Merge remote-tracking branch 'origin/v1.8.x'

11 files changed, 690 insertions, 0 deletions

diff --git a/examples/python/interceptors/default_value/default_value_client_interceptor.py b/examples/python/interceptors/default_value/default_value_client_interceptor.py
new file mode 100644
index 0000000000..c549f2b861
--- /dev/null
+++ b/examples/python/interceptors/default_value/default_value_client_interceptor.py
@@ -0,0 +1,68 @@
+# Copyright 2017 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.
+"""Interceptor that adds headers to outgoing requests."""
+
+import collections
+
+import grpc
+
+
+class _ConcreteValue(grpc.Future):
+
+    def __init__(self, result):
+        self._result = result
+
+    def cancel(self):
+        return False
+
+    def cancelled(self):
+        return False
+
+    def running(self):
+        return False
+
+    def done(self):
+        return True
+
+    def result(self, timeout=None):
+        return self._result
+
+    def exception(self, timeout=None):
+        return None
+
+    def traceback(self, timeout=None):
+        return None
+
+    def add_done_callback(self, fn):
+        fn(self._result)
+
+
+class DefaultValueClientInterceptor(grpc.UnaryUnaryClientInterceptor,
+                                    grpc.StreamUnaryClientInterceptor):
+
+    def __init__(self, value):
+        self._default = _ConcreteValue(value)
+
+    def _intercept_call(self, continuation, client_call_details,
+                        request_or_iterator):
+        response = continuation(client_call_details, request_or_iterator)
+        return self._default if response.exception() else response
+
+    def intercept_unary_unary(self, continuation, client_call_details, request):
+        return self._intercept_call(continuation, client_call_details, request)
+
+    def intercept_stream_unary(self, continuation, client_call_details,
+                               request_iterator):
+        return self._intercept_call(continuation, client_call_details,
+                                    request_iterator)
diff --git a/examples/python/interceptors/default_value/greeter_client.py b/examples/python/interceptors/default_value/greeter_client.py
new file mode 100644
index 0000000000..aba7571d83
--- /dev/null
+++ b/examples/python/interceptors/default_value/greeter_client.py
@@ -0,0 +1,38 @@
+# Copyright 2017 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.
+"""The Python implementation of the gRPC helloworld.Greeter client."""
+
+from __future__ import print_function
+
+import grpc
+
+import helloworld_pb2
+import helloworld_pb2_grpc
+import default_value_client_interceptor
+
+
+def run():
+    default_value = helloworld_pb2.HelloReply(
+        message='Hello from your local interceptor!')
+    default_value_interceptor = default_value_client_interceptor.DefaultValueClientInterceptor(
+        default_value)
+    channel = grpc.insecure_channel('localhost:50051')
+    channel = grpc.intercept_channel(channel, default_value_interceptor)
+    stub = helloworld_pb2_grpc.GreeterStub(channel)
+    response = stub.SayHello(helloworld_pb2.HelloRequest(name='you'))
+    print("Greeter client received: " + response.message)
+
+
+if __name__ == '__main__':
+    run()
diff --git a/examples/python/interceptors/default_value/helloworld_pb2.py b/examples/python/interceptors/default_value/helloworld_pb2.py
new file mode 100644
index 0000000000..e18ab9acc7
--- /dev/null
+++ b/examples/python/interceptors/default_value/helloworld_pb2.py
@@ -0,0 +1,134 @@
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# source: helloworld.proto
+
+import sys
+_b=sys.version_info[0]<3 and (lambda x:x) or (lambda x:x.encode('latin1'))
+from google.protobuf import descriptor as _descriptor
+from google.protobuf import message as _message
+from google.protobuf import reflection as _reflection
+from google.protobuf import symbol_database as _symbol_database
+from google.protobuf import descriptor_pb2
+# @@protoc_insertion_point(imports)
+
+_sym_db = _symbol_database.Default()
+
+
+
+
+DESCRIPTOR = _descriptor.FileDescriptor(
+  name='helloworld.proto',
+  package='helloworld',
+  syntax='proto3',
+  serialized_pb=_b('\n\x10helloworld.proto\x12\nhelloworld\"\x1c\n\x0cHelloRequest\x12\x0c\n\x04name\x18\x01 \x01(\t\"\x1d\n\nHelloReply\x12\x0f\n\x07message\x18\x01 \x01(\t2I\n\x07Greeter\x12>\n\x08SayHello\x12\x18.helloworld.HelloRequest\x1a\x16.helloworld.HelloReply\"\x00\x42\x36\n\x1bio.grpc.examples.helloworldB\x0fHelloWorldProtoP\x01\xa2\x02\x03HLWb\x06proto3')
+)
+
+
+
+
+_HELLOREQUEST = _descriptor.Descriptor(
+  name='HelloRequest',
+  full_name='helloworld.HelloRequest',
+  filename=None,
+  file=DESCRIPTOR,
+  containing_type=None,
+  fields=[
+    _descriptor.FieldDescriptor(
+      name='name', full_name='helloworld.HelloRequest.name', index=0,
+      number=1, type=9, cpp_type=9, label=1,
+      has_default_value=False, default_value=_b("").decode('utf-8'),
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+  ],
+  extensions=[
+  ],
+  nested_types=[],
+  enum_types=[
+  ],
+  options=None,
+  is_extendable=False,
+  syntax='proto3',
+  extension_ranges=[],
+  oneofs=[
+  ],
+  serialized_start=32,
+  serialized_end=60,
+)
+
+
+_HELLOREPLY = _descriptor.Descriptor(
+  name='HelloReply',
+  full_name='helloworld.HelloReply',
+  filename=None,
+  file=DESCRIPTOR,
+  containing_type=None,
+  fields=[
+    _descriptor.FieldDescriptor(
+      name='message', full_name='helloworld.HelloReply.message', index=0,
+      number=1, type=9, cpp_type=9, label=1,
+      has_default_value=False, default_value=_b("").decode('utf-8'),
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+  ],
+  extensions=[
+  ],
+  nested_types=[],
+  enum_types=[
+  ],
+  options=None,
+  is_extendable=False,
+  syntax='proto3',
+  extension_ranges=[],
+  oneofs=[
+  ],
+  serialized_start=62,
+  serialized_end=91,
+)
+
+DESCRIPTOR.message_types_by_name['HelloRequest'] = _HELLOREQUEST
+DESCRIPTOR.message_types_by_name['HelloReply'] = _HELLOREPLY
+_sym_db.RegisterFileDescriptor(DESCRIPTOR)
+
+HelloRequest = _reflection.GeneratedProtocolMessageType('HelloRequest', (_message.Message,), dict(
+  DESCRIPTOR = _HELLOREQUEST,
+  __module__ = 'helloworld_pb2'
+  # @@protoc_insertion_point(class_scope:helloworld.HelloRequest)
+  ))
+_sym_db.RegisterMessage(HelloRequest)
+
+HelloReply = _reflection.GeneratedProtocolMessageType('HelloReply', (_message.Message,), dict(
+  DESCRIPTOR = _HELLOREPLY,
+  __module__ = 'helloworld_pb2'
+  # @@protoc_insertion_point(class_scope:helloworld.HelloReply)
+  ))
+_sym_db.RegisterMessage(HelloReply)
+
+
+DESCRIPTOR.has_options = True
+DESCRIPTOR._options = _descriptor._ParseOptions(descriptor_pb2.FileOptions(), _b('\n\033io.grpc.examples.helloworldB\017HelloWorldProtoP\001\242\002\003HLW'))
+
+_GREETER = _descriptor.ServiceDescriptor(
+  name='Greeter',
+  full_name='helloworld.Greeter',
+  file=DESCRIPTOR,
+  index=0,
+  options=None,
+  serialized_start=93,
+  serialized_end=166,
+  methods=[
+  _descriptor.MethodDescriptor(
+    name='SayHello',
+    full_name='helloworld.Greeter.SayHello',
+    index=0,
+    containing_service=None,
+    input_type=_HELLOREQUEST,
+    output_type=_HELLOREPLY,
+    options=None,
+  ),
+])
+_sym_db.RegisterServiceDescriptor(_GREETER)
+
+DESCRIPTOR.services_by_name['Greeter'] = _GREETER
+
+# @@protoc_insertion_point(module_scope)
diff --git a/examples/python/interceptors/default_value/helloworld_pb2_grpc.py b/examples/python/interceptors/default_value/helloworld_pb2_grpc.py
new file mode 100644
index 0000000000..18e07d1679
--- /dev/null
+++ b/examples/python/interceptors/default_value/helloworld_pb2_grpc.py
@@ -0,0 +1,46 @@
+# Generated by the gRPC Python protocol compiler plugin. DO NOT EDIT!
+import grpc
+
+import helloworld_pb2 as helloworld__pb2
+
+
+class GreeterStub(object):
+  """The greeting service definition.
+  """
+
+  def __init__(self, channel):
+    """Constructor.
+
+    Args:
+      channel: A grpc.Channel.
+    """
+    self.SayHello = channel.unary_unary(
+        '/helloworld.Greeter/SayHello',
+        request_serializer=helloworld__pb2.HelloRequest.SerializeToString,
+        response_deserializer=helloworld__pb2.HelloReply.FromString,
+        )
+
+
+class GreeterServicer(object):
+  """The greeting service definition.
+  """
+
+  def SayHello(self, request, context):
+    """Sends a greeting
+    """
+    context.set_code(grpc.StatusCode.UNIMPLEMENTED)
+    context.set_details('Method not implemented!')
+    raise NotImplementedError('Method not implemented!')
+
+
+def add_GreeterServicer_to_server(servicer, server):
+  rpc_method_handlers = {
+      'SayHello': grpc.unary_unary_rpc_method_handler(
+          servicer.SayHello,
+          request_deserializer=helloworld__pb2.HelloRequest.FromString,
+          response_serializer=helloworld__pb2.HelloReply.SerializeToString,
+      ),
+  }
+  generic_handler = grpc.method_handlers_generic_handler(
+      'helloworld.Greeter', rpc_method_handlers)
+  server.add_generic_rpc_handlers((generic_handler,))
diff --git a/examples/python/interceptors/headers/generic_client_interceptor.py b/examples/python/interceptors/headers/generic_client_interceptor.py
new file mode 100644
index 0000000000..30b0755aaf
--- /dev/null
+++ b/examples/python/interceptors/headers/generic_client_interceptor.py
@@ -0,0 +1,55 @@
+# Copyright 2017 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.
+"""Base class for interceptors that operate on all RPC types."""
+
+import grpc
+
+
+class _GenericClientInterceptor(
+        grpc.UnaryUnaryClientInterceptor, grpc.UnaryStreamClientInterceptor,
+        grpc.StreamUnaryClientInterceptor, grpc.StreamStreamClientInterceptor):
+
+    def __init__(self, interceptor_function):
+        self._fn = interceptor_function
+
+    def intercept_unary_unary(self, continuation, client_call_details, request):
+        new_details, new_request_iterator, postprocess = self._fn(
+            client_call_details, iter((request,)), False, False)
+        response = continuation(new_details, next(new_request_iterator))
+        return postprocess(response) if postprocess else response
+
+    def intercept_unary_stream(self, continuation, client_call_details,
+                               request):
+        new_details, new_request_iterator, postprocess = self._fn(
+            client_call_details, iter((request,)), False, True)
+        response_it = continuation(new_details, new_request_iterator)
+        return postprocess(response_it) if postprocess else response_it
+
+    def intercept_stream_unary(self, continuation, client_call_details,
+                               request_iterator):
+        new_details, new_request_iterator, postprocess = self._fn(
+            client_call_details, request_iterator, True, False)
+        response = continuation(new_details, next(new_request_iterator))
+        return postprocess(response) if postprocess else response
+
+    def intercept_stream_stream(self, continuation, client_call_details,
+                                request_iterator):
+        new_details, new_request_iterator, postprocess = self._fn(
+            client_call_details, request_iterator, True, True)
+        response_it = continuation(new_details, new_request_iterator)
+        return postprocess(response_it) if postprocess else response_it
+
+
+def create(intercept_call):
+    return _GenericClientInterceptor(intercept_call)
diff --git a/examples/python/interceptors/headers/greeter_client.py b/examples/python/interceptors/headers/greeter_client.py
new file mode 100644
index 0000000000..2b0dd3e177
--- /dev/null
+++ b/examples/python/interceptors/headers/greeter_client.py
@@ -0,0 +1,36 @@
+# Copyright 2017 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.
+"""The Python implementation of the GRPC helloworld.Greeter client."""
+
+from __future__ import print_function
+
+import grpc
+
+import helloworld_pb2
+import helloworld_pb2_grpc
+import header_manipulator_client_interceptor
+
+
+def run():
+    header_adder_interceptor = header_manipulator_client_interceptor.header_adder_interceptor(
+        'one-time-password', '42')
+    channel = grpc.insecure_channel('localhost:50051')
+    channel = grpc.intercept_channel(channel, header_adder_interceptor)
+    stub = helloworld_pb2_grpc.GreeterStub(channel)
+    response = stub.SayHello(helloworld_pb2.HelloRequest(name='you'))
+    print("Greeter client received: " + response.message)
+
+
+if __name__ == '__main__':
+    run()
diff --git a/examples/python/interceptors/headers/greeter_server.py b/examples/python/interceptors/headers/greeter_server.py
new file mode 100644
index 0000000000..01968609b5
--- /dev/null
+++ b/examples/python/interceptors/headers/greeter_server.py
@@ -0,0 +1,52 @@
+# Copyright 2017 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.
+"""The Python implementation of the GRPC helloworld.Greeter server."""
+
+from concurrent import futures
+import time
+
+import grpc
+
+import helloworld_pb2
+import helloworld_pb2_grpc
+from request_header_validator_interceptor import RequestHeaderValidatorInterceptor
+
+_ONE_DAY_IN_SECONDS = 60 * 60 * 24
+
+
+class Greeter(helloworld_pb2_grpc.GreeterServicer):
+
+    def SayHello(self, request, context):
+        return helloworld_pb2.HelloReply(message='Hello, %s!' % request.name)
+
+
+def serve():
+    header_validator = RequestHeaderValidatorInterceptor(
+        'one-time-password', '42', grpc.StatusCode.UNAUTHENTICATED,
+        'Access denied!')
+    server = grpc.server(
+        futures.ThreadPoolExecutor(max_workers=10),
+        interceptors=(header_validator,))
+    helloworld_pb2_grpc.add_GreeterServicer_to_server(Greeter(), server)
+    server.add_insecure_port('[::]:50051')
+    server.start()
+    try:
+        while True:
+            time.sleep(_ONE_DAY_IN_SECONDS)
+    except KeyboardInterrupt:
+        server.stop(0)
+
+
+if __name__ == '__main__':
+    serve()
diff --git a/examples/python/interceptors/headers/header_manipulator_client_interceptor.py b/examples/python/interceptors/headers/header_manipulator_client_interceptor.py
new file mode 100644
index 0000000000..ac7c605144
--- /dev/null
+++ b/examples/python/interceptors/headers/header_manipulator_client_interceptor.py
@@ -0,0 +1,42 @@
+# Copyright 2017 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.
+"""Interceptor that adds headers to outgoing requests."""
+
+import collections
+
+import grpc
+import generic_client_interceptor
+
+
+class _ClientCallDetails(
+        collections.namedtuple('_ClientCallDetails',
+                               ('method', 'timeout', 'metadata',
+                                'credentials')), grpc.ClientCallDetails):
+    pass
+
+
+def header_adder_interceptor(header, value):
+
+    def intercept_call(client_call_details, request_iterator, request_streaming,
+                       response_streaming):
+        metadata = []
+        if client_call_details.metadata is not None:
+            metadata = list(client_call_details.metadata)
+        metadata.append((header, value,))
+        client_call_details = _ClientCallDetails(
+            client_call_details.method, client_call_details.timeout, metadata,
+            client_call_details.credentials)
+        return client_call_details, request_iterator, None
+
+    return generic_client_interceptor.create(intercept_call)
diff --git a/examples/python/interceptors/headers/helloworld_pb2.py b/examples/python/interceptors/headers/helloworld_pb2.py
new file mode 100644
index 0000000000..e18ab9acc7
--- /dev/null
+++ b/examples/python/interceptors/headers/helloworld_pb2.py
@@ -0,0 +1,134 @@
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# source: helloworld.proto
+
+import sys
+_b=sys.version_info[0]<3 and (lambda x:x) or (lambda x:x.encode('latin1'))
+from google.protobuf import descriptor as _descriptor
+from google.protobuf import message as _message
+from google.protobuf import reflection as _reflection
+from google.protobuf import symbol_database as _symbol_database
+from google.protobuf import descriptor_pb2
+# @@protoc_insertion_point(imports)
+
+_sym_db = _symbol_database.Default()
+
+
+
+
+DESCRIPTOR = _descriptor.FileDescriptor(
+  name='helloworld.proto',
+  package='helloworld',
+  syntax='proto3',
+  serialized_pb=_b('\n\x10helloworld.proto\x12\nhelloworld\"\x1c\n\x0cHelloRequest\x12\x0c\n\x04name\x18\x01 \x01(\t\"\x1d\n\nHelloReply\x12\x0f\n\x07message\x18\x01 \x01(\t2I\n\x07Greeter\x12>\n\x08SayHello\x12\x18.helloworld.HelloRequest\x1a\x16.helloworld.HelloReply\"\x00\x42\x36\n\x1bio.grpc.examples.helloworldB\x0fHelloWorldProtoP\x01\xa2\x02\x03HLWb\x06proto3')
+)
+
+
+
+
+_HELLOREQUEST = _descriptor.Descriptor(
+  name='HelloRequest',
+  full_name='helloworld.HelloRequest',
+  filename=None,
+  file=DESCRIPTOR,
+  containing_type=None,
+  fields=[
+    _descriptor.FieldDescriptor(
+      name='name', full_name='helloworld.HelloRequest.name', index=0,
+      number=1, type=9, cpp_type=9, label=1,
+      has_default_value=False, default_value=_b("").decode('utf-8'),
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+  ],
+  extensions=[
+  ],
+  nested_types=[],
+  enum_types=[
+  ],
+  options=None,
+  is_extendable=False,
+  syntax='proto3',
+  extension_ranges=[],
+  oneofs=[
+  ],
+  serialized_start=32,
+  serialized_end=60,
+)
+
+
+_HELLOREPLY = _descriptor.Descriptor(
+  name='HelloReply',
+  full_name='helloworld.HelloReply',
+  filename=None,
+  file=DESCRIPTOR,
+  containing_type=None,
+  fields=[
+    _descriptor.FieldDescriptor(
+      name='message', full_name='helloworld.HelloReply.message', index=0,
+      number=1, type=9, cpp_type=9, label=1,
+      has_default_value=False, default_value=_b("").decode('utf-8'),
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+  ],
+  extensions=[
+  ],
+  nested_types=[],
+  enum_types=[
+  ],
+  options=None,
+  is_extendable=False,
+  syntax='proto3',
+  extension_ranges=[],
+  oneofs=[
+  ],
+  serialized_start=62,
+  serialized_end=91,
+)
+
+DESCRIPTOR.message_types_by_name['HelloRequest'] = _HELLOREQUEST
+DESCRIPTOR.message_types_by_name['HelloReply'] = _HELLOREPLY
+_sym_db.RegisterFileDescriptor(DESCRIPTOR)
+
+HelloRequest = _reflection.GeneratedProtocolMessageType('HelloRequest', (_message.Message,), dict(
+  DESCRIPTOR = _HELLOREQUEST,
+  __module__ = 'helloworld_pb2'
+  # @@protoc_insertion_point(class_scope:helloworld.HelloRequest)
+  ))
+_sym_db.RegisterMessage(HelloRequest)
+
+HelloReply = _reflection.GeneratedProtocolMessageType('HelloReply', (_message.Message,), dict(
+  DESCRIPTOR = _HELLOREPLY,
+  __module__ = 'helloworld_pb2'
+  # @@protoc_insertion_point(class_scope:helloworld.HelloReply)
+  ))
+_sym_db.RegisterMessage(HelloReply)
+
+
+DESCRIPTOR.has_options = True
+DESCRIPTOR._options = _descriptor._ParseOptions(descriptor_pb2.FileOptions(), _b('\n\033io.grpc.examples.helloworldB\017HelloWorldProtoP\001\242\002\003HLW'))
+
+_GREETER = _descriptor.ServiceDescriptor(
+  name='Greeter',
+  full_name='helloworld.Greeter',
+  file=DESCRIPTOR,
+  index=0,
+  options=None,
+  serialized_start=93,
+  serialized_end=166,
+  methods=[
+  _descriptor.MethodDescriptor(
+    name='SayHello',
+    full_name='helloworld.Greeter.SayHello',
+    index=0,
+    containing_service=None,
+    input_type=_HELLOREQUEST,
+    output_type=_HELLOREPLY,
+    options=None,
+  ),
+])
+_sym_db.RegisterServiceDescriptor(_GREETER)
+
+DESCRIPTOR.services_by_name['Greeter'] = _GREETER
+
+# @@protoc_insertion_point(module_scope)
diff --git a/examples/python/interceptors/headers/helloworld_pb2_grpc.py b/examples/python/interceptors/headers/helloworld_pb2_grpc.py
new file mode 100644
index 0000000000..18e07d1679
--- /dev/null
+++ b/examples/python/interceptors/headers/helloworld_pb2_grpc.py
@@ -0,0 +1,46 @@
+# Generated by the gRPC Python protocol compiler plugin. DO NOT EDIT!
+import grpc
+
+import helloworld_pb2 as helloworld__pb2
+
+
+class GreeterStub(object):
+  """The greeting service definition.
+  """
+
+  def __init__(self, channel):
+    """Constructor.
+
+    Args:
+      channel: A grpc.Channel.
+    """
+    self.SayHello = channel.unary_unary(
+        '/helloworld.Greeter/SayHello',
+        request_serializer=helloworld__pb2.HelloRequest.SerializeToString,
+        response_deserializer=helloworld__pb2.HelloReply.FromString,
+        )
+
+
+class GreeterServicer(object):
+  """The greeting service definition.
+  """
+
+  def SayHello(self, request, context):
+    """Sends a greeting
+    """
+    context.set_code(grpc.StatusCode.UNIMPLEMENTED)
+    context.set_details('Method not implemented!')
+    raise NotImplementedError('Method not implemented!')
+
+
+def add_GreeterServicer_to_server(servicer, server):
+  rpc_method_handlers = {
+      'SayHello': grpc.unary_unary_rpc_method_handler(
+          servicer.SayHello,
+          request_deserializer=helloworld__pb2.HelloRequest.FromString,
+          response_serializer=helloworld__pb2.HelloReply.SerializeToString,
+      ),
+  }
+  generic_handler = grpc.method_handlers_generic_handler(
+      'helloworld.Greeter', rpc_method_handlers)
+  server.add_generic_rpc_handlers((generic_handler,))
diff --git a/examples/python/interceptors/headers/request_header_validator_interceptor.py b/examples/python/interceptors/headers/request_header_validator_interceptor.py
new file mode 100644
index 0000000000..95af4177ba
--- /dev/null
+++ b/examples/python/interceptors/headers/request_header_validator_interceptor.py
@@ -0,0 +1,39 @@
+# Copyright 2017 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.
+"""Interceptor that ensures a specific header is present."""
+
+import grpc
+
+
+def _unary_unary_rpc_terminator(code, details):
+
+    def terminate(ignored_request, context):
+        context.abort(code, details)
+
+    return grpc.unary_unary_rpc_method_handler(terminate)
+
+
+class RequestHeaderValidatorInterceptor(grpc.ServerInterceptor):
+
+    def __init__(self, header, value, code, details):
+        self._header = header
+        self._value = value
+        self._terminator = _unary_unary_rpc_terminator(code, details)
+
+    def intercept_service(self, continuation, handler_call_details):
+        if (self._header,
+                self._value) in handler_call_details.invocation_metadata:
+            return continuation(handler_call_details)
+        else:
+            return self._terminator