Simplify implementation

examples/python/helloworld/greeter_server.py

@@ -36,11 +36,8 @@ def serve():
     helloworld_pb2_grpc.add_GreeterServicer_to_server(Greeter(), server)
     server.add_insecure_port('[::]:50051')
     server.start()
-    try:
-        while True:
-            time.sleep(_ONE_DAY_IN_SECONDS)
-    except KeyboardInterrupt:
-        server.stop(0)
+
+    server.wait_for_termination()
 
 
 if __name__ == '__main__':

src/python/grpcio/grpc/__init__.py

@@ -1461,6 +1461,9 @@ class Server(six.with_metaclass(abc.ABCMeta)):
         Args:
           timeout: A floating point number specifying a timeout for the
             operation in seconds.
+
+        Returns:
+          A bool indicates if the operation times out.
         """
         raise NotImplementedError()
 

src/python/grpcio/grpc/_server.py

@@ -764,7 +764,8 @@ class _ServerState(object):
         self.interceptor_pipeline = interceptor_pipeline
         self.thread_pool = thread_pool
         self.stage = _ServerStage.STOPPED
-        self.shutdown_events = []
+        self.termination_event = threading.Event()
+        self.shutdown_events = [self.termination_event]
         self.maximum_concurrent_rpcs = maximum_concurrent_rpcs
         self.active_rpc_count = 0
 
@@ -959,15 +960,7 @@ class _Server(grpc.Server):
         _start(self._state)
 
     def wait_for_termination(self, timeout=None):
-        termination_event = threading.Event()
-
-        with self._state.lock:
-            if self._state.stage is _ServerStage.STOPPED:
-                return
-            else:
-                self._state.shutdown_events.append(termination_event)
-
-        termination_event.wait(timeout=timeout)
+        return self._state.termination_event.wait(timeout=timeout)
 
     def stop(self, grace):
         return _stop(self._state, grace)

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

@@ -87,6 +87,11 @@ class ServerWaitForTerminationTest(unittest.TestCase):
         termination_event.wait(timeout=test_constants.SHORT_TIMEOUT)
         self.assertTrue(termination_event.is_set())
 
+    def test_just_block(self):
+        server = grpc.server(futures.ThreadPoolExecutor())
+        server.start()
+        server.wait_for_termination(timeout=-1)
+
 
 if __name__ == '__main__':
     unittest.main(verbosity=2)