Revert "Revert "Merge pull request #25365 from gnossen/python_xds_creds""

This reverts commit 7bbefc8365.

src/python/grpcio/grpc/__init__.py

@@ -1609,6 +1609,21 @@ def ssl_channel_credentials(root_certificates=None,
                                       certificate_chain))
 
 
+def xds_channel_credentials(fallback_credentials=None):
+    """Creates a ChannelCredentials for use with xDS. This is an EXPERIMENTAL
+      API.
+
+    Args:
+      fallback_credentials: Credentials to use in case it is not possible to
+        establish a secure connection via xDS. If no fallback_credentials
+        argument is supplied, a default SSLChannelCredentials is used.
+    """
+    fallback_credentials = ssl_channel_credentials(
+    ) if fallback_credentials is None else fallback_credentials
+    return ChannelCredentials(
+        _cygrpc.XDSChannelCredentials(fallback_credentials._credentials))
+
+
 def metadata_call_credentials(metadata_plugin, name=None):
     """Construct CallCredentials from an AuthMetadataPlugin.
 
@@ -1708,6 +1723,29 @@ def ssl_server_credentials(private_key_certificate_chain_pairs,
             ], require_client_auth))
 
 
+def xds_server_credentials(fallback_credentials):
+    """Creates a ServerCredentials for use with xDS. This is an EXPERIMENTAL
+      API.
+
+    Args:
+      fallback_credentials: Credentials to use in case it is not possible to
+        establish a secure connection via xDS. No default value is provided.
+    """
+    return ServerCredentials(
+        _cygrpc.xds_server_credentials(fallback_credentials._credentials))
+
+
+def insecure_server_credentials():
+    """Creates a credentials object directing the server to use no credentials.
+      This is an EXPERIMENTAL API.
+
+    This object cannot be used directly in a call to `add_secure_port`.
+    Instead, it should be used to construct other credentials objects, e.g.
+    with xds_server_credentials.
+    """
+    return ServerCredentials(_cygrpc.insecure_server_credentials())
+
+
 def ssl_server_certificate_configuration(private_key_certificate_chain_pairs,
                                          root_certificates=None):
     """Creates a ServerCertificateConfiguration for use with a Server.
@@ -1983,7 +2021,8 @@ def server(thread_pool,
            interceptors=None,
            options=None,
            maximum_concurrent_rpcs=None,
-           compression=None):
+           compression=None,
+           xds=False):
     """Creates a Server with which RPCs can be serviced.
 
     Args:
@@ -2004,6 +2043,8 @@ def server(thread_pool,
       compression: An element of grpc.compression, e.g.
         grpc.compression.Gzip. This compression algorithm will be used for the
         lifetime of the server unless overridden. This is an EXPERIMENTAL option.
+      xds: If set to true, retrieves server configuration via xDS. This is an
+        EXPERIMENTAL option.
 
     Returns:
       A Server object.
@@ -2013,7 +2054,7 @@ def server(thread_pool,
                                  () if handlers is None else handlers,
                                  () if interceptors is None else interceptors,
                                  () if options is None else options,
-                                 maximum_concurrent_rpcs, compression)
+                                 maximum_concurrent_rpcs, compression, xds)
 
 
 @contextlib.contextmanager

src/python/grpcio/grpc/_cython/_cygrpc/aio/server.pyx.pxi

@@ -822,7 +822,8 @@ cdef class AioServer:
         init_grpc_aio()
         # NOTE(lidiz) Core objects won't be deallocated automatically.
         # If AioServer.shutdown is not called, those objects will leak.
-        self._server = Server(options)
+        # TODO(rbellevi): Support xDS in aio server.
+        self._server = Server(options, False)
         grpc_server_register_completion_queue(
             self._server.c_server,
             global_completion_queue(),

src/python/grpcio/grpc/_cython/_cygrpc/credentials.pxd.pxi

@@ -76,6 +76,13 @@ cdef class CompositeChannelCredentials(ChannelCredentials):
   cdef grpc_channel_credentials *c(self) except *
 
 
+cdef class XDSChannelCredentials(ChannelCredentials):
+
+  cdef readonly ChannelCredentials _fallback_credentials
+
+  cdef grpc_channel_credentials *c(self) except *
+
+
 cdef class ServerCertificateConfig:
 
   cdef grpc_ssl_server_certificate_config *c_cert_config

src/python/grpcio/grpc/_cython/_cygrpc/credentials.pyx.pxi

@@ -178,6 +178,18 @@ cdef class CompositeChannelCredentials(ChannelCredentials):
     return c_composition
 
 
+cdef class XDSChannelCredentials(ChannelCredentials):
+
+    def __cinit__(self, fallback_credentials):
+        self._fallback_credentials = fallback_credentials
+
+    cdef grpc_channel_credentials *c(self) except *:
+      cdef grpc_channel_credentials *c_fallback_creds = self._fallback_credentials.c()
+      cdef grpc_channel_credentials *xds_creds = grpc_xds_credentials_create(c_fallback_creds)
+      grpc_channel_credentials_release(c_fallback_creds)
+      return xds_creds
+
+
 cdef class ServerCertificateConfig:
 
   def __cinit__(self):
@@ -347,11 +359,31 @@ cdef class LocalChannelCredentials(ChannelCredentials):
 def channel_credentials_local(grpc_local_connect_type local_connect_type):
   return LocalChannelCredentials(local_connect_type)
 
+cdef class InsecureChannelCredentials(ChannelCredentials):
+
+  cdef grpc_channel_credentials *c(self) except *:
+    return grpc_insecure_credentials_create()
+
+def channel_credentials_insecure():
+  return InsecureChannelCredentials()
+
 def server_credentials_local(grpc_local_connect_type local_connect_type):
   cdef ServerCredentials credentials = ServerCredentials()
   credentials.c_credentials = grpc_local_server_credentials_create(local_connect_type)
   return credentials
 
+def xds_server_credentials(ServerCredentials fallback_credentials):
+  cdef ServerCredentials credentials = ServerCredentials()
+  credentials.c_credentials = grpc_xds_server_credentials_create(fallback_credentials.c_credentials)
+  # NOTE: We do not need to call grpc_server_credentials_release on the
+  # fallback credentials here because this will be done by the __dealloc__
+  # method of its Cython wrapper.
+  return credentials
+
+def insecure_server_credentials():
+  cdef ServerCredentials credentials = ServerCredentials()
+  credentials.c_credentials = grpc_insecure_server_credentials_create()
+  return credentials
 
 cdef class ALTSChannelCredentials(ChannelCredentials):
 

src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi

@@ -397,6 +397,16 @@ cdef extern from "grpc/grpc.h":
   void grpc_server_register_completion_queue(grpc_server *server,
                                              grpc_completion_queue *cq,
                                              void *reserved) nogil
+
+  ctypedef struct grpc_server_config_fetcher:
+    pass
+
+  void grpc_server_set_config_fetcher(
+       grpc_server* server, grpc_server_config_fetcher* config_fetcher) nogil
+
+  grpc_server_config_fetcher* grpc_server_config_fetcher_xds_create() nogil
+
+
   int grpc_server_add_insecure_http2_port(
       grpc_server *server, const char *addr) nogil
   void grpc_server_start(grpc_server *server) nogil
@@ -514,6 +524,16 @@ cdef extern from "grpc/grpc_security.h":
       void *reserved) nogil
   void grpc_channel_credentials_release(grpc_channel_credentials *creds) nogil
 
+  grpc_channel_credentials *grpc_xds_credentials_create(
+      grpc_channel_credentials *fallback_creds) nogil
+
+  grpc_channel_credentials *grpc_insecure_credentials_create() nogil
+
+  grpc_server_credentials *grpc_xds_server_credentials_create(
+      grpc_server_credentials *fallback_creds) nogil
+
+  grpc_server_credentials *grpc_insecure_server_credentials_create() nogil
+
   grpc_call_credentials *grpc_composite_call_credentials_create(
       grpc_call_credentials *creds1, grpc_call_credentials *creds2,
       void *reserved) nogil

src/python/grpcio/grpc/_cython/_cygrpc/server.pyx.pxi

@@ -15,7 +15,7 @@
 
 cdef class Server:
 
-  def __cinit__(self, object arguments):
+  def __cinit__(self, object arguments, bint xds):
     fork_handlers_and_grpc_init()
     self.references = []
     self.registered_completion_queues = []
@@ -25,6 +25,8 @@ cdef class Server:
     self.c_server = NULL
     cdef _ChannelArgs channel_args = _ChannelArgs(arguments)
     self.c_server = grpc_server_create(channel_args.c_args(), NULL)
+    if xds:
+      grpc_server_set_config_fetcher(self.c_server, grpc_server_config_fetcher_xds_create())
     self.references.append(arguments)
 
   def request_call(

src/python/grpcio/grpc/_server.py

@@ -945,9 +945,9 @@ class _Server(grpc.Server):
 
     # pylint: disable=too-many-arguments
     def __init__(self, thread_pool, generic_handlers, interceptors, options,
-                 maximum_concurrent_rpcs, compression):
+                 maximum_concurrent_rpcs, compression, xds):
         completion_queue = cygrpc.CompletionQueue()
-        server = cygrpc.Server(_augment_options(options, compression))
+        server = cygrpc.Server(_augment_options(options, compression), xds)
         server.register_completion_queue(completion_queue)
         self._state = _ServerState(completion_queue, server, generic_handlers,
                                    _interceptor.service_pipeline(interceptors),
@@ -989,7 +989,7 @@ class _Server(grpc.Server):
 
 
 def create_server(thread_pool, generic_rpc_handlers, interceptors, options,
-                  maximum_concurrent_rpcs, compression):
+                  maximum_concurrent_rpcs, compression, xds):
     _validate_generic_rpc_handlers(generic_rpc_handlers)
     return _Server(thread_pool, generic_rpc_handlers, interceptors, options,
-                   maximum_concurrent_rpcs, compression)
+                   maximum_concurrent_rpcs, compression, xds)

src/python/grpcio/grpc/_simple_stubs.py

@@ -60,16 +60,9 @@ else:
 def _create_channel(target: str, options: Sequence[Tuple[str, str]],
                     channel_credentials: Optional[grpc.ChannelCredentials],
                     compression: Optional[grpc.Compression]) -> grpc.Channel:
-    if channel_credentials is grpc.experimental.insecure_channel_credentials():
-        _LOGGER.debug(f"Creating insecure channel with options '{options}' " +
-                      f"and compression '{compression}'")
-        return grpc.insecure_channel(target,
-                                     options=options,
-                                     compression=compression)
-    else:
     _LOGGER.debug(
-            f"Creating secure channel with credentials '{channel_credentials}', "
-            + f"options '{options}' and compression '{compression}'")
+        f"Creating secure channel with credentials '{channel_credentials}', " +
+        f"options '{options}' and compression '{compression}'")
     return grpc.secure_channel(target,
                                credentials=channel_credentials,
                                options=options,

src/python/grpcio/grpc/experimental/__init__.py

@@ -22,6 +22,7 @@ import sys
 import warnings
 
 import grpc
+from grpc._cython import cygrpc as _cygrpc
 
 _EXPERIMENTAL_APIS_USED = set()
 
@@ -41,19 +42,16 @@ class UsageError(Exception):
     """Raised by the gRPC library to indicate usage not allowed by the API."""
 
 
-_insecure_channel_credentials_sentinel = object()
+# It's important that there be a single insecure credentials object so that its
+# hash is deterministic and can be used for indexing in the simple stubs cache.
 _insecure_channel_credentials = grpc.ChannelCredentials(
-    _insecure_channel_credentials_sentinel)
+    _cygrpc.channel_credentials_insecure())
 
 
 def insecure_channel_credentials():
     """Creates a ChannelCredentials for use with an insecure channel.
 
     THIS IS AN EXPERIMENTAL API.
-
-    This is not for use with secure_channel function. Intead, this should be
-    used with grpc.unary_unary, grpc.unary_stream, grpc.stream_unary, or
-    grpc.stream_stream.
     """
     return _insecure_channel_credentials
 

src/python/grpcio_tests/tests/tests.json

@@ -77,6 +77,7 @@
   "unit._session_cache_test.SSLSessionCacheTest",
   "unit._signal_handling_test.SignalHandlingTest",
   "unit._version_test.VersionTest",
+  "unit._xds_credentials_test.XdsCredentialsTest",
   "unit.beta._beta_features_test.BetaFeaturesTest",
   "unit.beta._beta_features_test.ContextManagementAndLifecycleTest",
   "unit.beta._connectivity_channel_test.ConnectivityStatesTest",

src/python/grpcio_tests/tests/unit/BUILD.bazel

@@ -40,6 +40,7 @@ GRPCIO_TESTS_UNIT = [
     "_server_shutdown_test.py",
     "_server_wait_for_termination_test.py",
     "_session_cache_test.py",
+    "_xds_credentials_test.py",
 ]
 
 py_library(

src/python/grpcio_tests/tests/unit/_cython/_cancel_many_calls_test.py

@@ -144,12 +144,10 @@ class CancelManyCallsTest(unittest.TestCase):
             test_constants.THREAD_CONCURRENCY)
 
         server_completion_queue = cygrpc.CompletionQueue()
-        server = cygrpc.Server([
-            (
+        server = cygrpc.Server([(
             b'grpc.so_reuseport',
             0,
-            ),
-        ])
+        )], False)
         server.register_completion_queue(server_completion_queue)
         port = server.add_http2_port(b'[::]:0')
         server.start()

src/python/grpcio_tests/tests/unit/_cython/_common.py

@@ -96,7 +96,7 @@ class RpcTest(object):
 
     def setUp(self):
         self.server_completion_queue = cygrpc.CompletionQueue()
-        self.server = cygrpc.Server([(b'grpc.so_reuseport', 0)])
+        self.server = cygrpc.Server([(b'grpc.so_reuseport', 0)], False)
         self.server.register_completion_queue(self.server_completion_queue)
         port = self.server.add_http2_port(b'[::]:0')
         self.server.start()

src/python/grpcio_tests/tests/unit/_cython/_read_some_but_not_all_responses_test.py

@@ -115,7 +115,7 @@ class ReadSomeButNotAllResponsesTest(unittest.TestCase):
         server = cygrpc.Server([(
             b'grpc.so_reuseport',
             0,
-        )])
+        )], False)
         server.register_completion_queue(server_completion_queue)
         port = server.add_http2_port(b'[::]:0')
         server.start()

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(None)
+        server = cygrpc.Server(None, False)
         server.register_completion_queue(server_call_completion_queue)
         server.register_completion_queue(server_shutdown_completion_queue)
         port = server.add_http2_port(b'[::]:0')

src/python/grpcio_tests/tests/unit/_cython/cygrpc_test.py

@@ -42,12 +42,10 @@ class TypeSmokeTest(unittest.TestCase):
         del completion_queue
 
     def testServerUpDown(self):
-        server = cygrpc.Server(set([
-            (
+        server = cygrpc.Server(set([(
             b'grpc.so_reuseport',
             0,
-            ),
-        ]))
+        )]), False)
         del server
 
     def testChannelUpDown(self):
@@ -59,12 +57,10 @@ class TypeSmokeTest(unittest.TestCase):
                                              b'test plugin name!')
 
     def testServerStartNoExplicitShutdown(self):
-        server = cygrpc.Server([
-            (
+        server = cygrpc.Server([(
             b'grpc.so_reuseport',
             0,
-            ),
-        ])
+        )], False)
         completion_queue = cygrpc.CompletionQueue()
         server.register_completion_queue(completion_queue)
         port = server.add_http2_port(b'[::]:0')
@@ -79,7 +75,7 @@ class TypeSmokeTest(unittest.TestCase):
                 b'grpc.so_reuseport',
                 0,
             ),
-        ])
+        ], False)
         server.add_http2_port(b'[::]:0')
         server.register_completion_queue(completion_queue)
         server.start()
@@ -97,12 +93,10 @@ class ServerClientMixin(object):
 
     def setUpMixin(self, server_credentials, client_credentials, host_override):
         self.server_completion_queue = cygrpc.CompletionQueue()
-        self.server = cygrpc.Server([
-            (
+        self.server = cygrpc.Server([(
             b'grpc.so_reuseport',
             0,
-            ),
-        ])
+        )], False)
         self.server.register_completion_queue(self.server_completion_queue)
         if server_credentials:
             self.port = self.server.add_http2_port(b'[::]:0',

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

@@ -0,0 +1,103 @@
+# Copyright 2021 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.
+"""Tests xDS server and channel credentials."""
+
+import unittest
+
+import logging
+from concurrent import futures
+import contextlib
+
+import grpc
+import grpc.experimental
+from tests.unit import test_common
+from tests.unit import resources
+
+
+class _GenericHandler(grpc.GenericRpcHandler):
+
+    def service(self, handler_call_details):
+        return grpc.unary_unary_rpc_method_handler(
+            lambda request, unused_context: request)
+
+
+@contextlib.contextmanager
+def xds_channel_server_without_xds(server_fallback_creds):
+    server = grpc.server(futures.ThreadPoolExecutor())
+    server.add_generic_rpc_handlers((_GenericHandler(),))
+    server_server_fallback_creds = grpc.ssl_server_credentials(
+        ((resources.private_key(), resources.certificate_chain()),))
+    server_creds = grpc.xds_server_credentials(server_fallback_creds)
+    port = server.add_secure_port("localhost:0", server_creds)
+    server.start()
+    try:
+        yield "localhost:{}".format(port)
+    finally:
+        server.stop(None)
+
+
+class XdsCredentialsTest(unittest.TestCase):
+
+    def test_xds_creds_fallback_ssl(self):
+        # Since there is no xDS server, the fallback credentials will be used.
+        # In this case, SSL credentials.
+        server_fallback_creds = grpc.ssl_server_credentials(
+            ((resources.private_key(), resources.certificate_chain()),))
+        with xds_channel_server_without_xds(
+                server_fallback_creds) as server_address:
+            override_options = (("grpc.ssl_target_name_override",
+                                 "foo.test.google.fr"),)
+            channel_fallback_creds = grpc.ssl_channel_credentials(
+                root_certificates=resources.test_root_certificates(),
+                private_key=resources.private_key(),
+                certificate_chain=resources.certificate_chain())
+            channel_creds = grpc.xds_channel_credentials(channel_fallback_creds)
+            with grpc.secure_channel(server_address,
+                                     channel_creds,
+                                     options=override_options) as channel:
+                request = b"abc"
+                response = channel.unary_unary("/test/method")(
+                    request, wait_for_ready=True)
+                self.assertEqual(response, request)
+
+    def test_xds_creds_fallback_insecure(self):
+        # Since there is no xDS server, the fallback credentials will be used.
+        # In this case, insecure.
+        server_fallback_creds = grpc.insecure_server_credentials()
+        with xds_channel_server_without_xds(
+                server_fallback_creds) as server_address:
+            channel_fallback_creds = grpc.experimental.insecure_channel_credentials(
+            )
+            channel_creds = grpc.xds_channel_credentials(channel_fallback_creds)
+            with grpc.secure_channel(server_address, channel_creds) as channel:
+                request = b"abc"
+                response = channel.unary_unary("/test/method")(
+                    request, wait_for_ready=True)
+                self.assertEqual(response, request)
+
+    def test_start_xds_server(self):
+        server = grpc.server(futures.ThreadPoolExecutor(), xds=True)
+        server.add_generic_rpc_handlers((_GenericHandler(),))
+        server_fallback_creds = grpc.insecure_server_credentials()
+        server_creds = grpc.xds_server_credentials(server_fallback_creds)
+        port = server.add_secure_port("localhost:0", server_creds)
+        server.start()
+        server.stop(None)
+        # No exceptions thrown. A more comprehensive suite of tests will be
+        # provided by the interop tests.
+
+
+if __name__ == "__main__":
+    logging.basicConfig()
+    unittest.main()