Merge master

18 files changed, 421 insertions, 176 deletions

diff --git a/src/python/grpcio/_parallel_compile_patch.py b/src/python/grpcio/_parallel_compile_patch.py
new file mode 100644
index 0000000000..4d03ef49ba
--- /dev/null
+++ b/src/python/grpcio/_parallel_compile_patch.py
@@ -0,0 +1,63 @@
+# Copyright 2018 The 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.
+"""Patches the compile() to allow enable parallel compilation of C/C++.
+
+build_ext has lots of C/C++ files and normally them one by one.
+Enabling parallel build helps a lot.
+"""
+
+import distutils.ccompiler
+import os
+
+try:
+    BUILD_EXT_COMPILER_JOBS = int(
+        os.environ.get('GRPC_PYTHON_BUILD_EXT_COMPILER_JOBS', '1'))
+except ValueError:
+    BUILD_EXT_COMPILER_JOBS = 1
+
+
+# monkey-patch for parallel compilation
+def _parallel_compile(self,
+                      sources,
+                      output_dir=None,
+                      macros=None,
+                      include_dirs=None,
+                      debug=0,
+                      extra_preargs=None,
+                      extra_postargs=None,
+                      depends=None):
+    # setup the same way as distutils.ccompiler.CCompiler
+    # https://github.com/python/cpython/blob/31368a4f0e531c19affe2a1becd25fc316bc7501/Lib/distutils/ccompiler.py#L564
+    macros, objects, extra_postargs, pp_opts, build = self._setup_compile(
+        output_dir, macros, include_dirs, sources, depends, extra_postargs)
+    cc_args = self._get_cc_args(pp_opts, debug, extra_preargs)
+
+    def _compile_single_file(obj):
+        try:
+            src, ext = build[obj]
+        except KeyError:
+            return
+        self._compile(obj, src, ext, cc_args, extra_postargs, pp_opts)
+
+    # run compilation of individual files in parallel
+    import multiprocessing.pool
+    multiprocessing.pool.ThreadPool(BUILD_EXT_COMPILER_JOBS).map(
+        _compile_single_file, objects)
+    return objects
+
+
+def monkeypatch_compile_maybe():
+    """Monkeypatching is dumb, but the build speed gain is worth it."""
+    if BUILD_EXT_COMPILER_JOBS > 1:
+        distutils.ccompiler.CCompiler.compile = _parallel_compile
diff --git a/src/python/grpcio/commands.py b/src/python/grpcio/commands.py
index 0a3097111f..b805f4277b 100644
--- a/src/python/grpcio/commands.py
+++ b/src/python/grpcio/commands.py
@@ -39,36 +39,6 @@ PROTO_STEM = os.path.join(GRPC_STEM, 'src', 'proto')
 PROTO_GEN_STEM = os.path.join(GRPC_STEM, 'src', 'python', 'gens')
 CYTHON_STEM = os.path.join(PYTHON_STEM, 'grpc', '_cython')
 
-CONF_PY_ADDENDUM = """
-extensions.append('sphinx.ext.napoleon')
-napoleon_google_docstring = True
-napoleon_numpy_docstring = True
-napoleon_include_special_with_doc = True
-
-html_theme = 'sphinx_rtd_theme'
-copyright = "2016, The gRPC Authors"
-"""
-
-API_GLOSSARY = """
-
-Glossary
-================
-
-.. glossary::
-
-  metadatum
-    A key-value pair included in the HTTP header.  It is a 
-    2-tuple where the first entry is the key and the
-    second is the value, i.e. (key, value).  The metadata key is an ASCII str,
-    and must be a valid HTTP header name.  The metadata value can be
-    either a valid HTTP ASCII str, or bytes.  If bytes are provided,
-    the key must end with '-bin', i.e.
-    ``('binary-metadata-bin', b'\\x00\\xFF')``
-
-  metadata
-    A sequence of metadatum.
-"""
-
 
 class CommandError(Exception):
     """Simple exception class for GRPC custom commands."""
@@ -124,25 +94,14 @@ class SphinxDocumentation(setuptools.Command):
     def run(self):
         # We import here to ensure that setup.py has had a chance to install the
         # relevant package eggs first.
-        import sphinx
-        import sphinx.apidoc
-        metadata = self.distribution.metadata
-        src_dir = os.path.join(PYTHON_STEM, 'grpc')
-        sys.path.append(src_dir)
-        sphinx.apidoc.main([
-            '', '--force', '--full', '-H', metadata.name, '-A', metadata.author,
-            '-V', metadata.version, '-R', metadata.version, '-o',
-            os.path.join('doc', 'src'), src_dir
-        ])
-        conf_filepath = os.path.join('doc', 'src', 'conf.py')
-        with open(conf_filepath, 'a') as conf_file:
-            conf_file.write(CONF_PY_ADDENDUM)
-        glossary_filepath = os.path.join('doc', 'src', 'grpc.rst')
-        with open(glossary_filepath, 'a') as glossary_filepath:
-            glossary_filepath.write(API_GLOSSARY)
-        sphinx.main(
-            ['', os.path.join('doc', 'src'),
-             os.path.join('doc', 'build')])
+        import sphinx.cmd.build
+        source_dir = os.path.join(GRPC_STEM, 'doc', 'python', 'sphinx')
+        target_dir = os.path.join(GRPC_STEM, 'doc', 'build')
+        exit_code = sphinx.cmd.build.build_main(
+            ['-b', 'html', '-W', '--keep-going', source_dir, target_dir])
+        if exit_code is not 0:
+            raise CommandError(
+                "Documentation generation has warnings or errors")
 
 
 class BuildProjectMetadata(setuptools.Command):
@@ -253,6 +212,12 @@ class BuildExt(build_ext.build_ext):
     LINK_OPTIONS = {}
 
     def build_extensions(self):
+        # This special conditioning is here due to difference of compiler
+        #   behavior in gcc and clang. The clang doesn't take --stdc++11
+        #   flags but gcc does. Since the setuptools of Python only support
+        #   all C or all C++ compilation, the mix of C and C++ will crash.
+        #   *By default*, the macOS use clang and Linux use gcc, that's why
+        #   the special condition here is checking platform.
         if "darwin" in sys.platform:
             config = os.environ.get('CONFIG', 'opt')
             target_path = os.path.abspath(
@@ -274,8 +239,14 @@ class BuildExt(build_ext.build_ext):
             extra_defines = [
                 'EXTRA_DEFINES="GRPC_POSIX_FORK_ALLOW_PTHREAD_ATFORK=1"'
             ]
+            # Ensure the BoringSSL are built instead of using system provided
+            #   libraries. It prevents dependency issues while distributing to
+            #   Mac users who use MacPorts to manage their libraries. #17002
+            mod_env = dict(os.environ)
+            mod_env['REQUIRE_CUSTOM_LIBRARIES_opt'] = '1'
             make_process = subprocess.Popen(
                 ['make'] + extra_defines + targets,
+                env=mod_env,
                 stdout=subprocess.PIPE,
                 stderr=subprocess.PIPE)
             make_out, make_err = make_process.communicate()
diff --git a/src/python/grpcio/grpc/BUILD.bazel b/src/python/grpcio/grpc/BUILD.bazel
index 3f214bf3b0..2e6839ef2d 100644
--- a/src/python/grpcio/grpc/BUILD.bazel
+++ b/src/python/grpcio/grpc/BUILD.bazel
@@ -2,7 +2,7 @@ load("@grpc_python_dependencies//:requirements.bzl", "requirement")
 
 package(default_visibility = ["//visibility:public"])
 
-py_binary(
+py_library(
     name = "grpcio",
     srcs = ["__init__.py"],
     deps = [
@@ -22,7 +22,6 @@ py_binary(
     data = [
         "//:grpc",
     ],
-    main = "__init__.py",
     imports = ["../",],
 )
 
diff --git a/src/python/grpcio/grpc/__init__.py b/src/python/grpcio/grpc/__init__.py
index 863696d236..88c5b6d5be 100644
--- a/src/python/grpcio/grpc/__init__.py
+++ b/src/python/grpcio/grpc/__init__.py
@@ -15,12 +15,14 @@
 
 import abc
 import enum
+import logging
 import sys
-
 import six
 
 from grpc._cython import cygrpc as _cygrpc
 
+logging.getLogger(__name__).addHandler(logging.NullHandler())
+
 ############################## Future Interface  ###############################
 
 
@@ -48,11 +50,13 @@ class Future(six.with_metaclass(abc.ABCMeta)):
         Returns:
             bool:
             Returns True if the computation was canceled.
+
             Returns False under all other circumstances, for example:
+
             1. computation has begun and could not be canceled.
             2. computation has finished
             3. computation is scheduled for execution and it is impossible
-              to determine its state without blocking.
+                to determine its state without blocking.
         """
         raise NotImplementedError()
 
@@ -66,7 +70,9 @@ class Future(six.with_metaclass(abc.ABCMeta)):
             bool:
             Returns True if the computation was cancelled before its result became
             available.
-            False under all other circumstances, for example:
+
+            Returns False under all other circumstances, for example:
+
             1. computation was not cancelled.
             2. computation's result is available.
         """
@@ -79,9 +85,9 @@ class Future(six.with_metaclass(abc.ABCMeta)):
         This method does not block.
 
         Returns:
-            bool:
             Returns True if the computation is scheduled for execution or
             currently executing.
+
             Returns False if the computation already executed or was cancelled.
         """
         raise NotImplementedError()
@@ -210,7 +216,33 @@ class ChannelConnectivity(enum.Enum):
 
 @enum.unique
 class StatusCode(enum.Enum):
-    """Mirrors grpc_status_code in the gRPC Core."""
+    """Mirrors grpc_status_code in the gRPC Core.
+
+    Attributes:
+      OK: Not an error; returned on success
+      CANCELLED: The operation was cancelled (typically by the caller).
+      UNKNOWN: Unknown error.
+      INVALID_ARGUMENT: Client specified an invalid argument.
+      DEADLINE_EXCEEDED: Deadline expired before operation could complete.
+      NOT_FOUND: Some requested entity (e.g., file or directory) was not found.
+      ALREADY_EXISTS: Some entity that we attempted to create (e.g., file or directory)
+        already exists.
+      PERMISSION_DENIED: The caller does not have permission to execute the specified
+        operation.
+      UNAUTHENTICATED: The request does not have valid authentication credentials for the
+        operation.
+      RESOURCE_EXHAUSTED: Some resource has been exhausted, perhaps a per-user quota, or
+        perhaps the entire file system is out of space.
+      FAILED_PRECONDITION: Operation was rejected because the system is not in a state
+        required for the operation's execution.
+      ABORTED: The operation was aborted, typically due to a concurrency issue
+        like sequencer check failures, transaction aborts, etc.
+      UNIMPLEMENTED: Operation is not implemented or not supported/enabled in this service.
+      INTERNAL: Internal errors.  Means some invariants expected by underlying
+        system has been broken.
+      UNAVAILABLE: The service is currently unavailable.
+      DATA_LOSS: Unrecoverable data loss or corruption.
+    """
     OK = (_cygrpc.StatusCode.ok, 'ok')
     CANCELLED = (_cygrpc.StatusCode.cancelled, 'cancelled')
     UNKNOWN = (_cygrpc.StatusCode.unknown, 'unknown')
@@ -357,6 +389,8 @@ class ClientCallDetails(six.with_metaclass(abc.ABCMeta)):
       metadata: Optional :term:`metadata` to be transmitted to
         the service-side of the RPC.
       credentials: An optional CallCredentials for the RPC.
+      wait_for_ready: This is an EXPERIMENTAL argument. An optional flag t
+        enable wait for ready mechanism.
     """
 
 
@@ -450,8 +484,7 @@ class StreamUnaryClientInterceptor(six.with_metaclass(abc.ABCMeta)):
             actual RPC on the underlying Channel. It is the interceptor's
             responsibility to call it if it decides to move the RPC forward.
             The interceptor can use
-            `response_future = continuation(client_call_details,
-                                            request_iterator)`
+            `response_future = continuation(client_call_details, request_iterator)`
             to continue with the RPC. `continuation` returns an object that is
             both a Call for the RPC and a Future. In the event of RPC completion,
             the return Call-Future's result value will be the response message
@@ -462,11 +495,11 @@ class StreamUnaryClientInterceptor(six.with_metaclass(abc.ABCMeta)):
           request_iterator: An iterator that yields request values for the RPC.
 
         Returns:
-            An object that is both a Call for the RPC and a Future.
-            In the event of RPC completion, the return Call-Future's
-            result value will be the response message of the RPC.
-            Should the event terminate with non-OK status, the returned
-            Call-Future's exception value will be an RpcError.
+          An object that is both a Call for the RPC and a Future.
+          In the event of RPC completion, the return Call-Future's
+          result value will be the response message of the RPC.
+          Should the event terminate with non-OK status, the returned
+          Call-Future's exception value will be an RpcError.
         """
         raise NotImplementedError()
 
@@ -482,13 +515,13 @@ class StreamStreamClientInterceptor(six.with_metaclass(abc.ABCMeta)):
                                 request_iterator):
         """Intercepts a stream-stream invocation.
 
+        Args:
           continuation: A function that proceeds with the invocation by
             executing the next interceptor in chain or invoking the
             actual RPC on the underlying Channel. It is the interceptor's
             responsibility to call it if it decides to move the RPC forward.
             The interceptor can use
-            `response_iterator = continuation(client_call_details,
-                                              request_iterator)`
+            `response_iterator = continuation(client_call_details, request_iterator)`
             to continue with the RPC. `continuation` returns an object that is
             both a Call for the RPC and an iterator for response values.
             Drawing response values from the returned Call-iterator may
@@ -499,10 +532,10 @@ class StreamStreamClientInterceptor(six.with_metaclass(abc.ABCMeta)):
           request_iterator: An iterator that yields request values for the RPC.
 
         Returns:
-            An object that is both a Call for the RPC and an iterator of
-            response values. Drawing response values from the returned
-            Call-iterator may raise RpcError indicating termination of
-            the RPC with non-OK status.
+          An object that is both a Call for the RPC and an iterator of
+          response values. Drawing response values from the returned
+          Call-iterator may raise RpcError indicating termination of
+          the RPC with non-OK status.
         """
         raise NotImplementedError()
 
@@ -609,7 +642,12 @@ class UnaryUnaryMultiCallable(six.with_metaclass(abc.ABCMeta)):
     """Affords invoking a unary-unary RPC from client-side."""
 
     @abc.abstractmethod
-    def __call__(self, request, timeout=None, metadata=None, credentials=None):
+    def __call__(self,
+                 request,
+                 timeout=None,
+                 metadata=None,
+                 credentials=None,
+                 wait_for_ready=None):
         """Synchronously invokes the underlying RPC.
 
         Args:
@@ -619,6 +657,8 @@ class UnaryUnaryMultiCallable(six.with_metaclass(abc.ABCMeta)):
           metadata: Optional :term:`metadata` to be transmitted to the
             service-side of the RPC.
           credentials: An optional CallCredentials for the RPC.
+          wait_for_ready: This is an EXPERIMENTAL argument. An optional
+            flag to enable wait for ready mechanism
 
         Returns:
           The response value for the RPC.
@@ -631,7 +671,12 @@ class UnaryUnaryMultiCallable(six.with_metaclass(abc.ABCMeta)):
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def with_call(self, request, timeout=None, metadata=None, credentials=None):
+    def with_call(self,
+                  request,
+                  timeout=None,
+                  metadata=None,
+                  credentials=None,
+                  wait_for_ready=None):
         """Synchronously invokes the underlying RPC.
 
         Args:
@@ -641,6 +686,8 @@ class UnaryUnaryMultiCallable(six.with_metaclass(abc.ABCMeta)):
           metadata: Optional :term:`metadata` to be transmitted to the
             service-side of the RPC.
           credentials: An optional CallCredentials for the RPC.
+          wait_for_ready: This is an EXPERIMENTAL argument. An optional
+            flag to enable wait for ready mechanism
 
         Returns:
           The response value for the RPC and a Call value for the RPC.
@@ -653,7 +700,12 @@ class UnaryUnaryMultiCallable(six.with_metaclass(abc.ABCMeta)):
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def future(self, request, timeout=None, metadata=None, credentials=None):
+    def future(self,
+               request,
+               timeout=None,
+               metadata=None,
+               credentials=None,
+               wait_for_ready=None):
         """Asynchronously invokes the underlying RPC.
 
         Args:
@@ -663,6 +715,8 @@ class UnaryUnaryMultiCallable(six.with_metaclass(abc.ABCMeta)):
           metadata: Optional :term:`metadata` to be transmitted to the
             service-side of the RPC.
           credentials: An optional CallCredentials for the RPC.
+          wait_for_ready: This is an EXPERIMENTAL argument. An optional
+            flag to enable wait for ready mechanism
 
         Returns:
             An object that is both a Call for the RPC and a Future.
@@ -678,7 +732,12 @@ class UnaryStreamMultiCallable(six.with_metaclass(abc.ABCMeta)):
     """Affords invoking a unary-stream RPC from client-side."""
 
     @abc.abstractmethod
-    def __call__(self, request, timeout=None, metadata=None, credentials=None):
+    def __call__(self,
+                 request,
+                 timeout=None,
+                 metadata=None,
+                 credentials=None,
+                 wait_for_ready=None):
         """Invokes the underlying RPC.
 
         Args:
@@ -688,6 +747,8 @@ class UnaryStreamMultiCallable(six.with_metaclass(abc.ABCMeta)):
           metadata: An optional :term:`metadata` to be transmitted to the
             service-side of the RPC.
           credentials: An optional CallCredentials for the RPC.
+          wait_for_ready: This is an EXPERIMENTAL argument. An optional
+            flag to enable wait for ready mechanism
 
         Returns:
             An object that is both a Call for the RPC and an iterator of
@@ -706,7 +767,8 @@ class StreamUnaryMultiCallable(six.with_metaclass(abc.ABCMeta)):
                  request_iterator,
                  timeout=None,
                  metadata=None,
-                 credentials=None):
+                 credentials=None,
+                 wait_for_ready=None):
         """Synchronously invokes the underlying RPC.
 
         Args:
@@ -717,6 +779,8 @@ class StreamUnaryMultiCallable(six.with_metaclass(abc.ABCMeta)):
           metadata: Optional :term:`metadata` to be transmitted to the
             service-side of the RPC.
           credentials: An optional CallCredentials for the RPC.
+          wait_for_ready: This is an EXPERIMENTAL argument. An optional
+            flag to enable wait for ready mechanism
 
         Returns:
           The response value for the RPC.
@@ -733,7 +797,8 @@ class StreamUnaryMultiCallable(six.with_metaclass(abc.ABCMeta)):
                   request_iterator,
                   timeout=None,
                   metadata=None,
-                  credentials=None):
+                  credentials=None,
+                  wait_for_ready=None):
         """Synchronously invokes the underlying RPC on the client.
 
         Args:
@@ -744,6 +809,8 @@ class StreamUnaryMultiCallable(six.with_metaclass(abc.ABCMeta)):
           metadata: Optional :term:`metadata` to be transmitted to the
             service-side of the RPC.
           credentials: An optional CallCredentials for the RPC.
+          wait_for_ready: This is an EXPERIMENTAL argument. An optional
+            flag to enable wait for ready mechanism
 
         Returns:
           The response value for the RPC and a Call object for the RPC.
@@ -760,7 +827,8 @@ class StreamUnaryMultiCallable(six.with_metaclass(abc.ABCMeta)):
                request_iterator,
                timeout=None,
                metadata=None,
-               credentials=None):
+               credentials=None,
+               wait_for_ready=None):
         """Asynchronously invokes the underlying RPC on the client.
 
         Args:
@@ -770,6 +838,8 @@ class StreamUnaryMultiCallable(six.with_metaclass(abc.ABCMeta)):
           metadata: Optional :term:`metadata` to be transmitted to the
             service-side of the RPC.
           credentials: An optional CallCredentials for the RPC.
+          wait_for_ready: This is an EXPERIMENTAL argument. An optional
+            flag to enable wait for ready mechanism
 
         Returns:
             An object that is both a Call for the RPC and a Future.
@@ -789,7 +859,8 @@ class StreamStreamMultiCallable(six.with_metaclass(abc.ABCMeta)):
                  request_iterator,
                  timeout=None,
                  metadata=None,
-                 credentials=None):
+                 credentials=None,
+                 wait_for_ready=None):
         """Invokes the underlying RPC on the client.
 
         Args:
@@ -799,6 +870,8 @@ class StreamStreamMultiCallable(six.with_metaclass(abc.ABCMeta)):
           metadata: Optional :term:`metadata` to be transmitted to the
             service-side of the RPC.
           credentials: An optional CallCredentials for the RPC.
+          wait_for_ready: This is an EXPERIMENTAL argument. An optional
+            flag to enable wait for ready mechanism
 
         Returns:
             An object that is both a Call for the RPC and an iterator of
@@ -972,8 +1045,7 @@ class ServicerContext(six.with_metaclass(abc.ABCMeta, RpcContext)):
         """Gets one or more peer identity(s).
 
         Equivalent to
-        servicer_context.auth_context().get(
-            servicer_context.peer_identity_key())
+        servicer_context.auth_context().get(servicer_context.peer_identity_key())
 
         Returns:
           An iterable of the identities, or None if the call is not
diff --git a/src/python/grpcio/grpc/_channel.py b/src/python/grpcio/grpc/_channel.py
index 6876601785..ab154d8512 100644
--- a/src/python/grpcio/grpc/_channel.py
+++ b/src/python/grpcio/grpc/_channel.py
@@ -466,10 +466,11 @@ def _end_unary_response_blocking(state, call, with_call, deadline):
         raise _Rendezvous(state, None, None, deadline)
 
 
-def _stream_unary_invocation_operationses(metadata):
+def _stream_unary_invocation_operationses(metadata, initial_metadata_flags):
     return (
         (
-            cygrpc.SendInitialMetadataOperation(metadata, _EMPTY_FLAGS),
+            cygrpc.SendInitialMetadataOperation(metadata,
+                                                initial_metadata_flags),
             cygrpc.ReceiveMessageOperation(_EMPTY_FLAGS),
             cygrpc.ReceiveStatusOnClientOperation(_EMPTY_FLAGS),
         ),
@@ -477,15 +478,19 @@ def _stream_unary_invocation_operationses(metadata):
     )
 
 
-def _stream_unary_invocation_operationses_and_tags(metadata):
+def _stream_unary_invocation_operationses_and_tags(metadata,
+                                                   initial_metadata_flags):
     return tuple((
         operations,
         None,
-    ) for operations in _stream_unary_invocation_operationses(metadata))
+    )
+                 for operations in _stream_unary_invocation_operationses(
+                     metadata, initial_metadata_flags))
 
 
 class _UnaryUnaryMultiCallable(grpc.UnaryUnaryMultiCallable):
 
+    # pylint: disable=too-many-arguments
     def __init__(self, channel, managed_call, method, request_serializer,
                  response_deserializer):
         self._channel = channel
@@ -494,15 +499,18 @@ class _UnaryUnaryMultiCallable(grpc.UnaryUnaryMultiCallable):
         self._request_serializer = request_serializer
         self._response_deserializer = response_deserializer
 
-    def _prepare(self, request, timeout, metadata):
+    def _prepare(self, request, timeout, metadata, wait_for_ready):
         deadline, serialized_request, rendezvous = _start_unary_request(
             request, timeout, self._request_serializer)
+        initial_metadata_flags = _InitialMetadataFlags().with_wait_for_ready(
+            wait_for_ready)
         if serialized_request is None:
             return None, None, None, rendezvous
         else:
             state = _RPCState(_UNARY_UNARY_INITIAL_DUE, None, None, None, None)
             operations = (
-                cygrpc.SendInitialMetadataOperation(metadata, _EMPTY_FLAGS),
+                cygrpc.SendInitialMetadataOperation(metadata,
+                                                    initial_metadata_flags),
                 cygrpc.SendMessageOperation(serialized_request, _EMPTY_FLAGS),
                 cygrpc.SendCloseFromClientOperation(_EMPTY_FLAGS),
                 cygrpc.ReceiveInitialMetadataOperation(_EMPTY_FLAGS),
@@ -511,9 +519,10 @@ class _UnaryUnaryMultiCallable(grpc.UnaryUnaryMultiCallable):
             )
             return state, operations, deadline, None
 
-    def _blocking(self, request, timeout, metadata, credentials):
+    def _blocking(self, request, timeout, metadata, credentials,
+                  wait_for_ready):
         state, operations, deadline, rendezvous = self._prepare(
-            request, timeout, metadata)
+            request, timeout, metadata, wait_for_ready)
         if state is None:
             raise rendezvous
         else:
@@ -527,17 +536,34 @@ class _UnaryUnaryMultiCallable(grpc.UnaryUnaryMultiCallable):
             _handle_event(event, state, self._response_deserializer)
             return state, call,
 
-    def __call__(self, request, timeout=None, metadata=None, credentials=None):
-        state, call, = self._blocking(request, timeout, metadata, credentials)
+    def __call__(self,
+                 request,
+                 timeout=None,
+                 metadata=None,
+                 credentials=None,
+                 wait_for_ready=None):
+        state, call, = self._blocking(request, timeout, metadata, credentials,
+                                      wait_for_ready)
         return _end_unary_response_blocking(state, call, False, None)
 
-    def with_call(self, request, timeout=None, metadata=None, credentials=None):
-        state, call, = self._blocking(request, timeout, metadata, credentials)
+    def with_call(self,
+                  request,
+                  timeout=None,
+                  metadata=None,
+                  credentials=None,
+                  wait_for_ready=None):
+        state, call, = self._blocking(request, timeout, metadata, credentials,
+                                      wait_for_ready)
         return _end_unary_response_blocking(state, call, True, None)
 
-    def future(self, request, timeout=None, metadata=None, credentials=None):
+    def future(self,
+               request,
+               timeout=None,
+               metadata=None,
+               credentials=None,
+               wait_for_ready=None):
         state, operations, deadline, rendezvous = self._prepare(
-            request, timeout, metadata)
+            request, timeout, metadata, wait_for_ready)
         if state is None:
             raise rendezvous
         else:
@@ -552,6 +578,7 @@ class _UnaryUnaryMultiCallable(grpc.UnaryUnaryMultiCallable):
 
 class _UnaryStreamMultiCallable(grpc.UnaryStreamMultiCallable):
 
+    # pylint: disable=too-many-arguments
     def __init__(self, channel, managed_call, method, request_serializer,
                  response_deserializer):
         self._channel = channel
@@ -560,16 +587,24 @@ class _UnaryStreamMultiCallable(grpc.UnaryStreamMultiCallable):
         self._request_serializer = request_serializer
         self._response_deserializer = response_deserializer
 
-    def __call__(self, request, timeout=None, metadata=None, credentials=None):
+    def __call__(self,
+                 request,
+                 timeout=None,
+                 metadata=None,
+                 credentials=None,
+                 wait_for_ready=None):
         deadline, serialized_request, rendezvous = _start_unary_request(
             request, timeout, self._request_serializer)
+        initial_metadata_flags = _InitialMetadataFlags().with_wait_for_ready(
+            wait_for_ready)
         if serialized_request is None:
             raise rendezvous
         else:
             state = _RPCState(_UNARY_STREAM_INITIAL_DUE, None, None, None, None)
             operationses = (
                 (
-                    cygrpc.SendInitialMetadataOperation(metadata, _EMPTY_FLAGS),
+                    cygrpc.SendInitialMetadataOperation(metadata,
+                                                        initial_metadata_flags),
                     cygrpc.SendMessageOperation(serialized_request,
                                                 _EMPTY_FLAGS),
                     cygrpc.SendCloseFromClientOperation(_EMPTY_FLAGS),
@@ -588,6 +623,7 @@ class _UnaryStreamMultiCallable(grpc.UnaryStreamMultiCallable):
 
 class _StreamUnaryMultiCallable(grpc.StreamUnaryMultiCallable):
 
+    # pylint: disable=too-many-arguments
     def __init__(self, channel, managed_call, method, request_serializer,
                  response_deserializer):
         self._channel = channel
@@ -596,13 +632,17 @@ class _StreamUnaryMultiCallable(grpc.StreamUnaryMultiCallable):
         self._request_serializer = request_serializer
         self._response_deserializer = response_deserializer
 
-    def _blocking(self, request_iterator, timeout, metadata, credentials):
+    def _blocking(self, request_iterator, timeout, metadata, credentials,
+                  wait_for_ready):
         deadline = _deadline(timeout)
         state = _RPCState(_STREAM_UNARY_INITIAL_DUE, None, None, None, None)
+        initial_metadata_flags = _InitialMetadataFlags().with_wait_for_ready(
+            wait_for_ready)
         call = self._channel.segregated_call(
             0, self._method, None, deadline, metadata, None
             if credentials is None else credentials._credentials,
-            _stream_unary_invocation_operationses_and_tags(metadata))
+            _stream_unary_invocation_operationses_and_tags(
+                metadata, initial_metadata_flags))
         _consume_request_iterator(request_iterator, state, call,
                                   self._request_serializer, None)
         while True:
@@ -618,32 +658,38 @@ class _StreamUnaryMultiCallable(grpc.StreamUnaryMultiCallable):
                  request_iterator,
                  timeout=None,
                  metadata=None,
-                 credentials=None):
+                 credentials=None,
+                 wait_for_ready=None):
         state, call, = self._blocking(request_iterator, timeout, metadata,
-                                      credentials)
+                                      credentials, wait_for_ready)
         return _end_unary_response_blocking(state, call, False, None)
 
     def with_call(self,
                   request_iterator,
                   timeout=None,
                   metadata=None,
-                  credentials=None):
+                  credentials=None,
+                  wait_for_ready=None):
         state, call, = self._blocking(request_iterator, timeout, metadata,
-                                      credentials)
+                                      credentials, wait_for_ready)
         return _end_unary_response_blocking(state, call, True, None)
 
     def future(self,
                request_iterator,
                timeout=None,
                metadata=None,
-               credentials=None):
+               credentials=None,
+               wait_for_ready=None):
         deadline = _deadline(timeout)
         state = _RPCState(_STREAM_UNARY_INITIAL_DUE, None, None, None, None)
         event_handler = _event_handler(state, self._response_deserializer)
+        initial_metadata_flags = _InitialMetadataFlags().with_wait_for_ready(
+            wait_for_ready)
         call = self._managed_call(
             0, self._method, None, deadline, metadata, None
             if credentials is None else credentials._credentials,
-            _stream_unary_invocation_operationses(metadata), event_handler)
+            _stream_unary_invocation_operationses(
+                metadata, initial_metadata_flags), event_handler)
         _consume_request_iterator(request_iterator, state, call,
                                   self._request_serializer, event_handler)
         return _Rendezvous(state, call, self._response_deserializer, deadline)
@@ -651,6 +697,7 @@ class _StreamUnaryMultiCallable(grpc.StreamUnaryMultiCallable):
 
 class _StreamStreamMultiCallable(grpc.StreamStreamMultiCallable):
 
+    # pylint: disable=too-many-arguments
     def __init__(self, channel, managed_call, method, request_serializer,
                  response_deserializer):
         self._channel = channel
@@ -663,12 +710,16 @@ class _StreamStreamMultiCallable(grpc.StreamStreamMultiCallable):
                  request_iterator,
                  timeout=None,
                  metadata=None,
-                 credentials=None):
+                 credentials=None,
+                 wait_for_ready=None):
         deadline = _deadline(timeout)
         state = _RPCState(_STREAM_STREAM_INITIAL_DUE, None, None, None, None)
+        initial_metadata_flags = _InitialMetadataFlags().with_wait_for_ready(
+            wait_for_ready)
         operationses = (
             (
-                cygrpc.SendInitialMetadataOperation(metadata, _EMPTY_FLAGS),
+                cygrpc.SendInitialMetadataOperation(metadata,
+                                                    initial_metadata_flags),
                 cygrpc.ReceiveStatusOnClientOperation(_EMPTY_FLAGS),
             ),
             (cygrpc.ReceiveInitialMetadataOperation(_EMPTY_FLAGS),),
@@ -683,6 +734,24 @@ class _StreamStreamMultiCallable(grpc.StreamStreamMultiCallable):
         return _Rendezvous(state, call, self._response_deserializer, deadline)
 
 
+class _InitialMetadataFlags(int):
+    """Stores immutable initial metadata flags"""
+
+    def __new__(cls, value=_EMPTY_FLAGS):
+        value &= cygrpc.InitialMetadataFlags.used_mask
+        return super(_InitialMetadataFlags, cls).__new__(cls, value)
+
+    def with_wait_for_ready(self, wait_for_ready):
+        if wait_for_ready is not None:
+            if wait_for_ready:
+                self = self.__class__(self | cygrpc.InitialMetadataFlags.wait_for_ready | \
+                    cygrpc.InitialMetadataFlags.wait_for_ready_explicitly_set)
+            elif not wait_for_ready:
+                self = self.__class__(self & ~cygrpc.InitialMetadataFlags.wait_for_ready | \
+                    cygrpc.InitialMetadataFlags.wait_for_ready_explicitly_set)
+        return self
+
+
 class _ChannelCallState(object):
 
     def __init__(self, channel):
@@ -979,5 +1048,9 @@ class Channel(grpc.Channel):
         # for as long as they are in use and to close them after using them,
         # then deletion of this grpc._channel.Channel instance can be made to
         # effect closure of the underlying cygrpc.Channel instance.
-        cygrpc.fork_unregister_channel(self)
-        _moot(self._connectivity_state)
+        if cygrpc is not None:  # Globals may have already been collected.
+            cygrpc.fork_unregister_channel(self)
+        # This prevent the failed-at-initializing object removal from failing.
+        # Though the __init__ failed, the removal will still trigger __del__.
+        if _moot is not None and hasattr(self, "_connectivity_state"):
+            _moot(self._connectivity_state)
diff --git a/src/python/grpcio/grpc/_common.py b/src/python/grpcio/grpc/_common.py
index 8358cbec5b..f69127e38e 100644
--- a/src/python/grpcio/grpc/_common.py
+++ b/src/python/grpcio/grpc/_common.py
@@ -65,18 +65,13 @@ def encode(s):
     if isinstance(s, bytes):
         return s
     else:
-        return s.encode('ascii')
+        return s.encode('utf8')
 
 
 def decode(b):
-    if isinstance(b, str):
-        return b
-    else:
-        try:
-            return b.decode('utf8')
-        except UnicodeDecodeError:
-            _LOGGER.exception('Invalid encoding on %s', b)
-            return b.decode('latin1')
+    if isinstance(b, bytes):
+        return b.decode('utf-8', 'replace')
+    return b
 
 
 def _transform(message, transformer, exception_message):
diff --git a/src/python/grpcio/grpc/_cython/BUILD.bazel b/src/python/grpcio/grpc/_cython/BUILD.bazel
index 7124e83dee..cfd3a51d9b 100644
--- a/src/python/grpcio/grpc/_cython/BUILD.bazel
+++ b/src/python/grpcio/grpc/_cython/BUILD.bazel
@@ -8,6 +8,7 @@ pyx_library(
         "__init__.py",
         "cygrpc.pxd",
         "cygrpc.pyx",
+        "_cygrpc/_hooks.pyx.pxi",
         "_cygrpc/grpc_string.pyx.pxi",
         "_cygrpc/arguments.pyx.pxi",
         "_cygrpc/call.pyx.pxi",
@@ -15,6 +16,7 @@ pyx_library(
         "_cygrpc/credentials.pyx.pxi",
         "_cygrpc/completion_queue.pyx.pxi",
         "_cygrpc/event.pyx.pxi",
+        "_cygrpc/fork_posix.pyx.pxi",
         "_cygrpc/metadata.pyx.pxi",
         "_cygrpc/operation.pyx.pxi",
         "_cygrpc/records.pyx.pxi",
@@ -24,12 +26,14 @@ pyx_library(
         "_cygrpc/time.pyx.pxi",
         "_cygrpc/grpc_gevent.pyx.pxi",
         "_cygrpc/grpc.pxi",
+        "_cygrpc/_hooks.pxd.pxi",
         "_cygrpc/arguments.pxd.pxi",
         "_cygrpc/call.pxd.pxi",
         "_cygrpc/channel.pxd.pxi",
         "_cygrpc/credentials.pxd.pxi",
         "_cygrpc/completion_queue.pxd.pxi",
         "_cygrpc/event.pxd.pxi",
+        "_cygrpc/fork_posix.pxd.pxi",
         "_cygrpc/metadata.pxd.pxi",
         "_cygrpc/operation.pxd.pxi",
         "_cygrpc/records.pxd.pxi",
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pxd.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pxd.pxi
index 6cb1bc0c05..e0e068e452 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pxd.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pxd.pxi
@@ -32,7 +32,7 @@ cdef class _ArgumentProcessor:
 
   cdef grpc_arg c_argument
 
-  cdef void c(self, argument, grpc_arg_pointer_vtable *vtable, references)
+  cdef void c(self, argument, grpc_arg_pointer_vtable *vtable, references) except *
 
 
 cdef class _ArgumentsProcessor:
@@ -42,5 +42,5 @@ cdef class _ArgumentsProcessor:
   cdef readonly list _references
   cdef grpc_channel_args _c_arguments
 
-  cdef grpc_channel_args *c(self, grpc_arg_pointer_vtable *vtable)
+  cdef grpc_channel_args *c(self, grpc_arg_pointer_vtable *vtable) except *
   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
index 2239e26b32..b7a4277ff6 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pyx.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pyx.pxi
@@ -52,7 +52,7 @@ cdef grpc_arg _unwrap_grpc_arg(tuple wrapped_arg):
 
 cdef class _ArgumentProcessor:
 
-  cdef void c(self, argument, grpc_arg_pointer_vtable *vtable, references):
+  cdef void c(self, argument, grpc_arg_pointer_vtable *vtable, references) except *:
     key, value = argument
     cdef bytes encoded_key = _encode(key)
     if encoded_key is not key:
@@ -89,7 +89,7 @@ cdef class _ArgumentsProcessor:
     self._argument_processors = []
     self._references = []
 
-  cdef grpc_channel_args *c(self, grpc_arg_pointer_vtable *vtable):
+  cdef grpc_channel_args *c(self, grpc_arg_pointer_vtable *vtable) except *:
     self._c_arguments.arguments_length = len(self._arguments)
     if self._c_arguments.arguments_length == 0:
       return NULL
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pyx.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pyx.pxi
index 38fd9e78b2..63048e8da0 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pyx.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pyx.pxi
@@ -144,8 +144,14 @@ cdef class SSLChannelCredentials(ChannelCredentials):
       return grpc_ssl_credentials_create(
           c_pem_root_certificates, NULL, NULL, NULL)
     else:
-      c_pem_key_certificate_pair.private_key = self._private_key
-      c_pem_key_certificate_pair.certificate_chain = self._certificate_chain
+      if self._private_key:
+        c_pem_key_certificate_pair.private_key = self._private_key
+      else:
+        c_pem_key_certificate_pair.private_key = NULL
+      if self._certificate_chain:
+        c_pem_key_certificate_pair.certificate_chain = self._certificate_chain
+      else:
+        c_pem_key_certificate_pair.certificate_chain = NULL
       return grpc_ssl_credentials_create(
           c_pem_root_certificates, &c_pem_key_certificate_pair, NULL, NULL)
 
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi
index 4781219319..23428f0b0c 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi
@@ -140,6 +140,10 @@ cdef extern from "grpc/grpc.h":
   const int GRPC_WRITE_NO_COMPRESS
   const int GRPC_WRITE_USED_MASK
 
+  const int GRPC_INITIAL_METADATA_WAIT_FOR_READY
+  const int GRPC_INITIAL_METADATA_WAIT_FOR_READY_EXPLICITLY_SET
+  const int GRPC_INITIAL_METADATA_USED_MASK
+
   const int GRPC_MAX_COMPLETION_QUEUE_PLUCKERS
 
   ctypedef struct grpc_completion_queue:
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/metadata.pyx.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/metadata.pyx.pxi
index c39fef08fa..53f0c7f0bb 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/metadata.pyx.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/metadata.pyx.pxi
@@ -15,6 +15,12 @@
 import collections
 
 
+class InitialMetadataFlags:
+  used_mask = GRPC_INITIAL_METADATA_USED_MASK
+  wait_for_ready = GRPC_INITIAL_METADATA_WAIT_FOR_READY
+  wait_for_ready_explicitly_set = GRPC_INITIAL_METADATA_WAIT_FOR_READY_EXPLICITLY_SET
+
+
 _Metadatum = collections.namedtuple('_Metadatum', ('key', 'value',))
 
 
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/security.pyx.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/security.pyx.pxi
index 7decae95bb..e17ca6d335 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/security.pyx.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/security.pyx.pxi
@@ -14,14 +14,16 @@
 
 from libc.string cimport memcpy
 
-import pkg_resources
+import pkgutil
 
 
 cdef grpc_ssl_roots_override_result ssl_roots_override_callback(
     char **pem_root_certs) nogil:
   with gil:
-    temporary_pem_root_certs = pkg_resources.resource_string(
-        __name__.rstrip('.cygrpc'), '_credentials/roots.pem')
+    pkg = __name__
+    if pkg.endswith('.cygrpc'):
+      pkg = pkg[:-len('.cygrpc')]
+    temporary_pem_root_certs = pkgutil.get_data(pkg, '_credentials/roots.pem')
     pem_root_certs[0] = <char *>gpr_malloc(len(temporary_pem_root_certs) + 1)
     memcpy(
         pem_root_certs[0], <char *>temporary_pem_root_certs,
diff --git a/src/python/grpcio/grpc/_cython/cygrpc.pyx b/src/python/grpcio/grpc/_cython/cygrpc.pyx
index 026f7ba2e3..ae5c07bfc8 100644
--- a/src/python/grpcio/grpc/_cython/cygrpc.pyx
+++ b/src/python/grpcio/grpc/_cython/cygrpc.pyx
@@ -15,7 +15,6 @@
 
 cimport cpython
 
-import pkg_resources
 import os.path
 import sys
 
diff --git a/src/python/grpcio/grpc/_grpcio_metadata.py b/src/python/grpcio/grpc/_grpcio_metadata.py
index c33911ebc1..42b3a1ad49 100644
--- a/src/python/grpcio/grpc/_grpcio_metadata.py
+++ b/src/python/grpcio/grpc/_grpcio_metadata.py
@@ -14,4 +14,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio/grpc/_grpcio_metadata.py.template`!!!
 
-__version__ = """1.15.0.dev0"""
+__version__ = """1.17.0.dev0"""
diff --git a/src/python/grpcio/grpc/_interceptor.py b/src/python/grpcio/grpc/_interceptor.py
index 1d2d374ad1..4345114026 100644
--- a/src/python/grpcio/grpc/_interceptor.py
+++ b/src/python/grpcio/grpc/_interceptor.py
@@ -46,7 +46,7 @@ def service_pipeline(interceptors):
 class _ClientCallDetails(
         collections.namedtuple(
             '_ClientCallDetails',
-            ('method', 'timeout', 'metadata', 'credentials')),
+            ('method', 'timeout', 'metadata', 'credentials', 'wait_for_ready')),
         grpc.ClientCallDetails):
     pass
 
@@ -72,7 +72,12 @@ def _unwrap_client_call_details(call_details, default_details):
     except AttributeError:
         credentials = default_details.credentials
 
-    return method, timeout, metadata, credentials
+    try:
+        wait_for_ready = call_details.wait_for_ready
+    except AttributeError:
+        wait_for_ready = default_details.wait_for_ready
+
+    return method, timeout, metadata, credentials, wait_for_ready
 
 
 class _FailureOutcome(grpc.RpcError, grpc.Future, grpc.Call):
@@ -193,28 +198,39 @@ class _UnaryUnaryMultiCallable(grpc.UnaryUnaryMultiCallable):
         self._method = method
         self._interceptor = interceptor
 
-    def __call__(self, request, timeout=None, metadata=None, credentials=None):
+    def __call__(self,
+                 request,
+                 timeout=None,
+                 metadata=None,
+                 credentials=None,
+                 wait_for_ready=None):
         response, ignored_call = self._with_call(
             request,
             timeout=timeout,
             metadata=metadata,
-            credentials=credentials)
+            credentials=credentials,
+            wait_for_ready=wait_for_ready)
         return response
 
-    def _with_call(self, request, timeout=None, metadata=None,
-                   credentials=None):
-        client_call_details = _ClientCallDetails(self._method, timeout,
-                                                 metadata, credentials)
+    def _with_call(self,
+                   request,
+                   timeout=None,
+                   metadata=None,
+                   credentials=None,
+                   wait_for_ready=None):
+        client_call_details = _ClientCallDetails(
+            self._method, timeout, metadata, credentials, wait_for_ready)
 
         def continuation(new_details, request):
-            new_method, new_timeout, new_metadata, new_credentials = (
+            new_method, new_timeout, new_metadata, new_credentials, new_wait_for_ready = (
                 _unwrap_client_call_details(new_details, client_call_details))
             try:
                 response, call = self._thunk(new_method).with_call(
                     request,
                     timeout=new_timeout,
                     metadata=new_metadata,
-                    credentials=new_credentials)
+                    credentials=new_credentials,
+                    wait_for_ready=new_wait_for_ready)
                 return _UnaryOutcome(response, call)
             except grpc.RpcError:
                 raise
@@ -225,25 +241,37 @@ class _UnaryUnaryMultiCallable(grpc.UnaryUnaryMultiCallable):
             continuation, client_call_details, request)
         return call.result(), call
 
-    def with_call(self, request, timeout=None, metadata=None, credentials=None):
+    def with_call(self,
+                  request,
+                  timeout=None,
+                  metadata=None,
+                  credentials=None,
+                  wait_for_ready=None):
         return self._with_call(
             request,
             timeout=timeout,
             metadata=metadata,
-            credentials=credentials)
+            credentials=credentials,
+            wait_for_ready=wait_for_ready)
 
-    def future(self, request, timeout=None, metadata=None, credentials=None):
-        client_call_details = _ClientCallDetails(self._method, timeout,
-                                                 metadata, credentials)
+    def future(self,
+               request,
+               timeout=None,
+               metadata=None,
+               credentials=None,
+               wait_for_ready=None):
+        client_call_details = _ClientCallDetails(
+            self._method, timeout, metadata, credentials, wait_for_ready)
 
         def continuation(new_details, request):
-            new_method, new_timeout, new_metadata, new_credentials = (
+            new_method, new_timeout, new_metadata, new_credentials, new_wait_for_ready = (
                 _unwrap_client_call_details(new_details, client_call_details))
             return self._thunk(new_method).future(
                 request,
                 timeout=new_timeout,
                 metadata=new_metadata,
-                credentials=new_credentials)
+                credentials=new_credentials,
+                wait_for_ready=new_wait_for_ready)
 
         try:
             return self._interceptor.intercept_unary_unary(
@@ -259,18 +287,24 @@ class _UnaryStreamMultiCallable(grpc.UnaryStreamMultiCallable):
         self._method = method
         self._interceptor = interceptor
 
-    def __call__(self, request, timeout=None, metadata=None, credentials=None):
-        client_call_details = _ClientCallDetails(self._method, timeout,
-                                                 metadata, credentials)
+    def __call__(self,
+                 request,
+                 timeout=None,
+                 metadata=None,
+                 credentials=None,
+                 wait_for_ready=None):
+        client_call_details = _ClientCallDetails(
+            self._method, timeout, metadata, credentials, wait_for_ready)
 
         def continuation(new_details, request):
-            new_method, new_timeout, new_metadata, new_credentials = (
+            new_method, new_timeout, new_metadata, new_credentials, new_wait_for_ready = (
                 _unwrap_client_call_details(new_details, client_call_details))
             return self._thunk(new_method)(
                 request,
                 timeout=new_timeout,
                 metadata=new_metadata,
-                credentials=new_credentials)
+                credentials=new_credentials,
+                wait_for_ready=new_wait_for_ready)
 
         try:
             return self._interceptor.intercept_unary_stream(
@@ -290,31 +324,35 @@ class _StreamUnaryMultiCallable(grpc.StreamUnaryMultiCallable):
                  request_iterator,
                  timeout=None,
                  metadata=None,
-                 credentials=None):
+                 credentials=None,
+                 wait_for_ready=None):
         response, ignored_call = self._with_call(
             request_iterator,
             timeout=timeout,
             metadata=metadata,
-            credentials=credentials)
+            credentials=credentials,
+            wait_for_ready=wait_for_ready)
         return response
 
     def _with_call(self,
                    request_iterator,
                    timeout=None,
                    metadata=None,
-                   credentials=None):
-        client_call_details = _ClientCallDetails(self._method, timeout,
-                                                 metadata, credentials)
+                   credentials=None,
+                   wait_for_ready=None):
+        client_call_details = _ClientCallDetails(
+            self._method, timeout, metadata, credentials, wait_for_ready)
 
         def continuation(new_details, request_iterator):
-            new_method, new_timeout, new_metadata, new_credentials = (
+            new_method, new_timeout, new_metadata, new_credentials, new_wait_for_ready = (
                 _unwrap_client_call_details(new_details, client_call_details))
             try:
                 response, call = self._thunk(new_method).with_call(
                     request_iterator,
                     timeout=new_timeout,
                     metadata=new_metadata,
-                    credentials=new_credentials)
+                    credentials=new_credentials,
+                    wait_for_ready=new_wait_for_ready)
                 return _UnaryOutcome(response, call)
             except grpc.RpcError:
                 raise
@@ -329,29 +367,33 @@ class _StreamUnaryMultiCallable(grpc.StreamUnaryMultiCallable):
                   request_iterator,
                   timeout=None,
                   metadata=None,
-                  credentials=None):
+                  credentials=None,
+                  wait_for_ready=None):
         return self._with_call(
             request_iterator,
             timeout=timeout,
             metadata=metadata,
-            credentials=credentials)
+            credentials=credentials,
+            wait_for_ready=wait_for_ready)
 
     def future(self,
                request_iterator,
                timeout=None,
                metadata=None,
-               credentials=None):
-        client_call_details = _ClientCallDetails(self._method, timeout,
-                                                 metadata, credentials)
+               credentials=None,
+               wait_for_ready=None):
+        client_call_details = _ClientCallDetails(
+            self._method, timeout, metadata, credentials, wait_for_ready)
 
         def continuation(new_details, request_iterator):
-            new_method, new_timeout, new_metadata, new_credentials = (
+            new_method, new_timeout, new_metadata, new_credentials, new_wait_for_ready = (
                 _unwrap_client_call_details(new_details, client_call_details))
             return self._thunk(new_method).future(
                 request_iterator,
                 timeout=new_timeout,
                 metadata=new_metadata,
-                credentials=new_credentials)
+                credentials=new_credentials,
+                wait_for_ready=new_wait_for_ready)
 
         try:
             return self._interceptor.intercept_stream_unary(
@@ -371,18 +413,20 @@ class _StreamStreamMultiCallable(grpc.StreamStreamMultiCallable):
                  request_iterator,
                  timeout=None,
                  metadata=None,
-                 credentials=None):
-        client_call_details = _ClientCallDetails(self._method, timeout,
-                                                 metadata, credentials)
+                 credentials=None,
+                 wait_for_ready=None):
+        client_call_details = _ClientCallDetails(
+            self._method, timeout, metadata, credentials, wait_for_ready)
 
         def continuation(new_details, request_iterator):
-            new_method, new_timeout, new_metadata, new_credentials = (
+            new_method, new_timeout, new_metadata, new_credentials, new_wait_for_ready = (
                 _unwrap_client_call_details(new_details, client_call_details))
             return self._thunk(new_method)(
                 request_iterator,
                 timeout=new_timeout,
                 metadata=new_metadata,
-                credentials=new_credentials)
+                credentials=new_credentials,
+                wait_for_ready=new_wait_for_ready)
 
         try:
             return self._interceptor.intercept_stream_stream(
diff --git a/src/python/grpcio/grpc_core_dependencies.py b/src/python/grpcio/grpc_core_dependencies.py
index 38f6b4d24c..2c929102cc 100644
--- a/src/python/grpcio/grpc_core_dependencies.py
+++ b/src/python/grpcio/grpc_core_dependencies.py
@@ -92,7 +92,6 @@ CORE_SOURCE_FILES = [
     'src/core/lib/iomgr/error.cc',
     'src/core/lib/iomgr/ev_epoll1_linux.cc',
     'src/core/lib/iomgr/ev_epollex_linux.cc',
-    'src/core/lib/iomgr/ev_epollsig_linux.cc',
     'src/core/lib/iomgr/ev_poll_posix.cc',
     'src/core/lib/iomgr/ev_posix.cc',
     'src/core/lib/iomgr/ev_windows.cc',
@@ -209,6 +208,7 @@ CORE_SOURCE_FILES = [
     'src/core/lib/transport/timeout_encoding.cc',
     'src/core/lib/transport/transport.cc',
     'src/core/lib/transport/transport_op_string.cc',
+    'src/core/lib/uri/uri_parser.cc',
     'src/core/lib/debug/trace.cc',
     'src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.cc',
     'src/core/ext/transport/chttp2/transport/bin_decoder.cc',
@@ -256,11 +256,14 @@ CORE_SOURCE_FILES = [
     'src/core/lib/security/credentials/oauth2/oauth2_credentials.cc',
     'src/core/lib/security/credentials/plugin/plugin_credentials.cc',
     'src/core/lib/security/credentials/ssl/ssl_credentials.cc',
-    'src/core/lib/security/security_connector/alts_security_connector.cc',
+    'src/core/lib/security/security_connector/alts/alts_security_connector.cc',
+    'src/core/lib/security/security_connector/fake/fake_security_connector.cc',
     'src/core/lib/security/security_connector/load_system_roots_fallback.cc',
     'src/core/lib/security/security_connector/load_system_roots_linux.cc',
-    'src/core/lib/security/security_connector/local_security_connector.cc',
+    'src/core/lib/security/security_connector/local/local_security_connector.cc',
     'src/core/lib/security/security_connector/security_connector.cc',
+    'src/core/lib/security/security_connector/ssl/ssl_security_connector.cc',
+    'src/core/lib/security/security_connector/ssl_utils.cc',
     'src/core/lib/security/transport/client_auth_filter.cc',
     'src/core/lib/security/transport/secure_endpoint.cc',
     'src/core/lib/security/transport/security_handshaker.cc',
@@ -279,7 +282,7 @@ CORE_SOURCE_FILES = [
     'src/core/tsi/alts/frame_protector/alts_unseal_privacy_integrity_crypter.cc',
     'src/core/tsi/alts/frame_protector/frame_handler.cc',
     'src/core/tsi/alts/handshaker/alts_handshaker_client.cc',
-    'src/core/tsi/alts/handshaker/alts_tsi_event.cc',
+    'src/core/tsi/alts/handshaker/alts_shared_resource.cc',
     'src/core/tsi/alts/handshaker/alts_tsi_handshaker.cc',
     'src/core/tsi/alts/zero_copy_frame_protector/alts_grpc_integrity_only_record_protocol.cc',
     'src/core/tsi/alts/zero_copy_frame_protector/alts_grpc_privacy_integrity_record_protocol.cc',
@@ -315,6 +318,7 @@ CORE_SOURCE_FILES = [
     'src/core/ext/filters/client_channel/client_channel_factory.cc',
     'src/core/ext/filters/client_channel/client_channel_plugin.cc',
     'src/core/ext/filters/client_channel/connector.cc',
+    'src/core/ext/filters/client_channel/health/health_check_client.cc',
     'src/core/ext/filters/client_channel/http_connect_handshaker.cc',
     'src/core/ext/filters/client_channel/http_proxy.cc',
     'src/core/ext/filters/client_channel/lb_policy.cc',
@@ -329,9 +333,8 @@ CORE_SOURCE_FILES = [
     'src/core/ext/filters/client_channel/retry_throttle.cc',
     'src/core/ext/filters/client_channel/subchannel.cc',
     'src/core/ext/filters/client_channel/subchannel_index.cc',
-    'src/core/ext/filters/client_channel/uri_parser.cc',
     'src/core/ext/filters/deadline/deadline_filter.cc',
-    'src/core/tsi/alts_transport_security.cc',
+    'src/core/ext/filters/client_channel/health/health.pb.c',
     'src/core/tsi/fake_transport_security.cc',
     'src/core/tsi/local_transport_security.cc',
     'src/core/tsi/ssl/session_cache/ssl_session_boringssl.cc',
@@ -350,10 +353,14 @@ CORE_SOURCE_FILES = [
     'src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel_secure.cc',
     'src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.cc',
     'src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.cc',
+    'src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc',
     'src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/google/protobuf/duration.pb.c',
     'src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/google/protobuf/timestamp.pb.c',
     'src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c',
-    'src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc',
+    'src/core/ext/filters/client_channel/lb_policy/xds/xds.cc',
+    'src/core/ext/filters/client_channel/lb_policy/xds/xds_channel_secure.cc',
+    'src/core/ext/filters/client_channel/lb_policy/xds/xds_client_stats.cc',
+    'src/core/ext/filters/client_channel/lb_policy/xds/xds_load_balancer_api.cc',
     'src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc',
     'src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc',
     'src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc',
diff --git a/src/python/grpcio/grpc_version.py b/src/python/grpcio/grpc_version.py
index 9337800a33..71113e68d9 100644
--- a/src/python/grpcio/grpc_version.py
+++ b/src/python/grpcio/grpc_version.py
@@ -14,4 +14,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio/grpc_version.py.template`!!!
 
-VERSION = '1.15.0.dev0'
+VERSION = '1.17.0.dev0'