging.DEBUG)
     unittest.main(verbosity=2)