Elide cygrpc.ChannelArg and cygrpc.ChannelArgs

20 files changed, 224 insertions, 165 deletions

diff --git a/src/python/grpcio/grpc/_channel.py b/src/python/grpcio/grpc/_channel.py
index bfc7208310..25a4210974 100644
--- a/src/python/grpcio/grpc/_channel.py
+++ b/src/python/grpcio/grpc/_channel.py
@@ -13,10 +13,10 @@
 # limitations under the License.
 """Invocation-side implementation of gRPC Python."""
 
+import logging
 import sys
 import threading
 import time
-import logging
 
 import grpc
 from grpc import _common
@@ -882,8 +882,12 @@ def _unsubscribe(state, callback):
 
 
 def _options(options):
-    return list(options) + [(cygrpc.ChannelArgKey.primary_user_agent_string,
-                             _USER_AGENT)]
+    return list(options) + [
+        (
+            cygrpc.ChannelArgKey.primary_user_agent_string,
+            _USER_AGENT,
+        ),
+    ]
 
 
 class Channel(grpc.Channel):
@@ -892,14 +896,13 @@ class Channel(grpc.Channel):
     def __init__(self, target, options, credentials):
         """Constructor.
 
-    Args:
-      target: The target to which to connect.
-      options: Configuration options for the channel.
-      credentials: A cygrpc.ChannelCredentials or None.
-    """
+        Args:
+          target: The target to which to connect.
+          options: Configuration options for the channel.
+          credentials: A cygrpc.ChannelCredentials or None.
+        """
         self._channel = cygrpc.Channel(
-            _common.encode(target), _common.channel_args(_options(options)),
-            credentials)
+            _common.encode(target), _options(options), credentials)
         self._call_state = _ChannelCallState(self._channel)
         self._connectivity_state = _ChannelConnectivityState(self._channel)
 
diff --git a/src/python/grpcio/grpc/_common.py b/src/python/grpcio/grpc/_common.py
index 130fc42630..bbb69ad489 100644
--- a/src/python/grpcio/grpc/_common.py
+++ b/src/python/grpcio/grpc/_common.py
@@ -79,16 +79,6 @@ def decode(b):
             return b.decode('latin1')
 
 
-def channel_args(options):
-    cygrpc_args = []
-    for key, value in options:
-        if isinstance(value, six.string_types):
-            cygrpc_args.append(cygrpc.ChannelArg(encode(key), encode(value)))
-        else:
-            cygrpc_args.append(cygrpc.ChannelArg(encode(key), value))
-    return cygrpc.ChannelArgs(cygrpc_args)
-
-
 def _transform(message, transformer, exception_message):
     if transformer is None:
         return message
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pxd.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pxd.pxi
new file mode 100644
index 0000000000..853bf6f8e0
--- /dev/null
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pxd.pxi
@@ -0,0 +1,40 @@
+# Copyright 2018 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+cdef void* _copy_pointer(void* pointer)
+
+
+cdef void _destroy_pointer(void* pointer)
+
+
+cdef int _compare_pointer(void* first_pointer, void* second_pointer)
+
+
+cdef class _ArgumentProcessor:
+
+  cdef grpc_arg c_argument
+
+  cdef void c(self, argument, grpc_arg_pointer_vtable *vtable, references)
+
+
+cdef class _ArgumentsProcessor:
+
+  cdef readonly tuple _arguments
+  cdef list _argument_processors
+  cdef readonly list _references
+  cdef grpc_channel_args _c_arguments
+
+  cdef grpc_channel_args *c(self, grpc_arg_pointer_vtable *vtable)
+  cdef un_c(self)
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pyx.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pyx.pxi
new file mode 100644
index 0000000000..65de30884c
--- /dev/null
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pyx.pxi
@@ -0,0 +1,88 @@
+# Copyright 2018 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+cimport cpython
+
+
+cdef void* _copy_pointer(void* pointer):
+  return pointer
+
+
+cdef void _destroy_pointer(void* pointer):
+  pass
+
+
+cdef int _compare_pointer(void* first_pointer, void* second_pointer):
+  if first_pointer < second_pointer:
+    return -1
+  elif first_pointer > second_pointer:
+    return 1
+  else:
+    return 0
+
+
+cdef class _ArgumentProcessor:
+
+  cdef void c(self, argument, grpc_arg_pointer_vtable *vtable, references):
+    key, value = argument
+    cdef bytes encoded_key = _encode(key)
+    if encoded_key is not key:
+      references.append(encoded_key)
+    self.c_argument.key = encoded_key
+    if isinstance(value, int):
+      self.c_argument.type = GRPC_ARG_INTEGER
+      self.c_argument.value.integer = value
+    elif isinstance(value, (bytes, str, unicode,)):
+      self.c_argument.type = GRPC_ARG_STRING
+      encoded_value = _encode(value)
+      if encoded_value is not value:
+        references.append(encoded_value)
+      self.c_argument.value.string = encoded_value
+    elif hasattr(value, '__int__'):
+      # Pointer objects must override __int__() to return
+      # the underlying C address (Python ints are word size). The
+      # lifecycle of the pointer is fixed to the lifecycle of the
+      # python object wrapping it.
+      self.c_argument.type = GRPC_ARG_POINTER
+      self.c_argument.value.pointer.vtable = vtable
+      self.c_argument.value.pointer.address = <void*>(<intptr_t>int(value))
+    else:
+      raise TypeError(
+          'Expected int, bytes, or behavior, got {}'.format(type(value)))
+
+
+cdef class _ArgumentsProcessor:
+
+  def __cinit__(self, arguments):
+    self._arguments = () if arguments is None else tuple(arguments)
+    self._argument_processors = []
+    self._references = []
+
+  cdef grpc_channel_args *c(self, grpc_arg_pointer_vtable *vtable):
+    self._c_arguments.arguments_length = len(self._arguments)
+    if self._c_arguments.arguments_length == 0:
+      return NULL
+    else:
+      self._c_arguments.arguments = <grpc_arg *>gpr_malloc(
+          self._c_arguments.arguments_length * sizeof(grpc_arg))
+      for index, argument in enumerate(self._arguments):
+        argument_processor = _ArgumentProcessor()
+        argument_processor.c(argument, vtable, self._references)
+        self._c_arguments.arguments[index] = argument_processor.c_argument
+        self._argument_processors.append(argument_processor)
+      return &self._c_arguments
+
+  cdef un_c(self):
+    if self._arguments:
+      gpr_free(self._c_arguments.arguments)
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/channel.pxd.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/channel.pxd.pxi
index 4b07e71cec..1ba76b7f83 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/channel.pxd.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/channel.pxd.pxi
@@ -15,5 +15,7 @@
 
 cdef class Channel:
 
+  cdef grpc_arg_pointer_vtable _vtable
   cdef grpc_channel *c_channel
   cdef list references
+  cdef readonly _ArgumentsProcessor _arguments_processor
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/channel.pyx.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/channel.pyx.pxi
index efe5f2e0db..a3966497bc 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/channel.pyx.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/channel.pyx.pxi
@@ -17,26 +17,25 @@ cimport cpython
 
 cdef class Channel:
 
-  def __cinit__(self, bytes target, ChannelArgs arguments,
+  def __cinit__(self, bytes target, object arguments,
                 ChannelCredentials channel_credentials=None):
     grpc_init()
-    cdef grpc_channel_args *c_arguments = NULL
-    cdef char *c_target = NULL
-    self.c_channel = NULL
+    self._vtable.copy = &_copy_pointer
+    self._vtable.destroy = &_destroy_pointer
+    self._vtable.cmp = &_compare_pointer
+    cdef _ArgumentsProcessor arguments_processor = _ArgumentsProcessor(
+        arguments)
+    cdef grpc_channel_args *c_arguments = arguments_processor.c(&self._vtable)
     self.references = []
-    if len(arguments) > 0:
-      c_arguments = &arguments.c_args
-      self.references.append(arguments)
     c_target = target
     if channel_credentials is None:
-      with nogil:
-        self.c_channel = grpc_insecure_channel_create(c_target, c_arguments,
-                                                      NULL)
+      self.c_channel = grpc_insecure_channel_create(c_target, c_arguments, NULL)
     else:
       c_channel_credentials = channel_credentials.c()
       self.c_channel = grpc_secure_channel_create(
           c_channel_credentials, c_target, c_arguments, NULL)
       grpc_channel_credentials_release(c_channel_credentials)
+    arguments_processor.un_c()
     self.references.append(target)
     self.references.append(arguments)
 
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/records.pxd.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/records.pxd.pxi
index 297bbadfe0..35e1bdb0ae 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/records.pxd.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/records.pxd.pxi
@@ -29,19 +29,6 @@ cdef class SslPemKeyCertPair:
   cdef readonly object private_key, certificate_chain
 
 
-cdef class ChannelArg:
-
-  cdef grpc_arg c_arg
-  cdef grpc_arg_pointer_vtable ptr_vtable
-  cdef readonly object key, value
-
-
-cdef class ChannelArgs:
-
-  cdef grpc_channel_args c_args
-  cdef list args
-
-
 cdef class CompressionOptions:
 
   cdef grpc_compression_options c_options
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/records.pyx.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/records.pyx.pxi
index b2343b53d6..ecd991685f 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/records.pyx.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/records.pyx.pxi
@@ -157,81 +157,6 @@ cdef class SslPemKeyCertPair:
     self.c_pair.certificate_chain = self.certificate_chain
 
 
-
-cdef void* copy_ptr(void* ptr):
-  return ptr
-
-
-cdef void destroy_ptr(void* ptr):
-  pass
-
-
-cdef int compare_ptr(void* ptr1, void* ptr2):
-  if ptr1 < ptr2:
-    return -1
-  elif ptr1 > ptr2:
-    return 1
-  else:
-    return 0
-
-
-cdef class ChannelArg:
-
-  def __cinit__(self, bytes key, value):
-    self.key = key
-    self.value = value
-    self.c_arg.key = self.key
-    if isinstance(value, int):
-      self.c_arg.type = GRPC_ARG_INTEGER
-      self.c_arg.value.integer = self.value
-    elif isinstance(value, bytes):
-      self.c_arg.type = GRPC_ARG_STRING
-      self.c_arg.value.string = self.value
-    elif hasattr(value, '__int__'):
-      # Pointer objects must override __int__() to return
-      # the underlying C address (Python ints are word size).  The
-      # lifecycle of the pointer is fixed to the lifecycle of the
-      # python object wrapping it.
-      self.ptr_vtable.copy = &copy_ptr
-      self.ptr_vtable.destroy = &destroy_ptr
-      self.ptr_vtable.cmp = &compare_ptr
-      self.c_arg.type = GRPC_ARG_POINTER
-      self.c_arg.value.pointer.vtable = &self.ptr_vtable
-      self.c_arg.value.pointer.address = <void*>(<intptr_t>int(self.value))
-    else:
-      # TODO Add supported pointer types to this message
-      raise TypeError('Expected int or bytes, got {}'.format(type(value)))
-
-
-cdef class ChannelArgs:
-
-  def __cinit__(self, args):
-    grpc_init()
-    self.args = list(args)
-    for arg in self.args:
-      if not isinstance(arg, ChannelArg):
-        raise TypeError("expected list of ChannelArg")
-    self.c_args.arguments_length = len(self.args)
-    with nogil:
-      self.c_args.arguments = <grpc_arg *>gpr_malloc(
-          self.c_args.arguments_length*sizeof(grpc_arg))
-    for i in range(self.c_args.arguments_length):
-      self.c_args.arguments[i] = (<ChannelArg>self.args[i]).c_arg
-
-  def __dealloc__(self):
-    with nogil:
-      gpr_free(self.c_args.arguments)
-    grpc_shutdown()
-
-  def __len__(self):
-    # self.args is never stale; it's only updated from this file
-    return len(self.args)
-
-  def __getitem__(self, size_t i):
-    # self.args is never stale; it's only updated from this file
-    return self.args[i]
-
-
 cdef class CompressionOptions:
 
   def __cinit__(self):
@@ -254,8 +179,10 @@ cdef class CompressionOptions:
     return result
 
   def to_channel_arg(self):
-    return ChannelArg(GRPC_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET,
-                      self.c_options.enabled_algorithms_bitset)
+    return (
+        GRPC_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET,
+        self.c_options.enabled_algorithms_bitset,
+    )
 
 
 def compression_algorithm_name(grpc_compression_algorithm algorithm):
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/server.pxd.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/server.pxd.pxi
index df4577e124..4588db30d3 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/server.pxd.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/server.pxd.pxi
@@ -15,6 +15,8 @@
 
 cdef class Server:
 
+  cdef grpc_arg_pointer_vtable _vtable
+  cdef readonly _ArgumentsProcessor _arguments_processor
   cdef grpc_server *c_server
   cdef bint is_started  # start has been called
   cdef bint is_shutting_down  # shutdown has been called
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/server.pyx.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/server.pyx.pxi
index e5d28a85d5..707ec742dd 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/server.pyx.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/server.pyx.pxi
@@ -57,16 +57,19 @@ cdef grpc_ssl_certificate_config_reload_status _server_cert_config_fetcher_wrapp
 
 cdef class Server:
 
-  def __cinit__(self, ChannelArgs arguments):
+  def __cinit__(self, object arguments):
     grpc_init()
-    cdef grpc_channel_args *c_arguments = NULL
     self.references = []
     self.registered_completion_queues = []
-    if len(arguments) > 0:
-      c_arguments = &arguments.c_args
-      self.references.append(arguments)
-    with nogil:
-      self.c_server = grpc_server_create(c_arguments, NULL)
+    self._vtable.copy = &_copy_pointer
+    self._vtable.destroy = &_destroy_pointer
+    self._vtable.cmp = &_compare_pointer
+    cdef _ArgumentsProcessor arguments_processor = _ArgumentsProcessor(
+        arguments)
+    cdef grpc_channel_args *c_arguments = arguments_processor.c(&self._vtable)
+    self.c_server = grpc_server_create(c_arguments, NULL)
+    arguments_processor.un_c()
+    self.references.append(arguments)
     self.is_started = False
     self.is_shutting_down = False
     self.is_shutdown = False
diff --git a/src/python/grpcio/grpc/_cython/cygrpc.pxd b/src/python/grpcio/grpc/_cython/cygrpc.pxd
index 01e2da6d54..b6a794c6d7 100644
--- a/src/python/grpcio/grpc/_cython/cygrpc.pxd
+++ b/src/python/grpcio/grpc/_cython/cygrpc.pxd
@@ -14,6 +14,7 @@
 
 include "_cygrpc/grpc.pxi"
 
+include "_cygrpc/arguments.pxd.pxi"
 include "_cygrpc/call.pxd.pxi"
 include "_cygrpc/channel.pxd.pxi"
 include "_cygrpc/credentials.pxd.pxi"
diff --git a/src/python/grpcio/grpc/_cython/cygrpc.pyx b/src/python/grpcio/grpc/_cython/cygrpc.pyx
index d8ac84a317..2ee2e6b73e 100644
--- a/src/python/grpcio/grpc/_cython/cygrpc.pyx
+++ b/src/python/grpcio/grpc/_cython/cygrpc.pyx
@@ -21,6 +21,7 @@ import sys
 # TODO(atash): figure out why the coverage tool gets confused about the Cython
 # coverage plugin when the following files don't have a '.pxi' suffix.
 include "_cygrpc/grpc_string.pyx.pxi"
+include "_cygrpc/arguments.pyx.pxi"
 include "_cygrpc/call.pyx.pxi"
 include "_cygrpc/channel.pyx.pxi"
 include "_cygrpc/credentials.pyx.pxi"
diff --git a/src/python/grpcio/grpc/_server.py b/src/python/grpcio/grpc/_server.py
index 9402941bab..0b79b50108 100644
--- a/src/python/grpcio/grpc/_server.py
+++ b/src/python/grpcio/grpc/_server.py
@@ -791,7 +791,7 @@ class Server(grpc.Server):
     def __init__(self, thread_pool, generic_handlers, interceptors, options,
                  maximum_concurrent_rpcs):
         completion_queue = cygrpc.CompletionQueue()
-        server = cygrpc.Server(_common.channel_args(options))
+        server = cygrpc.Server(options)
         server.register_completion_queue(completion_queue)
         self._state = _ServerState(completion_queue, server, generic_handlers,
                                    _interceptor.service_pipeline(interceptors),
diff --git a/src/python/grpcio_tests/tests/unit/_cython/_cancel_many_calls_test.py b/src/python/grpcio_tests/tests/unit/_cython/_cancel_many_calls_test.py
index 2ca1fa82f4..3765ce4fb0 100644
--- a/src/python/grpcio_tests/tests/unit/_cython/_cancel_many_calls_test.py
+++ b/src/python/grpcio_tests/tests/unit/_cython/_cancel_many_calls_test.py
@@ -141,13 +141,16 @@ class CancelManyCallsTest(unittest.TestCase):
             test_constants.THREAD_CONCURRENCY)
 
         server_completion_queue = cygrpc.CompletionQueue()
-        server = cygrpc.Server(
-            cygrpc.ChannelArgs([cygrpc.ChannelArg(b'grpc.so_reuseport', 0)]))
+        server = cygrpc.Server([
+            (
+                b'grpc.so_reuseport',
+                0,
+            ),
+        ])
         server.register_completion_queue(server_completion_queue)
         port = server.add_http2_port(b'[::]:0')
         server.start()
-        channel = cygrpc.Channel('localhost:{}'.format(port).encode(),
-                                 cygrpc.ChannelArgs([]))
+        channel = cygrpc.Channel('localhost:{}'.format(port).encode(), None)
 
         state = _State()
 
diff --git a/src/python/grpcio_tests/tests/unit/_cython/_channel_test.py b/src/python/grpcio_tests/tests/unit/_cython/_channel_test.py
index c22c77ddbd..7305d0fa3f 100644
--- a/src/python/grpcio_tests/tests/unit/_cython/_channel_test.py
+++ b/src/python/grpcio_tests/tests/unit/_cython/_channel_test.py
@@ -22,7 +22,7 @@ from tests.unit.framework.common import test_constants
 
 
 def _channel_and_completion_queue():
-    channel = cygrpc.Channel(b'localhost:54321', cygrpc.ChannelArgs(()))
+    channel = cygrpc.Channel(b'localhost:54321', ())
     completion_queue = cygrpc.CompletionQueue()
     return channel, completion_queue
 
diff --git a/src/python/grpcio_tests/tests/unit/_cython/_common.py b/src/python/grpcio_tests/tests/unit/_cython/_common.py
index d4b01ca38b..7fd3d19b4e 100644
--- a/src/python/grpcio_tests/tests/unit/_cython/_common.py
+++ b/src/python/grpcio_tests/tests/unit/_cython/_common.py
@@ -96,13 +96,11 @@ class RpcTest(object):
 
     def setUp(self):
         self.server_completion_queue = cygrpc.CompletionQueue()
-        self.server = cygrpc.Server(
-            cygrpc.ChannelArgs([cygrpc.ChannelArg(b'grpc.so_reuseport', 0)]))
+        self.server = cygrpc.Server([(b'grpc.so_reuseport', 0)])
         self.server.register_completion_queue(self.server_completion_queue)
         port = self.server.add_http2_port(b'[::]:0')
         self.server.start()
-        self.channel = cygrpc.Channel('localhost:{}'.format(port).encode(),
-                                      cygrpc.ChannelArgs([]))
+        self.channel = cygrpc.Channel('localhost:{}'.format(port).encode(), [])
 
         self._server_shutdown_tag = 'server_shutdown_tag'
         self.server_condition = threading.Condition()
diff --git a/src/python/grpcio_tests/tests/unit/_cython/_read_some_but_not_all_responses_test.py b/src/python/grpcio_tests/tests/unit/_cython/_read_some_but_not_all_responses_test.py
index ecd23afda7..bc63b54879 100644
--- a/src/python/grpcio_tests/tests/unit/_cython/_read_some_but_not_all_responses_test.py
+++ b/src/python/grpcio_tests/tests/unit/_cython/_read_some_but_not_all_responses_test.py
@@ -111,13 +111,14 @@ class ReadSomeButNotAllResponsesTest(unittest.TestCase):
 
     def testReadSomeButNotAllResponses(self):
         server_completion_queue = cygrpc.CompletionQueue()
-        server = cygrpc.Server(
-            cygrpc.ChannelArgs([cygrpc.ChannelArg(b'grpc.so_reuseport', 0)]))
+        server = cygrpc.Server([(
+            b'grpc.so_reuseport',
+            0,
+        )])
         server.register_completion_queue(server_completion_queue)
         port = server.add_http2_port(b'[::]:0')
         server.start()
-        channel = cygrpc.Channel('localhost:{}'.format(port).encode(),
-                                 cygrpc.ChannelArgs([]))
+        channel = cygrpc.Channel('localhost:{}'.format(port).encode(), set())
 
         server_shutdown_tag = 'server_shutdown_tag'
         server_driver = _ServerDriver(server_completion_queue,
diff --git a/src/python/grpcio_tests/tests/unit/_cython/_server_test.py b/src/python/grpcio_tests/tests/unit/_cython/_server_test.py
index 12bf40be6b..bbd25457b3 100644
--- a/src/python/grpcio_tests/tests/unit/_cython/_server_test.py
+++ b/src/python/grpcio_tests/tests/unit/_cython/_server_test.py
@@ -25,7 +25,7 @@ class Test(unittest.TestCase):
     def test_lonely_server(self):
         server_call_completion_queue = cygrpc.CompletionQueue()
         server_shutdown_completion_queue = cygrpc.CompletionQueue()
-        server = cygrpc.Server(cygrpc.ChannelArgs([]))
+        server = cygrpc.Server(None)
         server.register_completion_queue(server_call_completion_queue)
         server.register_completion_queue(server_shutdown_completion_queue)
         port = server.add_http2_port(b'[::]:0')
diff --git a/src/python/grpcio_tests/tests/unit/_cython/cygrpc_test.py b/src/python/grpcio_tests/tests/unit/_cython/cygrpc_test.py
index 561adf7dff..9045ff58a0 100644
--- a/src/python/grpcio_tests/tests/unit/_cython/cygrpc_test.py
+++ b/src/python/grpcio_tests/tests/unit/_cython/cygrpc_test.py
@@ -42,12 +42,16 @@ class TypeSmokeTest(unittest.TestCase):
         del completion_queue
 
     def testServerUpDown(self):
-        server = cygrpc.Server(
-            cygrpc.ChannelArgs([cygrpc.ChannelArg(b'grpc.so_reuseport', 0)]))
+        server = cygrpc.Server(set([
+            (
+                b'grpc.so_reuseport',
+                0,
+            ),
+        ]))
         del server
 
     def testChannelUpDown(self):
-        channel = cygrpc.Channel(b'[::]:0', cygrpc.ChannelArgs([]))
+        channel = cygrpc.Channel(b'[::]:0', None)
         del channel
 
     def test_metadata_plugin_call_credentials_up_down(self):
@@ -55,8 +59,12 @@ class TypeSmokeTest(unittest.TestCase):
                                              b'test plugin name!')
 
     def testServerStartNoExplicitShutdown(self):
-        server = cygrpc.Server(
-            cygrpc.ChannelArgs([cygrpc.ChannelArg(b'grpc.so_reuseport', 0)]))
+        server = cygrpc.Server([
+            (
+                b'grpc.so_reuseport',
+                0,
+            ),
+        ])
         completion_queue = cygrpc.CompletionQueue()
         server.register_completion_queue(completion_queue)
         port = server.add_http2_port(b'[::]:0')
@@ -66,8 +74,12 @@ class TypeSmokeTest(unittest.TestCase):
 
     def testServerStartShutdown(self):
         completion_queue = cygrpc.CompletionQueue()
-        server = cygrpc.Server(
-            cygrpc.ChannelArgs([cygrpc.ChannelArg(b'grpc.so_reuseport', 0)]))
+        server = cygrpc.Server([
+            (
+                b'grpc.so_reuseport',
+                0,
+            ),
+        ])
         server.add_http2_port(b'[::]:0')
         server.register_completion_queue(completion_queue)
         server.start()
@@ -85,8 +97,12 @@ class ServerClientMixin(object):
 
     def setUpMixin(self, server_credentials, client_credentials, host_override):
         self.server_completion_queue = cygrpc.CompletionQueue()
-        self.server = cygrpc.Server(
-            cygrpc.ChannelArgs([cygrpc.ChannelArg(b'grpc.so_reuseport', 0)]))
+        self.server = cygrpc.Server([
+            (
+                b'grpc.so_reuseport',
+                0,
+            ),
+        ])
         self.server.register_completion_queue(self.server_completion_queue)
         if server_credentials:
             self.port = self.server.add_http2_port(b'[::]:0',
@@ -96,16 +112,16 @@ class ServerClientMixin(object):
         self.server.start()
         self.client_completion_queue = cygrpc.CompletionQueue()
         if client_credentials:
-            client_channel_arguments = cygrpc.ChannelArgs([
-                cygrpc.ChannelArg(cygrpc.ChannelArgKey.ssl_target_name_override,
-                                  host_override)
-            ])
+            client_channel_arguments = ((
+                cygrpc.ChannelArgKey.ssl_target_name_override,
+                host_override,
+            ),)
             self.client_channel = cygrpc.Channel('localhost:{}'.format(
                 self.port).encode(), client_channel_arguments,
                                                  client_credentials)
         else:
             self.client_channel = cygrpc.Channel('localhost:{}'.format(
-                self.port).encode(), cygrpc.ChannelArgs([]))
+                self.port).encode(), set())
         if host_override:
             self.host_argument = None  # default host
             self.expected_host = host_override
diff --git a/src/python/grpcio_tests/tests/unit/_metadata_test.py b/src/python/grpcio_tests/tests/unit/_metadata_test.py
index a918066ea4..5908421011 100644
--- a/src/python/grpcio_tests/tests/unit/_metadata_test.py
+++ b/src/python/grpcio_tests/tests/unit/_metadata_test.py
@@ -80,7 +80,7 @@ _TRAILING_METADATA = (
 _EXPECTED_TRAILING_METADATA = _TRAILING_METADATA
 
 
-def user_agent(metadata):
+def _user_agent(metadata):
     for key, val in metadata:
         if key == 'user-agent':
             return val
@@ -88,16 +88,14 @@ def user_agent(metadata):
 
 
 def validate_client_metadata(test, servicer_context):
+    invocation_metadata = servicer_context.invocation_metadata()
     test.assertTrue(
-        test_common.metadata_transmitted(
-            _EXPECTED_INVOCATION_METADATA,
-            servicer_context.invocation_metadata()))
+        test_common.metadata_transmitted(_EXPECTED_INVOCATION_METADATA,
+                                         invocation_metadata))
+    user_agent = _user_agent(invocation_metadata)
     test.assertTrue(
-        user_agent(servicer_context.invocation_metadata())
-        .startswith('primary-agent ' + _channel._USER_AGENT))
-    test.assertTrue(
-        user_agent(servicer_context.invocation_metadata())
-        .endswith('secondary-agent'))
+        user_agent.startswith('primary-agent ' + _channel._USER_AGENT))
+    test.assertTrue(user_agent.endswith('secondary-agent'))
 
 
 def handle_unary_unary(test, request, servicer_context):