Use monkey patch function to solve namespace package issue

src/python/grpcio_status/grpc_status/rpc_status.py

@@ -17,11 +17,6 @@ import collections
 
 import grpc
 
-# TODO(https://github.com/bazelbuild/bazel/issues/6844)
-# Due to Bazel issue, the namespace packages won't resolve correctly.
-# Adding this unused-import as a workaround to avoid module-not-found error
-# under Bazel builds.
-import google.protobuf  # pylint: disable=unused-import
 from google.rpc import status_pb2
 
 _CODE_TO_GRPC_CODE_MAPPING = {x.value[0]: x for x in grpc.StatusCode}

src/python/grpcio_tests/tests/BUILD.bazel

@@ -0,0 +1,8 @@
+py_library(
+    name = "bazel_patch",
+    srcs = ["bazel_patch.py"],
+    visibility = ["//visibility:public"],
+    data=[
+        "//src/python/grpcio_tests/tests/unit/credentials",
+    ],
+)

src/python/grpcio_tests/tests/bazel_patch.py

@@ -0,0 +1,32 @@
+# Copyright 2019 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.
+
+import os
+import site
+import sys
+
+
+# TODO(https://github.com/bazelbuild/bazel/issues/6844) Bazel failed to
+# interpret namespace packages correctly. This monkey patch will force the
+# Python process to parse the .pth file in the sys.path to resolve namespace
+# package in the right place.
+# Analysis in depth: https://github.com/bazelbuild/rules_python/issues/55
+def bazel_patch():
+    """Add valid sys.path item to site directory to parse the .pth files."""
+    for item in sys.path:
+        if os.path.exists(item):
+            # The only difference between sys.path and site-directory is
+            # whether the .pth file will be parsed or not. A site-directory
+            # will always exist in sys.path, but not another way around.
+            site.addsitedir(item)

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

@@ -29,6 +29,7 @@ py_library(
     srcs = ["methods.py"],
     deps = [
         "//src/python/grpcio/grpc:grpcio",
+        "//src/python/grpcio_tests/tests:bazel_patch",
         "//src/proto/grpc/testing:py_empty_proto",
         "//src/proto/grpc/testing:py_messages_proto",
         "//src/proto/grpc/testing:py_test_proto",

src/python/grpcio_tests/tests/interop/methods.py

@@ -13,6 +13,9 @@
 # limitations under the License.
 """Implementations of interoperability test methods."""
 
+from tests.bazel_patch import bazel_patch
+bazel_patch()
+
 import enum
 import json
 import os

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

@@ -10,6 +10,7 @@ py_test(
     deps = [
         "//src/python/grpcio/grpc:grpcio",
         "//src/python/grpcio_status/grpc_status:grpc_status",
+        "//src/python/grpcio_tests/tests:bazel_patch",
         "//src/python/grpcio_tests/tests/unit:test_common",
         "//src/python/grpcio_tests/tests/unit/framework/common:common",
         requirement('protobuf'),

src/python/grpcio_tests/tests/status/_grpc_status_test.py

@@ -13,6 +13,9 @@
 # limitations under the License.
 """Tests of grpc_status."""
 
+from tests.bazel_patch import bazel_patch
+bazel_patch()
+
 import unittest
 
 import logging