Add Python xDS user agent (#26191)

* Add cpp macro to append wrapped language info to xDS user agent

* Add Python xDS user agent

* fix redefinition error and add macro for wrapped lang version

* clang-format

* Revert xds_api.cc changes

* Use two separate macros

* Yapf

* Regenerate projects

* Include _metadata.py in source distributions

* Attempt to fix quote escaping on Windows

Co-authored-by: Mark D. Roth <roth@google.com>

PYTHON-MANIFEST.in

@@ -24,3 +24,4 @@ include requirements.txt
 include etc/roots.pem
 include Makefile
 include LICENSE
+include _metadata.py

_metadata.py

@@ -0,0 +1,17 @@
+# 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.
+
+# AUTO-GENERATED FROM `$REPO_ROOT/templates/_metadata.py.template`!!!
+
+__version__ = """1.39.0.dev0"""

setup.py

@@ -41,6 +41,8 @@ from setuptools.command import egg_info
 import subprocess
 from subprocess import PIPE
 
+import _metadata
+
 # Redirect the manifest template from MANIFEST.in to PYTHON-MANIFEST.in.
 egg_info.manifest_maker.template = 'PYTHON-MANIFEST.in'
 
@@ -228,6 +230,9 @@ EXTRA_ENV_COMPILE_ARGS = os.environ.get('GRPC_PYTHON_CFLAGS', None)
 EXTRA_ENV_LINK_ARGS = os.environ.get('GRPC_PYTHON_LDFLAGS', None)
 if EXTRA_ENV_COMPILE_ARGS is None:
     EXTRA_ENV_COMPILE_ARGS = ' -std=c++11'
+    EXTRA_ENV_COMPILE_ARGS += ' \'-DGRPC_XDS_USER_AGENT_NAME_SUFFIX=\"\\\"Python\\\"\"\''
+    EXTRA_ENV_COMPILE_ARGS += ' \'-DGRPC_XDS_USER_AGENT_VERSION_SUFFIX=\"\\\"{}\\\"\"\''.format(
+        _metadata.__version__)
     if 'win32' in sys.platform:
         if sys.version_info < (3, 5):
             EXTRA_ENV_COMPILE_ARGS += ' -D_hypot=hypot'

templates/_metadata.py.template

@@ -0,0 +1,19 @@
+%YAML 1.2
+--- |
+  # 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.
+
+  # AUTO-GENERATED FROM `$REPO_ROOT/templates/_metadata.py.template`!!!
+
+  __version__ = """${settings.python_version.pep440()}"""